Lecture of Diphtheria

2021-03-23 12:00 AM

Ages susceptible to the disease are children under 15 years of age, the index of infection is about 15-20% in children who do not have immunity. new-born babies do not get sick because they have passive antibodies passed from their mother.

Define

Diphtheria is an acute infectious disease that spreads through the respiratory tract, caused by the diphtheria bacillus. The clinical feature of the disease is mucosal inflammation with pseudomembrane, accompanied by severe toxicity, damage to the nervous and cardiovascular system.

Research history

 The clinical picture of diphtheria was first described in the first century (A.Kapdokiski). Many announcements and researches have been done in the seventeenth and eighteenth centuries. In 1826 Bretonneau proved diphtheria as a disease. A Trousseau through his study of the outbreak that occurred in 1846 in Paris named the disease Diphtheria.

Klebs discovered that the cause of the disease was bacillus in 1833, F.loeffler isolated the pure diphtheria bacillus in 1884. In 1888, the toxin of the diphtheria bacillus was determined.

Epidemiology

Pathogens

Corynebacterium Diphtheriae (also known as the bacillus Klebs-Loeffler), is a rod-shaped bacillus, no shell, no bivalve spores, gram (+) non-cellular aerobic. Size 2-6 x 0.5-1mm. Observed under the microscope, they are often arranged together to form V, L, Y. In the culture medium, the colonies are grey to black.

There are 3 types of biology: Gravis intermedins and Mitis. These types of antigens have the same antigen as Polyosit, the diphtheria bacteria do not have this antigen.

Diphtheria has a high resistance to the environment, at room temperature, in imitation film has dried or sticks to clothes, utensils ... Can live quite a long time. In cold and dry climates, bacteria are better tolerated in raw milk for 20 days. Died at 500C in 6 minutes, 650C in 2 minutes. Under natural light can live a few days. In an environment with enough oxygen, rich in plasma, the temperature of 36-37 develops very quickly, after 10-12 hours, colonies are formed.

  1. Diphtheria produces exotoxins, easy to be activated with light temperature. This property of diphtheria exotoxins is used as an antitoxin. Diphtheria toxin is the main causative factor, the amount of toxin is related to the biological type.

Inoculum

Humans (patients and carriers) are the only source of the disease. The patient is the source of transmission from the end of the incubation period until it is recovered 2-3 weeks, sometimes monthly, in some cases up to 64 weeks. Asymptomatic carriers (10-50% rate during an outbreak) and carriers after getting sick are very dangerous sources of infection due to their difficulty to control.

Infection

The main way of transmission: Through the respiratory tract due to direct contact (coughing, sneezing, talking ...) the diphtheria bacillus is present in the secretions from the nose and throat of the patient.

Indirect transmission: Through utensils, clothes, food, especially raw milk contaminated with germs.

Sense of the body

Ages susceptible to the disease are children under 15 years of age, the index of infection is about 15-20% in children who do not have immunity. Newborn babies do not get sick because they have passive antibodies passed from their mother.

After the disease has a stable immunity. However, the recurrence rate is 2-5%. Hidden infections also have the same immunity as when sick.

Immunity gained after the detox injection is usually long but gradually diminishes so if you don't get the injection again you can get sick

Detecting immunity to diphtheria bacillus by Schick reaction is a neutral reaction, injected into the skin 0.1 ml of pure diphtheria toxin (equivalent to 1/50 MLD) mixed in Albumin. If the body does not have antibodies to the diphtheria toxin, a local inflammatory reaction will develop. If the body has antibodies to diphtheria toxin, there is no inflammatory reaction (negative reaction), the Schick reaction is usually only applied in the epidemiological investigation of diphtheria.

Mechanism of pathogenesis and pathology

Mechanism of pathogenesis

The entrance is the respiratory tract mucosa: nose, larynx, genital tract, and injured skin. At the entrance to the diphtheria bacillus reproduces and develops, secretes exotoxins. Exotoxins in the circulatory system and lymph travel throughout the body cause damage in all organs, especially in the heart and central nervous system, adrenal system.

The exotoxin of diphtheria is a polypeptide chain, when the lower Disulfide bridge splits into two parts: Part B attaches to the receptor of the cell membrane and part A penetrates the cell membrane, reducing metabolism. and protein synthesis leads to cell degeneration and death. The pathogenesis of diphtheria is not only related to the quantity and toxicity of the exotoxins, but also to the body's response to the pathogen and its metabolic products. When there is a combined streptococcal infection, diphtheria often gets worse.

