Cholera

Infectious diseases

Clinicals - History

Fact Explanation
Asymptomatic Some patients who are infected may remain asymptomatic. Asymptomatic
Some patients who are infected may remain asymptomatic.
Watery diarrhea Due to cholera enterotoxins. Sudden onset of painless watery diarrhea (rice water diarrhea). Later patient develops abdominal cramps. Watery diarrhea
Due to cholera enterotoxins. Sudden onset of painless watery diarrhea (rice water diarrhea). Later patient develops abdominal cramps.
Vomiting Occurs in the early stages of cholera. It may persist due to the subsequent development of acidosis. (Vomiting removes hydrogen ions from the body.) Vomiting
Occurs in the early stages of cholera. It may persist due to the subsequent development of acidosis. (Vomiting removes hydrogen ions from the body.)
Leg cramps Watery diarrhea, vomiting, and leg cramps are common symptoms. This is due to the electrolyte imbalance, especially potassium and calcium. Leg cramps
Watery diarrhea, vomiting, and leg cramps are common symptoms. This is due to the electrolyte imbalance, especially potassium and calcium.
Features of dehydration Patients present with increased thirst, reduced urine output, postural dizziness, weakness and fatigue. Features of dehydration
Patients present with increased thirst, reduced urine output, postural dizziness, weakness and fatigue.
Drowsiness and coma Due to dehydration and poor oral intake. Severe desease (cholera gravis or cholera sicca)results in vascular collapse, shock, and death in hours. Drowsiness and coma
Due to dehydration and poor oral intake. Severe desease (cholera gravis or cholera sicca)results in vascular collapse, shock, and death in hours.
Abdominal discomfort of cramps This is due to the distension of the fluid filled bowel loops. Abdominal discomfort of cramps
This is due to the distension of the fluid filled bowel loops.
History of travel to an endemic area Cholera is uncommon in developed countries and commonly seen in developing countries. Traveller to those endemic countries may manifest the disease within 24 to 48 hours of incubation period. History of travel to an endemic area
Cholera is uncommon in developed countries and commonly seen in developing countries. Traveller to those endemic countries may manifest the disease within 24 to 48 hours of incubation period.
History of ingestion of sea foods Sea foods are known sources of cholera infection. History of ingestion of sea foods
Sea foods are known sources of cholera infection.

Clinicals - Examination

Fact Explanation
Afebrile Unlike other infective diarrheas fever is typically absent in cholera. Fever can appear with secondary infection. Afebrile
Unlike other infective diarrheas fever is typically absent in cholera. Fever can appear with secondary infection.
Signs of dehydration Patient may fall in to mild, moderate or severe dehydration. About 10%-20% of patients present with severe diarrhoea. Features of dehydration (reduced skin turgor, sunken eyes, tachycardia, small volume pulse, dry mucous membranes) may present. In severe dehydration patient may have reduced blood pressure, postural hypotension or even shock. Signs of dehydration
Patient may fall in to mild, moderate or severe dehydration. About 10%-20% of patients present with severe diarrhoea. Features of dehydration (reduced skin turgor, sunken eyes, tachycardia, small volume pulse, dry mucous membranes) may present. In severe dehydration patient may have reduced blood pressure, postural hypotension or even shock.
Pulse Weak, rapid and thready, or absent pulse occurs due to dehydration and hypovolemia. Pulse
Weak, rapid and thready, or absent pulse occurs due to dehydration and hypovolemia.
Low blood pressure Hypovolemia occurs due to the dehydration and results in low blood pressure. Low blood pressure
Hypovolemia occurs due to the dehydration and results in low blood pressure.
Tachypnea and Kussmaul breathing Stool bicarbonate loss and lactic acidosis due to poor peripheral perfusion result in acidosis. The respiratory compensation to acidosis is with tachypnea and Kussmaul breathing. Tachypnea and Kussmaul breathing
Stool bicarbonate loss and lactic acidosis due to poor peripheral perfusion result in acidosis. The respiratory compensation to acidosis is with tachypnea and Kussmaul breathing.
Drowsiness Patients are drowsy due to dehydration and poor oral intake. Drowsiness
Patients are drowsy due to dehydration and poor oral intake.

