Malabsorption Syndrome

Malabsorption Syndrome
Malabsorption Syndrome

Malabsorption syndrome refers to a group of disorders in which the small intestine is unable to absorb essential nutrients. The symptoms of malabsorption syndrome vary from person to person, but usually, patients get diarrhea, bloating, distended stomach and weakness.

Food allergies like lactose intolerance and celiac disease, as well as certain genetic diseases and medicines, are among the known causes of malabsorption syndrome. Several tests are done to check for malabsorption syndrome in a patient. The treatment depends on the cause.

In the Indian adult population, tropical sprue and celiac disease are the most common causes of malabsorption syndrome.

Types of Malabsorption Syndrome

The basic function of the small intestine is to absorb essential nutrients from food into the bloodstream. At 20 feet long, the small intestine has three distinct sections. The first section, duodenum,  is where food from the stomach mixes with enzymes from the liver, pancreas and gallbladder. Next, muscle contractions or peristalsis push the food down to the second section known as the jejunum. The small intestine has multiple villi or folds to increase surface area - additionally, these folds have a “brush border” and enzymes to maximize absorption of nutrients from the food that is passing through. The third and final section, ileum, absorbs vitamin B12 and bile salts.

A disturbance in this complex process of digestion and absorption can potentially lead to malabsorption syndrome.

Broadly, malabsorption syndrome is of two types: global or complete malabsorption, in which the small intestine is unable to absorb most nutrients; and partial or isolated malabsorption, in which the absorption of a few specific nutrients is impaired.

Symptoms of Malabsorption Syndrome

Symptoms of malabsorption syndrome differ depending on the severity and duration of the disorder, as well as the nutrients which are not being absorbed - indeed, some symptoms of malabsorption syndrome are actually manifestations of these nutritional deficiencies.

Malabsorption of fats: 

  • Unabsorbed fats trap fat-soluble vitamins A, D, E, K and a few minerals, causing deficiencies of these vitamins and minerals
  • Unabsorbed bile salts stimulate water secretion in the colon, causing diarrhoea - the most common symptom of malabsorption
  • Steatorrhea or fatty stool is when a patient passes more than 7 grams of fat in their stool per day. The stool is usually foul-smelling, pale, bulky, and greasy

Malabsorption of carbohydrate:

  • Colon bacteria can ferment the unabsorbed carbohydrates, resulting in the formation of carbon dioxide, methane, hydrogen, and short-chain fatty acids (butyrate, propionate, acetate, and lactate)
  • These fatty acids cause diarrhoea
  • Accumulation of these gases in the gut cause abdominal distention and bloating

Malabsorption of protein:

  • Edema or water retention, and bloating


  • Anaemia - both hypochromic anaemia (in which the patient has low haemoglobin for any reason), and microcytic anaemia (in which the patient has fewer red blood cells which are also smaller than normal)

Vitamin B12 or folate:

  • Macrocytic anaemia, in which the patient has larger but fewer red blood cells and low overall haemoglobin 

Vitamin K and C:

Calcium and magnesium:

  • Carpopedal spasm, or spasms in hands and feets

Vitamins B2 and B12, folate, iron, niacin:

  • Glossitis, or tongue inflammation

Vitamin A:

Vitamin D and potassium, calcium and magnesium:

  • Pain in limbs, bones
  • Pathologic fractures

Vitamins B1, B6, B12:

Patients tend to lose significant amounts of weight, even when they are eating adequate portions of food.

Amenorrhoea, or missing menstrual periods, can occur in young women due to undernutrition. It is also a characteristic symptom of celiac disease.

Children with malabsorption syndrome stop growing, leading to dwarfism.

Causes of Malabsorption Syndrome

Malabsorption syndrome occurs due to underlying disorders or conditions such as:

Impaired digestion: People who have had gastric surgery - to remove a tumour or to lose unhealthy weight (bariatric surgery) - can have reduced surface area for digestion as well as absorption or damaged intestines. These can lead to malabsorption.

