Lecture of Cholera

2021-03-23 12:00 AM

Cholera is eliminated in the stool right from the incubation stage, but most in the diarrhoea stage. Patients with cholera can eliminate 107-108 bacteria/gram of fences.

Define

Cholera is an acute infectious disease caused by comma cholera (Vibrio cholerae), transmitted by the digestive tract. The disease has clinical manifestations of diarrhoea and vomiting many times, quickly leading to dehydration - electrolyte, cardiovascular collapse, depression and death if not treated promptly. It is classified as a "very dangerous" disease.

Research history

In 1817 Thomas Sydenham was the first to describe cholera differently from other diarrheal diseases, but it was not until 1854 that the cholera-causing bacteria were observed by Filippo Pacili from the faeces of a cholera patient during an outbreak in Italy and placed. The name is Vibrio cholerae (V.cholerae). The mode of transmission of cholera was discovered by John Snow in 1849 in London.

The world has experienced 7 cholera epidemics. From 1817 to 1923, there were 6 pandemics occurring, all of which started in India and were caused by V. cholerae O1 classic biological type. The seventh pandemic is different from the previous six. This outbreak was caused by V.cholerae of the biological type eltor and originated from the Indonesian island of Celebes in 1961. This outbreak is the longest and has a wider scope than 6 previous cases, so far many countries have reported these outbreaks. Cholera outbreaks are caused by this cause.

In 1992, V.cholerae non - O1 serum group O139 was identified as the culprit causing cholera in Madras and the Bay of Bengal, India to spread to some Asian countries (Pakistan, Nepal, Myanmar, Thailand, western China, Malaysia ...). Some experts believe that this is the 8th pandemic.

Epidemiology

Pathogens

Vibrio cholerae (Vibrio cholerae) belongs to the family Vibrionaceae, is a bacteria with curved shape like comma, catching gram-negative color, not producing spores, and being mobile thanks to hair. They grow well in nutrient media often alkaline environments (pH> 7). in a suitable environment such as water, food, marine animals (fish, crabs, sea clams ...), etc., especially in cold temperatures, cholera can live for a few days to 2- 3 weeks. Easily destroyed by temperature (80 ° C / 5 minutes), by common chemicals and acidic environments.

  1. cholerae has approximately 140 serogroups and is divided into V. cholerae-O1 and V.cholerae non-O1.
  2. cholerae O1 is classified into two biological subtypes (biotyp) based on phenotypic characteristics, namely V. cholerae classica and V. cholerae eltor. Based on the characteristics of A, B, C antigens of the O-body antigens, V.cholerae is classified into the following 3 serotypes:

Serotyp Ogawa (with A and B antigen determinations).

Serotyp Inaba (with A and C antigen determinants).

Serotyp Hikojima (has all three antigenic determinations A, B, C).

  1. cholerae-non O1 O139 serum group is the culprit causing cholera in India and some Asian countries from 1992 to present.

Cholera cholera causes disease through toxin (choleragen). These are endotoxins with a structure of two monomers: monomer A (molecular weight 27 000 daltons, with high toxicity) and monomer B with specific antigen-specific and a stimulating A2 bridge. Prefer to increase cyclic AMP (Adenosine 3,5-cyclic mono phosphate).

Inoculum

Are sick and asymptomatic carriers.

Cholera cholera is eliminated in the stool right from the incubation stage, but most in the diarrhea stage. Patients with cholera can eliminate 107-108 bacteria / gram of feces.

Cholera can exist and multiply in crustaceans (mainly in the sea) when environmental conditions are not suitable, they go into sleep state and can survive for months and years. In this state the bacteria are resistant to the chlorid and cannot be cultured.

Infection

The disease spreads through the gastrointestinal tract, particularly the oral-fecal tract through water, food, vegetables ... especially some seafood such as clams, snails, mussels caught from contaminated places or dirty hands. Contaminated eating utensils, flies, flies, mice, paste ... can spread germs.

Sensitivity and immunity

In general, immunity following cholera is durable. There is no cross immunity between strains O1 and O139.

Translation properties

The disease usually occurs in the summer months (hot-humid climate, many flies, flies, rats ..., food easily spoils), especially after floods ...

In countries and regions with low socio-economic and sanitation levels

Pathological anatomy

The main lesions in cholera are edema, congestion in the intestinal mucosa, there is no "peeling" or "sloughing" of the mucosa. In the area of ​​Lieberkymhn's gland cells there is a phenomenon of cell proliferation.

clinical

Divide the clinical form

Typical conventional form.

