IMAGE OF THE WEEK

WEEK 34

PSEUDOMEMBRANOUS COLITIS (PMC)

The endoscopic image shows multiple white patches with inflammation and mild bleeding. The findings are consistent with pseudomembranous colitis (PMC). On endoscopy, PMC may appear as non specific colitis that may be patchy to what is seen in this case, classical white patches. On radiological imaging, submucosal oedema is prominent features that can be extensive. On plain radiography, this may appear as thumb printing that is seen in ischaemic colitis.

PMC is a part of a spectrum of antibiotic associated diarrhoea (AAD) and can be considered the more severe form. The milder form of AAD consists of diarrhoea but without significant risk for death or complications. It is more commonly referred to as Clostridium difficile colitis (CDC).

PMC or AAD is often but not necessary due to Clostridium difficile. It is often associated with use of broad spectrum antibiotics: clindamycin, cephalosporins and penicillin. However, almost any type of antibiotics can be associated with AAD. Even metronidazole (Flagyl), used for treating PMC, can cause PMC.

It occurs as a result of alteration of the colonic bacterial flora secondary to antibiotic use. Antibiotics affect certain group of bacterial more allowing the remaining species to predominate and this includes Clostridium difficle.

In CDC, the clostridium species proliferate and produce toxin A and/or B. These toxins are responsible for the manifestations of PMC.

Patients at risk are those with recent antibiotic use, recent hospital admissions and those who are elderly and have diabetes mellitus. However, majority will not have these risk factors. PMC outbreaks still occur in institutions for the elderly and hospitals especially if antibiotic use is widespread and if there is slack in hygiene.

Often AAD and even PMC will settled with stopping antibiotic use. Treatment is required in those with symptoms such diarrhoea, fever, toxic, abdominal pain or distension. Untreated, such patient may progress to toxic megacolon. Treatment is usually with metronidazole or vancomycin. In the extreme cases, colectomy may need to be considered.

Images contributed by Dr Chong Vui Heng, Department of Medicine, RIPAS Hospital, Brunei Darussalam.

All images are copyrighted and property of RIPAS Hospital.