Global Public Health · Supplementary · from Global Public Health

Case 1: Cholera Outbreak Management

Patient Presentation

Demographics: 28-year-old female displaced person in a refugee camp, Eastern Democratic Republic of Congo

Chief Complaint: "Severe watery diarrhea and vomiting since yesterday morning."

History of Present Illness: The patient is brought to the cholera treatment center (CTC) by her husband after approximately 18 hours of profuse watery diarrhea and vomiting. She reports sudden onset of painless, voluminous watery stools described as "rice water" in appearance, with an estimated 15-20 episodes since onset. Vomiting began approximately 4 hours after diarrhea onset and has been persistent, preventing oral rehydration.

She reports severe thirst, dizziness, muscle cramps in her calves and forearms, and progressive weakness. She has been unable to urinate for the past 8 hours. She lives in a section of the camp that received a new water supply point 2 weeks ago. Several neighbors in her block have presented with similar symptoms over the past 5 days; the camp health coordinator reports 47 suspected cases and 3 deaths in the past week.

The camp houses approximately 28,000 internally displaced persons with inadequate sanitation infrastructure: one latrine per 85 people (minimum standard is 1:20), intermittent water supply averaging 8 liters per person per day (minimum standard 15 L/p/d), and no systematic water chlorination at the new distribution point.

Past Medical History:

• No significant medical history
• Last menstrual period: 3 weeks ago (not pregnant)
• HIV status: Unknown
• Vaccination: No oral cholera vaccine

Medications:

• None

Social History:

• Displaced from her village 6 months ago due to armed conflict
• Lives in emergency shelter with husband and 3 children (ages 2, 5, and 7)
• Sources water from the new distribution point (untreated)
• Shares a latrine with 12 other families
• Malnourished diet consisting mainly of WFP rations

Family History:

• 5-year-old child developed diarrhea this morning

Physical Examination

• Vital Signs: BP 72/40 mmHg (severe hypotension), HR 128 bpm (tachycardia), RR 28 (Kussmaul breathing), Temp 35.8°C (hypothermia), SpO2 94% on RA
• General: Severely ill, lethargic but responsive to voice, markedly dehydrated
• Dehydration assessment (WHO): Lethargic, sunken eyes, very slow skin turgor (pinch retracts > 2 seconds), unable to drink (vomiting), absent tears — SEVERE DEHYDRATION
• HEENT: Profoundly sunken eyes, dry cracked lips, dry oral mucosa with absent saliva, hoarse voice
• Cardiovascular: Tachycardic, weak thready pulse, cool peripheries, capillary refill 5 seconds
• Abdomen: Soft, diffusely tender, hyperactive gurgling bowel sounds, no rigidity
• Extremities: Washerwoman hands and feet (shriveled skin), painful muscle cramping in calves bilaterally
• Neurological: Lethargic but oriented, muscle cramps with spasms

Workup and Results

Laboratory Studies:

Imaging/Additional Studies:

• Estimated fluid deficit: 10% body weight (approximately 5.5 liters for a 55 kg patient)
• Stool culture (result at 48 hours): Vibrio cholerae O1, serotype Ogawa, biotype El Tor
• Antibiotic sensitivity: Sensitive to azithromycin and doxycycline, resistant to tetracycline and co-trimoxazole
• Environmental investigation: Water samples from the new distribution point positive for fecal coliforms (> 100 CFU/100 mL) and V. cholerae detected; chlorine residual 0 mg/L (standard > 0.2 mg/L at point of use)

Clinical Image

Diagram illustrating the pillars of cholera outbreak response: case management (rehydration and antibiotic therapy), water-sanitation-hygiene (WASH) interventions, surveillance and laboratory confirmation, oral cholera vaccination, and community engagement. Shows the fecal-oral transmission pathway and environmental intervention points. Source: Educational illustration.

