Question: 1
You are precepting a resident who has just evaluated a 4-year-old incompletely immunized immigrant boy who has classic varicella lesions and a history that is consistent with this diagnosis.
Of the following, the MOST accurate statement is that
A. lesions of both varicella and smallpox follow a 7- to 10-day course from eruption to resolution B. lesions of both varicella and smallpox frequently produce deep, pitted scars
C. varicella lesions appear in stages or crops; smallpox lesions are uniformly in the same stage of development
D. varicella lesions are concentrated on the face; smallpox lesions are concentrated over bony prominences
E. varicella lesions are transient vesicles; smallpox lesions are persistent pustules until resolution of the illness
Historically, the disease most often confused with severe varicella was smallpox. Smallpox, caused by the variola virus, a member of the orthopoxvirus family, has an incubation period of 7 to 17 days. During the incubation period, virus replicates in the upper respiratory tract. A primary viremia ensues, during which the liver and spleen are seeded. A secondary viremia follows, the skin is seeded, and the classic eruption appears.
Initial symptoms of smallpox may include fever as high as 104°F (40°C), generalized malaise, severe headache, vomiting, and backache. Characteristic skin findings appear 1 to 2 days after the onset of fever. The rash begins on the face and then spreads to involve the extremities and trunk. Initially, lesions are erythematous macules; they evolve into papules, vesicles, and firm pustules (Item C1A). Crusts form at 8 or 9 days and persist for 3 to 4 weeks. As crusts separate, patients often are left with significant scars or depigmentation. Aspects of smallpox that differentiate it from severe varicella are that the majority of lesions are observed on the face and extremities (with lesser numbers on the trunk) and that all lesions are in a similar stage of development.
In contrast, the lesions of varicella erupt initially on the trunk and later appear on the face and extremities. Lesions are erythematous papules that evolve to form superficial vesicles, pustules, and crusts. In varicella (unlike smallpox), lesions are observed in varying stages of development (ie, as older lesions crust, new lesions appear) (Item C1B). By 7 to 10 days after infection, all lesions have crusted. Permanent scars are rare, occurring only when lesions have been secondarily infected with bacteria.
References:
American Academy of Pediatrics. Smallpox (variola). In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006: 591-595
Cieslak J, Henretig FM. Biologic and chemical terrorism. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: WB Saunders Co; 2004:2378-2385
Myers MG, Stanberry LR, Sevard JF. Varicella-zoster virus. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: WB Saunders Co; 2004:1057-1062
Paller AS, Mancini AJ. Viral diseases of the skin. In: Hurwitz Clinical Pediatric Dermatology. 3rd ed. Philadelphia, Pa: Elsevier Inc; 2006: 397-423
Question: 2
A 15-year-old boy presents with melena and anemia. Endoscopy demonstrates a nodular gastritis of the antrum (Item Q2A) and an ulcer. Biopsies of the antrum demonstrate spiral-shaped organisms consistent with Helicobacter pylori (Item Q2B). You prescribe amoxicillin, clarithromycin, and lansoprazole for 2 weeks. At a follow-up visit, the family asks whether the treatment has been successful in eradicating the organism.
Of the following, the PREFERRED noninvasive test to evaluate whether the pathogen has been eradicated is
A. fecal Campylobacter-like organisms (CLO) test B. fecal H pylori antigen
C. salivary H pylori antibody concentrations D. serum H pylori immunoglobulin G serology E. serum H pylori urease concentrations
Helicobacter pylori infection is a known risk factor for gastritis and duodenal ulcers in children and adults. Rarely, and primarily in older adulthood, H pylori also is associated with a gastric lymphoma of the mucosal-associated lymphoid tissue (MALToma). The “gold standard” for the diagnosis of H pylori infection of the stomach is endoscopy with biopsy. Endoscopy may show a nodular gastritis of the antrum (Item C2A), and histology of the gastric mucosa demonstrates the characteristic curved organisms (Item C2B) in the gastric glands.
Because endoscopy is invasive, other surrogate markers of infection have been identified. Of the options offered, the H pylori fecal antigen is the best to document eradication in a previously treated host. Patients colonized with H pylori have detectable antigen in their stool that disappears upon eradication of the organism. H pylori immunoglobulin G serology (serum antibody) is a useful marker for epidemiologic studies of past or current infection, but its sensitivity and positive predictive value in children is suboptimal. The same is true for salivary antibody. Accordingly, a positive antibody screen should be confirmed by a second test (either fecal antigen, urea breath test, or endoscopy). The Campylobacter-like organisms (CLO) test is performed on a duodenal biopsy. In the CLO test, the duodenal biopsy specimen is placed in a test tube containing chemical reagents. The H pylori bacteria convert urea to ammonia and carbon dioxide via their urease enzyme, and the alkalinity of the ammonia can be detected using an indicator dye. The CLO test cannot be performed on feces. Serum urease concentrations are not helpful in identifying H pylori, which is a mucosal bacterium.
Diagnosis, treatment, and eradication of H pylori are well summarized in the American Academy of Pediatrics Red Book and in the North American Society for Pediatric
Gastroenterology practice guideline. Patients who have documented ulcers should be tested for H pylori and the organism eradicated if found, but it is unclear if asymptomatic children colonized with H pylori need to be treated. Therapy is given for 14 days and should include a proton pump inhibitor (eg, omeprazole, lansoprazole, pantoprazole) and two antibiotics (eg, tetracycline + clarithromycin, amoxicillin + metronidazole, amoxicillin + clarithromycin) (Item C2C). Treatment failures are common, either because of resistant bacteria or because of poor compliance with the regimen. Therefore, testing for eradication of the organism (either by fecal antigen, urease breath test, or endoscopy) should be performed more than 1 month after therapy has been completed.
References:
American Academy of Pediatrics. Helicobacter pylori infections. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006:321-322
Gold BD, Colletti RB, Abbott M, et al. Helicobacter pylori infection in children: recommendations for diagnosis and treatment. J Pediatr Gastroenterol Nutr. 2000;31:490-497. Available at: http://www.jpgn.org/pt/re/jpgn/fulltext.00005176-200011000-00007.htm
Question: 3
A term newborn is delivered by emergent cesarean section because of intrauterine growth restriction, oligohydramnios, and nonreassuring fetal heart rate monitoring in labor. Delivery room resuscitation includes endotracheal intubation and assisted ventilation with 100% oxygen, chest compressions, intravenous epinephrine, and volume expansion. Apgar scores are 1, 2, and 3 at 1, 5, and 10 minutes, respectively. An umbilical cord arterial blood gas measurement documents a pH of 6.9 and a base deficit of 20 mmol/L. At 12 hours of age, the infant
demonstrates tonic-clonic convulsive activity of the arms and legs with a concomitant decrease in heart rate and bedside pulse oximetry saturation.
Of the following, the MOST likely cause for this infant's seizure is A. hypercalcemia
B. hypercarbia C. hyperglycemia D. hypomagnesemia E. hypoxia
Seizures are the most frequent sign of central nervous system injury in the newborn. When seizures occur in a newborn who has depressed neuromotor tone, reflexes, and
cardiopulmonary function at birth that requires assisted ventilation, perinatal asphyxia is likely. In this event, Apgar scores typically are depressed to less than 3 at 5 or more minutes after birth, and there is a severely acidotic umbilical cord arterial pH (<7.0), with evidence of metabolic acidemia. Poor tolerance of labor and asphyxia are more common in fetuses that have
experienced intrauterine growth restriction. Because the infant in the vignette has the previously described features, hypoxic-ischemic encephalopathy (HIE) must be considered as a cause for the seizures.
