Pleural effusions in systemic amyloidosis.
PURPOSE OF REVIEW: Large, recurrent pleural effusions in systemic amyloidoses are rare but clinically challenging events predominantly affecting patients with primary systemic amyloidosis. Examining the mechanisms by which these effusions form and persist offers perspective on the pathophysiology and basis for therapeutic interventions. RECENT FINDINGS: Between 1977 and 2003, the literature consisted of approximately 21-25 case reports on pleural effusions in systemic amyloidosis. In 2003, Boston University published a retrospective single-center analysis of 35 primary systemic amyloidosis patients with large, refractory pleural effusions. To define the role of cardiomyopathy in large, refractory pleural effusions, the Boston University Amyloid Program compared demographics, pleural fluid chemistries, echocardiographic indices, and renal function measures of the pleural effusion group with data from 120 primary systemic amyloidosis cardiomyopathy patients with no pleural effusions. Neither cardiomyopathy nor nephrotic syndrome explained pleural effusions in primary systemic amyloidosis patients. The large number of exudative effusions supported primary disruption of the pleural surface and its function by amyloid. Disease mechanisms, natural history, and management options are discussed here. SUMMARY: Large pleural effusions in systemic amyloidosis occur most often in primary systemic amyloidosis, predominantly resulting from direct infiltration of the parietal pleural surface. Left atrial hypertension from primary systemic amyloidosis cardiomyopathy contributes to but is not sufficient to form and sustain these effusions. Untreated patients have a median survival of 1.6 months. Secondary, familial, and senile systemic amyloidosis do not infiltrate the pleural surfaces or induce pleural effusions in a clinically significant fashion.