Osmotic diarrhea is a type of diarrhea caused by excess water loss due to dehydration. The body normally produces small amounts of bicarbonate (HCO3-) which helps maintain normal blood pH levels. When there isn’t enough HCO3- in the blood, it causes symptoms like cramps, nausea and vomiting. Sometimes when there isn’t enough sodium (Na) in the blood, it causes symptoms like muscle pain or weakness.
The most common cause of osmotic diarrhea is severe dehydration. Other causes include:
Diabetes mellitus (high blood sugar level)
Hyponatremia (low salt concentration in the blood)
Hypernatremia (overly high salt concentration in the blood)
In cases where both factors are present, the kidneys may not be able to excrete enough urine. This leads to excessive water retention causing osmosis diarrhea.
Symptoms of osmotic diarrhea:
Nausea and vomiting
Cramping muscles and joints (gastric reflux disease)
Muscle aches and pains (myalgia) or numbness/tingling sensations in hands, feet, legs, arms, abdomen or back (paraparesis)
Causes of osmotic diarrhea:
Overconsumption of water
Diarrhea caused by viruses, bacteria or parasites (gut infection)
Consuming too much plain water during endurance events like long hikes, runs or races without consuming enough electrolytes and other vital nutrients
Anorexia or bulimia
Not eating enough fruits, vegetables and whole grains leading to vitamin deficiencies (malnutrition)
Low blood salt concentration (hypotonic dehydration) leads to brain swelling causing low blood pressure (hypovolemia) and eventually to respiratory failure
Prolonged or repeated vomiting, especially if it causes toxins to be released into the blood (refeeding syndrome leading to refeeding edema)
Use of certain drugs (diuretics, laxatives, antidiarrheals, insulin)
Use of some herbal teas (licorice root tea, bitter melon seeds, rhubarb stalks and leaves)
Celiac disease or other food intolerances
Autoimmune enteropathy
Bile acid malabsorption
Inflammatory bowel diseases (Crohn’s disease, ulcerative colitis)
Parasites in the intestines (Giardia lamblia, Entamoeba histolytica)
Inadequate treatment of H. pylori bacteria (with antibiotics) leading to ulcers
Pancreatic insufficiency leading to malabsorption
Gastric bypass surgery or gastric ulcers
Treatment of osmotic diarrhea:
Restricting physical activity and following a bland diet can help treat diarrhea. Eating foods that contain complex carbohydrates, like potatoes, rice, bananas and oats helps ease symptoms. Drinking sugar-free, fat-free clear liquids (water, broth, plain tea) is also recommended. Osmotic diarrhea can be treated with certain drugs like Lomotil and Imodium.
Patients are also usually instructed to increase their dietary fiber intake and to avoid alcohol and caffeine. In some severe cases, patients may require hospitalization for electrolyte solutions through an IV. Antibiotics are used to treat infection and sometimes surgery is required to remove part of the damaged intestine.
Complications of osmotic diarrhea:
Vitamin and mineral deficiencies (hypovitaminosis)
Dehydration (hypohydration) causing circulatory failure
Severe malnutrition
Infectious diarrhea caused by bacteria, viruses or parasites
Intestinal blockage or constipation caused by large amounts of undigested food in the digestive tract
Enteroaggregative Escherichia coli infection and antibiotic-associated colitis (symptoms appear 1-2 weeks after antibiotic treatment)
Liver problems caused by antibiotics
Death (in severe cases)
Xerostomia (dry mouth)
Osteopenia and osteoporosis from extended use of certain drugs (corticosteroids, HIV infection, Crohn’s disease, celiac disease, inflammatory bowel syndrome)
High cholesterol and high triglycerides from prolonged use of certain drugs (corticosteroids, Prednisone)
Worsening of ulcerative colitis
Leukoplakia (white patch in the mouth) caused by prolonged use of certain drugs (corticosteroids, prednisone)
Bruising and bleeding easily (hematemesis) caused by prolonged use of certain drugs (corticosteroids, prednisone)
Stunting of growth in children caused by prolonged use of certain drugs (corticosteroids, prednisone)
Psychological problems (anxiety, depression, insomnia, personality changes) caused by prolonged use of certain drugs (corticosteroids, prednisone)
Acne rosacea caused by prolonged use of certain drugs (corticosteroids, prednisone)
Hair loss caused by prolonged use of certain drugs (corticosteroids, prednisone)
Skin thinning caused by prolonged use of certain drugs (corticosteroids, prednisone)
Cataracts caused by prolonged use of certain drugs (corticosteroids, prednisone)
Glaucoma caused by prolonged use of certain drugs (corticosteroids, prednisone)
Poor wound healing caused by prolonged use of certain drugs (corticosteroids, prednisone)
Osteomyelitis (bone infection) caused by drug injections into the bones (corticosteroids, methylprednisolone)
Exacerbation of spinal cord disease caused by drug injections into the spinal column (corticosteroids, methylprednisolone)
Diabetic patients – sudden worsening of diabetic eye disease (corticosteroids, prednisone)
Stomach Ulcers caused by prolonged use of certain drugs (corticosteroids, prednisone)
Immunosuppression caused by prolonged use of certain drugs (corticosteroids, prednisone)
Skin thinning and osteoporosis caused by prolonged use of certain drugs (corticosteroids, prednisone)
Giant Cell Arteritis (inflammation of the walls of the arteries in the head, neck and shoulders) caused by drug injections into the scalp or arteries in the chest. (corticosteroids, prednisone)
Glaucoma caused by prolonged use of certain drugs (corticosteroids, prednisone)
Kidney damage caused by drug injections into the back (corticosteroids, methylprednisolone)
Immunosuppression caused by prolonged use of certain drugs (corticosteroids, prednisone)
Sudden onset of asthma caused by injection of drugs into the chest (corticosteroids, prednisone)
Dental abscess caused by drug injections into the jaw (corticosteroids, prednisone)
Cataract caused by drug injections into the eye (corticosteroids, prednisone)
Pseudotumor cerebri caused by drug injections into the spinal column (corticosteroids, prednisone)
Stroke caused by drug injections into the spinal
Sources & references used in this article:
Studies of osmotic diarrhea induced in normal subjects by ingestion of polyethylene glycol and lactulose. by HF Hammer, CA Santa Ana, LR Schiller… – The Journal of …, 1989 – Am Soc Clin Investig
Alterations in the colonic microbiota in response to osmotic diarrhea by G Gorkiewicz, GG Thallinger, S Trajanoski, S Lackner… – PloS one, 2013 – journals.plos.org
Fecal osmotic gap and pH in experimental diarrhea of various causes by AJ Eherer, JS Fordtran – Gastroenterology, 1992 – Elsevier
