The risk of perforation within 24 hours of the onset of symptoms is <30 per cent, and perforation occurs more commonly in children.
The omentum tends to wall off serosal inflammation of the appendix. Perforation may be contained by the omentum and other surrounding structures to form a localized abscess. If this does not happen, generalized peritonitis is likely.
answers
Clinical cases
CASE1.7– ‘I’ve got a really bad pain in my right side’
A1: Whatisthelikelydifferentialdiagnosis?
⦁ Acute appendicitis ⦁ Gastroenteritis ⦁ Mesenteric adenitis
⦁ Crohn’s disease of the terminal ileum
⦁ Less likely: ureteric colic, acute cholecystitis, pyelonephritis
A2: Whatfeaturesofthegivenhistorysupportthediagnosis?
Appendicitis is typically preceded by a vague abdominal pain, because visceral inflammation is often poorly localized to the midline; organs derived from the midgut usually have pain referred to the periumbilical region. As the serosa becomes inflamed, and involves the peritoneum, the pain tends to localize to where the appendix is located. Nausea and anorexia go hand in hand with gastrointestinal (GI) inflammation.
A3: Whatadditionalfeaturesinthehistorywouldyouseektosupporta
particulardiagnosis?
Has the patient had this type of pain previously? Recurrent pains are atypical of appendicitis (‘grumbling’ appendix, while much beloved of GPs, probably does not exist). Ask about other GI symptoms, particularly diarrhoea; in appendicitis, these usually follow the initial pain, rather than preceding it. Also check for family history of inflammatory bowel disease, and recent viral infections.
A4: Whatclinicalexaminationwouldyouperformandwhy?
Abdominal examination should seek to differentiate between tenderness (mild to moderate pain on palpation) and guarding (increased muscular tone) which is a sign of peritonism. Cough and percussion tenderness are hallmarks of peritonism, and when present with the appropriate history are often diagnostic of acute appendicitis. Rebound tenderness is non-specific and cruel, and should never be performed.
In most patients with suspected acute appendicitis DRE adds little information.
Repeated clinical assessment is very useful in borderline cases. A 12-hour period of assessment with repeated examination is almost always safe, and better than operating in the middle of the night.
A5: Whatinvestigationswouldbemostusefulandwhy?
⦁ Blood tests: In acute appendicitis, WCC and inflammatory markers (C-reactive protein (CRP)) are usually moderately raised. Other blood tests are normal.
⦁ The presence of UTI can be excluded by midstream urine (MSU).
⦁ Plain abdominal x-ray adds little. Computed tomography of the right iliac fossa is highly sensitive and specific for appendicitis, but is not usually required.
Appendicitis 23
A6: Whattreatmentoptionsareappropriate?
⦁ Supportive: no role
⦁ Medical: broad-spectrum antibiotics can alter the course of early appendicitis, but once serosal inflammation or ischaemia/necrosis of the wall has occurred, the appendix will progress to perforation if not removed. Antibiotics can be given as prophylaxis against wound infection at the time of anaesthetic induction, or as a course of post-operative treatment if the appendix has perforated.
⦁ Surgical: appendicectomy is indicated. This can be performed as an open operation with an incision in the right iliac fossa, or laparoscopically (see next section).
CASE1.8– ‘I’ve developed another episode of pain on the right side’
A1: Whatisthelikelydifferentialdiagnosis?
⦁ Non-specific abdominal pain ⦁ Acute appendicitis
⦁ Right-sided gynaecological pathology (ovarian cyst rupture or torsion, pelvic inflammatory disease, ectopic pregnancy, endometriosis, midcycle ovulatory pain)
⦁ Less likely: Crohn’s disease, gastroenteritis, cholecystitis or biliary colic, ureteric colic
A2: Whatfeaturesofthegivenhistorysupportthediagnosis?
The previous episodes of the same pain suggest a recurring problem, although it is possible to have similar episodes before frank acute appendicitis.
A3: Whatadditionalfeaturesinthehistorywouldyouseektosupporta
particulardiagnosis?
Could she be pregnant? A careful gynaecological and sexual history is mandatory in this situation. Urinary symptoms should also be elicited.
A4: Whatclinicalexaminationwouldyouperformandwhy?
In addition to abdominal examination, vaginal and pelvic examination should be performed. Masses, tenderness, vaginal discharge and cervical excitation should all be sought.
A5: Whatinvestigationswouldbemostusefulandwhy?
⦁ Perform a pregnancy test before anything else.
⦁ Blood tests: Obtain WCC, haemoglobin (Hb), urea and electrolytes (U&Es) and CRP. ⦁ Collect MSU to exclude UTI.
⦁ Imaging: traditionally ultrasonography (transvaginal being better than transabdominal) has been used to assess right iliac fossa pain in young women. However, this frequently fails to achieve a diagnosis. ⦁ Diagnostic laparoscopy: use if pain fails to resolve after a period of overnight observation, and other tests
have not achieved a diagnosis. It has the benefit of allowing direct visualization of the appendix and pelvic organs, and the ability to proceed to therapeutic intervention if necessary.
A6: Whattreatmentoptionsareappropriate?
