Cholera

Description of Medical Condition

An acute infectious disease caused by Vibrio cholerae (El Tor type is responsible for current epidemic, the other type, classic, is found only in Bangladesh). (New serotype now in Bangladesh, India (0139). Important because of lack of efficacy of standard vaccine.) Characteristics include severe diarrhea with extreme fluid and electrolyte depletion, and vomiting, muscle cramps and prostration. Usual course: acute; chronic; relapsing.

Clinical course is 3-5 days, and in the early stages a severely affected patient can lose one liter of fluid per hour

Endemic areas: India; Southeast Asia; Africa; Middle East; Southern Europe; Oceania; South and Central America

System(s) affected: Gastrointestinal

Genetics: N/A

Incidence/Prevalence in USA: 0.01 cases/100,000. The few cases in the U.S. have been in returning travelers or associated with food brought into the country illicitly.

Predominant age: All ages

Predominant sex: Male = Female

Medical Symptoms and Signs of Disease

Abdominal discomfort
Anorexia
Anuria
Apathy
Cholera gravis
Cyanosis
Decreased skin turgor
Dehydration
Diarrhea, painless
Distant heart sounds
Diuresis, sudden
Dysrhythmias
Fever
Hypotension
Hypothermia
Hypovolemic shock
Increased or decreased bowel sounds
Lethargy
Listlessness
Malaise
Non-tender abdomen
Oliguria
Rice-water diarrhea
Seizures
Sunken eyes
Tachycardia
Thirst
Vomiting
Washerwoman’s fingers
Weak peripheral pulses
Weakness

What Causes Disease?

Enterotoxin elaborated by gram-negative
Vibrio cholera (O-group 1)
Human host
Contaminated food
Contaminated water
Contaminated shellfish

Risk Factors

Traveling or living in epidemic areas
Exposure to contaminated food or water
Person-to-person transmission (rare)
In endemic areas, children under age 5
Attack more severe in blood group – as compared to AB
Individual with low gastric acid secretion
Gastrectomy
Individuals on acid-suppressing medications

Diagnosis of Disease

Differential Diagnosis

Other causes of severe diarrhea and dehydration (e.g., Shigella, E. coli, viruses)

Laboratory

Stool culture — on selective media (thiosulfate citrate bile salts sucrose [TCBS])
Typed antisera specific agglutination
Dark field microscopy — characteristic vibrio motility in stool
Increased vibriocidal antibodies in unimmunized individual

Laboratory abnormalities of severe dehydration:

Acidemia
Acidosis
Hypokalemia
Hyponatremia
Hypochloremia
Hypoglycemia
Increased specific gravity
Polycythemia
Mild neutrophilic leukocytosis

Drugs that may alter lab results: N/A

Disorders that may alter lab results: N/A

Pathological Findings

Electron microscopy — organism adherent to mucosa
Intact mucosa
Increased cellularity of lamina propria
Increased cellularity of mucosa
Vascular congestion
Lymphoid hyperplasia of Peyer’s patches
Lymphoid hyperplasia of mesenteric lymph nodes
Lymphoid hyperplasia of spleen
Cerebral edema
Acute tubular necrosis
Vacuolar hypokalemic nephropathy
Pulmonary edema
Hyaline membranes
Bronchopneumonia
Focal myocardial damage
Lipid-depleted adrenals
Tubularization of zona fasciculata

Imaging

Abdominal film — ileus
Chest x-ray — microcardia

Diagnostic Procedures

Physical examination and medical history that includes recent travel

Treatment (Medical Therapy)

Appropriate Health Care

Outpatient for mild cases, inpatient for moderate or severe cases

General Measures

Determination of the amount of fluid loss (may compare patient’s previous weight to current weight)
Rehydration therapy. Oral for mild to moderate cases. Patients with severe dehydration may require intravenous replacement.

Activity

Bedrest until symptoms resolved and strength returns

Diet

Small, frequent meals when vomiting stops and appetite returns

Patient Education

Centers for Disease Control. Traveler’s Information Hotline: (404)332-4559 (available 24 hours via a touch-tone telephone).
International Association for Medical Assistance to Travelers, 417Center St., Lewiston, NY 14092 (716)754-4883

Medications (Drugs, Medicines)

Drug(s) of Choice

Oral rehydration therapy, for mild disease:
- Oral rehydration solution (ORS) commercial brands available (Pedialyte, Rehydralyte, Resol, Rice-Lyte) OR
- ORS formula from World Health Organization (WHO)
per liter:
- Sodium chloride 3.5 grams
- Potassium chloride 1.5 grams
- Glucose 20 grams
- Trisodium citrate 2.9 grams
Rehydration for severely dehydrated patients:
- IV rehydration (Ringer’s lactate) is followed by oral or nasogastric administration of glucose or sucrose-electrolyte solution
Antibiotics
- For older children and adults — doxycycline (Vibramycin) — 300 mg once or 100 mg bid for 3 days or tetracycline 50 mg/kg/day for 3 days
- For young children — trimethoprim-sulfamethoxazole (SMX-TMP, Bactrim, Septra) 8 mg/kg trimethoprim plus 40 mg/kg sulfamethoxazole per day, divided q12h. This dosage is equivalent to 1 mL/kg of SMX/TMP suspension. Alternatively, furazolidone (Furoxone) 5-10 mg/kg/day divided q6h for 3 days.
- In pregnancy — furazolidone 100 mgqidx 7-10 days.

Contraindications:

Tetracycline: not for use in pregnancy or children < 8 years.
Furazolidone and alcohol may cause disulfiram-like reaction.

Precautions:

Tetracycline: may cause photosensitivity; sunscreen recommended.

Significant possible interactions:

Tetracycline: avoid concurrent administration with antacids, dairy products, or iron.

Alternative Drugs

N/A

Patient Monitoring

Follow patient until symptoms resolved

Prevention / Avoidance

Water purification
Careful food selection, e.g., no unpeeled raw fruits or vegetables, no raw or undercooked seafood
Enteric precautions
Tetracycline for contacts
Natural infection confers long-lasting immunity
Prophylactic vaccine
- 50% effective for 3 to 6 months
- Not recommended unless required by destination country, and if so, a single dose is sufficient
- Concomitant administration with yellow fever vaccine may result in reduced vaccine response to yellow fever
- Invariably associated with local side effects
- Systemic side effects of fever and malaise
- A new vaccine shows promise, but still in the testing stage

Possible Complications

Hypovolemic shock
Chronic biliary infection
Up to 50% mortality with untreated shock
Intermittent stool shedding

Expected Course / Prognosis

Prompt oral or IVtreatment can be lifesaving
Appropriate disposal of human waste
Antibiotic treatment reduces duration and infectivity of disease
Mortality less than 1 % with appropriate supportive care
Increased mortality with untreated hypovolemic shock

Miscellaneous

Associated Conditions

Increased risk of disease with gastric achlorhydria

Age-Related Factors

Pediatric:

Breast-feeding is protective against cholera
Vaccine not recommended for children less than 6 months

Geriatric: N/A

Pregnancy

N/A

Synonyms

Asiatic cholera
Epidemic cholera
Rice water diarrhea
Cholera gravis

International Classification of Diseases

001.9 Cholera, unspecified

Other Notes

Centers for Disease Control does not expect a major outbreak of cholera in the U.S., but it has issued a “Cholera Preparedness Plan,” outlining steps for proper surveillance, treatment, laboratory diagnosis, investigation of outbreaks, and public education