Necrotizing Tracheobronchitis: Case Report

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366 PEDIATRICS Vol. 77 No. 3 March 1986

Necrotizing

Tracheobronchitis:

Case

Report

Francis Mimouni, MD, Jeanne L. Ballard, MD, Edgar T. Ballard, MD,

and Robin T. Cotton, MD

From the Division of Neonatology, Crosley Memorial Nursery, Division of Pediatric

Pathology, Departments of Otolaryngology and of Pediatrics, The University of Cincinnati

College of Medicine, and Children’s Hospital Research Foundation, Cincinnati

ABSTRACT. A 33-week-gestation infant with respiratory

distress syndrome is reported. At five days of age, acute

life-threatening tracheal obstruction occurred, which was relieved after removal of a plug during bronchoscopy. Histologic examination of the plug revealed partially necrotic tracheal mucosa, compatible with the diagnosis

of necrotizing tracheobronchitis. At 31 days of age, ob-struction recurred due to the development of a tracheal stricture, which resolved after tracheal reintubation (to

maintain patency) and corticosteroid therapy. Tracheal stricture may be a long-term complication of necrotizing tracheobronchitis, when the initial episode does not lead

to death from obstruction. Pediatrics 1986;77:366-368;

respiratory distress syndrome, mechanical ventilation, kit-rogenic lesion, necrotizing tracheobronchitis, tracheal stricture.

A recent report by Metlay et al’ described a new, apparently iatrogenic lesion of newborns, which

was called “necrotizing tracheobronchitis.” This le-sion was found exclusively at autopsy in 35 new-borns and was thought to be related to intubation, mechanical ventilation, and length of survival. Al-though the exact cause was not defined, direct

trauma by the endotracheal tube was considered

unlikely, because bronchial lesions were also usu-ally present. We report a case of a premature infant who survived necrotizing tracheobronchitis.

CASE REPORT

The patient was a 33-week-gestation infant, born to a

preeclamptic mother, with an Apgar score of 4 and 6 at one and five minutes, respectively. Resuscitation in-cluded vigorous stimulation, suctioning, and positive

Received for publication Feb 11, 1985; accepted May 10, 1985.

Reprint requests to (J.L.B.) University of Cincinnati, College of Medicine, 231 Bethesda Aye, Cincinnati, OH 45267-0541.

pressure nonhumidified oxygen with bag and mask. At ten minutes of age, endotracheal intubation was per-formed because of persistent cyanosis. During the first day oflife, the patient received ventilatory assistance and continuous tolazoline and dopamine infusions for per-sistent pulmonary hypertension and peripheral hypoten-sion. Both drugs were discontinued by 16 hours. Chest radiographic findings were compatible with hyaline

mem-brane disease, and the infant received antibiotic treat-ment despite negative culture studies. During the first five days, the infant was ventilated at a maximal Fi02 of

1.0, a maximal peak inspiratory pressure of 32 cm H20, and a maximal positive end-expiratory pressure of 5 cm H20. The inspired oxygen was fully humidified and warmed, and there was no incident report of any excessive temperature. At five days of age, the infant suffered

severe acute respiratory embarassment with an increase in arterial Pco2 to 150 mmHg. This was not relieved by

changing the endotracheal tube. Emergency laryngoscopy

revealed a soft tissue mass occluding the distal trachea. The patient was referred to the Children’s Hospital

Med-ical Center, where laryngobronchoscopy was performed under general anesthesia. A “pseudomembranous cast”

of the carina and proximal bronchial tree was removed. The necrotic tissue was firmly attached to the walls of the trachea, and foreign body optical forceps were nec-essary to remove it. The tissue was submitted for culture

studies and histologic examination. Fungal, bacteriologic,

and viral cultures were negative. By gross inspection, the specimen consisted of a 2 x 1 x 0.5-cm mass of whitish tan soft tissue. The microscopic examination revealed that the tissue was composed of strips of sloughed

ne-crotic mucosa and submucosal tissue. There was bland

necrosis of submucosal tissue characterized by a homog-enized appearance and intense basophilia with minimal

to focally mild inflammation. Extensive areas of the

submucosal tissue were denuded of epithelium, but focal

areas had intact but necrotic epithelium (Figure). The

interpretation of the pathologic examination was that of a full-thickness detachment of necrotic tracheobronchial mucosa and submucosa. When the plug was removed, the infant’s ventilatory status significantly improved, with ventilator settings weaned very rapidly, and within a week the infant was breathing spontaneously in room air.

