1. DIARREAHA
Dr. Maha Arafah

2. Case
A 1 year old girl is brought to clinic with 3 days of watery diarrhea, vomiting, and irritability. On exam the child is lethargic, afebrile, with sunken eyes and a weak pulse of 140/minute. Which of the following is the best management plan?
Check CBC and stool tests for pathogens
Prescribe oral rehydration solution
Prescribe oral antibiotics
Begin IV fluids and hospitalize

4. Why important?
The loss of fluids through diarrhea can cause dehydration and electrolyte imbalances
Easy to treat but if untreated, may lead to death especially in children

5. Why important?
More than 70 % of almost 11 million child deaths every year are attributable to 6 causes:
Diarrhea
Malaria
neonatal infection
Pneumonia
preterm delivery
lack of oxygen at birth.
UNICEF

6. Fluid and small intestine

7. DIARREAHA DEFINITION World Health Organization
3 or more loose or liquid stools per day
Abnormally high fluid content of stool
> gm/day

8. CLASSIFICATION
Acute
Persistent
Chronic

9. CLASSIFICATION Acute if 2 weeks, Persistent if 2 to 4 weeks,
Chronic if 4 weeks in duration.

10. Is it diarrhea or not ?
Two common conditions, usually associated with the passage of stool totaling 200 g/d, must be distinguished from diarrhea, as diagnostic and therapeutic algorithms differ.
Pseudodiarrhea, or the frequent passage of small volumes of stool, is often associated with rectal urgency and accompanies the irritable bowel syndrome or anorectal disorders such as proctitis.
Fecal incontinence is the involuntary discharge of rectal contents and is most often caused by neuromuscular disorders or structural anorectal problems.

11. Pathophysiology Categories of diarrhea
Secretory
Osmotic
Exudative
Motility-related

12. Secretory diarrhea There is an increase in the active secretion
High stool output
Lack of response to fasting
Normal stool ion gap < 100 mOsm/kg
Stool  osmotic gap =      Stool osmolality - 2 x (stool Na + stool K)
Normal fecal fluid values:   Osmolality: ~290 mOsm/kg   Na+:  ~30 mmol/L   K+: ~75 mmol/L

13. Secretory diarrhea Causes
The most common cause of this type of diarrhea is a bacterial toxin ( E. coli , cholera) that stimulates the secretion of anions.
Hormonally mediated: VIPoma, carcinoid, medullary carcinoma of thyroid (calcitonin), Zollinger-Ellison syndrome (gastrin)     
Factitious diarrhea (laxative abuse); phenolphthalein, cascara, senna     
Villous adenoma     
Bile salt malabsorption (ileal resection; Crohn's ileitis; postcholecystectomy)     
Medications

14. PathophysiologyCholera
Cholera toxin binds to membrane receptors on enterocytes, irreversibly activating G protein that leads to enhanced cAMP production. This:
(1) inhibits apical electroneutral NaCl absorption
(2) induces Cl- secretion by activating apical Cl- channels.

15. Pathophysiology Cholera
No associated epithelial injury occurs, leaving intact apical Na+-coupled nutrient transporters (Na+-glucose, Na+-amino acid)

16. Osmotic diarrhea
Excess amount of poorly absorbed substances that exert osmotic effect………water is drawn into the bowels……diarrhea
Stool output is usually not massive
Fasting improve the condition
Stool ion gap is high, > 125 mOsm/kg
Can be the result of
Malabsorption in which the nutrients are left in the lumen to pull in water e.g. lactose intolerance
2. osmotic laxatives.

17. Osmotic diarrhea
CLUES: Stool volume decreases with fasting; increased stool osmotic gap 1. Medications: antacids, lactulose, sorbitol 2. Disaccharidase deficiency: lactose intolerance 3. Factitious diarrhea: magnesium (antacids, laxatives)

18. Osmotic
As stool leaves the colon, fecal osmolality is equal to the serum osmolality, ie, approximately 290 mosm/kg.
Under normal circumstances, the major osmoles are Na+, K+, Cl–, and HCO3–.

