Diarrhea After a Surgery – Diet and Treatment

Diarrhea from Bowel Surgery

An abdominal (or other) surgery may trigger irritable bowel syndrome (IBS), derange the normal gut flora or cause a bowel infection, all of which may result in diarrhea.

Dumping Syndrome (Rapid Gastric Emptying)

Within 6 months after a partial or complete surgical removal of the stomach or damage of its exit (pylorus), rapid stomach emptying may develop: undigested food from the stomach quickly entering the duodenum may drag water from the intestinal vessels into the intestinal hollow and 10-60 minutes after a meal the following symptoms may appear: nausea, vomiting, abdominal cramps, diarrhea, dizziness and rapid heartbeat.

After 1.5-4 hours, some of affected persons may experience anxiety, weakness, tremor or hunger, supposedly due to drop of blood glucose by the following mechanism: a load of glucose, suddenly coming from the stomach, is quickly absorbed from the small intestine into the blood; this triggers release of large amount of insulin that enables glucose to enter into body cells, resulting in a rapid fall of blood glucose.

Patients who start to avoid eating in a fear of symptoms, may start to lose weight.

Patients with diabetes, gastric reflux or those who take a drug metoclopramide may be of greater risk to develop dumping syndrome (1).

Diagnosis can be made from symptoms and a stomach emptying test.

Prevention of Dumping Syndrome

  • Diet: avoiding fructose, lactose and FODMAPs and having solid meals may prevent symptoms.
  • Lying down after a meal may slow down gastric emptying.
  • Drugs: pectin or guar gum increase viscosity of ingested food and thus slow down gastric emptying; acarbose slows down glucose absorption thus preventing huge insulin release and resulting hypoglycemia; octreoide slows down intestinal transit.
  • Surgery: reconstruction of pylorus or inserting of ‘reverse peristalsis’ intestinal segments does not always give satisfying results (2).


In most cases, a disorder improves on its own within several months.

Short Bowel Syndrome (SBS)

A reduced absorptive surface after surgical removal of a part of the small intestine, or due to other disorder like Crohn’s disease, may result in chronic diarrhea, fatigue and weight loss, a condition known as short bowel syndrome (SBS). Complications are dehydration, electrolyte imbalance, malnutrition and bile and kidney stones.

50% loss of the small intestinal length is usually well tolerated; in 50-75% loss, a special diet is needed; if more than 75% of the small intestine is lost, long term total parenteral nutrition (TPN, given intravenously) is usually required. Loss of the jejunum is usually tolerated well, since the remaining ileum may adapt (absorptive villi increase in size and amount); the adapting process may take up to 2 years. Loss of the ileum (the main site of bile acids and vitamin B12 absorption) can not be compensated, though. If bile acids can not be absorbed, fats and fat soluble vitamins (A, D, E, K) can not be absorbed and will be lost with the stool. If the valve betwen the small and large intestine ( ileocecal valve) is removed, colonic bacteria might invade the small intestine and cause diarrhea.

Removal of the colon does not have much impact on nutrients absorption.

How Is SBS Diagnosed?

History of intestinal disease or surgery and diarrhea, blood tests revealing deficiency of minerals and vitamins A, D, E and K, and stool tests revealing increased amount of sugars and proteins speak for SBS. Indirect calorimetry and a hydrogen breath test are used to evaluate extent of malabsorption (3,4).

Therapy of SBS

  • Diet: After extensive intestinal resection, total parenteral nutrition (TNP) is required to allow the remaining bowel to heal. Later, an enteral nutrition with an elemental diet (preparations of essential amino acids, carbohydrates, fats and electrolytes), which can be easily digested, is introduced through nasogastric tube (since it is unpalatable). An early start of enteral feeding is needed to ensure a successful adaptation of the intestine. Oral feeding with small portions of low-fat products may follow. A fairly normal diet can be achieved in many patients, but some of them will need long term or permanent total parenteral nutrition.
  • Supplements: vitamin B12 and other vitamins and minerals and digestive enzymes may be required.
  • Drugs: Cholestyramine binds unabsorbed bile acids thus preventing them to irritate the colonic wall. In severe diarrhea, octreotide, which suppresses secretion of gastric and pancreatic juice, can be used. Anti-acid drugs are often needed. Antibiotics are used in small intestinal bacterial overgrowth.
  • Surgery: Several operating techniques are available to artificially prolong the remaining small intestine or to slow down intestinal transit time and thus enhance absorption. Transplantation of the small intestine (and eventually damaged liver) is reserved for patients in whom re-establishing of oral feeding was not successful.

Diarrhea After Colon Removal

After a partial or complete colon removal, chronic diarrhea may occur because feces, when leaving the small intestine, is still quite watery. Diarrhea may improve in several weeks or months after colectomy as the small intestine adapts and can absorb more water. Diet with bland foods, such as bread, rice, polenta or pasta, should be tried; raw fruits and vegetables, sauces and spicy foods should be avoided. Fluid, lost with diarrhea should be replaced; sport drinks containing sodium, which promotes water absorption, may be appropriate (5). Loperamide may postpone diarrhea for several hours, but this drug is not for a long term use.

Related Articles:


  1. Dumping syndrome – treatment of diarrhea  (treatment-options.com)
  2. Dumping syndrome risk factors  (mayoclinic.com)
  3. Indirect calorimetry to evaluate absorption in SBS  (korr.com)
  4. Breath test for SBS  (nih.gov)
  5. Diet after colon removal  (med.umich.edu)
About Jan Modric (209 Articles)
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