HIE is the most common cause of seizures occurring in the first 24 hours of postnatal life and accounts for up to 67% of early neonatal seizures. Other causes of neonatal seizure include intracranial hemorrhage, cerebrovascular accidents (stroke), or hemorrhagic infarction (10% to 15%); intracranial malformation (<10%); transient hypoglycemia or hypocalcemia (<10%); drug withdrawal (<5%); and inborn errors of metabolism (<5%).
When seizures occur beyond the first 24 hours after birth, especially in the absence of any history of fetal or neonatal asphyxia, the evaluation should focus on potential causes other than HIE. An additional cause for later seizures is infection (meningitis, encephalitis).
Asphyxia may result in hypocalcemia and hypoglycemia; hyperglycemia and hypercalcemia are not associated with HIE and do not typically cause seizures. Hypomagnesemia may
accompany hypocalcemia in the infant of a diabetic mother, but it is not common following asphyxia and is not associated with neonatal seizures. Hypercarbia may occur in the depressed newborn who has inadequate ventilation, but it is not associated with seizures unless there is corresponding hypoxia.
References:
Allan WC. The clinical spectrum and prediction of outcome in hypoxic-ischemic encephalopathy. NeoReviews. 2002;3:e108-e115. Available at:
http://neoreviews.aappublications.org/cgi/content/full/3/6/e108
Hahn JS, Olson DM. Etiology of neonatal seizures. NeoReviews. 2004;5:e327-e335. Available at: http://neoreviews.aappublications.org/cgi/content/full/5/8/e327
Riviello JJ, Jr. Pharmacology review: drug therapy for neonatal seizures: part 2. NeoReviews. 2004;5:e262-e268. Available at: http://neoreviews.aappublications.org/cgi/content/full/5/6/e262 Thureen PJ, Anderson MS, Hay WW, Jr. The small-for-gestational age infant. NeoReviews. 2001;2:e139-e149. Available at: http://neoreviews.aappublications.org/cgi/content/full/2/6/e139 Wu YW, Backstrand KH, Zhao S, Fullerton HJ, Johnston SC. Declining diagnosis of birth asphyxia in California: 1991-2000. Pediatrics. 2004;114:1584-1590. Available at:
http://pediatrics.aappublications.org/cgi/content/full/114/6/1584
Question: 4
A 2-year-old boy presents with a 3-day history of diarrhea and vomiting. He has been able to tolerate small amounts of fluids. He is moderately dehydrated, with dry mucous membranes and a heart rate of 145 beats/min.
Of the following, the BEST management for this patient's fluid status is A. hospitalization with intravenous fluids and a restrictive bland diet B. hospitalization with intravenous fluids and gut rest for 24 hours
C. oral rehydration therapy at home followed by a clear liquid diet for 24 hours
D. oral rehydration therapy at home followed by a diet of fruits, vegetables, and meats E. oral rehydration therapy at home followed by a restrictive bland diet
Dehydration results from a total body loss of water and sodium. Acute infectious gastroenteritis is among the most common causes of dehydration in infants and young children. Both mild and moderate dehydration may be managed at home with oral rehydration therapy, even if the child continues to have intermittent vomiting. Commercial oral rehydration solutions (ORS) are widely available and should be used for this purpose. All ORS are designed to replace lost electrolytes (sodium, chloride, potassium, and bicarbonate) glucose, and water. Young children who have mild dehydration have an estimated water loss of 50 mL/kg, and this amount of ORS can be given via a spoon or syringe in small amounts over 2 to 4 hours. Those who have moderate dehydration should receive 100 mL/kg over 2 to 4 hours. Care should be taken to monitor ongoing losses from stool and emesis, and intravenous or nasogastric rehydration therapy should be considered if losses are excessive or if dehydration worsens or does not improve. Oral rehydration therapy should not be used for children who have severe dehydration, shock, suspected intestinal obstruction, obtundation, or ileus.
Once adequate hydration has been assured or rehydration is complete, a normal diet should be given to the child to ensure adequate caloric and nutrient intake. A period without
gastrointestinal intake is unnecessary and may delay nutritional recovery. Clear liquid and bland diets also should not be used because they do not provide adequate nutrition. Infants should be given human milk or their usual formula at full strength because diluted formula or human milk (eg, one-half or one-quarter strength formula) will not meet the child’s caloric requirements and may worsen electrolyte abnormalities. Lactose-free formulas are generally unnecessary
because most children do not develop lactase deficiency. Older children should be given a regular diet of complex carbohydrates, fruits, vegetables, and meats. High sugar-containing liquids should be avoided because the osmotic load of these liquids may worsen diarrhea. References:
Finberg L. Dehydration in infancy and childhood. Pediatr Rev. 2002;23:277-282. Available at: http://pedsinreview.aappublications.org/cgi/content/full/23/8/277
King CK, Glass R, Bresee JS, Duggan C, Centers for Disease Control and Prevention.
Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep. 2003;52(RR-16):1-16. Available at:
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5216a1.htm
Question: 5
A worried grandmother brings her 2-year-old grandchild to the emergency department
immediately upon finding the boy with an open bottle of 81-mg chewable aspirin (which is used by the grandfather for coronary artery disease prophylaxis). She is unsure of the number of tablets in the bottle prior to ingestion, but the original number was 30, and there are now three remaining. The child has vomited once and is fussy and lethargic. Physical evaluation reveals a 12-kg child who has tachypnea and tachycardia. Laboratory results include a pH of 7.45, carbon dioxide of 25 mEq/L (25 mmol/L), and bicarbonate of 18 mEq/L (18 mmol/L). A salicylate
measurement result is pending.
Of the following, the next BEST step in the management of this child is to A. administer activated charcoal
B. administer sodium bicarbonate intravenously C. administer syrup of ipecac
D. observe the child clinically in the emergency department E. remeasure the salicylate level in 6 hours
Salicylates are common in the homes of many children because many older adults (who may be parents or grandparents) use salicylates for prophylaxis against cardiovascular disease and for arthritis pain. Methylsalicylate present in liniments is especially concentrated. The toddler may ingest such preparations accidentally, as described for the boy in the vignette, and the
adolescent may use salicylates in suicide gestures or attempts.
Toxic effects of salicylates can include gastritis, anticoagulant effects, increased
metabolism, hyperventilation and respiratory alkalosis, and hepatitis. Reye syndrome, which is characterized by hepatitis and encephalopathy, may occur if aspirin is given during certain viral infections. Signs and symptoms include lethargy or coma, vomiting, tachypnea, and tachycardia.
The next best step in the management of the child described in the vignette is the
administration of activated charcoal. Multiple doses of activated charcoal adsorb salicylates from both the intestinal tract and the systemic circulation.
For a child who has ingested a potentially toxic dose of salicylates, serum salicylate
concentrations should be measured 2 to 6 hours after the ingestion. However, administration of activated charcoal should not be delayed until the salicylate concentration has been measured if a toxic dose has been ingested. The child in the vignette may have ingested 27 81-mg tablets for a total dose of more than 2,100 mg or 182 mg/kg. This dose can be expected to cause mild-to-moderate toxicity. A serum salicylate value higher than 30 mg/dL is considered toxic,
concentrations higher than 70 mg/dL reflect severe toxicity, and those greater than 100 mg/dL are life-threatening.
