Diarrhea, also spelled diarrhoea or diarrhœa, is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin with loss of the normal stretchiness of the skin and irritable behaviour. This can progress to decreased urination, loss of skin color, a fast heart rate, and a decrease in responsiveness as it becomes more severe. Loose but non-watery stools in babies who are exclusively breastfed, however, are normal.
Lactose intolerance is caused by a lessened ability or a complete inability to digest lactose, a sugar found in dairy products. Humans vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pain, bloating, diarrhea, flatulence, and nausea. These symptoms typically start thirty minutes to two hours after eating or drinking something containing lactose, with the severity typically depending on the amount consumed. Lactose intolerance does not cause damage to the gastrointestinal tract.
Coeliac disease or celiac disease is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barley. Classic symptoms include gastrointestinal problems such as chronic diarrhoea, abdominal distention, malabsorption, loss of appetite, and among children failure to grow normally. Non-classic symptoms are more common, especially in people older than two years. There may be mild or absent gastrointestinal symptoms, a wide number of symptoms involving any part of the body, or no obvious symptoms. Coeliac disease was first described in childhood; however, it may develop at any age. It is associated with other autoimmune diseases, such as Type 1 diabetes mellitus and Hashimoto's thyroiditis, among others.
Abetalipoproteinemia is a disorder characterized by abnormal absorption of fat and fat-soluble vitamins from food. It is caused by a mutation in microsomal triglyceride transfer protein resulting in deficiencies in the apolipoproteins B-48 and B-100, which are used in the synthesis and exportation of chylomicrons and VLDL respectively. It is not to be confused with familial dysbetalipoproteinemia.
The small intestine or small bowel is an organ in the gastrointestinal tract where most of the absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about 5.5 metres long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter.
Enterocytes, or intestinal absorptive cells, are simple columnar epithelial cells which line the inner surface of the small and large intestines. A glycocalyx surface coat contains digestive enzymes. Microvilli on the apical surface increase its surface area. This facilitates transport of numerous small molecules into the enterocyte from the intestinal lumen. These include broken down proteins, fats, and sugars, as well as water, electrolytes, vitamins, and bile salts. Enterocytes also have an endocrine role, secreting hormones such as leptin.
Small intestinal bacterial overgrowth (SIBO), also termed bacterial overgrowth, or small bowel bacterial overgrowth syndrome (SBBOS), is a disorder of excessive bacterial growth in the small intestine. Unlike the colon, which is rich with bacteria, the small bowel usually has fewer than 100,000 organisms per millilitre. Patients with bacterial overgrowth typically develop symptoms which may include nausea, bloating, vomiting, diarrhea, malnutrition, weight loss, and malabsorption by various mechanisms.
Tropical sprue is a malabsorption disease commonly found in tropical regions, marked with abnormal flattening of the villi and inflammation of the lining of the small intestine. It differs significantly from coeliac sprue. It appears to be a more severe form of environmental enteropathy.
The Schilling test was a medical investigation used for patients with vitamin B12 (cobalamin) deficiency. The purpose of the test was to determine how well a patient is able to absorb B12 from their intestinal tract. The test is now considered obsolete and is rarely performed, and is no longer available at many medical centers. It is named for Robert F. Schilling.
Short bowel syndrome is a rare malabsorption disorder caused by a lack of functional small intestine. The primary symptom is diarrhea, which can result in dehydration, malnutrition, and weight loss. Other symptoms may include bloating, heartburn, feeling tired, lactose intolerance, and foul-smelling stool. Complications can include anemia and kidney stones.
Blind loop syndrome, also known as stagnant loop syndrome, is a state that occurs when the normal bacterial flora of the small intestine proliferates to numbers that cause significant derangement to the normal physiological processes of digestion and absorption. In some cases of blind loop syndrome, overgrowth of pathogenic non-commensal bacteria has also been noted. It has long been understood that from birth, and throughout life, large amounts of bacteria reside symbiotically within animal gastrointestinal tracts such as the human gastrointestinal tract. The understanding of this gut flora has even led to novel treatments for bowel irregularity that utilize so called "probiotics" or good bacteria that aid in normal digestion. The problem of blind loop syndrome arises when the bacterial colonies residing in the upper gastrointestinal tract begin to grow out of control or are altered in their makeup thereby creating a burden on the normal physiological processes occurring in the small intestine. This results in problems, among others, of: vitamin B12 deficiency, fat malabsorption and steatorrhea, fat-soluble vitamin deficiencies and intestinal wall injury.
