Acute Diarrhea Management in Primary Care

Posted on Oct 7, 2024 in Medicine & Health

Acute Diarrhea in Primary Care

Syndrome

Diarrhea is defined as an increase in the volume or fluidity of stools relative to an individual’s normal bowel habit.

Acute diarrhea lasts less than 3 weeks, while chronic diarrhea persists for more than 3 weeks. It is an important health problem due to its high morbidity and mortality, and it can also lead to significant societal costs due to work and school absenteeism.

Causes

There are multiple causes of diarrhea, and determining the exact etiology is often impossible and unnecessary in primary care. Some common causes include:

  1. Viral: Norwalk virus, Rotavirus, Adenovirus, Herpesvirus, viral hepatitis, mononucleosis, HIV.
  2. Parasitic: Entamoeba histolytica, Giardia lamblia, Cryptosporidium, Isospora belli, Blastocystis hominis.
  3. Toxic: Fungi, toxins (fish/seafood), heavy metals, botulism, monosodium glutamate.
  4. Bacterial: Staphylococcus aureus, Clostridium sp., E. coli, Vibrio cholerae, Salmonella sp., Shigella sp., Campylobacter, Yersinia sp.
  5. Iatrogenic: Laxatives, antibiotics (amoxicillin-clavulanate), antihypertensives (beta-blockers), indomethacin, digitalis, theophylline, caffeine, alcohol, antacids, metformin.
  6. Other: Diverticulitis, fecal impaction, intestinal ischemia, inflammatory bowel disease (IBD), malabsorption syndrome, food allergy, appendicitis, colon carcinoma.

Microbiological Aspects

Diagnostic workup is only necessary in 25% of cases. Of these, 58% are bacterial (Salmonella and Campylobacter), 23% are parasitic (Giardia lamblia), and 18% are viral (rotaviruses and adenoviruses).

Pathophysiology

  1. Toxigenic Mechanism (Secretory/Watery Diarrhea): Occurs in the small intestine, resulting in abundant watery diarrhea, low abdominal pain, no fever, and dehydration. Pathogens include: Vibrio cholerae, enteropathogenic E. coli, S. aureus, Clostridium perfringens, rotavirus, Norwalk virus, Cryptosporidium, Giardia lamblia, and Isospora belli.
  2. Invasive Mechanism (Inflammatory Diarrhea): Occurs in the colon, causing dysentery syndrome with frequent, small bowel movements containing mucus, blood, and leukocytes. Symptoms include fever, colicky abdominal pain, and rectal tenesmus. Pathogens include: Salmonella sp., Shigella, enteroinvasive E. coli, Vibrio parahaemolyticus, Yersinia enterocolitica, Campylobacter, and Entamoeba.

Diagnosis

History: Family history, past medical history, predisposing factors, presenting illness (initial symptoms, similar cases in contacts, medications, sexual habits, recent travel).

Physical Examination: General assessment (heart rate, blood pressure, temperature), and in children, examination of the ears, nose, and throat, abdomen, and rectal assessment.

Point-of-Care Testing: Not usually indicated. If severe diarrhea is suspected: stool examination for parasites, stool culture, and serum electrolytes.

Further Investigations (if no improvement within 7 days): Fecal occult blood test (FOBT), serial stool examination for parasites and cultures, and fecal leukocytes.

Treatment

  1. Fluid Replacement: Oral rehydration is preferred unless dehydration is severe, in which case intravenous fluids are necessary. Oral rehydration solutions should contain glucose and electrolytes. Avoid hyperosmolar solutions. Homemade lemonade (2 liters of water, 7 lemons, 1 tablespoon of salt, 1 tablespoon of baking soda, and 4 tablespoons of sugar) can be used. Avoid lactose-containing foods. For unrelieved vomiting, consider metoclopramide.
  2. Abdominal Pain: Avoid spasmolytics. If needed, use acetaminophen or metamizol.
  3. Antidiarrheal Medications: Generally unnecessary. Avoid antimotility agents or astringents in children or cases of invasive diarrhea, especially if fluid replacement is insufficient.
    • Loperamide: Inhibits peristalsis and gastrointestinal secretion, increases anal sphincter tone. Use only if fluid replacement is adequate and diarrhea is not severe.
    • Diphenoxylate: Similar mechanism of action to loperamide but with more side effects.
    • Aluminum phosphate: Astringent effect. Use if a toxin is suspected.
    • Sucralfate: Antiulcer medication with an astringent effect. Minimal absorption.
    • Tannin derivatives: Astringent effect.
  4. Antibiotics: Not initially indicated. Use if stool culture is positive or empirically in cases of suspected sepsis, inflammatory diarrhea with suspected Shigella or enteroinvasive E. coli, presence of risk factors, or severe diarrhea pending stool culture results. Ideally, administer an orally absorbable antibiotic active against most enteric pathogens while preserving the colonic saprophytic flora. Quinolones (norfloxacin and ciprofloxacin) are preferred but are contraindicated in children due to effects on joint growth, as well as during pregnancy and lactation. Alternatives include amoxicillin-clavulanate and cotrimoxazole. Specific antibiotic choices based on the causal agent include: Salmonella (ciprofloxacin, norfloxacin, amoxicillin-clavulanate, cotrimoxazole), Shigella (same as Salmonella), Campylobacter jejuni (erythromycin), Yersinia (tetracycline), Vibrio cholerae (tetracycline, doxycycline), Clostridium difficile (vancomycin), E. coli (same as Salmonella), and Giardia lamblia (metronidazole, tinidazole).

Hospital Referral

Refer patients to the hospital if they present with signs of severe dehydration, invasive diarrhea, hypothermia or hyperthermia, hypotension, tachycardia, tachypnea, leukocytosis, leukopenia, coagulation abnormalities (petechiae), no resolution within 7 days, significant rectal bleeding, advanced age, severe underlying illness, or refractory vomiting.

General Advice for Travelers

  • Carefully wash fruits and vegetables.
  • Drink bottled beverages.
  • Peel fruits personally.
  • If in doubt, do not eat fruit.
  • Consume only thoroughly cooked meat and fish.
  • Be cautious of water used for ice cubes.
  • Practice frequent handwashing.