Because gastric emptying time is prolonged with salicylate ingestion, gastrointestinal decontamination by lavage may be effective up to 6 hours after ingestion. However, the child described in the vignette is fussy and lethargic. Therefore, syrup of ipecac is not indicated. Administration of sodium bicarbonate to alkalinize the urine as well as correction of acidosis, hyperkalemia, and hypocalcemia are important adjuncts to gastric decontamination.
Cautious administration of intravenous sodium bicarbonate may be indicated clinically in severe acidosis because acidosis enhances brain toxicity, but the patient must be monitored for worsening hypernatremia and hypokalemia as a response to alkalinization. Although the child in the vignette should be observed and repeat salicylate concentrations obtained, gastrointestinal decontamination with activated charcoal is therapeutic and, thus, the next best step.
References:
Mariscalco MM. Salicylism. In: McMillin JA, DeAngelis CD, Feigin RD, Warshaw JB, eds. Oski’s Pediatrics: Principles and Practice. 3rd ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 1999:623-625
Woolf AD. Poisoning in children and adolescents. Pediatr Rev. 1993;14:411-422
Question: 6
A mother brings her 10-month-old son to the emergency department because he has been vomiting for the past 10 days. The child has not experienced any diarrhea. On physical examination, he is lethargic and has dry mucous membranes, reduced tears, a full anterior fontanelle, and 2-second capillary refill. After a second intravenous bolus of 20 mL/kg of normal saline, the boy extends his arms and legs forcefully for 10 seconds.
Of the following, the MOST appropriate next step in the management of this child is administration of
A. additional intravenous normal saline bolus of 20 mL/kg B. intravenous dexamethasone of 1 mg/kg
C. intravenous fosphenytoin bolus at 20 mg/kg phenytoin equivalents over 10 minutes D. intravenous prochlorperazine of 5 mg
Brain tumors occur rarely in the pediatric population; the incidence is just under 1 in 25,000 children annually. Despite its rarity, the ominous nature of such a diagnosis requires that practitioners be able to recognize readily the clinical manifestations of a brain tumor. Clinical prodromes may include features of increased intracranial pressure (ICP) (Item C6A), findings of a localizing nature, or symptoms and signs without a localizing quality.
Elevated ICP often is insidious and nonspecific initially. Among school-age children, declining academic performance, fatigue, behavioral changes, and vague intermittent headaches are common. Over time, morning headaches, especially pain at the occipital or frontal region, along with vomiting and lethargy ensue. Horizontal diplopia from abducens nerve paresis is common. Papilledema may develop if the pressure is longstanding. Among infants, irritability, anorexia, failure to thrive, and even developmental regression can be early signs of increased ICP. Macrocephaly, splitting of the cranial sutures, or a bulging anterior fontanelle can follow. The “setting sun” sign, a downward deviation of the eyes, may be seen with attendant
hydrocephalus.
Localizing findings depend on the region of the brain involved. Supratentorial (cerebrum, basal ganglia, thalamus, hypothalamus, and optic chiasm) tumors can produce hemiparesis, hemisensory loss, hyperreflexia, seizures, or visual complaints. Infratentorial (cerebellum and brainstem) tumors lead to ataxia, hemiparesis, hyperreflexia, or cranial neuropathies, but not seizures.
Nonlocalizing symptoms and signs are perhaps the most subtle manifestations of a brain tumor. The child may display changes in affect, energy level, behavior, or weight. Sexual precocity or delayed puberty, growth failure, and somnolence can suggest hypothalamic or pituitary dysfunction. Vomiting can occur with direct irritation of the area postrema in the floor of the fourth ventricle or from a generalized increase in ICP.
The vomiting without diarrhea displayed by the 10-month-old in the vignette, along with a full anterior fontanelle in the face of mild dehydration, points to an intracranial process. In addition, the child is exhibiting posturing, not a seizure, from continued overhydration and worsening intracranial pressure following the saline administration. Accordingly, administration of intravenous dexamethasone, along with other measures to treat increased ICP, is most
appropriate. Treatment with prochlorperazine will only mask the child’s vomiting. Administration of fosphenytoin or lorazepam is not indicated in the absence of seizures. Continued aggressive hydration will worsen this child’s ICP.
References:
Kuttesch JF Jr, Alter JL. Brain tumors in childhood. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: WB Saunders; 2004:1702-1708 Strother DR, Pollock IF, Fisher PG, et al. Tumors of the central nervous system. In: Pizzo PA, Poplack DG, eds. Principles and Practice of Pediatric Oncology. 4th ed. Philadelphia, Pa: Lippincott, Williams & Wilkins; 2002:751-824
Question: 7
An 18-month-old child has been brought to your urgent care clinic for evaluation. He and his mother are in town visiting his grandmother. His mother tells you that she found him playing with an open bottle of his grandmother's medication. On physical examination, he is sleepy but arousable, pale, mildly diaphoretic, and afebrile. His respiratory rate is 20 breaths/min, heart rate is 60 beats/min, and blood pressure is 65/40 mm Hg. His lungs are clear, there are no murmurs, and his pulses are weak.
Of the following, the MOST likely cause for this patient's presentation is ingestion of A. beta blocker
B. captopril C. hydralazine D. pseudoephedrine E. tricyclic antidepressant
Accidental ingestion of medications continues to be a significant cause of pediatric morbidity and potential mortality. The problem is greatest in toddlers and is exacerbated when medications are left within reach of children or not appropriately secured in a locked cabinet. The reaction to ingestion of a given medication depends on the class and dose.
Beta blockers can have multiple and varying effects on the heart and other organ systems. In the heart, they typically exhibit some degree of negative chronotropic (slowing of the heart rate), dromotropic (slowing of the conduction through the AV node), and inotropic (decrease in the ventricular force of contraction) effects. As a result, this class of medications generally is used to control certain types of arrhythmia and hypertension and to reduce myocardial work and oxygen demand. The depressed sensorium, bradycardia for age, and hypotension with
diminished pulses described for the child in the vignette are most consistent with beta blocker ingestion.
Captopril is an angiotensin-converting enzyme (ACE) inhibitor. ACE activity converts
angiotensin I to angiotensin II, which is a potent vasoconstrictor. Therefore, ACE inhibitors lower the systemic vascular resistance and the systemic blood pressure, decreasing the afterload (work) of the left ventricle. Hydralazine is an arteriolar dilator that may have some positive inotropic effect. It often is used as antihypertensive therapy and typically increases the heart rate. Pseudoephedrine is an alpha agonist that is used commonly for relief of symptoms caused by nasal congestion. Its effects on the cardiovascular system are to cause systemic
vasoconstriction that may increase blood pressure, and it also may cause tachycardia. Tricyclic antidepressants are a diverse group of medications that can be used for a variety of noncardiac indications, including depression. When taken in high doses, they may affect the cardiovascular system by causing vasodilation, flushing, hypotension, and tachyarrhythmias.
Although captopril, hydralazine, and tricyclic antidepressants may be associated with hypotension, they all would be expected to cause (or be associated with) a corresponding tachycardia.
References:
Dobson JV, Webb SA. Life-threatening pediatric poisonings. J S C Med Assoc. 2004;100:327-332. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_ui ds=15835193&query_hl=11&itool=pubmed_docsum
Opie L, Gersh B. Drugs for the Heart. 6th ed. Philadelphia, Pa: WB Saunders Co; 2004 Riordan M, Rylance G, Berry K. Poisoning in children 1: general management. Arch Dis Child. 2002;87:392-396. Available at: http://adc.bmjjournals.com/cgi/content/full/87/5/392
Question: 8
The parents of a child who has Down syndrome and a 47,XX+21 karyotype come to you for counseling about future pregnancies.
