CLINICAL
SHORT BOWEL SYNDROME
Rebecca Gasche Specialist Dietitian, Countess of Chester Hospital NHS Trust Rebecca has a keen interest and specialises in gastroenterology dietetics. She currently works in the community setting in the Chester area, running clinics and group sessions to manage a wide range of gastroenterology conditions.
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Short bowel syndrome (SBS), where a patient is left with a shortened length of bowel following surgery, is a rare but serious condition. It can leave patients with chronic malabsorption and carries a number of nutritional consequences.1 It is important that healthcare professionals understand the causes, complications and management of SBS, so that the correct advice is provided for this patient group. To understand SBS we should first understand the bowel itself. The bowel consists of the large and small intestine. The large bowel (colon) consists of the caecum, ascending colon, transverse colon, descending colon, sigmoid colon and rectum, and its functions include: the absorption of water, electrolytes, short-chain fatty acids, moving colonic contents towards the rectum and eventually, defaecation.2 The small intestine consists of the duodenum, jejunum and ileum. The average length of the small intestine is 6.9m, with a surface area of 200-500m, due to the addition of mucosal folds, villi and microvilli.3 Its main functions are to complete digestion of food and absorb fluid, electrolytes and nutrients. 90% of fluid from oral and exocrine secretions is absorbed in the small intestine.2 WHAT IS SBS?
SBS can be defined as the inability to maintain protein-energy, fluid, electrolyte, or micronutrient balances, when on a normal diet, as a result of said occurrences4 and is classified if a patient has less than 200cm left of their small intestine.5 Conditions which may lead to SBS include: • Crohn’s disease (a form of inflammatory bowel disease); • volvulus (twisting of the intestine, which cuts off blood flow); • intestinal ischemia (lack of flow to blood vessels in the intestine); 24
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• birth defects, including: necrotizing enterocolitis (NEC – inflammation/ infection that damages bowel tissue in premature infants), intestinal atresia (where the intestines have not been formed correctly), gastroschisis (intestines develop outside of the body); • surgeries/treatments, such as surgery to remove cancer, radiotherapy, bariatric surgery complications, or traumatic injury.1 SBS may result in patients having anastomosis (where the parts of the intestine are reconnected after the diseased portion is removed), or a stoma (where the end of the intestine is brought to the abdomen to allow waste products into the stoma bag attached). The surgeries that result in <200cm small bowel and, therefore, SBS, are jejunocolonic anastomosis (where the jejunum is reconnected to the colon – see Figure 1), end jejunostomy (jejunum is brought to the abdomen and a stoma is formed – see Figure 2) and jejunoileal anastomosis (parts of the jejunum and ileum are removed and the intestines reconnected – see Figure 3).5 COMPLICATIONS OF SBS
The main nutritional consequence of SBS is the ability to maintain fluid and electrolyte balances. For patients with parts of the jejunum and ileum removed, digestive and absorption function is significantly reduced, and
CLINICAL for those with the colon also removed, additional fluids and electrolytes will be lost.6 Other complications may include: • vitamin and mineral deficiencies; • small intestine bacterial overgrowth (SIBO); • kidney stones (due to reduced absorption or calcium, fats and bile salts); • acidosis (as a result of undigested carbohydrates in the large intestine producing lactic acid); • nausea and vomiting.
Figure 1: Jejunocolic anastomosis
For patients who require parenteral nutrition (PN), this comes with its own risks, such as bloodstream infections or liver/kidney problems.1
FLUID AND ELECTROLYTE BALANCE MANAGEMENT
To help manage fluid and electrolyte balance, fluid restrictions and rehydration solutions can be used. The ESPEN guidelines recommend that those who have borderline dehydration, or sodium depletion, use a sodium oral rehydration solution to replace stoma sodium losses, as well as restricting hypotonic fluids (water, tea, coffee, or alcohol). The addition of salt to meals may also help with sodium levels.5 Evidence suggests that restricting hypotonic fluids to <1500ml per day can reduce intestinal losses by 23%,7 and that including an oral rehydration solution containing 90mmol/L sodium, 20g glucose, 3.5g sodium chloride and 2.5g of sodium bicarbonate, is advised.4
Figure 2: End-jejunostomy
Figure 3: Jejunoileal anastomosis
NUTRITIONAL MANAGEMENT
Patients with SBS may have a normal diet, or use enteral nutrition or PN to supplement this, or as their sole nutrition source. The length of bowel remaining and area of resection often dictates which nutritional support is required: • 100-200cm small intestine may be managed with oral diet and fluid management. • <100cm jejunum requires long-term parenteral fluid and electrolyte replacement. • <75cm requires long-term PN, fluid and electrolyte replacement. • <50cm jejunum plus colon requires longterm total parenteral nutrition (TPN), fluid and electrolyte replacement.8 www.NHDmag.com May 2019 - Issue 144
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CLINICAL Table 1: Vitamin and mineral supplements for patients with short bowel syndrome12 Vitamin A
10,000-50,000 units daily
Vitamin B12
300g subcutaneously monthly for those with terminal ileal resection/disease
Vitamin C
200-500mg
Vitamin D
1600 units DHT daily; may require 25-OHor 1,23 (OH2)-D3
Vitamin E
30 IU daily
Vitamin K
10mg weekly
Iron
As needed
Selenium
6-100g daily
Zinc
220-440mg daily
Bicarbonate
As needed
