Secretory diarrhea and hypokalemia associated with colonic pseudo-obstruction: A case study and systematic analysis of the literature.

Abstract

Colonic pseudo-obstruction (CPO) is characterized by colonic distention in the absence of mechanical obstruction or toxic megacolon. Concomitant secretory diarrhea (SD) with hypokalemia (SD-CPO) due to gastrointestinal (GI) loss requires further characterization. To perform a systematic review of SD-CPO, report a case study, and compare SD-CPO with classical CPO (C-CPO). We performed a search of MEDLINE, EMBASE, Cochrane, and Scopus for reports based on a priori criteria for CPO, SD and GI loss of potassium. An additional case at Mayo Clinic was included. Nine publications met inclusion criteria, with a total of 14 cases. Six studies had high, three moderate, and our case high methodological quality. Median age was 74years (66-97), with 2:1 male/female ratio. Kidney disease was present in 6/14 patients. Diarrhea was described as profuse, watery, or viscous in 10 patients. Median serum, stool, and urine potassium concentrations (mmol/L) were 2.4 (range: 1.9-3.1), 137 (100-180), and 17 (8-40), respectively. Maximal diameter of colon and cecum (median) were 10.2cm and 10.5cm, respectively. Conservative therapy alone was effective in five out of 14 patients. Median potassium supplementation was 124mEq/d (40-300). Colonic decompression was effective in three out of six patients; one had a total colectomy; three out of 14 had died. The main differences between SD-CPO and C-CPO were lower responses to treatments: conservative measures (35.7% vs 73.6%, P=.01), neostigmine (17% vs 89.2%, P<.001), and colonic decompression (50% vs 82.4%, P=.02). SD-CPO is a rare phenotype associated with increased fecal potassium and is more difficult to treat than C-CPO.