Of the following, their risk for giving birth to another child who has trisomy is CLOSEST to A. no greater than the general population at risk
B. 1% added to the mother's age-related risk C. 5% added to the mother's age-related risk D. 10% added to the mother's age-related risk E. 25% added to the mother's age-related risk
Approximately 94% of individuals who have Down syndrome have trisomy of chromosome 21. Studies of the origins of trisomy 21 (47 chromosomes with trisomy for chromosome 21) show that 90% to 95% of cases are due to a maternal meiotic error, with 75% of these occurring in meiosis I. Approximately 3% to 5% are due to paternal meiotic errors, and the remainder are due to mitotic nondisjunction.
Recurrence risk estimates for trisomy are based on empiric data. The overall recurrence risk for having a live-born child who has any trisomy is approximately 1% added to the mother’s age-related risk for having a child who has a trisomy, which increases over time. Risk estimates vary slightly from time of amniocentesis to time of term delivery because there is natural loss of some trisomic fetuses between the two events. As a woman’s age increases, her 1%
recurrence risk becomes relatively less significant compared with her age-related risk. For example, at the age of 40 years, a woman’s risk for having a child who has Down syndrome is 1 in 90 compared with a 1 in 1,500 risk for a 22-year-old woman. Thus, a 22-year-old woman who has a child affected with trisomy 21 has a 1/100 plus a 1/1,500 risk (approximately 1.1%) risk for having another affected child compared with a 0.07% risk for other 22-year-old women who have not had children affected with trisomy. In contrast, a 40-year-old woman who has a child with trisomy 21 has a 1/100 plus a 1/90 (approximately 2.1%) risk for having another affected child, which is similar to the 1.1% risk for 40-year-old women who have not had children with trisomy.
References:
Hall JG. Chromosomal clinical abnormalities. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia Pa: Saunders; 2004:382-391
Nussbaum RL, McInnes RR, Willard HF. Clinical cytogenetics: disorders of the autosomes and the sex chromosomes. In: Thompson & Thompson Genetics in Medicine. 6th ed, revised reprint. Philadelphia, Pa: Saunders; 2004:157-179
Roizen NJ, Stark AR. Epidemiology and genetics of Down syndrome. UpToDate. 2006:14.1. Available at:
http://www.utdol.com/utd/content/topic.do?topicKey=dis_chld/2412&type=P&selectedTitle=27~54
Question: 9
A 15-month-old infant has been breastfed since birth. He eats finger foods (eg, peas, carrots) and occasionally some cereal. His mother adheres to a vegan diet and plans the same for her child. A complete blood count documents anemia.
Of the following, the MOST likely cause of this infant's anemia is a deficiency of A. folic acid
B. niacin C. riboflavin D. thiamine E. vitamin B12
The infant described in the vignette has been exclusively breastfed by a strict vegan mother and is at risk for anemia due to vitamin B12 deficiency. The appearance of hypersegmented
neutrophils in the peripheral blood precedes the development of classic megaloblastic (macrocytic) anemia. The infant’s deficiency may be caused by reduced placental transfer of vitamin B12 in utero and lower vitamin content in the mother’s milk. In addition, the infant is being offered other foods that are consistent with a vegan diet and contain little vitamin B12. Deficiency of vitamin B12, including dietary deficiency, is unusual in infants and children in the United States. Other causes of deficiency are pernicious anemia; impaired gastric and small bowel absorption, including resections; and rare inherited metabolic disorders such as methylmalonic aciduria and intrinsic factor deficiency. Vitamin B12 deficiency is diagnosed by recognition of risk factors, documentation of low serum B12 concentrations in the infant, and a subsequent
response to treatment. Demonstration of low serum vitamin B12 values in the mother supports the diagnosis.
Folic acid deficiency is an unlikely cause of the anemia for the infant described in the vignette. Folate is present in many foods consumed by vegans, and human milk provides adequate folate for the breastfed infant. Folate deficiency rarely is present in newborns because the fetus extracts adequate folate from the mother, even in the presence of maternal deficiency. Defects of folate metabolism are rare, although infants exclusively fed goat milk are at risk for folate deficiency and possible megaloblastic anemia. A diagnosis of folate deficiency should be confirmed, including the exclusion of vitamin B12 deficiency, before initiating folate replacement therapy. Treatment with therapeutic doses of folate may delay the diagnosis of vitamin B12 deficiency and increase the risk of neurologic complications. Erythrocyte folic acid concentration is a better measure of folate sufficiency than serum folate concentrations.
Deficiencies of thiamine (vitamin B1), riboflavin (vitamin B2), and niacin (vitamin B3) are rare and not associated with anemia. Thiamine deficiency is associated with beriberi
(cardiomyopathy, peripheral neuropathy, and encephalopathy). Riboflavin deficiency is associated with cheilosis and glossitis. Pellagra (dementia, diarrhea, and dermatitis) is associated with niacin deficiency.
References:
Glader B. Megaloblastic anemias. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. Philadelphia, Pa: Saunders; 2004:1611-1613
Nutritional aspects of vegetarian diets. In: Kleinman RE, ed. Pediatric Nutrition Handbook. 5th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2004:191-208
Vitamins. In: Kleinman RE, ed. Pediatric Nutrition Handbook. 5th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2004:339-365
Question: 10
A 15-year-old boy comes to your office for a health supervision visit. He expresses concern that he is only 5 ft, 2 in tall and is not competitive in track. On physical examination, he appears healthy, has a height of 62 in, and weighs 96 lb. His testes are 8 mL in volume bilaterally, there is slight pubertal phallic enlargement, and he has Sexual Maturity Rating 3 pubic hair. He has a small amount of subareolar breast tissue. His last health supervision visit was 2 years ago. He did not have pubic hair at the last visit, and his testes were described as "prepubertal" in size. Of the following, the MOST likely cause of his short stature is
A. constitutional delayed puberty B. exercise-induced growth delay C. Klinefelter syndrome
D. prolactinoma E. undernutrition
Puberty is considered delayed in boys if there is no testicular enlargement by age 14 years. Unless other features are present on physical examination or history, it is very difficult to separate boys who have delayed puberty clinically from those who have true hypogonadotropic hypogonadism until failure of pubertal progression persists for several years. After puberty commences, adult testicular size usually is achieved by 3.2±1.8 years.
The boy described in the vignette is of normal height for age and is progressing into puberty, based on review of his previous visit and his present appearance. Most likely, he has only mild constitutional delayed puberty. Most boys who have constitutional delayed puberty are
underweight and do not have other signs of chronic illness.
Exercise and weight loss rarely induce the type of marked growth delay in boys that is seen in girls who are competitive gymnasts or active in ballet. Although Klinefelter syndrome may lead to failure to progress through puberty, the increasing testicular size of the boy in the vignette makes this diagnosis unlikely. Prolactinomas can inhibit pubertal growth, but are not common. Underweight caused by undernutrition must be severe before it inhibits growth and puberty.
Only close follow-up is required for a boy who seems to be progressing into puberty. However, if there is evidence of failure to progress into puberty, a full evaluation to determine if the boy has an underlying chronic illness such as celiac disease or inflammatory bowel disease, hypergonadotropic hypogonadism as seen in Klinefelter syndrome, or other endocrine disorder such as a prolactinoma, is indicated.
