Pediatric diffuse alveolar hemorrhage (DAH) is a life-threatening disorder characterized by pulmonary hemorrhage and respiratory insufficiency. Histologically, DAH with capillary inflammation is known as pulmonary capillaritis (PC), and like DAH, can be secondary to autoimmune disease (SLE, systemic vasculitis) or an isolated condition. The latter is a rare condition and the disease course and prognosis has yet to be well described in children. We describe the clinical presentation, disease course, and outcomes of a pediatric cohort with biopsy proven isolated PC.

Methods:

After IRB approval, we reviewed the records of children with biopsy proven PC diagnosed between 2004 to 2015 who were evaluated by pediatric rheumatology. Inclusion criteria were capillaritis on lung biopsy and no diagnosis of systemic autoimmunity at presentation. We describe clinical features, imaging, bronchoscopy, immunomodulation, and outcomes.

Results:

Seven patients met inclusion criteria. Over half of the patients were female (57%), and 29% were Caucasian. The median age at diagnosis was 6.8 years (range 1.8 to 16.3 years). Most presented with an acute onset, 71% reported symptoms for less than 1 month. All presented with anemia, abnormal chest x-ray findings, and had a CAT scan consistent with DAH (including multi-focal ground-glass opacities). All patients had bronchoalveolar lavage showing hemosiderin laden macrophages. However, only 57% presented with frank hemoptysis. Eighty six percent required respiratory support at diagnosis: 14% nasal cannula, 57% conventional mechanical ventilation, and 14% high frequency oscillatory ventilation. At presentation, 86% had a positive ANA titer but no other classification criteria for SLE while 14% had a positive anti-RNP antibody but were never found to have systemic autoimmune disease. Induction regimen for all patients included intravenous (IV) pulse-dose steroids and IV Immunoglobulin (IVIG). Seventy one percent also received IV Cyclophosphamide, for a median of 6 months (range 3-6 months), 14% Rituximab and 14% Mycophenolate Mofetil (MMF). Plasmapheresis (6 sessions) was used in 14% as part of induction therapy. All patients received oral steroids (daily dose with taper) for maintenance therapy in addition to other medications. Seventy one percent received Methotrexate, 43% received IV steroids, 29% monthly IVIG, 14% MMF, and 14% Hydroxychloroquine. The median length of follow-up was 3 years (range 1-8 years), and in the majority of patients (71%), DAH did not recur. Twenty nine percent required supplemental oxygen after discharge (at night) and 29% had recurrent infections. One patient died which was likely related to a co-morbid condition (complications from congenital heart disease).

Conclusion:

Review of isolated PC at our institution indicates children present acutely and typically require ventilator support at diagnosis. Despite ANA positivity, patients did not develop other antibodies or develop systemic autoimmune disorders. Mortality and morbidity rates were low with early, aggressive, multi-modal immunomodulatory regimens.