Acute Diarrhea - Definition, Etiology and Treatment

Acute diarrhea is a common gastrointestinal condition characterized by the sudden onset of loose or watery stools lasting less than 14 days.

This presentation covers its causes, pathophysiology, clinical features, diagnosis, management, and prevention strategies.

1. ACUTE DIARRHOEAL DISEASES Dr. Sandeep S Reddy MD, FRSPH, DTMH UK , MSc-TMIH UK , CTropMed USA Assistant Professor/ Lead Consultant Internal Medicine & Infectious Diseases Ramaiah Medical College/ Ramaiah Memorial Hospital .

2. DIARRHEA Diarrhea is defined as passage of abnormally liquid or unformed stools at an increased frequency of more than 3/ day. For adults on a typical Western diet, stool weight >200 g/d can generally be considered diarrheal. Diarrhea may be further defined Acute if <2 weeks, Persistent if 2–4 weeks, Chronic if >4 weeks

3. CAUSES OF ACUTE DIARRHEA >90% caused by infectious agents. Remaining 10% : Medications, Toxic ingestions, and Ischemia

4. INFECTIOUS CAUSES Five high-risk groups 1. Travelers - Enterotoxigenic or enteroaggregative Escherichia coli, Campylobacter, Shigella, Giardia 2. Consumers of certain foods - Chicken : Salmonella, Campylobacter, or Shigella Hamburger : Enterohemorrhagic E. coli (O157:H7) Fried rice or other reheated food : Bacillus cereus Mayonnaise : Staphylococcus aureus or Salmonella Eggs : Salmonella Soft cheese : Listeria Raw seafood : Vibrio species, Salmonella, or Acute hepatitis A

5. INFECTIOUS CAUSES Five high-risk groups 3. Immunodeficient persons Primary immunodeficiency (e.g., IgA deficiency, common variable hypogammaglobulinemia, chronic granulomatous disease) Secondary immunodeficiency states (e.g., AIDS, senescence, pharmacologic suppression) 4. Daycare attendees and their family members 5. Institutionalized persons

6. Pathogen Incubation Period Bacillus cereus, Staphylococcus aureus 1-8 hr Clostridium perfringens 8-24 hr Vibrio cholerae , enterotoxigenic Escherichia coli, Klebsiella pneumoniae , Aeromonas species 8–72 h Enteropathogenic and Enteroadherent E. coli, Giardia organisms 1-8 days C. difficile 1–3 d Hemorrhagic E. coli 12–72 h Rotavirus and norovirus 1–3 d Salmonella, Campylobacter , and Aeromonas species, Vibrio parahaemolyticus , Yersinia 12 h–11 d

7. INFECTIOUS CAUSES Infectious diarrhea may be associated with systemic manifestations Reiter's syndrome - arthritis, urethritis, and conjunctivitis may accompany or follow infections by Salmonella , Campylobacter , Shigella , and Yersinia . Hemolytic -uremic syndrome - enterohemorrhagic E. coli (O157:H7) and Shigella

8. NON - INFECTIOUS CAUSES Medications: Antibiotics (Azithromycin, Clindamycin, Cephalosporins) Cardiac : anti- arrrhythmics , antihypertensives. Nonsteroidal anti-inflammatory drugs (NSAIDs) Antidepressants Chemotherapeutic agents, Bronchodilators, Antacids, and Laxatives

9. Ischemic colitis – acute lower abdominal pain preceding watery, then bloody diarrhea ; acute inflammatory changes in the sigmoid or left colon while sparing the rectum Toxins – Organophosphate insecticides Amanita and other mushrooms; Arsenic

10. Approach to the Patient of Acute Diarrhea

11. Most episodes are mild and self-limited and do not justify the cost and potential morbidity rate of diagnostic or pharmacologic interventions. Indications for evaluation include Profuse diarrhea with dehydration, grossly bloody stools, fever 38.5°C (101°F), duration >48 h without improvement, recent antibiotic use, new community outbreaks, associated severe abdominal pain in patients >50 years, elderly (70 years) immunocompromised patients.

12. INVESTIGATIONS The cornerstone of diagnosis is microbiologic analysis of the stool. Workup: Direct inspection for ova and parasites Cultures for bacterial and viral pathogens, Immunoassays for certain bacterial toxins (C. difficile), viral antigens (rotavirus), and protozoal antigens (Giardia, E. histolytica).

13. Structural examination by Abdominal CT scanning (or other imaging approaches) may be appropriate in patients with uncharacterized persistent diarrhea to exclude IBD or as an initial approach in patients with suspected noninfectious acute diarrhea caused by ischemic colitis, diverticulitis, or partial bowel obstruction. Invasive methods : Flexible sigmoidoscopy with biopsies and upper endoscopy with duodenal aspirates and biopsies may be indicated.

14. Treatment: Acute Diarrhea

15. Fluid and electrolyte replacement are of central importance to all forms of acute diarrhea . Profoundly dehydrated patients, especially infants and the elderly, require IV rehydration. WHO ORS Sodium chloride 2.6 gm/ lt Glucose, anhydrous 13.5 gm/ lt Potassium chloride 1.5 gm/ lt Trisodium citrate, dihydrate 2.9 gm/dl

16. Antibiotics Antibiotic coverage is indicated, in patients who are immunocompromised, have mechanical heart valves or recent vascular grafts, or are elderly. Reduce severity and duration of diarrhea . Treat empirically without diagnostic evaluation using a gut-antibiotic : Rifaximin (550 mg bid for 3–5 d). Empirical treatment can also be considered for suspected Dysentry with Metronidazole (500 mg bd for 7 d).

17. In moderately severe non-febrile and non-bloody diarrhea , Antisecretory agents such as Racecodotril can be useful adjuncts to control symptoms.

18. Complications: Acute Diarrhea

19. Dehydration Prolongation into Chronic Diarrhea Electrolyte imbalances Secondary Infections Malnutrition and Micronutrient deficiencies Metabolic Acidosis

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