In addition to the problems which directly concern the digestive system, as well as operation risks, the following complications may occur:
- An overproduction of stomach acid may occur; this is caued by the lack of GIP and VIP hormones, which are normally produced in the jejunum; these hormones inhibit the production of stomach acid. This leads to an increase in diarrhea, fatty stools and stomach ulcers.
- Lactose intolerance which is caused by the lack/elimination of lactase, an enzyme normally produced in the jejunum. Milk sugar is now broken down into lactase D and L by intestinal bacteria . This leads to a metabolic overacidification of the blood (metabolic acidosis), increased diarrhea, and it may result in confusion, memory loss, wobbly gait, blurred vision etc.
- Gallstone formation caused by a decrease in bile acid, which is due to the fact that less bile acid can be reabsorbed from the digested food after the removal of the ileum. Since bile acids normally keep cholesterol in a solution state, the bile fluid tends to precipitate cholesterol stones if the concentration of bile acid decreases.
- Formation of kidney stones: Normally, oxalate from food is bonded to calcium in the intestine, it becomes insoluble in water and excreted with the feces. With the short bowel syndrome, however, calcium is not bonded to the fatty acids absorbed in the small intestine, which, in turn, increases the amount of free oxalate; the free oxolate is absorbed in the colon which still functions and this results in an increase in oxalate levels in the blood (hyperoxalatemia) and urine (hyperoxaluria).