NTA Level 6 • Semester 1 • PST06106

Pharmacotherapy of Cholera

Basic Pharmacotherapy • Source Session/Topic 29

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PST 06106

Basic Pharmacotherapy

Session 29: Pharmacotherapy of Cholera

Learning Objectives

By the end of this session students are expected to be able to:

Define cholera

Explain pathophysiology of cholera

Explain the clinical presentation of cholera

Outline diagnosis of cholera

Describe pharmacological treatment of cholera

Describe the monitoring of cholera therapy

Activity: Buzzing

What is Cholera?

Definition

of Cholera

Cholera

is an acute gastrointestinal infection caused by

Vibrio

cholerae

Infection occurs through ingestion of contaminated water or food by human faeces leading to severe diarrhoea and emesis associated with body fluid and electrolyte depletion

Pathophysiology of Cholera

V.

cholerae

is a gram-negative bacillus sharing similar characteristics with the family

Enterobacteriaceae

Most pathology of cholera results from an enterotoxin (cholera toxin) produced by the bacteria.

Conditions that reduce gastric acidity, such as the use of antacids, histamine receptor blockers, or proton pump inhibitors, or infections with

Helicobacter pylori,

increase

the

risk

for clinical disease.

Cholera toxin stimulates adenylate

cyclase,which

increases intracellular cyclic adenosine monophosphate (

cAMP

) and results in inhibition of sodium and chloride

absorption

microvilli and promotes the secretion of chloride and water by crypt cells.

Pathophysiology of

Cholera Cont…

The toxin likely acts along the entire intestinal tract, but most fluid loss occur in the duodenum.

The net effect of the cholera toxin is isotonic fluid secretion (primarily in the small intestine) that exceeds the absorptive capacity of the intestinal tract (primarily the colon).

This results in the production of watery diarrhea with electrolyte concentrations similar to that of plasma

Clinical presentation and diagnosis of Cholera

A sudden onset of painless watery diarrhoea that may quickly become severe with profuse watery stools, vomiting, severe dehydration and muscular cramps, leading to hypovolemic shock and death

The stool has a characteristic “rice water” appearance (non-bilious, grey, slightly cloudy fluid with flecks of mucus, no blood and inoffensive odour)

Laboratory evidence of dark field microscopic isolation of motile curved bacillus on a wet mount of fresh stool specimen OR

Isolation of bacteria through stool culture on TCBS agar.

Activity

: Brainstorming

What is the treatment of cholera

Pharmacological Treatment of Cholera

Treat according to Plan as indicated in the Standard Treatment Guideline (Tanzania)

Plan A: No dehydration,

Plan B: Moderate dehydration and

Plan C: Severe dehydration.

When a case of cholera is suspected at home, advise to rehydrate the patient using ORS if available while preparing to take a patient to the nearest health facility or Cholera Treatment Centre

Pharmacological Treatment of

Cholera Cont..

Manage a suspected cholera case in an isolation ward or in an established Cholera Treatment Centre

Assess the patient's level of dehydration as per National Guidelines for Prevention and Control of Cholera. It is of paramount importance to make correct diagnosis and administer the right treatment according to the Treatment

Pharmacological Treatment of Cholera Cont..

For severe Rehydration

Administer intravenous (IV) fluid immediately to replace fluid deficit; Use Ringer Lactate solution or, if that is not available, 0.9% sodium chloride solution. Give 100 ml/kg IV in 3 hours, 30 ml/kg as rapidly as possible (within 30 min) then 70 ml/kg in the next 2.5 hours

After the initial 30 ml/kg has been administered, the radial pulse should be strong and blood pressure should be normal. If the pulse is not yet strong, continue to give IV fluid rapidly. Administer ORS solution (about 5 ml/kg/hour) as soon as the patient can drink, in addition to IV fluid

If the patient can drink, begin giving A: oral rehydration salt solution (ORS) by mouth while the drip is being set up; ORS can provide the potassium, bicarbonate, and glucose that saline solution lacks.

Pharmacological Treatment of Cholera Cont..

Give an oral antibiotic to patients with severe dehydration as follows:

Adults

(Not for pregnant women) :

Doxycycline (PO) 300 mg as a single dose or 5mg/kg single dose OR

Ciprofloxacin (PO) 1g stat or 15mg/kg 12 hourly for 3 days AND

Folic acid (PO) 5mg once daily for the duration of the treatment.

Expectant mothers: Erythromycin (PO) 500mg 8 hourly for 5 days

Children: A: Erythromycin syrup (PO) 12.5mg/kg 6 hourly for 3 days OR

A: Co-

trimoxazole

48mg/kg once a day for 3 days AND

Pharmacological Treatment of Cholera Cont..

Folic acid AND Zinc.

For adolescents: Ciprofloxacin (PO) 12mg/kg 2 times for 3 days OR

Doxycycline (PO) 300mg as single dose or 5mg/kg single dose AND

Folic acid AND

Zinc

Start feeding 3-4 hours after oral rehydration begins. Preferably, give antibiotics with food to minimize vomiting

Give

ORS for rehydration; they have to be taken frequently

Pharmacological Treatment of Cholera Cont..

For moderate Dehydration

Give oral rehydration, approximately 75-100ml/kg in the first four hours

Reassess after four hours; if improved, continue giving WHO based ORS, in quantity corresponding to losses (

. after each stool) or 10 to 20ml/kg.

If not improved, treat as severe If no signs of dehydration

Pharmacological Treatment of Cholera Cont..

For moderate Dehydration

….

Patients

who have no signs of dehydration when first observed can be treated at home

Give these patients ORS packets to take home, enough for 2 days

Demonstrate how to prepare and give the solution

Instruct the patient or the caretaker to return if any of the following signs develop; increased number of watery stools repeated vomiting or any signs indicating other problems (

, fever, blood in stool)

Monitoring of Cholera therapy

It is important to monitor for resolution of the

symptoms,

adherence to medicines and adverse drug reactions and severe side effects; in case of any they should be reported and addressed

accordingly

Key

Points

Cholera

is an

infection of

the small

intestine by

some strains of the bacterium Vibrio

cholerae

Symptoms may range from none, to mild, to severe and the classic symptom is large amounts of watery

diarrhea

that lasts a few days.

Diarrhea

can be so severe that it leads within hours to severe dehydration and electrolyte imbalance

It is spread mostly by unsafe water and unsafe food that has been contaminated with human

feces

containing

the bacteria

Cholera can be successfully treated with oral rehydration therapy (ORT) and chemotherapy

Evaluation

What

is Cholera?

What is the pathophysiology of

Cholera?

What are the signs and symptoms of Cholera?

How is the treatment of Cholera?

References

Wells

BG,

DiPiro

J,

Schwinghammer

T (2013),

Pharmacotherapy Handbook

Ed). New York, NY: McGraw-Hill.

DiPiro

JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey ML, (2008):

Pharmacotherapy: A Pathophysiologic Approach

): New York, NY: McGraw-Hill.

Katz M D.,

Matthias KR.,

Chisholm-Burns M A.,

Pharmacotherapy(2011)

Principles & Practice Study Guide: A Case-Based Care Plan Approach

:

New York, NY: McGraw-Hill.

Schwinghammer

TL, Koehler JM (2009)

Pharmacotherapy Casebook: A Patient-Focused Approach

): New York, NY: McGraw-Hill.

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