Lymphangiectasia, also known as "lymphangiectasis", is a pathologic dilation of lymph vessels. When it occurs in the intestines it is known as intestinal lymphangiectasia, colloquially recognized as Waldmann's disease in cases where there is no secondary cause. The primary defect lies in the inability of the lymphatic system to adequately drain lymph, resulting in its subsequent accumulation and leakage into the intestinal lumen. This condition, first described by Waldmann in 1961, is typically diagnosed in infancy or early childhood. However, it can also manifest in adults, exhibiting a broad spectrum of clinical symptoms.
Radiation enteropathy is a syndrome that may develop following abdominal or pelvic radiation therapy for cancer. Many affected people are cancer survivors who had treatment for cervical cancer or prostate cancer; it has also been termed pelvic radiation disease with radiation proctitis being one of the principal features.
Gluten-sensitive enteropathy–associated conditions are comorbidities or complications of gluten-related gastrointestinal distress. GSE has key symptoms typically restricted to the bowel and associated tissues; however, there are a wide variety of associated conditions. These include bowel disorders, eosinophilic gastroenteritis and increase with coeliac disease (CD) severity. With some early onset and a large percentage of late onset disease, other disorders appear prior to the coeliac diagnosis or allergic-like responses markedly increased in GSE. Many of these disorders persist on a strict gluten-free diet, and are thus independent of coeliac disease after triggering. For example, autoimmune thyroiditis is a common finding with GSE.
Jejunoileal bypass (JIB) was a surgical weight-loss procedure performed for the relief of morbid obesity from the 1950s through the 1970s in which all but 30 cm (12 in) to 45 cm (18 in) of the small bowel were detached and set to the side.
Waldmann disease, also known as Primary Intestinal Lymphangiectasia (PIL), is a rare disease characterized by enlargement of the lymph vessels supplying the lamina propria of the small intestine. Although its prevalence is unknown, it being classified as a "rare disease" means that less than 200,000 of the population of the United States are affected by this condition and its subtypes and there have been approximately 50 reported cases of adult-onset PIL since 1961.
Chronic diarrheaof infancy, also called toddler's diarrhea, is a common condition typically affecting up to 1.7 billion children between ages 6–30 months worldwide every year, usually resolving by age 4. According to the World Health Organization (WHO), diarrheal disease is the second greatest cause of death in children 5 years and younger. Diarrheal disease takes the lives of 525,000 or more children per year. Diarrhea is characterized as the condition of passing of three or more loose or watery bowel movements within a day sometimes with undigested food visible. Diarrhea is separated into three clinical categories; acute diarrhea may last multiple hours or days, acute bloody diarrhea, also known as dysentery, and finally, chronic or persistent diarrhea which lasts 2–4 weeks or more. There is normal growth with no evidence of malnutrition in the child experiencing persistent diarrhea. In chronic diarrhea there is no evidence of blood in the stool and there is no sign of infection. The condition may be related to irritable bowel syndrome. There are various tests that can be performed to rule out other causes of diarrhea that don't fall under the chronic criteria, including blood test, colonoscopy, and even genetic testing. Most acute or severe cases of diarrhea have treatment guidelines revolving around prescription or non prescription medications based on the cause, but the treatment protocols for chronic diarrhea focus on replenishing the body with lost fluids and electrolytes, because there typically isn't a treatable cause.
Bile acid malabsorption (BAM), known also as bile acid diarrhea, is a cause of several gut-related problems, the main one being chronic diarrhea. It has also been called bile acid-induced diarrhea, cholerheic or choleretic enteropathy, bile salt diarrhea or bile salt malabsorption. It can result from malabsorption secondary to gastrointestinal disease, or be a primary disorder, associated with excessive bile acid production. Treatment with bile acid sequestrants is often effective. It is recognised as a disability in the United Kingdom under the Equality Act 2010.
Environmental enteropathy is an acquired small intestinal disorder characterized by gut inflammation, reduced absorptive surface area in small intestine, and disruption of intestinal barrier function. EE is most common amongst children living in low-resource settings. Acute symptoms are typically minimal or absent. EE can lead to malnutrition, anemia, stunted growth, impaired brain development, and impaired response to oral vaccinations.
Intestinal bypass is a bariatric surgery performed on patients with morbid obesity to create an irreversible weight loss, when implementing harsh restrictions on the diets have failed. Jejunocolic anastomosis was firstly employed. Nonetheless, it led to some unexpected complications such as severe electrolyte imbalance and liver failure. It was then modified to jejunoileal techniques. Viewed as a novel form of treatment for obesity, many intestinal bypass operations were carried out in the 1960s and 1980s. Significant weight loss was observed in patients, but this surgery also resulted in several complications, for instance, nutritional deficiencies and metabolic problems. Due to the presence of surgical alternatives and anti-obesity medications, intestinal bypass is now rarely used.
