pg1 Ethiology, epidemiology, pathogenesis, clinical features and the treatment principles of cholera. Dehydration – Rehydration. Cholera is a acute diarrheal disease involving the entire small bowel and that can cause death due to dehydration within several hours. 1) Etiology: Vibrio Cholerae: It is curved, motile, flagellated Gr Negative bacteria ( Aerobic Rod) The organism is killed by 100°C temperature in few seconds but can survive in ice for up to 6 weeks. 2 Main sero groups – O1 & O139 Bengal O1 has 2 biotypes – classical & El tor and 3 serotypes Inaba, Ogawa, Hikojima (All three strains are pathogenic) Vibra Cholerae Vibrae Heamolyticus Non Invasive Invasive Affects Small Bowel Affects Colon (Proximal Mainly) El Tor is the major cause of cholera now as it is a hardier organism. Infection with El Tor is frequently unrecognized because it produces milder clinical symptoms. 2) Epidemiology: Hosts : Human Cholera is spread by ingestion of H2O, seafood or other food contaminated by human excrement/faeces, (Excrement of persons with symptomatic or asymptomatic infection)/Faecaloral route transmission. Mostly the infection is seen in achlorhydrics or hypochlorhydrics(Antacids/gastrectomy) which facilitates the passage of the cholera bacilli. IP : Few hours to 6 days. Pathogenic dose > 108. 3) Pathogenesis: Ingestion Over comes gastric acid barrier (Achlorhydia or hypochlorhydria facilitates passage of the cholera bacilli) proliferate goes to small intestines colonizes and attaches to mucosa by toxic coregulate pilus (TCP) (It colonizes because of its motility,chemotactic, haemoagglutin/protease production properties) Produces cholera toxins, consisting of A & B subunits the B Subunit binds to specific GM1 ganglioside receptors and A Subunit which enters enterocyte activates adenylate cyclase / intracellular enzyme this inhibits the absorbtive Na transport system in villus cells and activates the excretory chloride transport system into crypt cells These events leads to accumulation of NaCl in the intestinal lumen. Since water moves passively to maintain osmolality isotonic fluid accumulates in the lumen. (Water moves passively into lumen) Diarrhea. 4) Clinical Features: i) Asymptomatic ii) Mild iii) Moderate iv) Severe * 3 phases classically recognized. A)Evacuative phase: Sudden onset of painless, profuse watery diarrhea , associated with vomiting in the severe forms. “Rice Water” Stools are characteristics of this stage. So called because mucous flecks floating in the watery stools. Fever usually absent. Patient has severe abdominal cramps & other muscle cramps. Stools typical “Fishy” smell. If appropriate supportive treatment not given patient passes on to the next phase. B)Collapse Phase: Dehydrative i) Mild – thirst , dry mouth, ↓ axillary sweating, slight weight loss. ii)Moderate – Postural hypotension, tachycardia, sunken eyes, hollow cheeks, sunken frontella in infants(dehydration) iii) Severe – Features of circulatory shock – cold clammy skin, tachycardia, hypotension, peripheral cyanosis, Oliguria.
In collapse stage two major problems are renal failure and aspiration of vomitus. If patient survives then the next stage. C)Recovery Phase: Gradual return to normal of clinical & biochemical parameters in 13 days. W18pg2 5) Diagnosis: i) Clinical mainly ii) Examination of freshly passed stools may demonstrate rapidly motile organisms. (D/D C. Jejuni) iii) Demonstration of rapidly motile vibrios by dark field illumination and subsequent inhibition of their movements with type specific antisero is diagnostic. iv) Stool & Rectal swabs for culture. Growth is in thiosulfatecitratebilesugar agar. (Grows as flat yellow colonies) 6) Treatment 1)Symptomatic Therapy – Oral rehydration. – For mild to moderate dehydration – Glucose electrolyte sol. a) For mildly dehydrated patient given ORS – 150ml/kg in 1st 4 hours followed by maintenance sol. Of 100 ml/ kg daily until diarrhea stops. b) For moderately dehydrated patient given 100ml/kg in 1st 4 hours followed by maintenance sol. of 1015 ml/kg/hour. ORS Solutions (WHO/UNICEF) [mmol/l] Na K Cl Glucose Citrate 90 20 80 111 10 for severely dehydrated with features of collapse I/V rehydration is done. Recommended by WHO include – Ringer lactate solution and the “Diarrheas Treatment Solution” NaCl KCl Na Acetate 4.0 g/l 1.0g/l 6.5 g/l
Glucose 9.0 g/l
Several Liters of IV Fluid required to overcome the features of shock. Maintenance effectively carried out by ORS. 2) Etiological therapy Children Adults a) Doxycycline 300 mg (Single dose) b) Trimethoprim 5mg/kg bid 160 2xday c) SMX 25mg/kg bid 800 mg 2xday d) Tetracycline 50mg/kg/d divided 500 mg 4xday into 4 doses 7)Prevention & Control I) Chemoprofilaxis with tetracycline 500 mg 2 x day – 3 days in adults – In children 125 mg/d effective TMP SMX also can be used II) Most effective preventing measures – Good Hygiene and sanitary living condition 8) Complications i) Dehydration ii) Electrolyte Imbalance – Hypokalemia (Causing arrhythmia) iii) Acidosis alterations : Consciousness Hyperventilation.
Report on Ethiology, epidemiology, pathogenesis, clinical features and the treatment principles of cholera. Dehydration – Rehydration. Report prepared by 1. Dr. Sajid Mahmood, MD (EU), Accident & Emergency Department, NHS Royal infirmary Liverpool United Kingdom. 2. Dr. Adnan Akram, MD (EU), Department of Infectious Diseases. University Hospital Riga Latvia. 3. Dr. Aftab Ahmed, MD (EU), Infection Control Department, Kaunas Medical University Clinic. Lithuania.
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