References:
Cannavo S, Venturino M, Curto L, et al. Clinical presentation and outcome of pituitary adenomas in teenagers. Clin Endocrinol (0xf). 2003;58:519-527. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_ui ds=12641637&query_hl=5&itool=pubmed_docsum
Israel EJ, Levitsky LL, Anupindi SA, Pitman MB. Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 3-2005. A 14-year-old boy with recent slowing of growth and delayed puberty. N Engl J Med. 2005;352:393-403
Lanfranco F, Kamischke A, Zitzmann M, Nieschlag E. Klinefelter’s syndrome. Lancet. 2004;364:273-283. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=Abstract&list_ui ds=15262106&query_hl=3&itool=pubmed_docsum
Misra M, Park-Bennett S. Disorders of puberty. In: Burg FD, Ingelfinger JR, Polin RA, Gershon AA, eds. Gellis & Kagan’s Current Pediatric Therapy. Philadelphia, Pa: WB Saunders; 2002:706-710
Rogol AD, Clark PA, Roemmich JN. Growth and pubertal development in children and adolescents: effects of diet and physical activity. Am J Clin Nutr. 2000;72(suppl):521S-528S Available at: http://www.ajcn.org/cgi/content/full/72/2/521S
Sedlmeyer IL, Palmert MR. Delayed puberty: analysis of a large case series from an academic center. J Clin Endocrinol Metab. 2002;87:1613-1620. Available at:
http://jcem.endojournals.org/cgi/content/full/87/4/1613
Question: 11
You are examining a 2-year-old girl who has a 6-month history of developmental regression. During her first postnatal year, she met all motor, language, and social milestones. Her head circumference, which currently is at the 3rd percentile, was at the 75th percentile at birth. On physical examination, she makes poor eye contact and repetitively wrings her hands.
Of the following, the MOST appropriate diagnostic test is A. arylsulfatase A
B. fragile X
C. hexosaminidase A D. MECP2 gene testing E. urine N-acetyl-aspartic acid
The developmental regression, acquired microcephaly, and hand-wringing movements
described for the girl in the vignette are typical findings in the X-linked condition Rett syndrome. Rett syndrome is a neurodegenerative disorder that is associated with developmental
regression as well as generalized tonic-clonic seizures, poor feeding, constipation, sleep
disorder, breath-holding spells, scoliosis, muscle wasting, cardiac arrhythmias, and death in late adolescence. The diagnosis can be made by testing for the MECP2 gene (chromosome X q28), a gene for a transcription factor that binds to methylated CpG island and silences transcription.
Deficiency of arylsulfatase A causes the degenerative lysosomal disorder metachromatic leukodystrophy. Fragile X testing is performed primarily in boys who have cognitive impairment and dysmorphic features. Hexosaminidase A deficiency causes Tay-Sachs disease.
Accumulation of N-acetyl-aspartic acid in the urine is associated with the leukodystrophy Canavan disease.
References:
Johnston MV. Neurodegenerative disorders of childhood. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelphia, Pa: WB Saunders Co; 2004:2029-2034
Rich J. In brief: degenerative central nervous system (CNS) disease. Pediatr Rev. 2001;22:175-176. Available at: http://pedsinreview.aappublications.org/cgi/content/full/22/5/175
Question: 12
A 7-year-old girl presents to your clinic with a 2- to 3-day history of a nonproductive cough, malaise, and temperature to 101°F (38.3°C). On physical examination, you note that the girl does not appear ill and are surprised to hear widespread crackles in the lungs bilaterally. Chest radiography demonstrates bilateral diffuse infiltrates (Item Q12A).
Of the following, the MOST appropriate antimicrobial agent to treat this girl's infection is A. amoxicillin
B. azithromycin C. doxycycline D. levofloxacin
School-age children are at risk for lower respiratory tract infections (LRTIs) from Mycoplasma pneumoniae. The highest incidence of LRTI from M pneumoniae occurs in children 5 to 14 years of age. Frequent symptoms associated with pneumonia due to Mycoplasma include fever, cough, and malaise. The lack of coryza can be useful in differentiating illness due to
Mycoplasma from other common viral agents. The radiographic pattern associated with this pathogen varies, but bilateral, diffuse infiltrates (Item C12A), as reported for the girl in the vignette, are common.
Macrolides (eg, erythromycin, clarithromycin, azithromycin) are the preferred antimicrobial agents to treat infections due to Mycoplasma. Because azithromycin can be administered once daily and has few adverse effects compared with the other macrolides, it has become the preferred agent. These agents also are effective against common respiratory flora such as Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pyogenes, and viridans streptococci. Other atypical pathogens, such as Chlamydia sp, Bordetella pertussis, and Legionella pneumophila, also can be treated with the macrolides. Clarithromycin and
azithromycin have activity against many nontuberculous mycobacterial species (eg, M avium complex, M kansasii), as well.
Doxycycline is effective against Mycoplasma sp, but should not be used in children younger than 8 years of age due to potential bone and teeth staining. Similarly, levofloxacin is effective against many atypical agents, including Mycoplasma sp, but should not be used routinely for children younger than 18 years of age because of the interference with cartilage growth demonstrated in puppies treated with the fluoroquinolones. Amoxicillin and trimethoprim-sulfamethoxazole are not effective against Mycoplasma.
References:
Gaston B. Pneumonia. Pediatr Rev. 2002;23:132-140. Available at: http://pedsinreview.aappublications.org/cgi/content/full/23/4/132
James LP, Rahman SM, Farrar HC, Jacobs RF. Antimicrobial agents. In: Long SS, Pickering LK, Prober CG, eds. Principles and Practice of Pediatric Infectious Diseases. 2nd ed. Philadelphia, Pa: Churchill Livingstone; 2003:1458-1510
Question: 13
A 7-year-old boy comes to your office with complaints of daily bedwetting for 2 months. He was completely toilet trained by 4 years of age and had been dry at night except for occasional (about once per month) minor bedwetting until recently. He denies daytime enuresis, dysuria, frequency, urgency, fever, abdominal pain, or constipation. He has no history of urinary tract infections. His physical examination reveals weight and height at the 75th percentiles and no abnormalities.
Of the following, the MOST important next step in this child's evaluation is to obtain A. abdominal radiography
B. renal ultrasonography
C. serum electrolyte measurement D. urinalysis
After achieving daytime and nighttime dryness, most children experience occasional episodes of nocturnal enuresis until the age of 5 to 6 years. Boys generally achieve dryness later than girls, and some boys continue to experience occasional bedwetting episodes to the age of 7 to 8 years. Indeed, about 15% of 7-year-old boys experience occasional bedwetting, although the symptoms resolve spontaneously in most.
History, physical examination, and urinalysis can identify the cause of new-onset nocturnal enuresis for most children who have secondary nocturnal enuresis (ie, achieved general nighttime dryness once toilet trained). A simple review of recent voiding patterns and general lifestyle issues may disclose the cause of the bedwetting in many patients. It is vital to consider the common causes of new-onset bedwetting, including psychosocial stress, urinary tract infection, and new disease (eg, diabetes mellitus or insipidus). For children who have normal findings on history, physical examination, and urinalysis, imaging studies such as abdominal radiography, renal ultrasonography, and voiding cystourethrography are unlikely to aid in determining the cause of bedwetting. Measurement of serum electrolytes rarely is warranted at the outset if the history, physical examination, and urinalysis results are normal.
