Malabsorption is a state arising from abnormality in absorption of food nutrients

Nutrient

A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...

 across the gastrointestinal (GI) tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

.

Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition

Malnutrition

Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

 and a variety of anaemias

Anemia

Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...

.

Classification

Some prefer to classify malabsorption clinically into three basic categories: selective, as seen in lactose malabsorption; partial, as observed in a-Beta-lipoproteinaemia, and total as in coeliac disease

Coeliac disease

Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward...

.

Pathophysiology

The main purpose of the gastrointestinal tract

Gastrointestinal tract

The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....

 is to digest

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

 and absorb nutrients (fat

Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...

, carbohydrate

Carbohydrate

A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...

, protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

, and fiber

Fiber

Fiber is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread.They are very important in the biology of both plants and animals, for holding tissues together....

), micronutrients (vitamin

Vitamin

A vitamin is an organic compound required as a nutrient in tiny amounts by an organism. In other words, an organic chemical compound is called a vitamin when it cannot be synthesized in sufficient quantities by an organism, and must be obtained from the diet. Thus, the term is conditional both on...

s and trace minerals

Dietary mineral

Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen present in common organic molecules. Examples of mineral elements include calcium, magnesium, potassium, sodium, zinc, and iodine...

), water, and electrolytes. Digestion

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

 involves both mechanical and enzymatic

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 breakdown of food. Mechanical processes include chewing, gastric churning, and the to-and-fro mixing in the small intestine

Small intestine

The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...

. Enzymatic hydrolysis is initiated by intraluminal processes requiring gastric, pancreatic, and biliary secretions. The final products of digestion are absorbed through the intestinal epithelial

Epithelium

Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...

 cells.

Malabsorption constitutes the pathological interference with the normal physiological sequence of digestion

Digestion

Digestion is the mechanical and chemical breakdown of food into smaller components that are more easily absorbed into a blood stream, for instance. Digestion is a form of catabolism: a breakdown of large food molecules to smaller ones....

 (intraluminal process), absorption (mucosal process) and transport (postmucosal events) of nutrients.

Intestinal

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

 malabsorption can be due to:

• Mucosal damage (enteropathy
  Enteropathy
  -Types:Specific types of enteropathy include:* Gluten-sensitive enteropathy * Hemorrhagic enteropathy* Protein-losing enteropathy* Porcine proliferative enteropathy * Radiation enteropathy...
  
  )
• Congenital
  Congenital disorder
  A congenital disorder, or congenital disease, is a condition existing at birth and often before birth, or that develops during the first month of life , regardless of causation...
  
   or acquired reduction in absorptive surface
• Defects of specific hydrolysis
  Hydrolysis
  Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
  
  
• Defects of ion
  Ion
  An ion is an atom or molecule in which the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge. The name was given by physicist Michael Faraday for the substances that allow a current to pass between electrodes in a...
  
   transport
• Pancreatic
  Pancreas
  The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
  
   insufficiency
• Impaired enterohepatic circulation
  Enterohepatic circulation
  Enterohepatic circulation refers to the circulation of biliary acids from the liver, where they are produced and secreted in the bile, to the small intestine, where it aids in digestion of fats and other substances, back to the liver....
  
  

Causes

Due to infective agents Whipple's disease Whipple's disease Whipple's disease is a rare, systemic infectious disease caused by the bacterium Tropheryma whipplei. First described by George Hoyt Whipple in 1907 and commonly considered a gastrointestinal disorder, Whipple's disease primarily causes malabsorption but may affect any part of the body including... Intestinal tuberculosis Tuberculosis Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body... HIV HIV Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...  related malabsorption Tropical sprue Tropical sprue Tropical sprue is a malabsorption disease commonly found in the tropical regions, marked with abnormal flattening of the villi and inflammation of the lining of the small intestine.It differs significantly from coeliac sprue.-Symptoms and signs:... traveller's diarrhoea Parasites Parasitism Parasitism is a type of symbiotic relationship between organisms of different species where one organism, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred to organisms with lifestages that needed more than one host . These are now called macroparasites...  e.g. Giardia lamblia Giardiasis Giardiasis or beaver fever in humans is a diarrheal infection of the small intestine by a single-celled organism Giardia lamblia. Giardiasis occurs worldwide with a prevalence of 20–30% in developing countries. In the U.S., 20,000 cases are reported to the CDC annually, but the true annual... , fish tape worm  (B12 malabsorption); roundworm Strongyloides stercoralis Strongyloides stercoralis, also known as the threadworm, is the scientific name of a human parasitic roundworm causing the disease of strongyloidiasis....  , hookworm Hookworm The hookworm is a parasitic nematode that lives in the small intestine of its host, which may be a mammal such as a dog, cat, or human. Two species of hookworms commonly infect humans, Ancylostoma duodenale and Necator americanus. A. duodenale predominates in the Middle East, North Africa, India...  (Ancylostoma duodenale and Necator americanus)