Light form.

Dry description.

Hemorrhagic form.

Symptoms study according to each disease

Conventional clinical form typically is severe

Incubation period:

The earliest 12-24 hours, the longest 10 days, average 2-5 days.

Period of onset (stage of diarrhea and vomiting):

The disease has a sudden onset of intense diarrhea, often without a symptom. At first the stools may be small, the latter thicken quickly becomes typical with the properties: Liquid, all water, cloudy white like rice water mixed with lumpy white seeds, fishy smell or pale white crab bricks. Going out easily, large amounts (up to 300-500ml / time), many times (up to 30-40 times or more / day) make dehydration much and quickly: 10-15 liters / day or 1l / hour in adults.

Vomiting comes a few hours after passing away. Vomiting is easy, in large amounts, the vomitus is water and food at first, and then looks like fecal fluid.

No abdominal pain or just mild pain, no pressure.

Usually there is no fever, a few have mild fever (<5%).

The patient is exhausted, thirsty, showing signs of muscle contraction (cramps) quickly goes into the stage of dizziness.

Full-blown period (dizziness or cold):

Usually appears after a few hours - 1 day after finding out.

Patient continues to vomit, has lethargy, or has subsided but is characterized by dizziness, lethargy, lethargy, intermittent or unspoken swearing, dizziness, tinnitus, shortness of breath, sometimes difficulty breathing. . The face was emaciated, the eyes were sunken, the cheeks were concave, the skin was dry - wrinkled and bluish-purple, the extremities were cold, pinched. Temperature <35 ° C, strong, small, difficult to spin. Drop in blood pressure (maximum blood pressure <80mmHg), blurred heart sound, sometimes arrhythmia. Patients with oliguria or anuria.

Laboratory tests: There are manifestations of her blood, electrolyte disturbance (decreased Na +, K +, Cl-, Ca ++); metabolic acidosis (decreased HCO3-, decreased blood pH). In addition, blood urea is high, blood glucose is decreased.

If not treated in time, the patient will die of irreversible dizziness. Promptly treated the patient will enter the recovery phase.

Recovery period ("reaction" phase of the body):

Patients recover quickly after a few hours, sometimes very quickly (30 minutes).

Clinical: Stop vomiting after a few hours, the skin becomes pink again, less dry, the patient is less worried, pulse, temperature - blood pressure gradually returns to normal. Loosen up gradually and stop after 3-5 days. Begins to pee a lot. Full recovery after 5-7 days.

Laboratory: Gradual decrease in blood concentration. Acidosis and electrolyte disturbances can improve after 2-3 hours in adults and 8 hours in children. Particularly, K + may continue to decrease.

Asymptomatic bacterial infection

During an outbreak it should be noted that asymptomatic infections are more common than symptomatic ones (especially with Eltor strains). V. cholerae eltor ratio 1 patient / 30-100 people carry bacteria. V. cholerae classica: 1 patient / 2-4 carriers of bacteria

Light form

Mainly in children. Patients who have had diarrhea several times, usually do not vomit, have no abdominal pain, and show no signs of dehydration. This form is very important in terms of epidemiology because it is easily ignored, the diagnosis must be based on fecal culture.

Dry description

Mainly found in the elderly or in depleted bodies. The disease occurred quickly, the patient died quickly due to a state of dizziness before appearing diarrhea and vomiting. Anatomy of the body showed intestinal paralysis, in the intestine filled with fluid.

Hemorrhagic form

Initially cholera, then there is blood clotting disorders causing bleeding under the skin, mucous membranes, viscera. Symptoms of scattered intravascular coagulation syndrome (DIC) are present. During gastrointestinal bleeding, the patient defecates with fecal water and blood like meat washing liquid.