If a specific cause is identified (eg, urinary tract infection), treatment of the primary condition often results in resolution of the bedwetting. However, behavioral or pharmacotherapy may be required for many children in whom a primary cause cannot be identified and who experience unabated episodes of enuresis. Therapeutic options include counseling, hypnosis, urine alarm, imipramine, no treatment, or desmopressin. Counseling may be helpful if the child’s bedwetting is due to psychosocial stress, but it has mixed results. Behavioral therapy such as hypnosis also induces resolution in some patients but success is very dependent on the expertise of the therapist. Results also have been mixed with urine alarms. Success requires strict compliance, but if the child and parents are motivated, many children experience at least a moderate reduction in bedwetting episodes. Anticholinergic medications (eg, oxybutynin) or medications that have anticholinergic properties (eg, imipramine) that alter bladder physiology in favor of prolonged filling and decreased contractions are most successful in children who have
underlying bladder dyssynergy. Common adverse effects of imipramine include dry mouth and constipation. Rarely, it may cause blood pressure changes or arrhythmias. Common adverse effects of oxybutynin include gastrointestinal symptoms and urinary retention. Finally, intranasal desmopressin may improve water reabsorption during the nighttime, but the ability to
concentrate the urine is not impaired in most children who experience bedwetting, thus limiting the overall effectiveness of this medication. Common adverse effects of desmopressin include gastrointestinal symptoms, headache, flushing, and rarely, hyponatremia.
References:
Bower WF, Yip SK, Yeung CK. Dysfunctional elimination symptoms in childhood and adulthood. J Urol. 2005;174:1623-1627. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_ui ds=16148668&query_hl=21&itool=pubmed_docsum
Lee T, Suh HJ, Lee HJ, Lee JE. Comparison of effects of treatment of primary nocturnal enuresis with oxybutynin plus desmopressin, desmopressin alone or imipramine alone: a randomized controlled clinical trial. J Urol. 2005;174:1084-1087. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_ui ds=16094064&query_hl=18&itool=pubmed_docsum
Yagci S, Kibar Y, Akay O, et al. The effect of biofeedback treatment on voiding and urodynamic parameters in children with voiding dysfunction. J Urol. 2005;174:1994-1997. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&li st_uids=16217376
Question: 14
You are speaking to the mother of a child who attends a junior high school where one of the students was diagnosed with meningococcal disease 24 hours ago. Her child does not have any classes with the index patient and, except for passing him in the hall during lunch 3 days ago, has had no other contact with the patient. The child's mother is frantic because the school sent home a notice asking parents to bring their children to the public health department or their private physician to receive antibiotic prophylaxis.
Of the following, the MOST appropriate advice for this parent is that her child A. does not require antibiotic prophylaxis and does not need to be seen
B. does not require antibiotic prophylaxis but needs to be evaluated to determine if she is developing symptoms of meningococcal disease
C. needs to be seen to obtain nasopharyngeal cultures for meningococcal organisms and if the cultures are positive, may require antibiotic prophylaxis
D. requires antibiotic prophylaxis and should be seen immediately
E. should be seen immediately to determine if she needs to be hospitalized and treated for possible meningococcal disease
Close contacts of all persons who have invasive meningococcal disease, whether sporadic or in an outbreak, are at high risk for infection and should receive chemoprophylaxis within 24 hours of diagnosis of the primary case, regardless of vaccination status. Close contacts include all household contacts, child care and nursery school contacts during the previous 7 days, persons who have had direct contact with the patient’s oral secretions, and persons who frequently eat or sleep in the same dwelling as the index patient. However, classroom contacts of students who have meningococcal disease, such as the child described in the vignette, are considered casual contacts (no history of direct exposure to the index patient’s oral secretions), and the use of prophylactic antibiotics is not recommended. In view of this and the fact that the contact is asymptomatic, she does not require medical evaluation at this time, and
nasopharyngeal cultures are not indicated.
Because secondary cases of meningococcal disease can occur several weeks after the onset of disease in the index case, the use of meningococcal vaccine is a possible adjunct to chemoprophylaxis if the serogroup is contained in the vaccine.
Other infections can spread easily in the household setting and may require the use of postexposure prophylactic immunoglobulin, antibiotics, or vaccines to prevent development of disease in individuals exposed to the index case. Selected diseases and prophylactic
interventions are summarized in Item C14A. For detailed advice regarding management of specific cases, pediatricians should consult the most recent Report of the Committee on Infectious Diseases (Red Book), the Centers for Disease Control and Prevention, or a pediatric infectious disease specialist.
References:
American Academy of Pediatrics. Haemophilus influenzae infections. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006:310-318
American Academy of Pediatrics. Hepatitis A. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of
Pediatrics; 2006:326-335
American Academy of Pediatrics. Meningococcal infections. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006:452-460
American Academy of Pediatrics. Pertussis. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of
Pediatrics; 2006:498-520
American Academy of Pediatrics. Varicella-zoster infections. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2006:711-725
Robinson J. Infectious diseases in schools and child care facilities. Pediatr Rev. 2001;22:39-46. Available at: http://pedsinreview.aappublications.org/cgi/content/full/22/2/39
Question: 15
An 18-year-old boy presents to the emergency department 30 minutes after eating at a seafood restaurant. He states that approximately 10 minutes into his meal he developed generalized hives, pruritus, and difficulty breathing. He has a history of shellfish food allergy, although he had ordered steak and denies eating any crab, lobster, or shrimp. On physical examination, the patient appears to have labored breathing, audible wheezing, and diffuse raised erythematous lesions (Item Q15A) on his trunk and extremities. His vital signs include a temperature of 98.5°F (37°C), heart rate of 100 beats/min, respiratory rate of 22 breaths/min, blood pressure of 110/60 mm Hg, and pulse oximetry of 92% on room air.
Of the following, the MOST appropriate immediate action is
A. administration of 100% oxygen
B. administration of 1 L intravenous normal saline C. administration of intramuscular epinephrine D. administration of beta-2 agonist nebulization E. observation
The adolescent described in the vignette most likely is experiencing an adverse food reaction, specifically anaphylaxis to shellfish. Patients who have known food allergies, such as this boy, must remain vigilant regarding food choices and reading of food labels because foods may contain hidden ingredients or may be contaminated with allergenic proteins. Most likely, the nonallergenic food (steak) in this case was contaminated with an allergenic food (shellfish) while being prepared. For highly allergic individuals, only a small amount of antigen is required to cause a reaction. Because of the risk of cross-contamination, many allergists recommend strict avoidance of the allergenic food within the home. The rapid (<30 min) onset of urticaria and wheezing in a shellfish-allergic patient who is eating in a seafood restaurant is likely anaphylaxis and warrants prompt administration of intramuscular epinephrine. Other supportive measures, such as administration of oxygen, intravenous fluids, and beta-2 agonists, may improve some clinical symptoms, but they do not reverse anaphylaxis. Simple observation clearly is not indicated in a person who has food allergy and is experiencing anaphylaxis with respiratory symptoms.
Other causes that should be considered during an acute food reaction include food poisoning, particularly scombroid fish poisoning. Members of the Scomberesocidae or
Scombridae families (eg, albacore, mackerel, tuna, kingfish) that have spoiled can have bacterial overgrowth. The bacterial overgrowth is responsible for converting histidine, found in high
concentrations in the flesh of scombroid fish, to histamine. Reactions may be indistinguishable from anaphylaxis, with affected individuals developing rapid-onset flushing, tachycardia, and a rash, but food poisoning is more likely to involve many restaurant patrons. Observation may be all that is needed in these cases, although more severe symptoms of hypotension and wheezing can be managed with epinephrine, intravenous fluids, antihistamines, and steroids.