Due to structural defects Blind loops Blind loop syndrome Blind loop syndrome, also known as Stagnant loop syndrome, is a medical condition that occurs when the intestine is obstructed, slowing or stopping the progress of digested food, and thus facilitating the growth of bacteria to the point that problems in nutrient absorption occur.-Physiology:The... Inflammatory bowel diseases commonly in Crohn's Disease Crohn's disease Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms... Intestinal hurry from Post-gastrectomy Gastrectomy A gastrectomy is a partial or full surgical removal of the stomach.-Indications:Gastrectomies are performed to treat cancer and perforations of the stomach wall.... ; post-vagotomy Vagotomy A vagotomy is a surgical procedure that involves resection of the vagus nerve.-Applications:Truncal vagotomy is a treatment option for chronic duodenal ulcers... , gastro-jejunostomy Fistulae, diverticulae Diverticulum A diverticulum is medical or biological term for an outpouching of a hollow structure in the body. Depending upon which layers of the structure are involved, they are described as being either true or false....  and strictures, Infiltrative conditions such as amyloidosis Amyloidosis In medicine, amyloidosis refers to a variety of conditions whereby the body produces "bad proteins", denoted as amyloid proteins, which are abnormally deposited in organs and/or tissues and cause harm. A protein is described as being amyloid if, due to an alteration in its secondary structure, it... , lymphoma Lymphoma Lymphoma is a cancer in the lymphatic cells of the immune system. Typically, lymphomas present as a solid tumor of lymphoid cells. Treatment might involve chemotherapy and in some cases radiotherapy and/or bone marrow transplantation, and can be curable depending on the histology, type, and stage... , Eosinophilic gastroenteropathy Radiation enteritis Systemic sclerosis and collagen vascular diseases Short bowel syndrome Short bowel syndrome Short bowel syndrome is a malabsorption disorder caused by the surgical removal of the small intestine, or rarely due to the complete dysfunction of a large segment of bowel. Most cases are acquired, although some children are born with a congenital short bowel...

Due to mucosal abnormality Coeliac disease Coeliac disease Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward... Cows' milk intolerance Soya milk intolerance Fructose malabsorption Fructose malabsorption Fructose malabsorption, formerly named "dietary fructose intolerance," is a digestive disorder in which absorption of fructose is impaired by deficient fructose carriers in the small intestine's enterocytes. This results in an increased concentration of fructose in the entire intestine.Fructose...

Due to enzyme deficiencies Lactase deficiency inducing lactose intolerance Lactose intolerance Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...  (constitutional, secondary or rarely congenital) Sucrose intolerance Sucrose intolerance Sucrose intolerance, also called congenital sucrase-isomaltase deficiency or Sucrase-isomaltase deficiency, is the condition in which sucrase, an enzyme needed for proper metabolization of sucrose, is not produced in the small intestine.... Intestinal disaccharidase deficiency Intestinal enteropeptidase deficiency

Due to digestive failure Pancreatic insufficiencies: cystic fibrosis Cystic fibrosis Cystic fibrosis is a recessive genetic disease affecting most critically the lungs, and also the pancreas, liver, and intestine... chronic pancreatitis Chronic pancreatitis Chronic pancreatitis is a long-standing inflammation of the pancreas that alters its normal structure and functions. It can present as episodes of acute inflammation in a previously injured pancreas, or as chronic damage with persistent pain or malabsorption.... carcinoma of pancreas Zollinger-Ellison syndrome Zollinger-Ellison syndrome Zollinger–Ellison syndrome is a triad of gastric acid hypersecretion, severe peptic ulceration, and non-beta cell islet tumor of pancreas . In this syndrome increased levels of the hormone gastrin are produced, causing the stomach to produce excess hydrochloric acid. Often the cause is a tumor of... Bile salt malabsorption terminal ileal disease obstructive jaundice bacterial overgrowth primary bile acid diarrhea

