Epidemic dropsy: observations on pathophysiology and clinical features during the Delhi epidemic of 1998.

Epidemic dropsy results from the consumption of edible oils adulterated with Argemone mexicana oil by unscrupulous traders. Twenty consecutive 'in-door' patients of dropsy were intensively studied during the recent Delhi epidemic. Samples of edible oil used by them, their urine and their serum samples tested positive for sanguinarine on thin layer chromatography. The illness starts as a gastro-enteric illness followed by oliguria and pedal oedema. The following are often observed: cutaneous erythema with blanching and tenderness on pressure; violacious pigmentation of the skin; shortness of breath with orthopnoea; right-sided heart failure with normal left ventricle (LV) functions; as well as severe anaemia and hypoalbuminaemia. Renal function tests showed: bland urinary sediments; decreased glomerular filtration rate (GFR); mild to moderate azotaemia; acute tubular necrosis; patchy pneumonitis; moderate hypoxia with respiratory alkalosis; and restrictive ventilatory defects on blood gas analysis; and spirometry suggestive of interstitial pulmonary oedema of non-cardiogenic origin. 99mTc colloid sulphur liver scans showed colloid shift. There was marked dilatation and proliferation of dermal capillaries in the absence of significant inflammation in the biopsy specimens. Toxic alkaloids of Argemone mexicana oil induce widespread capillary dilatation and permeability causing leakage of protein rich plasma into the interstitial tissues of various organs. A hypovolaemic state is thus induced producing renal hypoperfusion which may progress to acute tubular necrosis. Interstitial fluid in alveoli causes restrictive ventilatory dysfunction with hypertension and right-sided failure with well-preserved LV function. The hepatic venous congestion induces Kupffer's cell dysfunction, which results in colloid shift on a radionuclide liver scan.