References:
Chegini S, Metcalfe DD. Contemporary issues in food allergy: seafood toxin-induced disease in the differential diagnosis of allergic reactions. Allergy Asthma Proc. 2005;26:183-190. Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&li st_uids=16119031
Sampson HA, Leung DYM. Adverse reactions to foods. In: Behrman RE, Kliegman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 17th ed. Philadelpha, Pa: WB Saunders Co; 2004:789-792
Question: 16
A 3-year-old child is rushed to the emergency department after the mother found her with an open and empty bottle of acetaminophen. The mother has no idea how many tablets were in the bottle. She estimates that no more than 1 hour has passed since the child ingested the tablets. The child began to vomit during the trip to the emergency department, and has vomited three times more since her arrival. The child is awake and alert but clearly unhappy, crying even in her mother's arms. She appears pale and diaphoretic. Her heart rate is 110 beats/min, respiratory rate is 26 breaths/min, temperature is 98.6°F (37°C), and blood pressure is 90/60 mm Hg.
Of the following, the MOST appropriate statement about acetaminophen toxicity is that A. an antidote is available, but its use can be deferred until further information is gathered B. given the short duration since the ingestion, it will be helpful to administer syrup of ipecac C. multiple episodes of vomiting indicate that irreversible liver damage already has occurred D. the administration of activated charcoal is contraindicated in acetaminophen toxicity
E. the contents of one bottle of acetaminophen are not sufficient to cause life-threatening toxicity in a child
N-acetyl cysteine is a highly effective antidote to acetaminophen (APAP) toxicity if administered within 10 hours of ingestion, but there is time to evaluate the level of APAP exposure before resorting to this management option for the patient described in the vignette. The level of APAP exposure is determined by measuring serum APAP concentrations 4 or more hours after
ingestion and plotting the result on a nomogram (Item C16A). Serum APAP concentrations below the lower line are not likely to result in toxicity, levels between the two lines represent possible toxicity, and levels above the upper line indicate a significant risk of toxicity. If it can be
established definitively that a child has ingested more than the minimal toxic dose of 140 mg/kg from the history alone, immediate administration of the antidote is appropriate, especially if serum APAP concentrations are not immediately available.
The primary toxicity of APAP is severe hepatic damage due to the binding of toxic
metabolites to the hepatocytes. Normally, the metabolites conjugate with glutathione, rendering them harmless, but in severe overdose, glutathione is depleted. The benefit of N-acetylcysteine stems from its ability to act as a glutathione precursor.
The first stage of APAP toxicity occurs within several hours of ingestion and includes
anorexia, nausea, and vomiting. These symptoms generally resolve within 12 to 24 hours. In the case of significant toxicity, a latent phase develops and lasts 1 to 4 days, during which time liver enzyme concentrations may begin to rise. In severe toxicity, jaundice and liver tenderness develop at the end of the latent phase. About 2% to 4% of patients who develop toxic plasma concentrations and do not receive antidotal treatment progress to hepatic failure and death.
Since 2003, the American Academy of Pediatrics has recommended against the use of ipecac in toxic ingestions, partly because the prolonged vomiting that can result interferes with other management options. Although toxicologists advised against the administration of activated charcoal in the recent past due to concerns about interference with the absorption of
N-acetylcysteine, recent studies have shown clinically insignificant reductions in N-acetylcysteine absorption following charcoal administration. Charcoal now is recommended after most cases of APAP overdose.
Vomiting is a nonspecific response to APAP ingestion and does not predict hepatic toxicity. Toxicity is confirmed by an increase in serum transaminases and a prolonged prothrombin time. There are many different APAP-containing products on the market, with a wide range of total medication per bottle. The potential for toxicity depends on the weight of the child and the
contents of the bottle. In the absence of that information, it is not possible to state that the child in the vignette has received a subtoxic dose.
References:
American Academy of Pediatrics Committee on Drugs. Acetaminophen toxicity in children. Pediatrics. 2001;108:1030-1024. Available at:
http://pediatrics.aappublications.org/cgi/content/full/108/4/1020
American Academy of Pediatrics Committee on Injury, Violence, and Poison Prevention. Poison treatment in the home. Pediatrics. 2003;112:1182-1185 Available at:
http://pediatrics.aappublications.org/cgi/content/full/112/5/1182
Bond GR. Home syrup of ipecac use does not reduce emergency department use or improve outcome. Pediatrics. 2003;112:1061-1064. Available at:
http://pediatrics.aappublications.org/cgi/content/full/112/5/1061
McGuigan ME: Poisoning potpourri. Pediatr Rev. 2001:22:295-302. Available at: http://pedsinreview.aappublications.org/cgi/content/full/22/9/295
Osterhoudt KC, Ewald MB, Shannon M, Henretig FM. Toxicologic emergencies. In: Fleisher GR, Ludwig S, Henretig FM, eds. Textbook of Pediatric Emergency Medicine. 5th ed. Philadelphia, Pa: Lippicott Williams & Wilkins; 2006:951-1008
Question: 17
A sexually active adolescent male presents with the primary complaint of pubic and perianal pruritus. Careful examination reveals pubic or "crab" lice infestation (Item Q17A).
Of the following, the MOST characteristic feature of this infestation is that the lice
A. are difficult to detect because of their rapid movement
B. lay viable eggs that may hatch up to 7 days after being attached to a hair shaft C. may survive for 36 hours without a blood meal
D. only infest pubic and perianal regions E. rarely infest African-American patients
Pediculosis, the infestation of humans by lice, has been documented for millennia. Three species of lice infest humans: Pediculus humanus humanus, the body louse; Pediculus humanus capitis, the head louse; and Pthirus pubis, the crab louse. The hallmark of louse infestation is pruritus at the site of bites. Lice are more active at night, frequently disrupting sleep of the host, which is the derivation of the term “feeling lousy.”
Adult crab lice can survive without a blood meal for 36 hours. Unlike head lice, which may travel up to 23 cm/min, pubic lice are sluggish, traveling a maximum of 10 cm/d. Viable eggs on pubic hairs may hatch up to 10 days later. Crab louse infestation is localized most frequently to the pubic and perianal regions but may spread to the mustache, beard, axillae, eyelashes, or scalp hair. Infestation usually is acquired through sexual contact, and the finding of pubic lice in children (often limited to the eyelashes) should raise concern for possible sexual abuse.
Maculae caeruleae (Item C17A), blue-gray macules observed on the abdomen and thighs at sites where lice have fed, is a useful, although less common finding. Crab lice affect all races and ethnic groups. This is in contrast to head lice, which rarely infest African-Americans, perhaps because the oval cross-sectional shape of their scalp hair does not permit lice to grasp the hair effectively.
The preferred treatments for pubic lice infestation are permethrin 1% or pyrethrin with piperonyl butoxide. Other options include permethrin 5% or malathion (although the latter agent is expensive, potentially flammable, and may be irritating when applied to the groin). Lindane is effective, but concerns about toxicity if used improperly or ingested inadvertently limit its use. It is considered a second-line therapy, is contraindicated for use in neonates and pregnant
women, and should be used with caution in those weighing less than 110 lb. If the eyelashes are affected, petrolatum may be applied to them three to five times daily for 10 days.
