Diarrhea

DiarrheaDr. Nabila Hassan

MD. Tropical Medicine

Definition: It means an increase of stool liquidity , quantity (N: 200g/d) or frequency (N: 3-4 motions/d).classsification acute if <2 weeks, persistent if 2–4 weeks, chronic if >4 weeks

Acute Diarrhea: >90% caused by infectious

agents Remaining 10% medications,

toxic, ischemia

 1- Infection:Bacterial : Salmonella , Shigella , E.coli , Campylobacter, Cholera, (Salmonella,Staph, Clostridium)Viral : Rota virus , Norwalk virus, Adenovirus, enterovirus.Protozoa: E.histolytica , Malaria , Giaradia, Blantadium coliHelminthes: Trichinella spiralis, strongyloids stercoralis.

Causes:

2- Iatrogenic:* Laxatives * Antibiotic * Chemotherapy * Parasympathetic * Mg containing antacid. * allopurinol3- Toxins: *-Lead - arscenic- Mercury- Bacterial toxins4- Diet:* Unripe fruit * Alcohol * Mushroom. * food allergy5- Nervous: psychological stress6- Ischemic colitis

chronic diarrhea1- malabsorption syndrome. ( enumerate its causes )2- Diseases of the colon : (ABCD)Ameabic ---- AIDS--------Bilharizal--------Cancer colon& IBD-----Diverticulosis.3- Endocrinal causes :• Thyrotoxicosis.• Diabetic neuropathy.• Addison’s disease.• Zollinger Ellison syndrome.• Carcinoid syndrome• Pancreatic cholera (verner Morrison

syndrome)

4- Drugs: Laxative Anti- acids

- inflammatory - arrhythmia - biotics - neoplastic

1. Osmotic diarrhea: Presence of non absorbed , hypertonic substances in intestinal lumen maintain fluid & prevent absorption (e.g. lactulose, sorbitol, magnesium ).

2. Secretory diarrhea (watery diarrhea) : increase secretion of water & electrolytes into the lumen.e.g. cholera , E.coli , _ VIPs ( vaso - active intestinal peptides)

3. Abnormality of intestinal motility : e.g. Thyrotoxicosis, IBS, D neuropathy.

4. Abnormality of intestinal mucosa : e.g. inflammation.

Mechanisms of Diarrhea

H2O _ dehydration. K _ hypokalemia. HCO3 _ Acidosis.

Complications:

1- History analysis: Frequency: >4/d _ diarrhea- If the stool is of large volume & not excessive frequent small bowel disease.- If the stool is of small volume & excessive frequent large bowel disease. Consistency: - watery: inflammation - greasy: malabsorption. Color of stool: - bloody as in ulcerative colitis. - pale as in steatorrhea. – tarry as in melena. Relation to meal:

Diagnosis

Associated symptoms:• Abdominal pain: all causes of diarrhea

except drug induced & Thyrotoxicosis.• Nausea & vomiting: Acute infections.• Fever: infection, inflammation. • Constipation: IBS.

Diagnosis

2- Examination: abdominal tenderness bowel sounds degree of general hydration examination per rectum: to exclude

rectal mass or blood.

Diagnosis

3- Investigations: 4 SNot every patient who presents with diarrhea needs to be evaluated with these expensive tests, watchful waiting & symptomatic therapy with oral fluid are very enough.

Stool examination: - for ova, cysts & parasites. - stool osmolarity - fat assay. Sigmoidoscopy: if a large bowel cause is suspected. Small bowel radiology: if a small bowel cause is suspected. Serological tests. Plus Investigations of malabsorption syndrome.

Diagnosis

PreventionTreatment Specific : treatment of the cause. Symptomatic:- Anti diarrhea : Diphenoxylate ( lomotil ) , Loperamide ( loperazine )- Anti emetic: motilium Supportive:- Diet: _ avoid fat, _ irritants , light diet.- Treatment of complications: Fluid – K – HCO3 .

Treatment :

Cholera

Cholera is an acute diarrheal illness caused by infection of the intestine with the bacteria Vibrio cholerae.

Cholera

•Gram negative.•Type of

Gammaproteobacteria•Distinguishing factors :

•Oxidase-positive ,•motile via polar flagellum,

and both respiratory and fermentative metabolism.

•Organism can multiply freely in water

Vibrio cholerae

Drinking contaminated water.

eating raw or undercooked shellfish

Causes (transmission mood)

•Rare in developed countries•Common in Asia, Africa, & Latin

AmericaPoor sanitary

conditions•Contaminated seafood, even in

developed countries.•Especially shellfish.

Raw or undercooked

food• People with low levels of stomach

acid •Such as children, older adults,

and some medications.

Hypochlorhydria

• Reasons aren't entirely clear•Twice more likelyType O blood

Risk Factors

V. cholerae accumulates in stomach

Produces toxins

Toxins will bind to G-

protein coupled receptor

Inactivation of GTPase

G- protein stuck in

"on" position

increase cAMP

activation of ion channels

NaCl influx into

intestinal lumen to

drag water into lumen

lead to watery

diarrhea

Pathophysiology of cholera

Most people remain asymptomatic. The symptoms of cholera include :

Signs & Symptoms

profuse, watery

diarrhea

stomach pains

leg cramps

Mild fever

Vomiting Sunken eyes and cheeks

Dry mucous

membranes

Decreased urinary output

Incubation period is 24-48 hours.

severe dehydration Shock

Renal failure Death

Complications

diagnosis

Clinical diagnosis

Cholera should be considered in all cases

with severe watery diarrhea and vomiting.

Traveling to affected areas and eating

shellfish

No distinguishing clinical manifestations

for cholera.

Differential diagnosis

Enterotoxigenic e. Coli

Bacterial food poisoning

Viral gastroenteritis

Culture•Vibrios often detected by

dark field or phase contrast microscopy of stool

•Organisms are motile, appearing like “shooting stars”

•Microscopy show sheets of curved Gram negative rods.

•When plated on sucrose dishes, yellow colonies appear confirming cholera present

Laboratory Diagnosis

Additional methods of detection include PCR and monoclonal antibody-based stool tests.

Laboratory Diagnosis

Oral rehydration salts•Up to 80% of cases can be treated

through this.

Intravenous fluids (Ringer lactate)

•For severe cases.

Antimicrobial Therapy•can diminish duration of diarrhea,

reduce volume of rehydration fluids needed, and shorten duration of V. cholerae excretion.

Treatment

DRUG THERAPY

The goals of drug therapy are to eradicate infection, reduce morbidity and prevent complications.

The drugs used for adults include tetracycline, doxycycline, cotrimoxazole & ciprofloxacin. For children erythromycin, cotrimoxazole

and furazolidone are the drugs of choice.

• Basic health education and hygiene• Mass chemoprophylaxis• Provision of safe water and

sanitation• Comprehensive Multidisciplinary

Approach: water, sanitation, education, and communication

Prevention

Parenteral Vaccine: •2 doses administered 2 weeks apart

•Efficacy of approximately 50% and hardly exceeds 6 months•Not recommended

Killed WC/rBS Vaccine: •Killed whole-cell V.cholerae in combination with a recombinant B-

subunit of cholera toxin•Safe in pregnancy and breastfeeding

•Efficacy of approximately 50% after 3 years•Only mild side-effectsLive, attenuated CVD 103-HgR Vaccine:

•Protection as early as 1 week after vaccination, with >90%•Unknown efficacy for children under 2

•No adverse side-effects

Vaccines