Due to other systemic disease Systemic disease Life-threatening disease redirects here.A systemic disease is one that affects a number of organs and tissues, or affects the body as a whole. Although most medical conditions will eventually involve multiple organs in advanced stage Life-threatening disease redirects here.A systemic disease is one... s affecting GI tract Coeliac disease Coeliac disease Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward... Hypothyroidism Hypothyroidism Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...  and hyperthyroidism Hyperthyroidism Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous... Addison's disease Addison's disease Addison’s disease is a rare, chronic endocrine disorder in which the adrenal glands do not produce sufficient steroid hormones... Diabetes mellitus Diabetes mellitus Diabetes mellitus, often simply referred to as diabetes, is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced... Hyperparathyroidism Hyperparathyroidism Hyperparathyroidism is overactivity of the parathyroid glands resulting in excess production of parathyroid hormone . The parathyroid hormone regulates calcium and phosphate levels and helps to maintain these levels...  and Hypoparathyroidism Hypoparathyroidism Hypoparathyroidism is decreased function of the parathyroid glands with under production of parathyroid hormone. This can lead to low levels of calcium in the blood, often causing cramping and twitching of muscles or tetany , and several other symptoms... Carcinoid syndrome Carcinoid syndrome Carcinoid syndrome refers to the array of symptoms that occur secondary to carcinoid tumors. The syndrome includes flushing and diarrhea, and, less frequently, heart failure and bronchoconstriction... Malnutrition Fiber Deficiency Abeta-lipoproteinaemia Abetalipoproteinemia Abetalipoproteinemia, or Bassen-Kornzweig syndrome, is a rare autosomal recessive disorder that interferes with the normal absorption of fat and fat-soluble vitamins from food. It is caused by a deficiency of apolipoprotein B-48 and B-100, which are used in the synthesis and exportation of...

Clinical features

They can occur in a variety of ways and features might give a clue to the underlying condition. Symptoms can be intestinal

Intestine

In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...

 or extra-intestinal - the former predominates in severe malabsorption.

• Diarrhoea, often steatorrhoea is the most common feature. Watery, diurnal and nocturnal, bulky, frequent stools are the clinical hallmark of overt malabsorption. It is due to impaired water, carbohydrate
  Carbohydrate
  A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
  
   and electrolyte
  Electrolyte
  In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
  
   absorption or irritation from unabsorbed fatty acid
  Fatty acid
  In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
  
  . Latter also results in bloating
  Bloating
  Bloating is any abnormal general swelling, or increase in diameter of the abdominal area. As a symptom, the patient feels a full and tight abdomen, which may cause abdominal pain sometimes accompanied by increased borborygmus or more seriously the total lack of borborygmus.-Symptoms:The most common...
  
  , flatulence
  Flatulence
  Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestion process of mammals and other animals. The medical term for the mixture of gases is flatus, informally known as a fart, or simply gas...
  
   and abdominal discomfort. Cramping pain usually suggests obstructive intestinal segment e.g. in Crohn's disease
  Crohn's disease
  Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
  
  , especially if it persists after defecation.
• Weight loss can be significant despite increased oral intake of nutrients.
• Growth retardation, failure to thrive, delayed puberty
  Puberty
  Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...
  
   in children
• Swelling or oedema from loss of protein
  Protein
  Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
  
  
• Anaemias, commonly from vitamin B₁₂
  Vitamin B12
  Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...
  
  , folic acid
  Folic acid
  Folic acid and folate , as well as pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are forms of the water-soluble vitamin B9...
  
   and iron deficiency
  Iron deficiency (medicine)
  Iron deficiency is one of the most common of the nutritional deficiencies. Iron is present in all cells in the human body, and has several vital functions...
  
   presenting as fatigue and weakness.
• Muscle cramp
  Cramp
  Cramps are unpleasant, often painful sensations caused by muscle contraction or over shortening. Common causes of skeletal muscle cramps include muscle fatigue, low sodium, and low potassium...
  
   from decreased vitamin D
  Vitamin D
  Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
  
  , calcium
  Calcium
  Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
  
   absorption. Also lead to osteomalacia
  Osteomalacia
  Osteomalacia is the softening of the bones caused by defective bone mineralization secondary to inadequate amounts of available phosphorus and calcium, or because of overactive resorption of calcium from the bone as a result of hyperparathyroidism...
  
   and osteoporosis
  Osteoporosis
  Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
  
  
• Bleeding tendencies from vitamin K
  Vitamin K
  Vitamin K is a group of structurally similar, fat soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives...
  
   and other coagulation factor deficiencies.

