Pyoderma Gangrenosum (PG) is a rare inflammatory disorder of the skin characterized by the presence of irregular ulcers with violaceous borders, often in the setting of systemic disease. The histopathology features non-specific neutrophilic infiltration; the pathogenesis is thought to involve dysfunction of neutrophil chemotaxis. Extracutaneous manifestations are rare but pulmonary involvement has been reported. We report a case of a pulmonary PG and acute respiratory distress.
This 61-year-old never-smoker was admitted with hypoxic respiratory failure. He was in good health until 2 years ago when he suffered multiple non-healing ulcers on his arms and abdomen originally diagnosed as necrotizing fasciitis. He failed multiple therapies and had consistently sterile cultures. Biopsy showed neutrophillic infiltrates. He was diagnosed with PG and treated with infliximab resulting in prompt resolution of symptoms. Initial evaluation for concurrent systemic disease revealed splenomegaly, for which he underwent a splenectomy. Subsequently he developed thrombocytosis and monocytosis, and a bone marrow biopsy confirmed the diagnosis of underlying CMML for which he was treated with hydroxyurea. Six weeks prior to admission he redeveloped suspicious skin lesions and was restarted on infliximab. He then presented to the emergency room with a one-week history of progressive dyspnea, weakness and fatigue. Physical examination revealed a well-nourished male in acute respiratory distress, fever of 101.7, tachypnea and accessory muscle use. Coarse crackles were auscultated bilaterally on chest exam. Laboratory examination showed a WBC of 9500 with 3% bands, 22%. Platelet count was 355,000. ABG showed a paO2 of 67 mmHg on 40% FiO2. Chest x-ray showed bilateral pulmonary infiltrates. A CT angiogram revealed centrilobular and peribronchial ground glass infiltrates. An echocardiogram showed a normal ejection fraction and moderate pulmonary hypertension. He was immediately started on broad spectrum antibiotics. His respiratory status continued to decline and he required intubation and mechanical ventilation. Interestingly, he had rapid improvement of symptoms initially and was extubated within 2 days only to be re-intubated within 48 hours. Over the following 6 weeks, the patient fell into a pattern of improved respiratory status and extubation followed by recurrence of hypoxic respiratory distress and re-intubation. He had in the interim been started on empiric corticosteroid therapy and antifungal therapy as well as given a tracheostomy. Multiple bronchoalveolar lavages failed to reveal an infectious or malignant source of his symptoms. Repeated cultures were negative. Serological studies and inflammatory markers were nondiagnostic. The patient then underwent a surgical lung biopsy. Pathology showed a uniform process of numerous fibroblastic foci, thickening of alveolar septi, and focal areas of acute inflammation without granulomas. It was then decided to treat the patient empirically for PG involvement of the lungs with 1g methylprednisolone daily for three days. The patient’s respiratory status dramatically improved allowing liberation from mechanical ventilation for the rest of his hospitalization. Review of the patients chart demonstrated a correlation between steroid tapers and decline of respiratory function.
Our patient’s profound response to corticosteroids led us to believe that he had PG involvement of his lungs. We suspect this particularly because he had a recent flare of cutaneous PG. Our pathologic findings are consistent with PG although non-diagnostic. Other possibilities do exist, including drug-induced pneumonitis secondary to either hydroxyurea or infliximab.
While pulmonary involvement of PG is rare it should be considered in a patient with PG and respiratory symptoms.
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