Diagnosis

Diarrhea

Etiology

Cause/Pathophysiology [wqy]

1. Watery diarrhea: Lactose intolerance

2. Fatty diarrhea: Celiac disease, chronic pancreatitis

3. Secretory diarrhea: increased active secretion or reduced absorption

   • Cholera toxin

4. Exudative diarrhea: blood and pus in the stool

   • Crohns disease, ulcerative colitis, and severe E. coli infection

5. Inflammatory diarrhea: inflammatory damage to the mucosa --> loss of protein-rich fluids

   • Bacterial: E.coli, Campylobacter, Salmonellae, Shigellae, Clostridium difficile

   • Viral: rotavirus, norovirus, adenovirus, astrovirus

   • Parasitic: Giardia, Entamoeba histolytica, cryptosporidium, tuberculosis

   • Colon cancer

   • Inflammatory bowel disease

6. Dysentery: inflammatory disorder of the intestine with severe diarrhea containing blood and mucus combined with fever

   • Shigella, Entamoeba histolytica, and Salmonella.

7. Motility-related diarrhea: rapid movement of food through the intestines -->  not enough time for absorbtion

   • Hyperthyroidism

   • Short bowel syndrome

8. Drug side effects: antibiotics, cholinergica, SSRIs, chemotherapy, misoprostol, orlistat

Complications [wqy]

• Dehydration and severe hypovolemia

• Renal failure

• Intussusception

• Hemolytic-uremic syndrome

• Hemorrhagic colitis

• Sepsis

• GI perforation

• Toxic megacolon

Epidemiology

Incidence per 100.000 [4ad][vf1][i1e][ick][g8f][hmw][ihw]

Approach

• Blood test

• Osmolality

• Calprotectin

• Gastroscopy

• Colonoscopy

Treatment

Prevention: [vf1]

• Vaccines

• Handwash and hygiene

• Breastfeeding & Nutrition

• Oral Rehydration Solutions & Zinc

Treatment: Oral rehydration therapy is the cornerstone of treatment [vf1]

1. Mild dehydration:

   • <10 kg body weight --> 60-120 mL oral rehydration for each diarrhea/vomiting episode

   • >10 kg body weight --> 120-140 mL oral rehydration for each diarrhea/vomiting episode

2. Moderate dehydration:

   1. Oral rehydration solution (50-100 mL/kg over 3-4 hours)

   2. Oral rehydration for each diarrhea/vomiting depending on body weight

3. Severe dehydration:

   1. Intravenous lactated Ringer solution or normal saline: 20 mL/kg

   2. Followed by 100 mL/kg oral rehydration solution over 4 hours

   3. Oral rehydration for each diarrhea/vomiting depending on body weight

Treatment depending on etiology: [vf1]

• Antimotility agents

• Antimicrobial therapy:

  • Aeromonas species: Cefixime, 3rd/4th gen cephalosporins

  • Campylobacter species: Erythromycin

  • C difficile: Discontinue causative antibiotics, use oral metronidazole or vancomycin

  • Cryptosporidium parvum: Paromomycin, Nitazoxanide (antihelmintic)

  • Entamoeba histolytica: Metronidazole followed by iodoquinol or paromomycin

  • E coli: Trimethoprim-sulfamethoxazole, 2nd/3rd generation cephalosporin

  • G lamblia: Metronidazole or nitazoxanide

  • Plesiomonas species: Trimethoprim-sulfamethoxazole or cephalosporin

  • Salmonella species: Treatment is not indicated for nontyphoid-uncomplicated diarrhea. Treat infants and high-risk patients (immunocompromised, sickle cell disease). TMP-SMX, ceftriaxone and cefotaxime

  • Shigella species: TMP-SMX, cefixime, ceftriaxone, and cefotaxime

  • V cholerae: Doxycycline, and erythromycin

  • Yersinia species: TMP-SMX, cefixime, ceftriaxone, and cefotaxime

Differential diagnoses

Acute pancreatitis, Appendicitis, Bacterial overgrowth syndrome, Bile acid malabsorption, Carcinoid tumor, Celiac disease, Cholecystitis, Chronic pancreatitis, Clostridium difficile, Colorectal cancer, Crohn disease, Drug side effects, Gastric bypass, Gastroenteritis, Giardiasis, Hyperthyroidism, Infectious colitis, Intussusception, Irritable bowel syndrome, Ischemic colitis, Lactose intolerance, Malabsorption, Meckels diverticulum, Shigellosis, Short bowel syndrome, Ulcerative colitis, Viral hepatitis