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Should I Worry About Diarrhea?

  • 19 Aug 2022
  • 4 mins

Diarrhea is a common condition that everyone suffers occasionally. Most times, it will last a few days, but in some cases, it lasts longer like weeks. We asked Dr. Robert Lo, our gastroenterology specialist about the condition, managing it and when it’s time to see a doctor.

What is diarrhea and what causes it?

Diarrhea is the passage of a greater number of stools of decreased form from the normal. They are usually accompanied by loss of fluid and electrolytes. “Normal” stool frequency varies between individuals and ranges from three times a week to three times a day. Ideal stool has been described as either sausage-like with cracks on the surface, or snake-like that is smooth and soft. With diarrhea, consistency of stool can range from soft blobs (mild), mushy to entirely liquid (severe).

Diarrhea can be classified into acute diarrhea and chronic diarrhea. Acute diarrhea lasts for less than 4 weeks, although typically only for a few days. Diarrhea lasting longer than 4 weeks is termed chronic diarrhea. Acute diarrhea is much more prevalent than chronic diarrhea. In western populations, reported annual incidences of acute diarrhea and chronic diarrhea are approximately 20% and 5%, respectively. Local data on prevalence of diarrhea is lacking.

The causes and management of acute diarrhea and chronic diarrhea differ. Most acute diarrhea cases are due to gastrointestinal infection (a wide range of viruses, bacteria, and parasites can cause this). The commonest of which is viral gastroenteritis, and the usual culprits are norovirus, rotavirus, and adenovirus. Gastrointestinal infections may be acquired through ingestion of unhygienic or contaminated food or beverages, contact with sick persons carrying the infection, exposure during travel, or with recent usage of antibiotics. Diarrhea may also be a side effect of certain medications such as magnesium-containing antacid, metformin, proton pump inhibitors, antibiotics, and non-steroidal anti-inflammatory drugs.

On the other hand, chronic diarrhea can be due to organic or functional causes. Organic causes are inflammatory disorders (e.g., ulcerative colitis, Crohn’s), malabsorption (e.g., coeliac disease), maldigestion (e.g., chronic pancreatitis), hormonal disorders (e.g., overactive thyroid), and colon cancer. A functional cause is irritable bowel syndrome (IBS) which is benign but can decrease quality of life. IBS is a diagnosis by exclusion i.e., other organic causes need to be excluded.

How to treat diarrhea at home?

As the majority of acute diarrhea cases are secondary to viral gastroenteritis and are short-lived and self-limiting, they are suitable to be treated at home.
The priority here is to prevent dehydration and electrolyte imbalance. This can be achieved by increasing and optimizing fluid and salt intake by consuming water, juices, sports drinks, soups, or saltine crackers. An oral rehydration solution (ORS) should be considered especially in more severe cases. This is because the sugar and electrolytes in an ORS help the intestines to absorb fluids more efficiently and to correct electrolytes more effectively. ORS salt is available in most pharmacies in a pre-packaged sachet, to be mixed with water before consumption. If commercial ORS salt is not available, one can try a homemade ORS recipe: dissolve 6 teaspoons of sugar and half-teaspoon of salt in 1 liter of clean water. An adult should drink approximately 3 liters of ORS daily until dehydration resolves. The signs of adequate rehydration are: skin goes back normally when pinched, thirst has subsided, able to pass copious amount of urine and pulse is strong.

Beverages that can irritate the digestive tract such as caffeinated or carbonated drinks and alcohol should be avoided.

Anti-diarrheal medications are generally not recommended initially, as these may mask symptoms, delay diagnosis, and potentially make the digestive tract injury worse.

Antibiotics should only be considered for travel-associated diarrhea, bloody diarrhea, and prolonged cases of severe watery diarrhea with fever.

If patients with acute diarrhea do not improve after 48 hours, they should seek immediate medical attention.

What should I eat if I have diarrhea?

Eat small frequent meals slowly, 5 to 6 times a day instead of 3 large meals. Stick to bland and easy-to-digest foods such as rice, porridge, white bread, egg, chicken, fish, banana, apple, or well-cooked vegetables. Avoid fried, oily, spicy, or highly seasoned food, as well as artificial sweetener or sugar-free candies which may worsen diarrhea. Some patients may become temporarily lactose-intolerant with diarrhea so avoiding milk and dairy products may also help.

When is diarrhea the sign of a serious medical problem?

For acute diarrhea, presence of the following red flag symptoms and signs for severe disease warrants immediate medical attention:

  • Evidence of dehydration or shock (tachycardia with heart rate >100 beats per minute, systolic blood pressure <100mmHg, weakness, confusion, inability to pass urine/significant decrease in urine volume)
  • Weight loss
  • Rectal bleeding
  • Abdominal pain
  • High fever
  • Inability to maintain adequate oral intake

For chronic diarrhea, it is important to exclude underlying organic causes and therefore assessment by a gastroenterologist is recommended.

If symptoms and signs are ignored and left untreated, acute diarrhea may lead to severe dehydration which may cause acute kidney injury or failure. Low blood pressure from dehydration may also lead to a stroke or heart attack. Sepsis or overwhelming infection may also occur in those with bacterial gastroenteritis. All of these may lead to prolonged hospitalization and may even be life-threatening.

For chronic diarrhea due to an organic cause, a delay in diagnosis may lead to worsening of the condition such as further bowel injury for those with inflammatory bowel disease, as well as missing the window of opportunity to intervene for those with colon cancer.

Can diarrhea be a sign of COVID-19 infection?

SARS-CoV-2, the causal agent of Covid-19, enters human cells using the ACE2 (angiotensin-converting enzyme 2) protein as a receptor. ACE2 is thus key to the infection and symptoms of COVID-19. ACE2 is found in the respiratory and gastrointestinal tracts, thus diarrhea may also be a manifestation of COVID-19 infection.

Published reports show that approximately 20% of COVID-19 patients have diarrhea which is usually associated with other COVID-19 symptoms and it is rare to have diarrhea as the only symptom.

Conversely, having diarrhea does not imply COVID-19 infection. Nevertheless, it can serve as a warning sign especially if there is any close contact with someone who has COVID-19 infection.

Could acute diarrhea be prevented?

Always maintain good personal and food hygiene to minimise the risk of contracting infective gastroenteritis. Hand washing, avoiding undercooked/unhygienic/unheated/stale food, drinking clean treated water (or bottled water in its absence), are some examples of such good practices.


Diarrhea is a common gastrointestinal symptom. Acute diarrhea is likely secondary to infective gastroenteritis, predominantly with a viral origin, and are usually short-lived and self-limiting. Rehydration is the mainstay of treatment. In contrast, all chronic diarrhea instances should be assessed further to exclude underlying organic disorders.

Contributed by

Dr. Robert Lo
Farrer Park Hospital