Cholera

Table of Contents

Cholera is an infection of the small intestine caused by the bacterium Vibrio cholerae.

The infection is characterized by profuse watery stools, vomiting, dehydration, and collapse.

Cause

Cholera is specifically caused by the bacterium Vibrio cholerae.

This bacterium is Gram stain negative and possesses a flagellum, a long projecting part that enables it to move, and pili, hair-like structures that it uses to attach to the intestinal tissue.

Transmission

The primary mode of transmission for cholera is through the fecal contamination of food and water, often resulting from poor sanitation practices. When individuals infected with cholera have untreated diarrheal discharge, the bacteria can enter waterways or drinking water supplies, contaminating them.
Consuming food that has been washed in contaminated water can also lead to transmission. It is important to note that cholera is rarely spread directly from person to person.

Susceptibility: Several factors influence the susceptibility to cholera:

Ingestion of bacteria: In a normal, healthy adult, approximately 100 million bacteria must typically be ingested to cause cholera. This highlights the importance of a significant bacterial load for infection to occur.
Age: Children, particularly those between the ages of two and four, are more susceptible to cholera infection. This could be attributed to their underdeveloped immune systems and increased likelihood of exposure due to their behavior and hygiene practices.
Lowered immunity: Individuals with weakened immune systems, such as those with AIDS or malnourished children, are at higher risk of experiencing severe cases if they become infected with cholera. Their compromised immune function makes it more difficult for their bodies to fight off the infection effectively.

Pathophysiology of Cholera

Cholera is a gastrointestinal illness caused by the bacterium Vibrio cholerae. The bacteria produce a toxin that causes the body to lose water and electrolytes, leading to severe diarrhea.

How the Bacteria Enter the Body

Most Vibrio cholerae bacteria are killed by the acidic environment of the stomach. However, a small number of bacteria can survive and travel to the small intestine. The bacteria attach to the intestinal wall and produce a toxin that causes the body to lose water and electrolytes.

The Toxin

The toxin produced by Vibrio cholerae is called cholera enterotoxin. The toxin binds to cells in the small intestine and activates an enzyme that causes the cells to pump water and electrolytes into the intestine. This results in the production of large amounts of watery diarrhea.

More Detailed Pathophysiology:
Upon consumption, most Vibrio cholerae bacteria do not survive the acidic conditions of the human stomach. However, a small number of bacteria manage to survive. As they exit the stomach and reach the small intestine, they need to navigate through the thick mucus lining in order to reach the intestinal walls, where they can establish themselves and multiply. Vibrio cholerae bacteria possess flagella for mobility and pili to attach to the intestinal tissue.

Vibrio cholerae bacteria produce a toxin that is responsible for causing the most severe symptoms of cholera. This toxin, known as an enterotoxin, acts on human cells, prompting them to extract water and electrolytes from the body, primarily from the upper gastrointestinal tract. The extracted fluid and electrolytes are then pumped into the intestinal lumen, resulting in the excretion of diarrheal fluid.

Signs and Symptoms

The incubation period for cholera is typically 2-3 days. The first signs and symptoms of cholera are watery diarrhea and vomiting. The diarrhea can be so profuse that it can lead to dehydration and shock.

In a typical case of severe cholera, the disease progresses through three stages:

Stage I:

Profuse watery stools are expelled by the patient. Over time, fecal matter becomes nearly clear fluid with mucous flakes, giving it the characteristic “rice-water” appearance.
Vomiting occurs, initially expelling food and later becoming restricted to rice-water-like fluid.
Severe cramps develop in the abdomen and limbs due to salt loss.

Stage II:

Dehydration and collapse occur during this stage.
The body becomes cold, and the skin appears dry and inelastic.
Blood pressure drops, sometimes becoming unrecordable.
The pulse becomes rapid and weak.
Urine production stops, and the patient may be at risk of shock.

Stage III:

This stage marks the recovery phase, which can happen spontaneously or with treatment.
Diarrhea decreases, allowing the patient to tolerate fluids.
The general condition of the patient rapidly improves.