Clinical classification according to the degree of dehydration

Symptoms, signs

No dehydration

There is dehydration

Severe dehydration

Look and ask

- Neuropsychiatric


- Eyes

- Mouth, lips, tongue

- Thirst


- Urine

 

- Conscious


- Normal

- Wet

- Drink normally, not thirsty

- Normal

 

- Restlessness, agitation

- Sun down

- Dried

- dried


- Very thirsty *

- Reduction

 

- Lethargic, lethargic, lethargic

- Very sunken, dry

- Very dry

- Poor drinking, can not drink

- Not at all

Examination

- Feet, hands, nose

- Skin elasticity


- The instep circuits

- Circuit rotation

- Cramp

 

- warm hot

- Skin wrinkles lose fast


- Still, clear


- Normal

- Not at all

 

- A little cold, slightly wrinkled

- Skin pinch loss slowly

- Still, weak


-> 100 / min, clear

- Sometimes

 

 

- Cold, wet, sometimes purple, wrinkled

- Skin wrinkles take off very slowly

- Lost; also, inguinal circuit

- Hard to catch, lose

- Often met

Decision

Cannot be dehydrated

Dehydration can occur when there are at least 2 signs, including 1

Severe dehydration occurs when there are at least 2 signs, including 1

Complications and prognosis

If the emergency is not timely, the following complications may occur:  

Shock, heart failure after 4-12 hours.

Metabolic acidosis.

Acute renal failure.

Hypoglycaemia (common in children).

Reducing K + blood leads to arrhythmia, paralysis of the intestine.

Some other complications such as corneal ulcers, necrosis of the extremities ...

The signs of a severe prognosis are: persistent or recurrent diarrhea and diarrhoea; minimal - prolonged anuria, constant cramps, sharp cold, complications in the lungs. Signs of recovery are when the patient is able to urinate. Signs of early recovery are stopping vomiting, cardiovascular stability, warm limbs and less graying ...

Implementing the quadrants

clinical

Sudden onset, no evidence.

Leecorrhea comes first with the fecal nature of cholera with or without vomiting.

There is usually no fever or mild fever, no abdominal pain or just shady pain.

Disease progresses rapidly: rapid dehydration, dizziness or heart failure; Death or rapid recovery.

Test

Peripheral blood: WBCs are normal, may increase in patients with severe cholera

Isolate cholera comma from the patient's manure on APW or agar media, and conduct diagnostic tests.

Rapid diagnostic methods: Black-background contrast microscopy method, immunofluorescence method, latex agglutination ...

Epidemiology

In epidemic areas: Pay attention to rely on cholera comma isolation test to detect mild, atypical cases.

In areas without translation: Pay attention to suspect cases and the first case.

Differential diagnosis

Patients with mild or moderate dehydration are difficult to distinguish from diarrhoea caused by other etiologist such as diarrhoea caused by ETEC, viral Rota ... Patients with severe dehydration are easier to diagnose because there is no cause of rapid dehydration. and get worse in just a few hours like cholera

 However, cholera can be distinguished from the following diseases:

Salmonella food poisoning

Often there is high fever, abdominal pain cramps, vomiting occurs before diarrhoea.

Severe bacillary dysentery.

High fever, abdominal cramping, burning - anal burning, mixed bloody stools.

Treatment

Rule

Treat as soon as possible, after having a suspected diagnosis, immediately treat it, try local treatment, limit transport away.

Mechanism treatment is very important: Mainly fast and timely replenishment of lost water and electrolytes, actively combating acidosis and cardiovascular failure.

In an epidemic zone: All cases of diarrhoea should be treated as cholera.

Typical physical therapy involves severe dehydration and dizziness

Immediately administer intravenous fluids

Translation type: choose one of the following translation types:

Ringer lactate, Sodium chloride 9 0/00, Sodium bicarbonate 12,5-14 0/00.

Phillips’s solution (5g NaCl + 4g NaHCO3 + 1g KCl + 1000ml water)

WHO solution (4g NaCl + 1g KCl + 6.5 g sodium acetate + 8g glucose + 1000 ml water).

Transfer rate:

For children ³1 year old and adults’ infusion 100ml / kg / 3 hours.

In which: 30 ml / kg for the first 30 minutes + 70 ml / kg for the next 2.5 hours

For children <1 year old, infuse 100ml / kg / 6 hours.

In which: 30 ml / kg in the first hour + 70 ml / kg in the next 5 hours

It is also possible to calculate the amount of infusion by proportion of plasma using the Phillips formula:

                        V = (D-1,025) x P x 103 k.

                        V: volume of fluid to be infused (ml).                     

                        D: patient plasma density.

                        P: patient's body weight (kg).       

                        k: constant (adults = 4, children = 5-6).

Always monitor the patient's condition

After the first 30 ml / kg has been infused, the rotary must be strong. If the circuit is not strong, continue to give fast infusion.

Combination for oral administration of ORS solution (Oresol)

Give 5ml / kg / hour, as soon as possible, when the patient can drink.

Re-evaluate the patient's condition

Follow up closely and assess the patient's condition after 3 hours (for adults) and after 6 hours (for children <1 year).