Infection: Acute bacterial, viral, and parasitic infections of the gut may cause transient malabsorption - or malabsorption as a result of temporary, superficial damage to the villi and microvilli. Some of the infections that can lead to malabsorption are:

  • Tropical sprue: A rare digestive disorder in which malabsorption of certain nutrients occur
  • Whipple's disease: A bacterial infection that affects the digestion and absorption of fats and carbohydrates
  • Acute infectious enteritis: Inflammation of the small intestine due to viral or bacterial infection
  • Giardia
  • AIDS
  • Helminthiasis: Caused by a range of parasitic worms like roundworms that are usually transmitted through the soil or contaminated food 

Reduced bile secretion: The liver produces bile - it contains cholesterol, bile acid, water, salts like potassium, minerals like copper and bilirubin (a product of the natural breakdown of red blood cells). Bile salts increase the solubilization of fats by forming micelle - neat spheres of fat that are easier to absorb. Conditions like liver cirrhosis can impact bile secretion. Other conditions that can impair bile secretion are: 

  • Liver disease
  • Bacterial overgrowth in the small intestine
  • Ileal disease or resection: Usually an inflammation in the final section of the small intestine, the ileum

Abnormalities of the intestinal mucosa: The intestinal mucosa (also known as the intestinal barrier) has epithelial cells that keep the digestive enzymes inside the small intestine while also aiding absorption. Abnormalities in this layer include:

  • Disaccharidase deficiency: Deficiency of enzymes that break down complex sugars like lactose in milk
  • Impaired monosaccharide transport: Where the absorption of glucose from the intestine is affected
  • Folate or cobalamin deficiency  
  • Nontropical sprue or celiac disease: An inflammatory condition in which the body is unable to tolerate gluten
  • Nongranulomatous ileojejunitis 
  • Amyloidosis: Build-up of amyloid protein that can lead to organ failure in severe cases
  • Crohn's disease: An inflammatory bowel disease
  • Eosinophilic gastroenteritis
  • Radiation enteritis 
  • Abetalipoproteinemia: A hereditary fat-absorption disorder
  • Cystinuria: A genetic disorder in which the patient is unable to reabsorb cystine (a protein) from the kidneys
  • Hartnup disease: a rare genetic disorder of protein metabolism

Inadequate surface for absorption  

  • Short bowel syndrome
  • Jejunoileal bypass: A weight-loss surgery that was popular in the 1970s, and that shortened the intestine from 20 meters to under 45 cm in most cases

Lymphatic obstruction 

  • Intestinal lymphoma 
  • Tuberculosis 
  • Lymphangiectasia: A disease in which the lymph vessels get dilated - it can lead to hypoproteinemia, or low levels of proteins in the blood, among other conditions

Cardiovascular disorders 

  • Congestive heart failure
  • Constrictive pericarditis: A rare condition in which the pericardium membrane around the heart becomes inflamed
  • Mesenteric vascular insufficiency: A condition in which blocked arteries reduce blood flow to the small intestine 

Drug-induced: Some drugs might also interfere with the process of digestion, like:

  • Cholestyramine usually prescribed to lower cholesterol levels 
  • Neomycin; antibiotics that are usually prescribed after intestine surgery
  • Colchicine is used to decrease uric acid build-up and swelling in gout
  • Phenindione, an anticoagulant
  • Irritant laxatives

Diagnosis of Malabsorption Syndrome

Your doctor will take a detailed medical history by asking questions about your bowel movements and characteristics, signs and symptoms, previous medical and surgical history. They may also ask about any family history of conditions like celiac disease - an autoimmune condition in which the body has a reaction to gluten.

Malabsorption is suspected in a patient with chronic diarrhoea, weight loss, and anaemia. Many a time, just by taking the patient history, the doctor is able to roughly identify the syndrome. For example, if a patient has celiac disease and complains of diarrhoea, mouth ulcers and fatigue, it is possible that they might have malabsorption syndrome. Or if they have a distended abdomen, excessive flatus (farting), and watery diarrhoea occurring 30 minutes to 90 minutes after eating carbs, it could suggest impaired digestion of carbohydrates.

