Lymphoscintigraphy in plastic bronchitis, A pediatric case report

Abstract

Plastic bronchitis (PB) is an uncommon, potentially fatal disease, marked by endobronchial cast formation causing variable degrees of respiratory distress. Primary and secondary pulmonary lymphatic abnormalities have been identified among the underlying mechanisms of cast formation. We present a case of PB where lymphoscintigraphy demonstrated the underlying lymphatic defect. A 6-year-old Hispanic male with congenital heart disease (CHD; post-Fontan) presented with recurrent pneumonia, respiratory distress. Bronchoscopy showed inflamed hypervascular mucosa and thick mucus plugs; no casts were seen. Later, PB was diagnosed after the patient expectorated a bronchial cast. Cast analysis showed lymphocytic aggregates with mucin and fibrin. Lymphoscintigraphy revealed abnormal lymphatic collaterals and retrograde trace reflux into the superior mediastinum, a picture consistent with thoracic duct lymph leakage into the tracheobronchial tree. The pathogenesis of PB is not fully understood, especially in patients with CHD. Chyle in bronchial casts suggests abnormal lymphatic flow. Reports of lymph flow abnormalities, especially endobronchial lymph leakage in CHD are limited. Lymphoscintigraphy in our case demonstrated clear evidence of retrograde lymph reflux and leakage into the bronchial tree. The case presented suggests that in some patients following Fontan surgery, high intrathoracic lymphatic pressure and retrograde lymph flow may contribute to recurrent cast formation. Finding the underlying lymphatic abnormality helps in specific case management. Lymphoscintigraphy is a safer and easier method than lymphangiography. Surgical lymphatic-venous shunting may be possible in select cases.

Fontan-Associated Protein-Losing Enteropathy and Plastic Bronchitis

“…Each of these associations has been previously demonstrated in small, retrospective single center studies 13, 18, 19 , but never confirmed in a multicenter analysis. For PB, single right ventricle and lymphatic abnormalities have been suggested in case reports, but never confirmed in a large, controlled study 4, 14, 20 .…”

Percutaneous Lymphatic Embolization of Abnormal Pulmonary Lymphatic Flow as Treatment of Plastic Bronchitis in Patients With Congenital Heart Disease

“…2 Lymphatic involvement has been shown and is believed to play a role in the disease process, but the pathogenesis of PB associated with it is poorly understood. 7,[21][22][23] Treatments of PB in patients post-TCPC have focused primarily on facilitation of cast expectoration (inhaled tissue plasminogen activator, heparin inhalations, dornase, hypertonic saline, and vibration vest), reduction of CVP (fenestration and sildenafil), and steroid anti-inflammatory therapy. It is possible that improvement of CVP is 1 mechanism by which heart transplantation results in cessation or cure of PB.…”

A Multifaceted Approach to the Management of Plastic Bronchitis After Cavopulmonary Palliation

“…Finally, lymphatic malformations and endobronchial lymph leakage may contribute to cast formation [22]. Reports of chyle in plastic bronchitis casts suggest that pulmonary lymph flow may be abnormal and may be a potential treatment target [23].…”