Diagnosis of Cholera

The diagnosis of cholera is based on the following:

History: The patient may have a history of travel to an area where cholera is common, or they may have been in contact with someone who has cholera.
Symptoms: The patient will typically have watery diarrhea and vomiting. The diarrhea may be so profuse that it can lead to dehydration and shock.
Physical examination: The doctor will examine the patient for signs of dehydration, such as dry skin, sunken eyes, and decreased urination.
Laboratory tests: The following laboratory tests may be performed to diagnose cholera:
- Stool culture: This test is used to grow the bacteria in the laboratory.
- Polymerase chain reaction (PCR): This test is used to detect the genetic material of the bacteria.
- Rapid diagnostic test (RDT): This test is a rapid way to detect the bacteria.

Prevention of Cholera

Cholera is a serious disease that can be fatal, but it is preventable. The best way to prevent cholera is to follow proper sanitation practices.

Here are some specific steps you can take to prevent cholera:

Hand hygiene: Always wash hands with water and soap before preparing, serving, or consuming food. Additionally, it is important to wash hands with soap and water after using a latrine.
Safe drinking water: Boil all drinking water or treat it with chlorine. Store the treated water in a clean container to prevent recontamination.
Food safety: Consume food when it is still hot. If consuming raw foods such as fruits and vegetables, ensure they are properly washed, and when possible, peeled before eating.
Food storage: Cover all foods to prevent contamination by dust, house flies, and cockroaches.
Reporting and burial practices: In the unfortunate event of a cholera-related death, report it immediately to health authorities. Burial should take place promptly, and it is crucial to avoid serving food during this time.
Surveillance and reporting: Active surveillance and prompt reporting of suspected cases allow for the rapid containment of cholera epidemics.
Disinfection: Kill the germs by sprinkling germ-killing solutions, such as JIK, on stool or vomitus, as well as on any other materials used by the person suffering from cholera.
Water and sanitation improvement: Enhance water and sanitation infrastructure to reduce the transmission of infection, such as by improving access to clean water sources and implementing proper waste management systems.
Outbreak investigations: Conduct thorough investigations of diarrheal outbreaks to identify the source of contamination and implement appropriate control measures.
Cholera vaccination: Consider immunization with cholera vaccines in areas prone to outbreaks or for individuals at high risk of exposure.
Treatment of malnutrition: Address malnutrition, as individuals with weakened immune systems are more susceptible to severe cholera. Providing adequate nutrition can help improve their overall resilience.

Management and Treatment

Patient admission: The patient can be admitted to temporary hospitals, schools, or churches. Cholera beds with a central hole are used, allowing continuous stools to pass into a calibrated bucket containing a disinfectant.
Oral Rehydration Solution (ORS): ORS is the primary treatment for cholera. It is recommended for rehydrating patients and replenishing electrolytes lost through diarrhea. In cases of severe dehydration, intravenous Ringer’s lactate or normal saline, along with ORS, may be administered. The patient should be reassessed every one to two hours, and hydration should be continued. If there is no improvement in hydration, the intravenous drip rate may be increased. During the first 24 hours of treatment, the patient may require 200ml/kg or more of fluid. If hydration improves and the patient is able to drink, switching to ORS solution is recommended.
Nasogastric tube: In young children, a nasogastric tube can be used to administer fluids if necessary, ensuring adequate hydration.
Antibiotics: In certain cases, antibiotics may be prescribed. Doxycycline 300mg or ciprofloxacin as a single dose can be given, but they are contraindicated in pregnancy. For pregnant women, septrin can be used. In children, cotrimoxazole, doxycycline, ciprofloxacin, or erythromycin may be considered based on the specific circumstances.
Hypoglycemia management: If hypoglycemia is present, intravenous dextrose should be administered to correct low blood sugar levels.
Zinc supplementation: Zinc supplementation is effective in treating and preventing diarrhea, especially among children. It can be provided to aid in recovery.
Isolation and infection control: Patients should be isolated to prevent the spread of infection, as stools and vomit are highly infectious. Proper disposal of stools and vomit should be carried out, preferably into a pit latrine.
Equipment and instrument disinfection: Hospital equipment should be cleaned with a disinfectant such as JIK. Instruments can be cleaned with JIK or sterilized to prevent the transmission of the infection.
Fluid balance chart: A fluid balance chart should be instituted to monitor the patient’s hydration status closely.

Complications

Shock
Electrolyte imbalance
Acute renal failure
Convulsions/Fits
Anaemia
Coma