19. Exudative
Results from the outpouring of blood protein, or mucus from an inflamed or ulcerated mucosa
Presence of blood and pus in the stool.
Persists on fasting
Occurs with inflammatory bowel diseases, and invasive infections.

20. Inflammatory conditions
CLUES: Fever, hematochezia, abdominal pain 1. Ulcerative colitis 2. Crohn's disease 3. Microscopic colitis 4. Malignancy: lymphoma, adenocarcinoma (with obstruction and pseudodiarrhea) 5. Radiation enteritis

21. Motility-related
Caused by the rapid movement of food through the intestines (hypermotility).
Irritable bowel syndrome (IBS) – a motor disorder that causes abdominal pain and altered bowel habits with diarrhea predominating
Diabetes mellitus – neurogenic dysfunction
Scleroderma – stasis of the bowel with resultant bacterial overgrowth, steatorrhea and diarrhea

22. Motility disorders CLUES: Systemic disease or prior abdominal surgery
Postsurgical: vagotomy, partial gastrectomy, blind loop with bacterial overgrowth     
Systemic disorders: scleroderma, diabetes mellitus, hyperthyroidism     
Irritable bowel syndrome

23. Aetiology Acute diarrhea?
Approximately 80% of acute diarrheas are due to infections (viruses, bacteria, helminths, and protozoa).
Viral gastroenteritis (viral infection of the stomach and the small intestine) is the most common cause of acute diarrhea worldwide.
Food poisoning
Drugs
Others
Rotavirus the cause of nearly 40% of hospitalizations from diarrhea in children under 5

25. Antibiotic-Associated Diarrheas
Diarrhea occurs in 20% of patients receiving broad-spectrum antibiotics; about 20% of these diarrheas are due to Clostridium difficile

27. Aetiology Chronic diarrhea?
Infection e.g.Giardia lamblia .
AIDS often have chronic infections of their intestines that cause diarrhea.
Post-infectious. Following acute viral, bacterial or parasitic infections
Malabsorption
Inflammatory bowel disease (IBD)
Endocrine diseases
Colon cancer
Irritable bowel syndrome.

28. Complications Fluids ………………Dehydration
Electrolytes …………….. Electrolytes imbalance
Sodium bicarbonate……. Metabolic acidosis
If persistent ……Malnutrition

29. Tests useful in the evaluation of diarrhea
Acute diarrhea
Fecal leukocytes
Inflammatory Diarrhea
Noninflammatory Diarrhea
Fecal leukocytes are not present
Fecal leukocytes are present
Suggests a small bowel source caused by either
Toxin-producing bacterium (enterotoxigenic E coli [ETEC], Staphylococcus aureus, Bacillus cereus, Clostridium perfringens)
other agents (viruses, Giardia) that disrupt normal absorption and secretory process in the small intestine
The presence of fever and bloody diarrhea (dysentery) indicates colonic tissue damage caused by invasion (shigellosis, salmonellosis, Campylobacter or Yersinia infection, amebiasis) or a toxin (C difficile, E coli O157:H7).

31. Diagnosis Chronic diarrhea 72 H Stool collection
> 200 gm – indicates diarrhea
> gm – suggests Secretory diarrhea
> 10 gm of fecal fat – malabsorption
Stool pH …….5.5 or less indicates carbohydrate intolerance, which is usually secondary to viral illness and transient in nature.
Stool anion gap …… osmolar > 100 > secretory
290 - [(Na+K) X 2].

32. Diagnosis Chronic diarrhea
If osmotic gap and/or
fecal fat increased
If blood and/or WBC in the stool
If symptoms and signs of
endocrine diseases
Infection
Endocrine diseases.
Malabsorption
Inflammatory bowel disease (IBD)
D-Xylose Test
Colon cancer
cortisol and thyroid hormone
Bile salt breath test
Stool culture
Hydrogen breath test
X-rays of the intestines
Small intestine biopsy
Irritable bowel syndrome.
Endoscopy
gluten autoantibodies
Diagnosis of exclusion