05. Diarrhea

OTHER NAMES
stools, watery; frequent bowel movements; loose bowel movements
DEFINITION
The frequent passage of unformed watery stools.

MECHANISM

To expel the contents of the lower digestive tract, the fluidity of the contents of the small and large intestines is increased. Active transport of Na⁺ back into the gut initiates a reverse sodium transport. This causes both Cl^– and HCO₃^– to follow passively, as well as water. Now in the intestines, the water dilutes toxins as well as triggering contractions of the intestine due to increase in intestinal distension. These contractions push the contents of the lower GI tract towards and out of the anal canal.

COMMON CAUSES
Diarrheal diseases can be grouped into several general categories.
INFECTIOUS
- viruses
- rotavirus
- cytomegalovirus (CMV)
- adenovirus
- echovirus
- HIV virus
- bacteria
- shigella
- salmonella
- cholera
- E. coli
- Staphylococcus aureus
- parasites
- Giardia Lamblia
- Cryptosporidium parvum
- Balantidium coli
- occasionally roundworm (ascariasis) or tapeworm (cestodiasis) infestation
- funguses
- Candida albicans (seen in immunocompromised individuals)
TOXIC
Often referred to as “food poisoning” Toxins may be produced in foods as bacteria grow. These toxins are responsible for the associated vomiting and diarrhea. The most common toxin is an enterotoxin produced by staphylococcus species.
MALABSORPTION
- lactose intolerance,
- celiac disease (sprue) or gluten malabsorption
- cystic fibrosis
- disaccharide malabsorption
- cows milk protein intolerance.
There are other less frequently encountered causes of malabsorption.
INFLAMMATORY DISEASES OF THE BOWEL
- Crohn’s disease
- ulcerative colitis
IMMUNE DEFICIENCY
- severe combined immunodeficiency

 hypogammaglobulinemia
- panhypogamniaglobulinemia (Bruton)
- chronic granulomatous disease
- IgA deficiellcy
MEDICATIONS
- antibiotics
- chemotherapy
CERTAIN TREATMENTS
- gastrectomy
- gastroenterostomy
- high-dose radiation therapy
OTHER
- Zollinger-Ellison syndrome
- autonomic neuropathy (diabetic neuropathy)

TYPES OF DIARRHOEA

There are at least four types of diarrhea: secretory diarrhea, osmotic diarrhea, motility-related diarrhea, and inflammatory diarrhea.

Secretory diarrhea

Secretory diarrhea means that there is an increase in the active secretion, or there is an inhibition of absorption. There is little to no structural damage. The most common cause of this form of this type of diarrhea is a cholera toxin that stimulates the secretion of anions, especially chloride ions. Therefore, to maintain a charge balance in the lumen, sodium is carried with it, along with water.

Osmotic diarrhea

Osmotic diarrhea occurs when there is a loss of water due to a heavy osmotic load. This can occur when there is maldigestion (e.g., pancreatic disease or Coeliac disease), where the nutrients are left in the lumen, which pulls water into the lumen.

Motility-related diarrhea

Motility-related diarrhea occurs when the motility of the gastrointestinal tract is abnormal. If the food moves too quickly, there is not enough contact time between the food and the membrane, meaning that there is not enough time for the nutrients and water to be absorbed. This can follow a vagotomy or diabetic neuropathy.

Inflammatory diarrhea

Inflammatory diarrhea occurs when there is damage to the mucosal lining or brush border, which leads to a passive loss of protein-rich fluids, and a decreased ability to absorb these lost fluids. Features of all three of the other types of diarrhea can be found in this type of diarrhea. It can be caused by bacterial infections, viral infections, parasitic infections, or autoimmune problems such as inflammatory bowel disease.

Treatment Options      

Treatment Strategy    

Because diarrhea is a symptom, treatment should be dictated by the cause (or causes).   For acute, uncomplicated diarrhea, it may be sufficient to reassure patients that the   diarrhea is benign and will resolve in a couple of days and simply treat the symptoms.  For some chronic diarrhea, dietary change can be sufficient without additional evaluation.  Serious acute bloody diarrhea and chronic diarrhea will require evaluation and treatment   of underlying cause(s). Hospitalization should be considered with dehydration; in any   case, replacement of fluids (clear fluids without caffeine and rehydration fluids) and   electrolytes-particularly with very young and very old patients-is critical.        

Drug Therapies

    Because some medications prescribed for diarrhea can delay resolution of certain   infectious diarrhea conditions (as well as other contraindications), diarrhea should be   diagnosed before drug therapy is undertaken. Common drug therapies (many OTC)   include the following.    _... Opioid derivatives: diphenoxylate-atropine (Lomotil) and loperamide (Imodium).   May have CNS effect.     _... Adsorbents: bismuth salts (Pepto-Bismol), kolin, and pectin (Kaopectate),   aluminum hydroxide (Amphojel), cholestyramine (Questran)     _... Bulk-forming medications: psyllium (Metamucil, Konsyl)   Specific guidelines include:    _... Bismuth salts for traveler's diarrhea     _... Cholestyramine for bile-acid-induced diarrhea         

Complementary and Alternative Therapies

    Severe diarrhea can be life-threatening, and it is imperative that the underlying etiology   be assessed before initiating any treatment other than fluid replacement. Nutrition   suggestions should be followed for all types of diarrhea.        

Nutrition

      _... Avoid coffee, chocolate, dairy products, strong spices, and solid foods. Introduce   clear soup, crackers and white bread, rice, potatoes, applesauce, and bananas   as diarrhea begins to resolve. Sips of black tea may help settle the stomach when   nausea is present.     _... To restore and maintain fluid and electrolyte balance, consider rice and/or barley   water, fresh vegetable juices (especially carrot and celery), miso broth, or other   clear broths. Rice and barley water are made using 1 cup of grain to 1 quart of   boiling water. Let steep for 20 minutes. Strain and drink throughout the day.     _... Lactobacillus species taken as powder or in capsules helps to normalize bowel   flora and may help resolve diarrhea. Take as directed, or one dose with each   meal. Saccharomyces bolardii and brewer's yeast are specific for treating   antibiotic-induced diarrhea that has caused Clostridium difficile overgrowth.     _... Vitamin C (1,000 mg tid to qid) and vitamin A (10,000 to 20,000 IU/day) support   immune function. High doses of vitamin C may cause diarrhea. High doses of   vitamin A should not be taken long-term without physician supervision.     _... Glutamine (3,000 mg tid) is helpful to treat diarrhea that is caused by mucosal   irritation rather than infection, such as chemotherapy-induced diarrhea.

HOME CARE
The risk of developing the most common forms of diarrhea can be reduced by observing good hygiene including hand washing and avoiding contaminated food, utensils or other objects. Children should be taught not to put objects in their mouth. Hand washing is recommended before and after using the bathroom and before meals.
Don’t try to stop diarrhea as soon as it develops. Diarrhea is the body’s way of getting rid of whatever food, virus, or bug that is causing it.
Diarrhea that comes on suddenly and ends in a day or two is usually caused by an infection or food poisoning.
Treatment for simple diarrheal illness consists of giving clear liquids and maintaining adequate hydration. This may be accomplished by giving fluids including oral rehydration fluids. If a child has nausea or vomiting the liquids should be given in small amounts but very frequently, often every 15 minutes. If the child has no nausea or vomiting, larger volumes of liquids may be given. Home mixed electrolyte solutions should be avoided; mixing mistakes can cause significant problems. Commercial preparations are safe and may be useful.

 

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Compiled and Shared By: Habib Anwar 

habib.anwar@hotmail.com