If dizziness persists (usually rare): Continue intravenous administration again.

If draining but still signs of dehydration: Give ORS 70-80ml / kg / 4 hours.

If there are no signs of dehydration, stop the infusion when: the patient has a pink face, is awake, has stopped vomiting and diarrhoea, has urine and urine output is normal, pulse is below 100 / min, blood pressure is normal and stable, plasma density = 1.025-1.027 ... then switch to the ORS diet for each diarrhoea as follows:

<2 years old: 100ml.

 2-9 years: 200 ml.       

³10 years old: depending on your will.

Continued assessment of the patient's condition

Observe at least every 4 hours until diarrhoea stops.

Use antibiotics

 Antibiotics used in the treatment of cholera have the effect of reducing the volume and time of diarrhoea, shortening the time of excretion of cholera comma in feces.

Principle: Use oral antibiotics only. Parenteral antibiotics are not beneficial. Give antibiotics immediately after vomiting stops (usually 3-4 hours after rehydration).

You can choose one of the following antibiotics with the following dosage (dose for 1 time).

 

                 Antibiotic

  Children

Adults

- Doxycyclin 1 single dose

- tetracycline 4 times / day ' 3 days

- Trimethoprim (TMP) + Sulfamethoxazole (SMX) 2 times / days ' 3 days 

- Furazolidon 4 times / day ' 3 days

12,5 mg/kg

TMP 5 mg/kg

SMX 25mg/kg

 

1,25mg/kg

     300mg

      500mg

     160mg

      800mg

     100mg

It is possible to use erythromycin or chloramphenicol instead when there is no such antibiotic or when cholera is resistant to these antibiotics.

Doxycycline is the best antibiotic for adults, except for pregnant women.

Tetracycline is used for children because of its short dose (3 days).

TMP + SMX is the best antibiotic for children.

Furazolidone: Antibiotic is good for pregnant women and when the above antibiotics are resistant.

Do not use anti-diarrhoea, antiemetic, anti-vasoconstrictive, heart-assisted, corticoid ... drugs in the treatment of cholera.

Nurturing the patient

After 3-4 hours of treatment (after rehydration) must feed the patient normally (when vomiting has stopped). For children to continue to breastfeed.

Treat for a number of other forms

Treatment of dry cholera

 In addition to infusion as if severe dehydration, the following method can be applied: from the beginning of infusion 1 liter / 15 minutes (70 ml / min, until the 1 liter / 30-45 minute infusion circuit appears (25 ml / minutes) and when the pulse is clear, the blood pressure is normal, the patient has diabetes, and the purple is gone, maintain the rate of 3-10 ml / min. .

Treatment cannot be dehydrated

Just give ORS at home enough for 2 days with the following dosage:

Year old

The amount of ORS required after each diarrhoea

Number of ORS packages required

 <2 years old

 2-9 years old

 ³ 10 years old

50 - 100 ml

100 - 200 ml

depending on your will

Enough for 500ml / day (1/2 pack)

Enough for 1000ml / day (1 pack)

Enough for 500ml / day (2 packs)

If there is no ORS, you can mix the soup + salt + sugar according to the ORS formula, and add ripe bananas. Do not use plain or plain water.

Prevention

General prevention

People who get cholera are caused by drinking water or eating food contaminated with cholera, so cholera prevention is based on reducing the risks of ingestion of the pathogen.

When cholera appears in the community to do the following:

Reporting: This is a disease that requires reporting to the head of the unit, the medical superior.

Immediately bring people with suspected cholera to medical facilities for treatment. During translation, perform on-site quarantine.

Hygienic treatment of human waste.

Ensure safe and clean water supply (boiled water, chlorinated water ...).

Ensuring environmental hygiene and food safety.

Implement well health education in the community, make it clear that people need to eat cooked food, drink boiled water, wash their hands after contact with specimens and before eating, when cooking, killing flies and flies. , mouse ...

Vaccination for disease prevention

The current preventive treatment is only needed for people in direct contact, no longer applies to the community. Cholera vaccine only protects for 3-6 months, vaccination does not reduce the rate of asymptomatic cases, does not prevent the spread of the disease. Currently, oral cholera vaccine WC-BS (Whole-cell plus B subunit) has been shown to be effective in protection, should be repeated after 3-5 years. Recombinant techniques to produce B subunit vaccines that have been deployed in Vietnam are continuing to be studied.