Diagnosis

There is no specific test for malabsorption. As for most medical conditions, investigation is guided by symptom

Symptom

A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...

s and signs. A range of different conditions can produce malabsorption and it is necessary to look for each of these specifically. Many tests have been advocated, and some, such as tests for pancreatic function are complex, vary between centres and have not been widely adopted. However, better tests have become available with greater ease of use, better sensitivity and specificity for the causative conditions. Test are also needed to detect the systemic effects of deficiency of the malabsorbed nutrients (such as anaemia with vitamin B12 malabsorption).

Blood tests

• Routine blood test
  Blood test
  A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a needle, or via fingerprick....
  
  s may reveal anaemia, high ESR
  Erythrocyte sedimentation rate
  The erythrocyte sedimentation rate , also called a sedimentation rate or Biernacki Reaction, is the rate at which red blood cells sediment in a period of 1 hour...
  
   and CRP
  C-reactive protein
  C-reactive protein is a protein found in the blood, the levels of which rise in response to inflammation...
  
   or low albumin
  Serum albumin
  Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...
  
  ; which shows a high correlation for the presence of an organic disease. In this setting, microcytic anaemia
  Microcytic anemia
  Microcytic anemia is a generic term for any type of anemia characterized by small red blood cells. The normal mean corpuscular volume is 76-100 fL, with smaller cells as macrocytic....
  
   usually implies iron deficiency and macrocytosis
  Macrocytosis
  Macrocytosis is the enlargement of red blood cells with near-constant hemoglobin concentration, and is defined by a mean corpuscular volume of greater than 100 femtolitres .- Causes :...
  
   can be caused by impaired folic acid
  Folic acid
  Folic acid and folate , as well as pteroyl-L-glutamic acid, pteroyl-L-glutamate, and pteroylmonoglutamic acid are forms of the water-soluble vitamin B9...
  
   or B12
  Vitamin B12
  Vitamin B12, vitamin B12 or vitamin B-12, also called cobalamin, is a water-soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins...
  
   absorption or both. Low cholesterol or triglyceride may give a clue toward fat malabsorption as low calcium and phosphate toward osteomalacia
  Osteomalacia
  Osteomalacia is the softening of the bones caused by defective bone mineralization secondary to inadequate amounts of available phosphorus and calcium, or because of overactive resorption of calcium from the bone as a result of hyperparathyroidism...
  
   from low vitamin D.
• Specific vitamins like vitamin D
  Vitamin D
  Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
  
   or micro nutrient like zinc
  Zinc
  Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
  
   levels can be checked. Fat soluble vitamins (A, D, E & K) are affected in fat malabsorption. Prolonged prothrombin time
  Prothrombin time
  The prothrombin time and its derived measures of prothrombin ratio and international normalized ratio are measures of the extrinsic pathway of coagulation. This test is also called "ProTime INR" and "INR PT". They are used to determine the clotting tendency of blood, in the measure of warfarin...
  
   can be caused by vitamin K
  Vitamin K
  Vitamin K is a group of structurally similar, fat soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives...
  
   deficiency.
• Serological studies

Specific tests are carried out to determine the underlying cause.

IgA

IGA

Iga or IGA may stand for:-Given name:* a female given name of Polish origin. The name originates from the female given name Jadwiga and stands for gia,or gina in the USA....

 Anti-transglutaminase antibodies

Anti-transglutaminase antibodies

Anti-transglutaminase antibodies are autoantibodies against the transglutaminase protein. Antibodies serve an important role in the immune system by detecting cells and substances that the rest of the immune system then eliminates. These cells and substance can be foreign and also can be producd...

 or IgA Anti-endomysial antibodies for Coeliac disease

Coeliac disease

Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward...

(gluten sensitive enteropathy).

