Gastroenteritis

Gastroenteritis, also known as infectious diarrhoea, is an inflammation of the stomach and small intestine. It is a common medical condition characterised by diarrhoea, vomiting, and abdominal pain. Fever and dehydration may also occur. The condition typically lasts less than two weeks. Although it is sometimes referred to as the "stomach flu," it is not related to influenza.

Signs and Symptoms

Gastroenteritis often presents with both diarrhoea and vomiting, though sometimes only one symptom is present. Accompanying symptoms may include abdominal cramps, fever, fatigue, headache, and muscle pain. Signs usually begin 12–72 hours after infection and typically resolve within a week. Bloody stools are less likely to be caused by viruses and more likely to be bacterial in origin. Severe dehydration may manifest as poor skin turgor, prolonged capillary refill, and abnormal breathing, particularly in young children.

Cause

Gastroenteritis is primarily caused by viruses, particularly rotavirus in children and norovirus in adults. Bacteria such as Escherichia coli and Campylobacter are also common culprits. Parasites like Giardia lamblia and fungi may also cause gastroenteritis, though they are less common. Risk factors include poor hygiene, contaminated food or water, and close contact with infected individuals.

Diagnosis

Diagnosis is typically clinical, based on symptoms. Stool cultures are recommended for cases involving bloody diarrhoea, suspected food poisoning, or recent travel to developing countries. Additional tests, such as measuring serum glucose and checking electrolytes and kidney function, are suggested for severe dehydration.

Prevention

Preventative measures include hand washing, drinking clean water, and proper disposal of human waste. Breastfeeding is recommended in areas with poor hygiene. The rotavirus vaccine is advised for children globally and has significantly reduced severe disease rates.

Treatment

Rehydration

The primary treatment for gastroenteritis is rehydration, preferably with oral rehydration solution (ORS). For severe cases, intravenous fluids may be necessary. Drinks high in simple sugars, such as soft drinks, are not recommended for children under five.

Dietary Recommendations

Breastfed infants should continue breastfeeding, and formula-fed infants should resume their usual formula post-rehydration. Normal dietary intake is encouraged, except for foods high in simple sugars. The BRAT diet is no longer recommended due to its lack of nutrients.

Medications

Antiemetics like ondansetron and metoclopramide may be used for severe vomiting. Antibiotics are usually not required unless symptoms are severe or a specific bacterial cause is suspected. Antimotility agents such as loperamide are discouraged in cases of bloody diarrhoea or fever but may be used in mild cases.

Epidemiology

Gastroenteritis is prevalent worldwide, with an estimated two billion cases and 1.3 million deaths in 2015. It particularly affects children and those in developing nations. In the United States, gastroenteritis is a common condition leading to millions of physician visits and substantial healthcare costs annually.

Pathophysiology

Gastroenteritis involves inflammation of the gastrointestinal tract, often due to infection. The condition can affect both the small and large bowel, with inflammatory changes typically occurring in the large bowel.

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Self-assessment MCQs (single best answer)

Gastroenteritis is primarily characterised by:

Which virus is most commonly associated with gastroenteritis in children?

What is the most very important treatment for gastroenteritis?

Which of the following is NOT a recommended dietary practice during gastroenteritis?

Which of the following pathogens is less likely to cause bloody stools in gastroenteritis?

What diagnostic measure is recommended for cases of gastroenteritis involving bloody diarrhoea?

Which of the following is NOT a common symptom of gastroenteritis?

Which preventive measure is recommended globally for children to reduce severe gastroenteritis?

Severe dehydration in gastroenteritis may manifest as:

Which of the following medications might be used for severe vomiting in gastroenteritis?