Our small intestine plays a crucial role in processing the food we eat and extracting the nutrients our body needs for energy and proper functioning. With its impressive length of around six meters, it is divided into three parts— the duodenum, jejunum, and ileum. “In certain health conditions, large portion of small intestine is removed surgically (resection) resulting in the loss of intestinal length to less than 200 centimetres. This condition is known as short bowel syndrome,” says Dr Piyush Ranjan, senior consultant and vice-chairman, department of gastroenterology, Sir Gangaram Hospital, New Delhi.
Those with short bowel syndrome have difficulty in absorbing nutrients, fluids, and electrolytes due to loss of absorptive area in the small intestine. In the long run, it results in malnutrition, adds Dr Ranjan.
What are the causes
Often, resection is done due to gangrene in intestine (most common cause), trauma, or when one has Crohn’s disease. In severe cases, even colon is partially or completely removed, says Dr Ranjan.
The symptoms and severity of short bowel syndrome can depend on the length of bowel that remains. “Greater the length of bowel removed, more severe are the symptoms,” says Dr Ranjan. Some of the symptoms include:
- Continuous diarrhoea as water is not being absorbed
- Dehydration and electrolyte imbalance
- Loss of nutrients due to loss of absorptive area
- Protein calorie malnutrition as amino acids are not being absorbed. This can result in stunted growth, fatigue, loss of muscle mass and weakness.
- Severe malnutrition and weight loss
- Vitamin deficiency (fat-soluble and water-soluble vitamin deficiencies). Vitamin deficiencies will be more in the absence of terminal ileum
- Small intestinal bacterial overgrowth
Short bowel syndrome can result in life-altering and even life-threating condition due to an inability to maintain nutrients, fluids, electrolyte, or micronutrient levels in the body. “It is a difficult condition for the affected person. Multiple complications also occur in the later course, including reduction in liver and pancreas function, sepsis, and mortality,” explains Dr Ranjan.
Intestinal adapts in short bowel syndrome
In the case of massive resection, the intestine displays remarkable adaptation, which is a chief determining factor for nutritional autonomy (no supplements required) of a person. “Adaptation is the normal response of the intestine, which improves the absorption of nutrients, water and electrolytes” says Dr Ranjan. It is mediated by various intestinal hormones and growth factors, which promote changes in the structure and function of remaining small bowel as well as colon to increase absorptive surface and capacity.
“Both small intestine and large intestine shows adaptation. In small intestine, the internal surface has finger like projections called as villi which increases the absorptive surface area of small intestine. During short bowel syndrome there is enlargement of the villi, thereby increasing overall absorptive area,” says Dr Ranjan.
Over time, the colon can start to adapt to the condition, increasing the amount of water and electrolytes it absorbs. In the presence of terminal ileum, colon compensates for the functions of small intestine. Moreover, it results in lower level of diarrhoea, adds Dr Ranjan.
With these adaptations, one can maintain the nutrients, fluids, and electrolyte balance for longer period of time. If the remaining bowel length is less than 100 centimetres then it is very difficult for anything to compensate, he cautions.
Management is multifaceted
Management of short bowel syndrome involves a number of measures depending upon the length of the small bowel left. This includes:
A diet and nutrient supplementation:
If the person has some portion of colon, then with adaptation and supplementation of nutrients, fluids, and electrolytes, his condition can be managed, says Dr Ranjan. Individuals are asked to have small frequent meals and oral rehydration solutions. They should follow a high calorie diet, followed by fat as tolerated, and adequate protein intake. Individuals require careful monitoring and replacement of micronutrients especially vitamins and minerals. In severe cases, nutrient, fluids, and electrolyte supplementation can be done via intravenous (IV) route also.
“We have seen persons having small intestine of even 150 centimetres doing well, due to adaptation and supportive nutrition,” says Dr Ranjan.
Antidiarrheal medications are used to reduce motility and increase transit time in the gut to facilitate absorption of fluids, and nutrients. Various trophic factors to increase the absorptive area of intestine and other adaptive changes are in different stages of clinical trials.
If the person cannot manage with shorter intestine, then intestinal transplant is also an option, says Dr Ranjan. However, high rejection rate of the intestinal graft remains a significant barrier in the long-term success of this approach. Moreover, the rate of intestinal donation is low, and it cannot be taken from a living person, he adds. Intestinal transplant is therefore reserved for the 10–15 per cent of individuals with chronic intestinal failure when the nutrition supplementation is inadequate.
“Very few intestine transplantations have been done. In our hospital, only one intestinal transplant [has been] done in the last 20 years and the person did not survive for very long. This is published as a first case of intestinal transplant in India,” says Dr Ranjan.
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