High-volume postobstructive choleresis after transhepatic external biliary drainage resolves with conversion to internal drainage.

We report high-volume postobstructive choleresis in two patients who underwent transhepatic external drainage for malignant biliary obstruction. Excessive loss of bicarbonate-rich biliary fluid (up to 6.5 L/day) caused orthostatic hypotension, prerenal insufficiency, hyponatremia, and a decrease in serum bicarbonate. Therapy with isotonic fluids containing sodium, chloride, lactate, bicarbonate, and potassium was based on measurement of biliary fluid volume and electrolyte concentrations. Biliary fluid loss was terminated by conversion to internal biliary drainage. The reason for this rare complication of external drainage of biliary obstruction is unknown, but such patients must be closely monitored for volume loss. When high-volume choleresis occurs, biliary fluid and electrolyte losses should be precisely measured and replaced, and external biliary drainage converted to internal drainage.