Stool studies

• Microscopy is particularly useful in diarrhoea, may show protozoa like Giardia, ova, cyst and other infective agents.
• Fecal fat study
  Fecal fat
  In medicine, the fecal fat test is a diagnostic test for fat malabsorption conditions, which lead to excess fat in the feces .-Background:...
  
   to diagnose steatorrhoea is rarely performed nowadays.
• Low fecal pancreatic elastase
  Elastase
  In molecular biology, elastase is an enzyme from the class of proteases that break down proteins.- Forms and classification:There exist eight human genes for elastase:Bacterial forms: Organisms such as P...
  
   is indicative of pancreatic insufficiency. Chymotrypsin
  Chymotrypsin
  Chymotrypsin is a digestive enzyme that can perform proteolysis. Chymotrypsin preferentially cleaves peptide amide bonds where the carboxyl side of the amide bond is a tyrosine, tryptophan, or phenylalanine. These amino acids contain an aromatic ring in their sidechain that fits into a...
  
   and pancreolauryl can be assessed as well

Radiological studies

• Barium follow through is useful in delineating small intestinal
  Small intestine
  The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
  
   anatomy
  Anatomy
  Anatomy is a branch of biology and medicine that is the consideration of the structure of living things. It is a general term that includes human anatomy, animal anatomy , and plant anatomy...
  
  . Barium enema
  Barium enema
  A lower gastrointestinal series, also called a barium enema, is a medical procedure used to examine and diagnose problems with the human colon . X-ray pictures are taken while barium sulfate fills the colon via the rectum.-Procedure:...
  
   may be undertaken to see colon
  Colon (anatomy)
  The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
  
  ic or ileal lesion
  Lesion
  A lesion is any abnormality in the tissue of an organism , usually caused by disease or trauma. Lesion is derived from the Latin word laesio which means injury.- Types :...
  
  s.
• CT abdomen is useful in ruling out structural abnormality, done in pancreatic protocol when visualising pancreas
  Pancreas
  The pancreas is a gland organ in the digestive and endocrine system of vertebrates. It is both an endocrine gland producing several important hormones, including insulin, glucagon, and somatostatin, as well as a digestive organ, secreting pancreatic juice containing digestive enzymes that assist...
  
  .
• Magnetic resonance cholangiopancreatography
  Magnetic resonance cholangiopancreatography
  Magnetic resonance cholangiopancreatography is a medical imaging technique that uses magnetic resonance imaging to visualise the biliary and pancreatic ducts in a non-invasive manner...
  
   (MRCP) to complement or as an alternative to ERCP

Interventional studies

• OGD
  OGD
  OGD is a three-letter initialism with the following meanings:* Open Government Data * The British medical abbreviation for oesophagogastroduodenoscopy, a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract up to the duodenum.* The IATA airport code for...
  
   to detect duodenal
  Duodenum
  The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms anterior intestine or proximal intestine may be used instead of duodenum...
  
   pathology and obtain D2 biopsy
  Biopsy
  A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
  
   (for coeliac disease
  Coeliac disease
  Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward...
  
  , tropical sprue
  Tropical sprue
  Tropical sprue is a malabsorption disease commonly found in the tropical regions, marked with abnormal flattening of the villi and inflammation of the lining of the small intestine.It differs significantly from coeliac sprue.-Symptoms and signs:...
  
  , Whipple's disease
  Whipple's disease
  Whipple's disease is a rare, systemic infectious disease caused by the bacterium Tropheryma whipplei. First described by George Hoyt Whipple in 1907 and commonly considered a gastrointestinal disorder, Whipple's disease primarily causes malabsorption but may affect any part of the body including...
  
  , abetalipoproteinaemia etc.)
• Enteroscopy
  Enteroscopy
  Enteroscopy is the procedure of using an enteroscope for the direct visualization of small bowel.*video chip endoscope**Double-balloon enteroscopy**Single-balloon enteroscopy**Spiral enteroscopy*wireless endoscopy system**Capsule endoscopy...
  
   for enteropathy and jejunal
  Jejunum
  The jejunum is the middle section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear and the terms middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...
  
   aspirate and culture
  Cell culture
  Cell culture is the complex process by which cells are grown under controlled conditions. In practice, the term "cell culture" has come to refer to the culturing of cells derived from singlecellular eukaryotes, especially animal cells. However, there are also cultures of plants, fungi and microbes,...
  
   for bacteria
  Bacteria
  Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
  
  l overgrowth
• Capsule Endoscopy
  Capsule endoscopy
  Capsule endoscopy is a way to record images of the digestive tract for use in medicine. The capsule is the size and shape of a pill and contains a tiny camera. After a patient swallows the capsule, it takes pictures of the inside of the gastrointestinal tract...
  
   is able to visualise the whole small intestine
  Small intestine
  The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
  
   and is occasionally useful.
• Colonoscopy
  Colonoscopy
  Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
  
   is necessary in colonic and ileal disease.
• ERCP will show pancreatic and biliary structural abnormalities.