Diphtheria toxin resistance: Only able to neutralize toxins still circulating in the blood that has not yet penetrated into the cells.

Pathological anatomical injury

The primary damage in diphtheria is the process of fibromyositis forming a pseudomembrane at the entrance, epithelial cells are necrotic, accompanied by effusion haemorrhage rich in fibrinogen. Fibrinogen met Thrombokinase released from necrotic cell organization will coagulate to form a Fibrin membrane that adhere to the epithelial layer. In the pseudomembrane also see phagocytic cells and diphtheria bacilli.

The heart is often enlarged, the heart muscle degenerates.

Nerve: Inflammation of the degenerative nerve of the Myelin layer and damage to the anterior keratinous layer and to the spinal cord are often damaged, and rarely, hemorrhagic edema and meningitis.

Other organs: Body enlargement and oedema of interstitial tissue, hepatocytes, spleen necrosis.

clinical

Divide the clinical form

Corresponding to the location of the diphtheria bacillus infiltration can be

Pharyngeal diphtheria.

Diphtheria of the larynx.

Diphtheria of the nose.

Diphtheria in other places.

Divide according to the severity of the disease is based on intoxication syndrome

Mild diphtheria.

Moderate diphtheria.

Severe diphtheria.

Malignant diphtheria (toxin).

Physical symptoms of the disease

Pharyngeal diphtheria

The most common form of disease, accounting for 40% - 70% of cases.

Incubation: Usually 2-5 days to 10 days.

Body: Usually mild fever 37 0 5 - 38 0 C, but very tired, pale skin, rapid pulse, poor appetite, not feeding, crying…. peripheral blood leukocyte count increased slightly.

Throat: Red, painful inflammation when swallowing the two sides of the neck swelling up, making the neck open, lymph nodes are slightly swollen, a little pain exam the throat and see a fake membrane on the face of Amydal. The pseudo-film is white or gray, with shiny yellow luster, and adheres to the slightly solid surface of Amydal, very difficult to reliably, if the bleeding into the water is not dissolved.

If the patient is treated promptly, the pseudomembrane does not spread around and dissolves in 3-4 days.

In diphtheria pharynx there are the following forms:

Localized pharyngeal diphtheria: Diaphragm only localized in Amydal.

Diphtheria of pharynx can spread: When the pseudomembrane spreads out Amydal (the anterior column, the posterior column of the palate, the posterior wall of the throat, the reed ...).

Other bodies: The light form of pseudomembrane is as small as bean seed, the pseudomembrane is only found in one Amydal.

Diphtheria of the larynx

Meet in 20-30% of cases.

Most are secondary to pharyngeal diphtheria, due to the false membrane spreading from the throat. Laryngeal diphtheria usually progresses through 3 stages:

Hoarse phase: His voice is hoarse with a low fever and intoxication.

Stage of dyspnea: Wheezing, breathing in, there is a hissing sound, the respiratory muscles contract above and below the breast. Shortness of breath is divided into 3 degrees:

Grade I: Breathing difficulty increases with stimulation.

Grade II: Persistent difficulty breathing, patient is restless but awake.

Grade III: Fast, shallow, pale, lethargic breathing and lethargy.

Stage asphyxiation and death due to laryngeal narrowing.

Diphtheria of the nose

Meet in 4-10% of cases.

In the nose there is a clear discharge or blood, pus is usually on one side of the nose, outside the mouth of the nostrils with ulcers and cracks. Inside the nostrils, there is a false membrane.

Diphtheria of the nose is common in children.

Diphtheria in other places

Diphtheria skin: At the spot where the skin is scratched the diphtheria bacillus penetrates to form an ulcer with a diameter of 0.5 - 3 mm deep sunken with a gray scaly easy to haemorrhage.

Diphtheria of the eye conjunctiva: Conjunctival congestion, swelling of the eyelids, discharge mixed with pus from the eye of the pseudo-membrane in the easy eye conjunctiva, bleeding after shedding

Diphtheria can be found in other organs depending on the entrance of the bacteria such as the urinary-genital tract mucosa, anus, ear canal ...

Malignant diphtheria

This form of the disease is usually caused by the development of the diphtheria pharynx. It happened very fast, heavy

Body as a whole: High fever, fast blood pressure, heart failure, blue skin, tiredness, liver, vomiting, nosebleed, nosebleeds, gastrointestinal bleeding, urinary bleeding

Spot: pseudomembranous spread to the nasopharynx, larynx accompanied by necrotic haemorrhage around the cervical ganglia, sticking to blocks. The neck is swollen and swollen, and it can spread to the collarbone or even down the chest. Bad breath usually dies after the longest 24 to 48 hours in a week due to complications

Symptoms

Diphtheria forms all have complications.