Patient history is always accompanied by physical examination of the patient. A professional expert will check the abdomen for the severity of distention. An in-depth examination is done by running several tests in order to:

  • Detect malabsorption, identify its underlying cause, and evaluate the types and severity of nutrient deficiencies
  • Detect complications like anaemia
  • Monitor the effectiveness of treatment in people with malabsorption syndrome

A single test does not give all the details, therefore, your health care provider might ask you to get more than one test done in order to get to the root cause. The basic tests for this include:

  • Complete blood count (CBC) is done to detect the type of anaemia, and whether it is due to iron deficiency or vitamin B12 or folate deficiency
  • Comprehensive metabolic panel (CMP) is done to evaluate proteins and organ function, including the liver, and detect electrolyte imbalances
  • Prealbumin is a marker for protein malabsorption and indicates general nutritional status
  • Erythrocyte sedimentation rate (ESR) helps detect inflammation in the body, which may be caused by inflammatory bowel disease among other medical reasons
  • Fecal fat examination is done to detect decreased ability for fat digestion
  • Stool culture is done to detect bacterial infection in the gut
  • Clostridium difficile and Clostridium difficile toxin is done to detect bacterial overgrowth as it is one of the causes of persistent diarrhoea
  • Ova and parasite examination (O and P) is done to detect parasites - one of the causes of persistent diarrhoea
  • Stool white blood cells test is recommended for patients who have had severe diarrhoea for some days. It helps detect infection by bacteria such as Salmonella and Shigellosis and inflammatory bowel diseases like Crohn’s disease
  • Gastrointestinal pathogens panel is performed on a stool sample. It simultaneously tests for virus, bacteria and parasites that are common causative agents of digestive tract infections and diarrhoea

On the basis of results of basic tests, the patient’s symptoms, and the healthcare practitioner's suspicions, a few more tests can be done. These tests are also recommended for follow-up patients:

  • Fecal occult blood test is done to detect bleeding in the digestive tract
  • Vitamin B12, A, D test is done to detect deficiency of the respective vitamins
  • Prothrombin time test is done to check for vitamin K deficiency
  • Celiac disease test is done to elicit celiac disease as an underlying condition for malabsorption syndrome

There are a few more tests which are not done routinely for malabsorption syndrome but can be useful sometimes. These include:

  • Methylmalonic acid (MMA) test is done to detect vitamin B12 deficiency at an early stage
  • Hydrogen breath test is done to elicit lactose intolerance and bacterial overgrowth in the digestive system (seen in case of carbohydrate malabsorption)
  • Xylose absorption test helps to evaluate carbohydrate indigestion
  • Biopsy of the intestine

Another set of non-laboratory tests are performed for an examination of the digestive tract, liver and pancreas:

Treatment of Malabsorption Syndrome

Symptomatic treatment is done for managing malabsorption syndrome, starting with more common symptoms like diarrhoea.

Treatment might vary from individual to individual, as malabsorption syndrome can occur due to a wide range of underlying diseases or conditions. Addressing the underlying disease helps in limiting malabsorption to a large extent.

Your doctor might recommend a change in diet. For example, they may ask you to go gluten-free or lactose-free if you have celiac disease or lactose intolerance, respectively. It is a good idea to consult a dietician, to get a customised diet plan that helps you meet your daily requirement of nutrients.

Based on an evaluation of your diet plan, your doctor or dietician may also ask you to take supplements for vitamin B12, A, K, and C, as well as for minerals like iron, calcium, and magnesium supplements.

Certain enzymes like lactase are also available in pill form. Your doctor may prescribe these to restore the deficient enzyme and aid in the process of digestion. Your doctor may also prescribe medicines to induce appetite.


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