Gastroenteritis

From Encyclopedia Jr, free information reference for Kids

Gastroenteritis involves diarrhea or vomiting, with noninflammatory infection of the upper small bowel, or inflammatory infection of the colon, both part of the gastrointestinal tract.^[1][2][3][4]

Usually this is caused by an infection,^[2] but this is not always the case. It usually is of acute onset, normally lasting less than 10 days and self-limiting. Sometimes it is referred to simply as 'gastro'. It is often called the stomach flu or gastric flu even though it is not related to influenza.

If the inflammation is limited to the stomach, the term gastritis is used, and if the small bowel alone is affected it is enteritis.

[edit] Epidemiology

Globally, diarrhea caused 4.6 million deaths in children in 1980 alone, most of these in the developing world.^[2] The Harrison's Principles of Internal Medicine estimates the current total figure to be 2.4 to 2.9 million per year.^[3] This number has now come down significantly to approximately 1.5 million deaths annually, largely due to global introduction of proper oral rehydration therapy.^[5]

The incidence in the developed countries is as high as 1-2.5 cases per child per year and a major cause of hospitalisation in this age group.

Age, living conditions, hygiene and cultural habits are important factors. Another factor is the location. Aetiological agents vary depending on the climate. Furthermore, most cases of gastroenteritis are seen during the winter in temperate climates and during summer in the tropics.^[2]

[edit] Clinical features

The main symptoms include poor feeding in infants. Diarrhea is common, and may be (but not always) followed by vomiting. Viral diarrhea usually causes frequent watery stools, whereas blood stained diarrhea may be indicative of bacterial colitis. In some cases, even when the stomach is empty, bile can be vomited up.

The child with gastroenteritis may be lethargic, or running a low fever and have signs of dehydration, dry mucous membranes, tachycardia, reduced skin turgor, sunken fontanelles and sunken eye balls, poor perfusion and ultimately shock.

[edit] Differential diagnosis

It is important to consider infectious gastroenteritis as a diagnosis per exclusionem. A few loose stools and vomiting may be the result of systemic infection such as pneumonia, septicaemia, urinary tract infection and even meningitis. Surgical conditions like appendicitis, intussusception and, rarely, even Hirschsprung's disease may mislead the clinician.

Non-infectious causes to consider are poisoning with heavy metals (i.e. arsenic, cadmium), seafood (i.e. ciguatera, scombroid, toxic encephalopathic shellfish poisoning) or mushrooms (i.e. Amanita phalloides). Secretory tumours (i.e. carcinoid, medullary tumour of the thyroid, vasoactive intestinal peptide-secreting adenomas) and endocrine disorders (i.e. thyrotoxicosis and Addison's disease) are disorders that can cause diarrhea. Also pancreatic insufficiency, short-gut syndrome, Whipple's disease, coeliac disease and laxative abuse should be excluded as possibility.^[4]

[edit] Treatment

A common treatment is to eat dry food (e.g. cooked toast with nothing on it) daily until the infection disappears.

[edit] Rehydration

The principal treatment of diarrheal illness in both children and adults is rehydration, i.e. replenishment of water lost in the stools. Depending on the degree of dehydration, this can be done orally with (oral rehydration solutions (ORS)), commercial or home-made rehydration fluids, or through intravenous delivery. Symptoms may exhibit themselves for up to 6 days. Bowel movements will return to normal within a week after that.

Because of the stomach's fragility due to the disease, rehydration through the drinking of fluids must be slow and spaced out as to not overwhelm the stomach and cause further nausea and vomiting. Doctors recommend that one take slow sips every few minutes, and if vomiting still occurs, it is best to refrain from any drinking or eating for the next half hour.

[edit] Drug therapy

[edit] Antibiotics

When the symptoms are severe one usually starts empirical antimicrobial therapy, i.e. fluoroquinolone.^[1] Pseudomembranous colitis is treated by discontinuing the causative agent and starting with metronidazole.^[1][2][3][4]

[edit] Antidiarrheal agents

Loperamide is an opioid analogue commonly used for symptomatic treatment of diarrhea. It slows down gut motility, but does not cross the mature blood-brain barrier^[1] to cause the central nervous effect of other opioids. In too high doses, loperamide may cause constipation and significant slowing down of passage of feces, but an appropriate single dose will not slow down the duration of the disease.^[6] Although antimotility agents have the risk of exacerbating the condition, this fear is not supported by clinical experience according to Sleisenger & Fordtran's Gastrointestinal and Liver Disease and the Oxford Textbook of Medicine.^[1][4] Nevertheless, Harrison's Principles of Internal Medicine discourages the use of antiperistaltic agents and opiates in febrile dysentery, since they may mask, or exacerbate the symptoms.^[3] All these textbooks agree that in severe colitis antimotility drugs should not be used.

Loperamide prevents the body from flushing toxins from the gut, and should not be used when an active fever is present or there is a suspicion that the diarrhea is associated with organisms that can penetrate the intestinal walls, such as E. coli O157:H7 or salmonella.

Loperamide is also not recommended in children, especially in children younger than 2 years of age, as it may cause systemic toxicity due to an immature blood brain barrier, and oral rehydration therapy remains the main stay treatment for children.

Bismuth subsalicylate (BSS), an insoluble complex of trivalent bismuth and salicylate, is another drug that can be used in mild-moderate cases.^[1][4]

Combining an antimicrobial drug and an antimotility drug, seems to be effective more rapidly.^[1][4]

Antibiotics are of little or no use, unless persistent symptomatic colonisation (as seen in Giardia lamblia infestations) or septicaemia is present.^{[citation needed]}

[edit] Complications

Dehydration is the most serious complication of the diarrhea caused by gastroenteritis and needs prompt rectification by a clinician if severe.

Febrile convulsions are not uncommon in children, especially with rotavirus infections.

Sugar malabsorption is the most common complication, especially in infants. This may result in the reappearance of diarrhea after milk, and hence the sugar lactose, is reintroduced into the diet.

[edit] External links

• The World Health Organisation on diarrhea
• eMedicine Health