Tracheal web

A tracheal web is a membrane that narrows the tracheal lumen, sometimes perforated.

Epidemiology

The incidence of congenital tracheal web is 1:10,000 births. In adults, tracheal webs can form following infection, inflammation or intubation.

Clinical presentation

Clinical features depend on the degree of narrowing and include wheeze, stridor, recurrent infections and respiratory failure and can mimic asthma or COPD. Minor webs may be asymptomatic but are a cause of difficult intubation. High webs cause inspiratory difficulty and lower webs cause expiratory symptoms ⁸.

Pathology

There are two types of tracheal webs:

• congenital

  • typically diagnosed in the pediatric population ⁸ and do not involve the tracheal cartilage

• acquired

  • more often seen in adults ⁸ following surgery or prolonged or traumatic intubation (post-intubation tracheal stenosis, PITS)

  • high-pressure cuffs and low capillary pressure due to hypotension cause mucosal ischemia and sometimes chondritis that heals with fibrosis ⁶

Radiographic features

Webs are usually occult on x-ray. CT shows the anatomy of the thin web, the degree of stenosis and the morphology of surrounding structures ⁸.

Treatment and prognosis

Direct visualization via bronchoscopy is gold standard investigation ⁸ and may break a thin web ¹¹. Alternative treatments include balloon dilatation, Nd-YAG laser, argon plasma coagulation, resection or stent ⁵.

After web excision, mitomycin C may be applied topically to prevent scar formation. Edema can be reduced by administration of intravenous dexamethasone ⁹.

Differential diagnosis

• tracheal stenosis due to complete tracheal cartilaginous rings

• laryngeal stenosis

• mucus in the trachea which may be cleared by coughing

See also

• tracheal lesions