References:
Meinking T, Taplin D. Infestations: lice. In: Schachner LA, Hansen RC, eds. Pediatric Dermatology. 3rd ed. St. Louis, Mo: Mosby; 2003:1141-1160
Paller AS, Mancini AJ. Bites and infestations. In: Hurwitz Clinical Pediatric Dermatology. 3rd ed. Philadelphia, Pa: Elsevier Inc; 2006:479-502
Question: 18
A 6-year-old girl presents with a 1-year history of periumbilical, nonradiating abdominal pain. The pain occurs at least three times per week and lasts up to 30 minutes. There is no history of heartburn, constipation, or diarrhea. Physical examination, complete blood count, erythrocyte sedimentation rate, and urinalysis yield normal results. A Helicobacter pylori serology
(immunoglobulin G antibody) is positive.
Of the following, a TRUE statement regarding this patient is that
A. empiric therapy with omeprazole and trimethoprim-sulfamethoxazole should be instituted B. the H pylori antibody test is more sensitive in younger children than older children
C. the positive serology should be confirmed by another diagnostic test D. the prevalence of H pylori increases with higher socioeconomic status E. this patient most likely has a gastric ulcer
There is no clear association between Helicobacter pylori and chronic recurrent abdominal pain of childhood. Chronic recurrent abdominal pain affects approximately 10% to 15% of school-age children. No structural or inflammatory cause of the pain is identified in most cases. Affected children usually have functional bowel disease. Functional bowel disease in children and teens can be categorized as: nonulcer dyspepsia (epigastric discomfort, early satiety, and bloating), irritable bowel syndrome (abdominal cramps associated with diarrhea or constipation), and classic functional pain of childhood (periumbilical, crampy, and nonradiating).
A subset of children who have chronic recurrent abdominal pain also have concurrent H pylori infection. Commonly, this infection is identified on routine serologic screening by their primary care physicians, as described for the girl in the vignette. In most such children, especially in those who have no epigastric symptoms, the H pylori probably represents asymptomatic colonization rather than the cause of the pain. The only firm indications for eradicating H pylori in adults are duodenal ulcer and gastric lymphoma (MALToma).
Randomized, controlled trials in adults who have nonulcer dyspepsia suggest that eradication of H pylori does not resolve dyspeptic symptoms. Similar large-scale trials have not been
conducted in children. Therefore, it remains controversial whether children who have chronic abdominal pain and H pylori infection should receive therapy for their colonization.
Nevertheless, some open-label studies in children do suggest that eradicating H pylori may alleviate pain. In addition, eradicating H pylori may prevent the development of subsequent peptic ulcer disease or (far less commonly) gastric lymphoma. However, the serology has a poor predictive value in a low-prevalence population. Therefore, one approach is to confirm a positive serology with a second diagnostic test (fecal antigen, urea breath test, or endoscopy). If results of the second test are positive, therapy should be considered. Although endoscopy is the “gold standard” diagnostic test for H pylori and can identify other causes of abdominal pain (eg, esophagitis, gastritis, ulcers, celiac disease), it is also the most invasive test. Thus, the
physician must determine benefits, risks, and cost of diagnostic testing and treatment in individual patients.
Omeprazole and trimethoprim/sulfisoxazole do not eradicate H pylori. The H pylori antibody test is less sensitive in younger children. The prevalence of H pylori decreases with increasing socioeconomic status. Gastric ulcers are uncommon in children, and a child who has
periumbilical abdominal pain most likely has functional abdominal pain without peptic ulcer disease.
References:
AAP Subcommittee on Chronic Abdominal Pain. Chronic abdominal pain in children. Pediatrics. 2005;115:e370-e381. Available at:
http://pediatrics.aappublications.org/cgi/content/full/115/3/e370
Gold BD, Colletti RB, Abbott M, et al. Helicobacter pylori infection in children: recommendations for diagnosis and treatment. J Pediatr Gastroenterol Nutr. 2000;31:490-497 Available at:
http://www.jpgn.org/pt/re/jpgn/fulltext.00005176-200011000-00007.htm
McNamara DA, Buckley M, O’Morain CA. Nonulcer dyspepsia. Current concepts and management. Gastroenterol Clin North Am. 2000;29:807-818 Abstract available at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_ui ds=11190065&query_hl=11&itool=pubmed_docsum
Question: 19
You are conducting rounds in the newborn nursery with a group of residents. You describe the choices for infant nutrition that might optimize growth and development.
Of the following, you are MOST likely to state that
A. preterm and term infants both require 100 to 120 kcal/kg per day of energy to grow B. preterm infants require less caloric intake per kilogram to grow than do term infants C. term infants require 60 to 80 kcal/kg per day of energy to grow
D. term infants require 30 to 50 mL/kg per day of fluid intake
E. term infants whose birthweights are greater than 2,500 g require more energy per kilogram to grow than those whose birthweights are less than 2,500 g
The energy (caloric) requirement for newborns to grow and develop varies with gestational age, presence of illness, a history of surgery and need for wound healing, and the neonatal
environment. Energy use is partitioned into that required for basic metabolic function (basal metabolic rate), thermic expenditure of enteral feeding and digestion, physical activity, and the synthesis of new tissue. For term and preterm infants, these categories have the following requirements:
Categorykcal/kg per day Resting metabolic rate50 to 60 Activity0 to 10
Temperature regulation0 to 10 Growth of new tissue10 to 15
Storage of energy (mostly fat)20 to 30 Energy excreted (urine and stool)10 to 15 TOTAL90 to 140
Special considerations for preterm infants and low-birthweight (LBW) term infants (<2,500 g) warrant administration of the higher end of this caloric range. The preterm and LBW infant have lower fat stores and cannot conduct thermoregulation well, resulting in greater expenditure in heat production than at term. Similarly, such infants must accomplish a greater proportion of organ system development and new tissue synthesis (as well as production of storage fat) than the term infant, and this uses more energy. All of these considerations are greater still in the very low-birthweight (<1,500 g) or extremely low-birthweight (<1,000 g) infant. Further, conditions such as heart or lung disease, surgery, or infection increase energy expenditure. Because digestive or absorptive problems also may increase the excretion of unused energy, attention must be paid to the source of energy (carbohydrate, fat, and protein composition and content) in the milk provided to infants. The correct fluid volume for term newborns is 60 to 100 mL/kg per day.
References:
Adamkin D. Feeding the preterm infant. In: Bhatia J, ed. Perinatal Nutrition: Optimizing Infant Health and Development. New York, NY: Marcel Dekker; 2005:165-190
Denne SC, Poindexter BB, Leitch CA, Ernst JA, Lemons PK, Lemons JA. Nutrition and metabolism in the high-risk neonate: enteral nutrition. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin’s Neonatal-Perinatal Medicine: Diseases of the Fetus and Infant. 8th ed. Philadelphia, Pa: Mosby-Elsevier; 2006:661-678
Kleinman RE. Nutritional needs of the preterm infant. In: AAP Nutrition Handbook. 5th ed. Elk Grove Village, Ill: American Academy of Pediatrics; 2004:23-46
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Question: 20
A 3-year-old child who has a history of recurrent otitis media with effusion (OME) in infancy is brought to the clinic. His mother is afraid that he has a hearing loss because he does not talk as much as his brother did at the same age. He speaks in three-word sentences, and you can understand fewer than 50% of his words. Results of his physical examination, including the ears, are normal.
Of the following, the MOST appropriate statement regarding this child's condition is that A. even mild conductive hearing loss could affect his later school performance without frank speech delay
B. OME does not cause conductive hearing loss severe enough to cause speech delay C. performing hearing screening solely in response to parental concern is not recommended D. testing air and bone conduction thresholds in the office will help you rule out hearing loss E. the absence of middle ear fluid rules out conductive hearing loss