⦁ Supportive: fluids, analgesia and a period of observation are useful when the diagnosis is equivocal. Those with mild pain which resolves may then eat and drink and be discharged without follow-up. ⦁ Medical: there is no role, although antibiotics should be started once a diagnosis of appendicitis has
⦁ Surgical: surgery is indicated for definite signs of acute appendicitis. It is generally accepted that removing a normal appendix (‘negative appendicectomy’) is less dangerous than equivocating and allowing the appendix to perforate, an abscess to form, or generalized peritonitis to develop.
CASE1.9– ‘The pain is getting worse and I’ve started to vomit’
A1: Whatisthelikelydifferentialdiagnosis?
⦁ Appendix abscess ⦁ Appendix mass
⦁ Perforated ileal Crohn’s disease ⦁ Perforated caecal cancer
A2: Whatfeaturesofthegivenhistorysupportthediagnosis?
This story is typical of ‘missed’ appendicitis; patients usually present to hospital within 24 to 48 hours of symptoms starting. If the appendix perforates, systemic signs of sepsis (tachycardia, tachypneoa, pyrexia) are often more severe.
A3: Whatadditionalfeaturesinthehistorywouldyouseektosupporta
particulardiagnosis?
GI symptoms that have been present for a long period may point to underlying pathology such as inflammatory bowel disease. Neoplasms may be asymptomatic in the caecum as a result of the liquid stool and large calibre of the caecal lumen, but may result in iron-deficiency anaemia and consequent lethargy.
A4: Whatclinicalexaminationwouldyouperformandwhy?
Abdominal examination should be performed to confirm the presence of a tender right iliac fossa mass. It may also be felt on DRE.
A5: Whatinvestigationswouldbemostusefulandwhy?
⦁ Blood tests: raised WCC, raised CRP. Iron-deficiency anaemia may suggest a caecal malignancy. In systemic sepsis, LFTs can be deranged (raised alanine aminotransaminase (ALT) and aspartate aminotransaminase (AST) and reduced albumin).
⦁ Imaging: plain abdominal x-ray may show signs of an ileus or frank bowel obstruction. Plain erect chest x-ray may show free gas under the diaphragm if bowel perforation has occurred. Ultrasound or CT of the abdomen must be performed urgently to differentiate an appendix mass from an appendix abscess, or to diagnose an underlying caecal malignancy or features of Crohn’s disease, as these clinical entities will be managed differently.
A6: Whattreatmentoptionsareappropriate?
⦁ Supportive: fluid resuscitation and analgesia are needed.
⦁ Medical: if an appendix mass (without an abscess) is diagnosed, broad-spectrum antibiotics targeted against GI organisms should be given. If the patient settles with this treatment, only 20 per cent develop recurrent appendicitis. Performing an ‘interval’ appendicectomy is no longer recommended. Any underlying bowel pathology should be excluded by either colonoscopy or CT colonography in patients over the age of 40.
Appendicitis 25
⦁ Surgical: surgery will be required if the inflammation is localized (appendicectomy via the usual right iliac fossa incision or midline laparotomy), or if generalized peritonitis is present (midline laparotomy to allow appendicectomy and washout of the abdominal cavity). Perforated Crohn’s disease or caecal cancer may require laparotomy and resection of the affected bowel segment. Rejoining the bowel may be unwise in the presence of infection, so a temporary stoma may be necessary.
OSCE Counselling cases
OSCECOUNSELLINGCASE1.5– ‘I’m going to overwinter in the
Antarctic. Should I have my appendix
removed beforehand?’
Appendicitis affects between 7 and 12 per cent of individuals in their lifetime, most often in the second and third decades. The risk for any individual in a given 6-month period is relatively small, and impossible to predict. The risk of complications associated with removing a normal appendix must be weighed against the risks of developing appendicitis when access to medical care might be difficult.
Laparoscopic appendicectomy has reduced the risk of complications and morbidity associated with the operation, and most surgeons would at least consider such a request in appropriate circumstances.
OSCECOUNSELLINGCASE1.6– ‘Why has my wife developed
complications after her
appendicectomy?’
All medical interventions have the potential to cause harm as well as good. Informed consent should include information about common adverse events, as well as rare but significant complications. Patients should always have the opportunity to ask as much about their care as they feel appropriate. This is sometimes harder to do in an emergency situation.
Pelvic abscess is an uncommon but recognized complication of appendicitis. Appropriate medical care, including antibiotics and drainage should minimize the risk of long-term sequelae.
reVision panel
⦁ Appendicitis is a common cause of the acute abdomen in younger patients.
⦁ The diagnosis of appendicitis is primarily a clinical assessment. Pregnancy should always be excluded in females of childbearing age.
⦁ Sometimes CT scanning or other imaging may be required to obtain the diagnosis in equivocal cases. Examples include the elderly, or when a mass is present.
⦁ Surgical treatment is preferred for acute appendicitis. Diagnostic laparoscopy followed by laparoscopic (or open) appendicectomy is now commonly performed, particularly in women. ⦁ A macroscopically normal appendix may sometimes be left in situ with a laparoscopic approach,
especially if other pathology is identified. A normal appendix should never be left in place after an open appendicectomy incision has been made.