Other investigations

• ⁷⁵SeHCAT
  SeHCAT
  SeHCAT is the usual name for 23-seleno-25-homo-tauro-cholic acid . It is used in a clinical test to diagnose bile acid malabsorption.-Development:...
  
   test to diagnose bile acid malabsorption
  Bile acid malabsorption
  Bile acid malabsorption is a cause of chronic diarrhea. It can result from malabsorption secondary to gastro-intestinal disease or be a primary disorder. Treatment with bile acid sequestrants is often effective.-Classification:...
  
   in ileal disease or primary bile acid diarrhea.
• Glucose hydrogen breath test for bacterial overgrowth
• Lactose
  Lactose
  Lactose is a disaccharide sugar that is found most notably in milk and is formed from galactose and glucose. Lactose makes up around 2~8% of milk , although the amount varies among species and individuals. It is extracted from sweet or sour whey. The name comes from or , the Latin word for milk,...
  
   hydrogen breath test for lactose intolerance
  Lactose intolerance
  Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...
  
  
• Sugar probes or ⁵¹Cr-EDTA to determine intestinal permeability.

Obsolete tests no longer used clinically

• D-xylose absorption test for mucosal disease or bacterial overgrowth. Normal in pancreatic insufficiency.
• Bile salt breath test (¹⁴C-glycocholate) to determine bile salt malabsorption.
• Schilling test
  Schilling test
  The Schilling test is a medical investigation used for patients with vitamin B deficiency. The purpose of the test is to determine whether the patient has pernicious anemia.It is named for Robert F. Schilling.-Process:The Schilling test has multiple stages...
  
   to establish cause of B₁₂ deficiency.

Management

Treatment is directed largely towards management of underlying cause:

• Replacement of nutrients, electrolyte
  Electrolyte
  In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
  
  s and fluid may be necessary. In severe deficiency, hospital admission may be required for parenteral administration, often advice from dietitian
  Dietitian
  Dietitians supervise the preparation and service of food, develop modified diets, participate in research, and educate individuals and groups on good nutritional habits. The goals of dietitians are to provide medical nutritional intervention, and to obtain, safely prepare, serve and advise on...
  
   is sought. People whose absorptive surface are severely limited from disease or surgery may need long term total parenteral nutrition
  Total parenteral nutrition
  Parenteral nutrition is feeding a person intravenously, bypassing the usual process of eating and digestion. The person receives nutritional formulae that contain nutrients such as glucose, amino acids, lipids and added vitamins and dietary minerals...
  
  .
• Pancreatic enzymes are supplemented orally in insufficiencies.
• Dietary modification is important in some conditions:
  • Gluten-free diet in coeliac disease
    Coeliac disease
    Coeliac disease , is an autoimmune disorder of the small intestine that occurs in genetically predisposed people of all ages from middle infancy onward...
    
    .
  • Lactose avoidance in lactose intolerance
    Lactose intolerance
    Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...
    
    .
• Antibiotic
  Antibiotic
  An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
  
   therapy will treat Small Bowel Bacterial overgrowth.
• Cholestyramine
  Cholestyramine
  Cholestyramine or colestyramine is a bile acid sequestrant, which binds bile in the gastrointestinal tract to prevent its reabsorption. It is a strong ion exchange resin, which means that it can exchange its chloride anions with anionic bile acids in the gastrointestinal tract and bind them...
  
   or other bile acid sequestrants will help reducing diarrhoea in bile acid malabsorption
  Bile acid malabsorption
  Bile acid malabsorption is a cause of chronic diarrhea. It can result from malabsorption secondary to gastro-intestinal disease or be a primary disorder. Treatment with bile acid sequestrants is often effective.-Classification:...
  
  .

External links

• Practice guideline from World Gastroenterology Organisation
• Tests for malabsorption; from British Society for Gastroenterology (2003)