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Figure. Tissue removed from trachea consisted of

ne-crotic submucosa with focally intact necrotic mucosal epithelium. There was intense basophilia and a variable

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mild acute inflammatory cell infiltration of the

submu-cosa (hematoxylin and eosin; x520).

ARTICLES 367

Endotracheal suctioning had to be repeated frequently,

however, because of thick and abundant secretions. At 13

days of age, the infant again became hypercarbic and

hypoxic, with rapidly increasing oxygen requirements.

Chest radiographs showed atelectatic areas in the right

and left lower lobes. Laryngobronchoscopy was repeated

and this time the findings were a “denuded” tracheal mucosa with thick secretions and bleeding but without any obvious plug or significant debris. The secretions

were again sterile. The infant was placed in the prone,

Trendelenburg position and treated with frequent gentle

tracheal lavages of saline and sodium bicarbonate, 0.25

mEcijmL. Dexamethasone (2 mg/kg/d) and cefotaxime (100 mg/kg/d) were administered intravenously. The ate-lectatic areas of the lungs reexpanded, and by 26 days of age, the infant no longer required assisted pulmonary ventilation. Dexamethasone administration was de-creased progressively and stopped when the infant was 29 days old. Antibiotic treatment was also discontinued. Forty-eight hours after dexamethasone was withdrawn,

the infant’s respiratory status deteriorated with

increas-ing carbon dioxide retention and requirement for oxygen. Chest radiographs showed multiple areas of atelectasis

and irregular narrowing of the distal trachea and

main-stem bronchi. Laryngobronchoscopy was repeated, and a

circumferential band of granulation tissue in the distal

centimeter of the trachea was found. The left and right main bronchi could not be seen, because it was impossible to pass the bronchoscope through the stricture; however,

it was possible to discern that the lumen was larger beyond the stricture. A 2.5-mm lumen nasotracheal tube was passed through the narrowed area. Dexamethasone

and antibiotic therapy were reinstituted. The atelectatic portions of the lungs reexpanded, and the endotracheal tube was removed a week later. However, the

dexameth-asone was continued at 1 mg/kg/d for 2 additional weeks

and then tapered during a period of 4 months. There has been no recurrence of respiratory problems and the in-fant, now 8 months old, is asymptomatic, with normal

findings on chest radiographs. There was mild hyperten-sion (100/40 to 120/72 mm Hg) which gradually resolved

as the dexamethasone dosage was decreased.

DISCUSSION

Necrotizing tracheobronchitis appears to be a

severe complication of intubation and ventilation in newborn infants. To our knowledge, it has been reported only in infants who died of an acute tra-cheobronchial obstruction.1 If necrotizing tracheo-bronchitis is truly iatrogenic, then prevention is

likely to be the most effective means of therapy.

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368 NECROTIZING TRACHEOBRONCHITIS

The cause of this life-threatening condition, how-ever, remains unknown. Endotracheal injury is

known to occur as a result of direct abrasion2 and

smoke and chemical3 inhalation. Thermal4 and

pressure5 injuries have also been reported. Endog-enous humoral substances such as biogenic amines

and peptides,3 gastric acid,6 and infectious

patho-gens, bacterial7 and viral,8 have also been impli-cated in instances of tracheal damage.

