Acquired Lesions

Postintubation stenoses are preponderant among acquired airway lesions in children.48 Unfortunately, these injuries include laryngotracheal stenoses resulting from the preferential use in this age group of endotracheal tubes, often uncuffed, for ventilatory support. Laryngotracheal stenosis is much more difficult to correct than a purely tracheal lesion. In a study of 854 newborns who required intubation and ventilation (1979-1983), Marcovich and colleagues discovered a 0.6% incidence of severe subglottic stenosis, where uncuffed, small diameter tubes had been used nasotracheally.49 As in adults, the length of the period of intubation does not seem to be critical, although the period of risk is obviously greater with prolonged intubation. The reported incidence of injury has varied widely, and it remains difficult to define specific conditions that produce sufficient erosion to cause stenosis in one patient and not in another (see Chapter 11, "Postintubation Stenosis").

Tracheostomy, used either by choice to limit the period of endotracheal intubation or as treatment for laryngeal or subglottic obstruction resulting from endotracheal intubation, may produce its own stenotic or other obstructive lesions in infants and children. The uses of carefully placed vertical incisions in cartilage and specifically designed pediatric uncuffed tracheal tubes for tracheostomy in the infant have reduced the incidence of stomal tracheal stenosis (see Chapter 10, "Tracheostomy: Uses, Varieties, Complications"). Obstruction also occurs, although less often, by compression deformity of the soft tracheal wall of infants, just proximal to the stoma, due to pressure by the curvature of the tube. This is correctable by use of T tubes, which, however, may be difficult to care for in infants due to their tiny diameter. Overall, nasotracheal intubation has more often been selected for prolonged ventilation in these age groups.

A small number of postintubation tracheoesophageal fistulae have been seen, and, fortunately, only a rare tracheo-innominate artery fistula (see Chapter 12, "Acquired Tracheoesophageal and Broncho-esophageal Fistula" and Chapter 13, "Tracheal Fistula to Brachiocephalic Artery"). Post-traumatic stenosis from external injury is uncommon except in older children. Stenosis due to inhalation burns is difficult to treat because of the basic pathology of burned tissue (see Chapter 9, "Tracheal and Bronchial Trauma").

Tumors, benign or malignant, occur uncommonly. In 198 primary tracheal tumors, only 4 were in patients under the age of 10 years, and 8 occurred in patients between 11 and 19 years of age.50 These included granular cell tumor, fibrous histiocytoma, neurofibroma, mucoepidermoid tumor, carcinoid (most common), adenoid cystic carcinoma, and rhabdomyosarcoma. Other tracheal tumors noted in childhood were fibrosarcoma, squamous cell carcinoma, hemangiopericytoma, and chondroma. "Congenital" tumors compressing the trachea or bronchi included cystic hygroma, hemangioma, teratoma, and thymic cyst.51

Recurrent respiratory papillomatosis due to the human papilloma virus causes wart-like excrescences in the larynx and trachea, in children as well as in adults. Patients present with hoarseness, a weakened cry, cough, respiratory infections, choking, and obstruction of progressive severity. The disease is vertically transmitted in children. Present treatment is repeated laser vaporization. Multiple antiviral adjuvants have been tried, including interferon. Although most children enter spontaneous remission, recurrences do emerge. Malignant degeneration has rarely been reported in children.52

Hemangiomas of the airway are frequently associated with cutaneous hemangiomas of the chin, lips, mandibular region, and neck.53 In the subglottic region, proliferation produces hoarseness and stridor. Respiratory failure can follow, often at between 6 to 12 weeks of age. Management includes corticosteroids and tra-cheostomy since the lesions usually regress spontaneously. Cryotherapy and laser therapy have been used, but scarring and stenosis can follow, especially if the subglottic lesion is extensive.

Rarely, an extrinsic lesion such as a bronchogenic cyst or mediastinal tumor will produce compression of the trachea or secondary malacia in early childhood.54 For example, apparent malacia over a long tracheal segment, seen in a 2/2-year-old child, proved to be due to compression by a large thymic cyst (Figure 6-16). Because of prolonged compression of the trachea by the cyst, which had apparently been present since birth, removal alone did not immediately restore a satisfactory airway. Splinting with a tracheostomy tube was required until the cartilages became firm with further growth. Rarely, a bronchogenic cyst at the carina may produce compressive symptoms in children. Adenocarcinoma was discovered in the base of an obstructing cyst in an 8-year-old girl, and curative carinal resection was secondarily performed (Figure 6-17).

Obstruction of the trachea or bronchi has resulted from infection with tuberculosis, histoplasmosis, diphtheria, rhinoscleroma, and syphilis (see Chapter 14, "Infectious, Inflammatory, Infiltrative, Idiopathic,

figure 6-16 Thymic cyst compressing the trachea in a 2/ -year-old boy. A, The lateral roentgenogram demonstrates tracheal deformation. B, The cyst as it was being extracted from the mediastinum via cervical incision.

and Miscellaneous Tracheal Lesions"). All except histoplasmosis (in adults) are vanishingly uncommon in developed countries. Bulky tuberculous enlargement of mediastinal or hilar lymph nodes can compress and erode the relatively soft trachea or bronchi of children.55 Subcarinal nodes are commonly involved.

figure 6-17 Computed tomography scan in an 8-year-old girl, showing a bronchogenic cyst deforming the carina, but with irregular protrusion into the lumen, which proved to be adeno-carcinoma in the base of the cyst. After secondary carinal resection, she remained disease free in 16-year follow-up.

Sequelae include pulmonary collapse or hyperinflation, airway perforation, bronchostenosis, and caval or esophageal obstruction. Glandular enlargement can occur despite antituberculosis drug treatment, and indeed has been observed to likely increase on initial treatment.

Surgical treatment is reserved for symptomatic patients. Acute obstruction may demand emergent surgery. Enucleation and curettage of obstructing nodes and of caseous material, suture and muscle flap repair of a bronchial opening, and conservation of all but destroyed lung are effective.56 Lymph node excision is avoided in order to minimize complications. Late fibrous bronchostenosis is best treated by segmental bronchial resection and anastomosis with preservation of the lung, unless it is irretrievably damaged. Corticosteroids are unlikely to improve gross airway obstruction.

Pneumonectomy has become a rare procedure in childhood, so that postpneumonectomy syndrome, once thought to occur principally in childhood, is now seen largely in adults (see Chapter 15, "Tracheobronchial Malacia and Compression").

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