Diagnosis

Acute Cholera (Vibrio cholerae O1 Ogawa, El Tor biotype) with Severe Dehydration, Hypovolemic Shock, Severe Metabolic Acidosis, Hypokalemia, Acute Kidney Injury, and Hypoglycemia, in the Context of a Camp-Based Cholera Outbreak

Key Diagnostic Criteria:

• Clinical presentation: acute profuse watery "rice water" diarrhea with rapid severe dehydration consistent with cholera
• Positive rapid diagnostic test (Crystal VC) for V. cholerae O1
• Culture confirmation of V. cholerae O1 Ogawa, El Tor
• WHO severe dehydration criteria met (lethargy, sunken eyes, very slow skin turgor, unable to drink)
• Epidemiological context: outbreak setting in displaced population camp with identified contaminated water source

Treatment Plan

1. Immediate resuscitation (WHO Plan C for severe dehydration):

• IV Ringer's Lactate 100 mL/kg over 3 hours for adults: 30 mL/kg in first 30 minutes (rapid bolus), then 70 mL/kg over next 2.5 hours
• Total initial IV volume target: approximately 5.5 liters (10% body weight)
• Reassess dehydration status every 15-30 minutes; if still severely dehydrated after 3 hours, repeat IV bolus
• Monitor urine output (target > 0.5 mL/kg/hr)
• IV dextrose 50 mL of 50% dextrose for hypoglycemia

1. Ongoing fluid replacement:

• Replace ongoing stool losses: measure stool output and replace volume-for-volume with ORS once patient can drink
• ORS (reduced osmolarity WHO formula) as soon as patient can tolerate oral intake
• Target: match ongoing losses plus maintenance fluids

1. Electrolyte correction:

• Potassium replacement: IV KCl 40 mEq in first liter of maintenance fluid (do not exceed 10 mEq/hr), transition to oral KCl or potassium-rich foods when tolerating oral intake
• Ringer's Lactate provides some bicarbonate correction (lactate metabolized to bicarbonate); monitor pH and bicarbonate with serial ABGs

1. Antibiotic therapy:

• Azithromycin 1 g single dose orally (once tolerating oral intake) — reduces stool volume by 50%, shortens illness duration by 1-2 days, reduces bacterial shedding; chosen based on local resistance pattern (tetracycline-resistant strain)

1. Nutrition: Resume feeding as soon as patient can tolerate oral intake; breastfeeding mothers should continue breastfeeding
2. Contact management: Evaluate and prophylactically treat 5-year-old child with diarrhea; give household ORS packets and chlorine tablets; hygiene education on handwashing

OUTBREAK RESPONSE (Public Health Interventions):

1. Immediate WASH interventions:

• Emergency chlorination of the implicated water distribution point (target free chlorine residual > 0.5 mg/L at source, > 0.2 mg/L at point of use)
• Distribution of household water treatment supplies (chlorine tablets, Aquatabs) to all affected blocks
• Emergency latrine construction to achieve minimum standard of 1:20 ratio
• Handwashing station installation at latrines and feeding centers

1. Surveillance and case management:

• Establish cholera treatment center (CTC) and oral rehydration points (ORPs) according to WHO guidelines
• Active case finding: house-to-house surveillance in affected blocks
• Line listing of all suspected cases with mapping for spatial analysis
• Case fatality rate monitoring (target < 1% with adequate treatment)

1. Vaccination campaign:

• Request oral cholera vaccine (OCV, Shanchol) from the WHO Global OCV Stockpile through ICG mechanism
• Target: single-dose reactive campaign for all residents > 1 year (28,000 doses)
• Single-dose OCV provides 40-80% short-term protection during outbreaks

1. Community engagement:

• Community health workers for household education on water treatment, hygiene, and early ORS initiation
• Address cultural beliefs about diarrhea causation and treatment-seeking behavior
• Establish community-based surveillance and reporting

Key Learning Points

• Cholera can cause death from dehydration within 12-24 hours if untreated; aggressive IV fluid resuscitation with Ringer's Lactate following WHO Plan C is the cornerstone of management, with a case fatality rate dropping from 25-50% (untreated) to < 1% with appropriate rehydration
• Hypokalemia is the most dangerous electrolyte disturbance in cholera (not hyponatremia) because severe hypokalemia causes cardiac arrhythmias and ileus; potassium must be aggressively replaced alongside volume resuscitation
• Outbreak response requires simultaneous clinical management AND public health interventions (WASH, surveillance, vaccination, community engagement); treating individual patients without addressing the contaminated water source will not control the outbreak
• Oral cholera vaccine from the global stockpile can be deployed reactively during outbreaks; even a single dose provides meaningful short-term protection and is a critical complement to WASH interventions
• Antibiotic resistance patterns vary geographically and temporally in V. cholerae; local susceptibility data should guide antibiotic selection, and azithromycin has emerged as a reliable first-line agent in many settings where tetracycline resistance is prevalent

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