Repeat bronchoscopy showed marked neutrophilia with negative microbiology and cytology specimens. Upper gastrointestinal endoscopy was normal. Electromyography revealed sensorimotor polyneuropathy, with predominant demyelinating features. Open lung, nerve and muscle biopsies were performed under general anesthesia to establish a definitive diagnosis. The open lung biopsy (Figures 3, 4) showed fibrosis of bronchioles and interstitium, foci of obliterative bronchiolitis, thickening of alveolar walls, numerous foamy macrophages and hyperplastic type II cells.A sural nerve biopsy confirmed a demyelinating neuropathy with severe secondary axonal degeneration (not shown). Electron microscopic review of the nerve biopsy revealed numerous lysosome-like inclusions within Schwann, fibroblastic and endothelial cells compatible with amio-darone neuropathy (not shown). A right vastus lateralis muscle biopsy (Figure 5) showed type II atrophy with vacuolization. The biopsy results supported the suspicion of amiodarone toxicity.
The patient had a lengthy stay in the intensive care unit complicated by nosocomial pneumonia, sepsis, unstable angina and Clostridium difficile diarrhea. The amiodarone was discontinued after a total of 10 months of therapy, and intravenous methylprednisolone 100 mg every 6 h for five days was administered. After a gastrojejunal tube was inserted, oral prednisone was initiated at a dose of 50 mg once daily for four weeks followed by a tapering schedule of 5 mg every two weeks.
Figure 3) A lung biopsy (elastic trichrome stain) demonstrating extensive parenchymal fibrosis, foci of obliterative bronchiolitis, thickened alveolar walls and foamy macrophages. Original magnification x40
Figure 4) A lung biopsy specimen (Hematoxylin & Eosin stain) showing foamy macrophages in the alveoli consistent with amio-darone effect. Original magnification x400
Figure 5) A right vastus lateralis muscle biopsy (adenosine triphosphatase stain – pH 9.4) showing type 2 muscle fibre atrophy. Original magnification x40