The endotracheal tube itself should probably be exonerated, because the injury appears to be at its

worst beyond the tip of the tube and extends into

the mainstem bronchi. Direct pressure may be ex-cluded for the same reason. Chemical (including oxygen), thermal, and endogenous substances, as well as infectious agents, may all participate in causation; however, none of them seemed to be

involved in this patient. Whatever the cause, our

report indicates that infants suffering from this complication may survive. We have no doubt that relieving the obstruction immediately under direct vision by laryngobronchoscopy is life-saving. Sub-sequent lavage, gentle suctioning, and drainage of

the trachea are useful in assuring the patency of the airway, but further injury to an already

trau-matized tracheal lining must be avoided. The like-lihood of subsequent stricture of the trachea is probably high, because the formation of granulation and scar tissue frequently follows endotracheal

in-jury in infants.9 Also, the loss of lamina propria in

the trachea would seem to preclude regeneration of normal mucosal cells. A severe circumferential stricture of the trachea developed in our patient, but this would not have been evident had he not

survived the initial occlusion. Therefore, therapy includes immediate removal of the occlusive debris, probably followed by efforts to promote

regenera-tion of normal tissue by avoiding infection and trauma, while suppressing cicatricial reaction

within the tracheal lumen. Glucocorticoid

treat-ment is known to inhibit the inflammatory reaction

in all of its stages, including fibroblast

prolifera-tion.1#{176}Use of glucocorticoid agents, although

con-troversial, has been advocated in some cases of

smoke inhalation to reduce the risk of strictures.1’ No controlled studies have been done in infants,

hence, we cannot be certain that the steroid therapy contributed to the survival of this infant. Reintu-bation through the carinal stricture at 31 days may

have effected temporary mechanical dilation. The

tracheal mucosa has not been examined recently

because the child has been relatively well.

There-fore, we do not know whether it is normal now or

whether it will remain functionally adequate.

Long-term follow-up of this infant will be important, because tracheal narrowing could conceivably recur at a later date.

Necrotizing tracheobronchitis is not a universally fatal disease. We could not identify the cause of the

lesion in this patient and, therefore, cannot rec-ommend a method of prevention. Necrotizing

tracheobronchitis should be suspected in

mechani-cally ventilated infants with increasing signs of obstruction. Prompt recognition and immediate treatment of obstruction may be life-saving.

ACKNOWLEDGMENTS

This work was supported, in part, by US Public Health Service MCH MCT 174 training in perinatal care and

research.

We thank Dr R. Tsang for reviewing the manuscript and Jean Sennett for her help preparing it.

REFERENCES

1. Metlay LA, MacPherson TA, Doshi N, et al: A new

iatro-genous lesion in newborns requiring assisted ventilation. N

EngI J Med 1983;309:111-112

2. Ching NP, Ayres SM, Spina RC, et al: Endotracheal damage during continuous ventilatory support. Ann Surg 1974;

179:123-127

3. Said SI: Environmental injury of the lung: Role of humoral

mediators. Fed Proc 1978;37:2504-2507

4. Brinkmann B, Puschel K: Heat injuries to the respiratory system. Virchows Arch (Pat/wI Anat) 1978;379:299-31 1

5. Katlic MR, Burke JF: Severe low-pressure cuff tracheal

injury in burn patients. Intens Care Med 1981;7:89-92 6. Neifeld JP, Berman WF, Lawrence W, et al: Management

of congenital microgastria with a jejunal reservoir pouch. J Pediatr Surg 1980;15:882-885

7. Niederman MS, Ferranti RD, Zeigler A, et al: Respiratory infection complicating long term tracheostomy: The

impli-cation of persistent gram-negative tracheobronchial coloni-zation. Chest 1984;85:39-44

8. Vernon SE: Cytologic features of non-fatal herpes virus

tracheobronchitis. Acta Cytolog 1982;26:237-242

9. Szekely E, Farkas E: Bronchoscopic findings: Stenoses,

oc-clusion, in Szekely E (ed): Pediatric Bronchology. Baltimore,

University Park Press, 1978, p 114

10. Minguell JJ, Martinez J, Walter T: Effect of hydrocortisone on the growth of human bone marrow fibroblasts. Br J

Haematol 1982;52:307-310

11. Robinson NB, Hudson LD, Riem M, et al: Steroid therapy

following isolated smoke inhalation injury. J Trauma

1982;22:876-879

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1986;77;366

Pediatrics

Francis Mimouni, Jeanne L. Ballard, Edgar T. Ballard and Robin T. Cotton