Table 2: Recommendations to aid digestion for patients with SBS1 Chew all food thoroughly: • Try for about 40 chews per bite Eat smaller meals more often: • Up to six to eight smaller meals each day • Space each meal out over the course of the day • Eat the most nutritious foods first
Studies suggest that as patients with SBS lack areas of absorption, their total energy and protein intake is around two thirds of their oral energy and protein intake. For this reason, a diet which compensates for this is recommended: 3060kcal/kg/day and 0.2-0.25gN2/kg/day.5,9-11 Polymeric feed is recommended for those being enterally fed, as it has been suggested that nutrient absorption is similar when compared with elemental feeds, but are generally better tolerated, less costly and may better enhance intestinal adaption.5 For patients with a preserved colon, a diet higher in complex carbohydrates and lower in fat, but including medium-chain triglycerides, may be of benefit. However, deficiencies in fat soluble vitamins A, D, E and K and fatty acids should be monitored. For patients without a colon, the fat:carbohydrate ratio is deemed to have less importance.5 The addition of soluble fibre to enhance intestinal absorption is not recommended, neither is removal of lactose unless a lactose intolerance has been confirmed. The ESPEN guidelines also document that dietary management should be guided by a dietitian who is an expert in this field.5 26
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Limit fluids with meals: • Drink half a glass of fluid (4oz) or less at each meal • Stick with isotonic beverages, like oral rehydration solutions Separate solids and liquids at meals: • Eat solid foods first, as they slow down digestion
Each patient’s dietary advice will vary, depending on their initial diagnosis, exact surgery and symptoms following this. However, the recommendations in Table 2 may help to aid digestion on a general basis for patients with SBS. ONS/MICRONUTRIENTS
A patient’s ability to absorb nutrients will also depend on how much of their small bowel is remaining and if their colon has been removed or not. Most nutrients are absorbed in the first 100-150cm of the small intestine (except for bile acids and B12, which are absorbed in the terminal ileum). As a result, there is evidence that patients with SBS experience a high prevalence of micronutrient deficiencies.2 Supplementation of micronutrients, often over the recommended dose, is required to manage this. The American Gastroenterology Association published ‘rough’ guidelines for vitamin and mineral supplements for patients with SBS (see Table 1).12 The ESPEN guidelines suggest that clinical signs and symptoms, as well as biochemical measures of trace element deficiency (or
CLINICAL
The management of patients with SBS is complex and needs to be adapted on an individual basis depending on initial diagnosis, length of bowel removed and area of resection. toxicity), be regularly evaluated, and that baseline serum trace element concentrations be measured at the onset of home parenteral nutrition (HPN), followed up at least once per year. It is also noted that trace element doses should be adjusted as needed, and that the route of trace element supplementation should be selected according to the characteristics of the individual patient.5 PHARMACOLOGICAL
Medications are often required for patients with SBS to help manage symptoms, slow transit time and, therefore, improve nutrient absorption. The use of H2-receptor antagonists, or proton pump inhibitors, may be used to reduce faecal wet weight and sodium excretion. This is especially useful during the first six months after surgery, mainly for patients with a faecal output exceeding 2L/day. They may also be prescribed for long-term management.5 Examples of these medications, which are often used in this patient group, include omeprazole and ranitidine.13 Antimotility medications can be used to increase gut transit time, therefore decreasing intestinal output and reducing nutritional losses.14 The most commonly used medication is loperamide hydrochloride, which may be given in higher than recommended doses and often in conjunction with codeine phosphate.15 For patients with an intact colon, but <100cm of their jejunum remaining, cholestyramine may be prescribed to bind to unabsorbed bile acids which may be contributing to symptoms of
diarrhoea. In addition to this, supplements to replace vitamin/mineral deficiencies may be prescribed.15 PSYCHOLOGICAL
I think it is important to mention the psychological impact SBS may have on patients. Extensive surgery and often long hospital admissions, followed by potentially long-term enteral or parenteral feeding is a huge life change for anyone and may have psychological impacts. As well as managing medical/nutritional requirements, healthcare professionals should be aware of this and ensure that they are listening to patientsâ&#x20AC;&#x2122; concerns, ensuring they can signpost to suitable support groups and counselling, as well as wider charities such as the Short Bowel Syndrome Foundation16 and MIND.17 CONCLUSION
The management of patients with SBS is complex and needs to be adapted on an individual basis depending on initial diagnosis, length of bowel removed and area of resection. Particular attention should be made to managing fluid and electrolytes, especially initially after surgery. Often patients are fed enterally or parenterally, and for those consuming orally, a high calorie diet should be advised. Ongoing review of micronutrient deficiencies is recommended, as well as medications to help manage symptoms. All these measures highlight the importance of a multidisciplinary team approach in managing patients with SBS â&#x20AC;&#x201C; surgeons, pharmacists, stoma nurses and dietitians all play vital roles. www.NHDmag.com May 2019 - Issue 144
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