Investigations - Diagnosis

Fact Explanation
Gram stain of a stool sample Cholera is a gram-negative curved bacillus with a single flagellum. Gram stain of a stool sample
Cholera is a gram-negative curved bacillus with a single flagellum.
Rapid diagnostic test (RDT) Allows early and quick diagnosis of the disease. Specially useful in epidemics. Rapid diagnostic test (RDT)
Allows early and quick diagnosis of the disease. Specially useful in epidemics.
Serotype and biotype identification Specific antisera can be used in immobilization tests. O1 or O139 serogroups are known to infect humans. O139 is commonly detected in South Asia. Serotype and biotype identification
Specific antisera can be used in immobilization tests. O1 or O139 serogroups are known to infect humans. O139 is commonly detected in South Asia.
Full blood count Hematocrit rises due to hemo-concentration. Leukocytosis without a left shift occurs in initial stages. Full blood count
Hematocrit rises due to hemo-concentration. Leukocytosis without a left shift occurs in initial stages.

Investigations - Management

Fact Explanation
Arterial blood gas analysis (ABGA) Detects acid-base disturbances. Bicarbonate levels are reduced. Cholera causes loss of bicarbonate ions in stools. When the respiratory compensation is no longer effective in maintaining the acid-base balance acidosis occurs. In ABGA the pH is less than 7, with low plasma bicarbonate and an increased serum anion gap Arterial blood gas analysis (ABGA)
Detects acid-base disturbances. Bicarbonate levels are reduced. Cholera causes loss of bicarbonate ions in stools. When the respiratory compensation is no longer effective in maintaining the acid-base balance acidosis occurs. In ABGA the pH is less than 7, with low plasma bicarbonate and an increased serum anion gap
Random blood sugar Hypoglycemia is a consequence and a killer. It occurs due to poor oral intake and defective gluconeogenesis. Commonly encountered in children. Random blood sugar
Hypoglycemia is a consequence and a killer. It occurs due to poor oral intake and defective gluconeogenesis. Commonly encountered in children.
Serum potassium Cholera causeloss of potassium in stools. However acidosis if not corrected can result in normal or high levels of potassium. Hypokalemia can induce arrhythmias. Serum potassium
Cholera causeloss of potassium in stools. However acidosis if not corrected can result in normal or high levels of potassium. Hypokalemia can induce arrhythmias.
Serum calcium Hypocalcemia can occur secondary to reperfusion with bicarbonate containing fluids. Serum calcium
Hypocalcemia can occur secondary to reperfusion with bicarbonate containing fluids.
Renal function test Enables detection of acute renal failure due to dehydration. Renal function test
Enables detection of acute renal failure due to dehydration.

Management - Supportive

Fact Explanation
Rehydration Cholera can lead to severe dehydration even death can occur within hours. Rehydration is attempted with oral rehydration solution (ORS) or with intravenous fluids. The choice depends on the degree of dehydration (Patients with severe dehydration may need rapid intravenous fluid administration) The preferred intravenous fluid is Ringer lactate. Rehydration
Cholera can lead to severe dehydration even death can occur within hours. Rehydration is attempted with oral rehydration solution (ORS) or with intravenous fluids. The choice depends on the degree of dehydration (Patients with severe dehydration may need rapid intravenous fluid administration) The preferred intravenous fluid is Ringer lactate.
Nutrition optimization High energy diet should be commenced after dehydration is been settled. This prevents the occurrence of hypoglycemia. Nutrition optimization
High energy diet should be commenced after dehydration is been settled. This prevents the occurrence of hypoglycemia.
Health education Patients in endemic areas should be provided with enough information about the route of transmission (feco-oral) and preventive measures. (Hand washing before cooking, meals and after using toilets) People should be encouraged to use boiled and cooled drinking water. Health education
Patients in endemic areas should be provided with enough information about the route of transmission (feco-oral) and preventive measures. (Hand washing before cooking, meals and after using toilets) People should be encouraged to use boiled and cooled drinking water.
Oral cholera vaccines (OCV) This is a killed vaccine. The vaccine contains two doses. Oral cholera vaccines (OCV)
This is a killed vaccine. The vaccine contains two doses.

Management - Specific

Fact Explanation
Antibiotic treatment Limits the duration of diarrhea and reduces the risk of dehydration. Tetracycline is commonly used. Antibiotic treatment
Limits the duration of diarrhea and reduces the risk of dehydration. Tetracycline is commonly used.
Zinc This is known to reduce the duration of diarrhea in pediatric population under the age of five years. Children below 6 months of age should be prescribed 10mg daily, and children older than that should be prescribed 20mg daily. For both age groups the treatment is for 2 weeks Zinc reduces the duration and volume of diarrhea. Zinc
This is known to reduce the duration of diarrhea in pediatric population under the age of five years. Children below 6 months of age should be prescribed 10mg daily, and children older than that should be prescribed 20mg daily. For both age groups the treatment is for 2 weeks Zinc reduces the duration and volume of diarrhea.

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