Short bowel syndrome (SBS) is a malabsorption disorder, which occurs due to a resection of a large amount and/or functionally significant part of the small intestine. The extent of the clinical appearance depends firstly on the length of the remaining intestine and secondly on the location of the resection.
SBS in adults is significantly different from SBS in children. For example, just 40cm of small intestine will be enough for an infant to survive without the need for long-term parenteral nutrition. With an ileocecal valve, even 15 cm will be sufficient.
Adults with SBS may require long-term parenteral nutrition if less than 70cm of the small intestine remains (< 20% of the normal length).
Due to lack of precise data, it is estimated that there is a prevalence of 1 to 3:100,000 inhabitants. According to estimates, there are an additional approx. two to five suffers per 1 million inhabitants each year, with the trend increasing. These estimations are based on figures from home parenteral nutrition, of which 35% is for short bowel patients.
The most frequent causes which lead to the resection of parts of the small intestine in adults include Crohn's disease and disorders of the intestinal blood flow and intestinal volvulus. For children, in particular newborn babies, the main reasons are gastrointestinal malformations, intestinal ischemia and necrotising enterocolitis with 3–5 newborn babies/1000 births suffering from SBS. There is a significant quantity of trauma-related intestinal necroses.
Clinically, short bowel syndrome is expressed as global malabsorption syndrome, the symptoms and characteristics of which are determined by the extent and location of the resection, the underlying condition and the time since the operation (adaptation phases).
Rapid weight loss, diarrhoea with and without steatorrhoea, vitamin deficiency states (including A, D, E, K, folic acid, B12) and a deficiency of trace elements (including zinc, manganese, selenium) are classic manifestations of the syndrome.
Malabsorption has the following effects: weight loss, neuromuscular problems (tetany), osteopathy (calcium metabolism disorders), haemorrhagic diathesis, anemia, gallstone formation and oxalate stone formation. Various nutrients may be affected by malabsorption depending on the location of the resection. In the event of duodenal resection, iron, calcium, magnesium and folic acid deficiencies will occur. If the jejunum has been operatively removed, the water, electrolyte and nutrient absorption will be reduced. In the event of an ileum resection, there will be vitamin B12 deficiency and bile acid loss. The ileum can carry out the function of the jejunum, but the reverse is not true.
Maldigestion occurs as a result of disrupted fat emulsification due to bile acid loss in the event of ileum resection (decompensated bile acid loss syndrome), due to a deconjugation of bile acids e.g. in the event of abnormal bacterial colonisation and as a result of the short time that the chyme is in the small intestine. Maldigestion is expressed, for example, in the form of chologenous diarrhoea (e.g. in the case of bile resorption problems) and steatorrhoea
The treatment depends on the post-operative phase and the stage of the condition, the ability of the remaining intestine to adapt and any possible accompanying conditions.
Short bowel syndrome can be differentiated into the following phases: hypersecretion phase (up to three months), adaptation (3–12 months) and stabilisation.
In the hypersecretion phase, it is advisable to use parenteral nutrition and additional medical treatment (acid blockage, restriction of intestinal motility). This form of nutrition should be carried out for as little time as possible, but for as long as necessary.
In the adaptation phase, the parenteral nutrition should be gradually overlapped with enteral nutrition (dual nutrition). It is advisable to use oligopeptide diets and supplements.
Finally, an attempt must be started to transition to an oral diet, which will initially include 6–8 smaller meals per day. In order to avoid volume loads, fluid intake should not be carried out at the same time as the food supply, but instead between meals (approx. 1 hour apart). High-energy and nutrient-rich meals and snacks should be used with nutritional supplements if necessary.
From a remaining length of around 60 cm, formula diets can be started and then there can be a transition to a light balanced diet. Around 50–70% of the fat requirement should be covered with MCT fats. It is important that foods rich in oxalic acid (e.g. spinach, beetroot, chard, cocoa) are avoided. Complex carbohydrates should be chosen over monosaccharides.
In the event of resection of the terminal ileum, it must be ensured that there is sufficient parenteral supply of vitamin B12. The supply of fat-soluble vitamins and calcium, magnesium and zinc must be regularly checked in order to react quickly with the administration of supplements if deficiencies occur.