A 74 year old woman with longstanding hip osteoarthritis presents complains of constipation and loose stool. She undergoes a sigmoidoscopy. A rectal biopsy shows pigment-laden macrophages in the lamina propria.
What is the most likely cause?
3.Non-steroidal anti inflammatory drugs
The pigment laden macrophages suggest that there is melanosis coli. The most common association is with laxatives. To a lesser extent, melanosis coli is also associated with ulcerative colitis.