Pyelonephritis as a cause of pleural effusion.

Although pancreatitis and subphrenic abscess frequently cause pleural effusion, renal disease rarely does so. We report a case of a young patient who presented with pleural effusion due to pyelonephritis and renal outflow obstruction secondary to nephrolithiasis. The effusion and the initial absence of urinary abnormalities resulted in delay in diagnosis and initiation of appropriate therapy.