Dr. Haraga presented a case of a man with vascular disease and end-stage renal disease (ESRD) who recieved sodium-polysytrene-sulfonate for hyperkalemia. One day later he developed fever, hypotension and acute on chronic RLQ pain without diarrhea or hematochezia. CT showed pneumatosis coli. The differential included colonic necrosis from sodium-polystyrene sulfonate vs ischemic colitis given his comorbidities. At this point, the etiology remains unclear, but the patient improved with antibiotics for sepsis of unclear (but suspected abdominal) source.
Pneumatosis Intestinalis: It literally means gas in the wall of the small or large intestine. The differential for pneumatosis intestinalis is vast. To quote the an article from the American Journal of Roentgenology, etiologies range from "benign to life-threatening." History and risk factors are the key to discerning cause and need for acute workup.
Pneumatosis Intestinalis can be seen on abdominal x-ray or CT and is characterized by “thumbprinting.” On exams, it is classically associated with pseudomembranous colitis. Here are some actual photos of thumb-printing (the example from noon report was incorrect).
A note about sodium-polystyrene-sulfonate:
Intestinal necrosis is a rare side effect of SPS, but the risk is not zero. Many studies associate the SPS + sorbitol formulation as having the highest risk, and the FDA has removed sorbitol from SPS formulations. However, it is unclear if sorbitol alone was the clear culprit. At this point it is wise to avoid SPS in patients with altered gut motility (see below).
There is one small case series of patients with ESRD showing no development of colonic necrosis with daily low-dose sorbitol-free SPS. However, this is not standard of care, and hemodialysis is still the best way to normalize potassium in patients with ESRD.
As a general rule, AVOID sodium-polystyrene-sulfonate (SPS) in:
patients with ileus or receiving chronic opioids
patients with large or small bowel obstruction
patients with underlying bowel disease (UC, crohn’s, C diff)
patients with ESRD where iHD is readily available.