Malabsorption

Malabsorption
Whipple's disease: Alcian blue with apparently eosin counterstain enlarged villus with many macrophages
Specialty	Gastroenterology
Complications	Malnutrition; anaemia; steatorrhoea; diarrhoea
Causes	Coeliac disease; short bowel syndrome; lactase deficiency; exocrine pancreatic insufficiency; small intestinal bacterial overgrowth; Whipple's disease; genetic diseases; certain medications[1]
Treatment	Depends on cause

Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety of anaemias.^[1]

Normally the human gastrointestinal tract digests and absorbs dietary nutrients with remarkable efficiency. A typical Western diet ingested by an adult in one day includes approximately 100 g of fat, 400 g of carbohydrate, 100 g of protein, 2 L of fluid, and the required sodium, potassium, chloride, calcium, vitamins, and other elements. ^{[citation needed]} Salivary, gastric, intestinal, hepatic, and pancreatic secretions add an additional 7–8 L of protein-, lipid-, and electrolyte-containing fluid to intestinal contents. This massive load is reduced by the small and large intestines to less than 200 g of stool that contains less than 8 g of fat, 1–2 g of nitrogen, and less than 20 mmol each of Na⁺, K⁺, Cl^–, HCO₃^–, Ca²⁺, or Mg²⁺.

If there is impairment of any of the many steps involved in the complex process of nutrient digestion and absorption, intestinal malabsorption may ensue. If the abnormality involves a single step in the absorptive process, as in primary lactase deficiency, or if the disease process is limited to the very proximal small intestine, then selective malabsorption of only a single nutrient may occur. However, generalized malabsorption of multiple dietary nutrients develops when the disease process is extensive, thus disturbing several digestive and absorptive processes, as occurs in coeliac disease with extensive involvement of the small intestine.^[1]