Myocarditis

This is the most common complication, myocarditis may appear early in the early days of illness but maybe late at 3-5 weeks of the disease when the disease is in the recovery phase, usually seen on day 6. 14.

Peripheral neuritis

Week 1-2 of the disease: encounter early complications such as paralysis of cranial nerves (wire III, IV, VI, VII, IX, X ... causing paralysis of the eye, paralysis of the eye muscles, paralysis of the ability to regulate with light .

Week 4-6: Polyneuritis, causing soft paralysis of extremities, diaphragmatic paralysis, intercostal muscle leading to respiratory failure.

Other complications

Kidney: Proteinuria, cylindrical, red blood cells in the urine.

Superinfection of the lungs.

Thrombocytopenic purpura.

Implementing the quadrants

Clinical basis

Symptoms of severe systemic intoxication, low fever.

Subclinical

The dummy membrane has characteristics as described above on the assay.

Search for pathogenic bacteria by staining and culture. Get the pasteurized broth to inject under the skin for rats, mice die after 2-4 days. If injected into the skin for mice, the injection site will cause necrosis

Epidemiology

Diphtheria is common in young children in the same kindergarten, kindergarten classroom

Differential diagnosis

It is necessary to distinguish diphtheria from:

Staphylococcal pharyngitis: Amydal pharyngeal mucosa may have a white coating but easy to peel, peel off bleeding, soluble in water.

Plaut-Vencent pharyngitis: Amydal unilateral necrotic ulcer. Systemic mild intoxication in the pharynx contains B.Fusilormis and Borelia Vincentii.

In addition, it is necessary to differentiate with mononucleosis, syphilis infections, Candida pharyngitis ... ... laryngeal, laryngeal pressure, laryngeal pressure, laryngospasm.

Treatment

The principles of treatment

Neutralize toxins as soon as possible.

Antibiotics kill bacteria.

Anti-superinfection and recurrence.

Treatment in bed, absolute rest, monitoring, prevention and treatment of the syndromes.

Adequate nutrition.

Neutralizes diphtheria toxins

Anti-diphtheria toxin (Serum Anti Diphtheriae- SAD). This is the best remedy, should be used early, right from when diphtheria is suspected. SAD works only with toxins circulating in the blood

Dosage

Diphtheria of the pharynx or larynx: Dose of 20,000-40,000 UI in the first 48 hours.

Diphtheria of the pharynx spread to the nose: 40,000 - 60,000 UI.

Widespread, malignant diphtheria 80,000 - 100,000 UI.

How to use

Phase SAD in saline isotonic, slow intravenous infusion time more than 60 minutes to neutralize toxins quickly.

Note: SAD is produced by immunizing horses so it can cause allergies. Before use, it is necessary to test the endoderm reaction (0.1 ml of SAD diluted 1/1000 with 0.9% sodium chloride). Follow up for 10-30 minutes if there are no red circles on the skin and negative reaction. If the reaction is positive, it is necessary to inject according to the method of susceptibility Besredka.

Antibiotic

Antibiotics used in treatment to kill Corynebacterium Diphtheriae are: Penicillin, ampicillin, erythromycin, rifampicin, clindamycin, Cephalosporin ... But penicillin is most commonly used.

Dosage

Penicillin 25000–50,000 UI / Kg / day or erythromycin 40-50mg / Kg / day.

Duration of antibiotic treatment: 10-14 days.

Symptomatic treatment, prevention and treatment of complications

Bed rest: Absolute rest, at least 2-3 weeks, when the most complicated complication is 55-day resting myocarditis.

Cardiovascular, respiratory, sedative.

Sufficient nutrition, eat a liquid, easy-to-digest diet.

When complications of myocarditis: Prednisolon 1-1.5 / Kg/day, for 2 weeks, for diuretics, cardiovascular support.

Monitor respiratory conditions: When having difficulty breathing 2 to open the trachea.

Criteria for discharge

No fever, all fake membranes, weight gain, strength.

Complications are gone.

Remove pharyngeal negative bacteria, 2 times at least 7 days apart.

Prevention

Regularly monitor children's collectives to prevent epidemics from occurring. Pay attention to usual hygiene measures to prevent respiratory infections.

Early detection, isolation of patients with suspected diphtheria, and early treatment.

The patient's chamber must be disinfected regularly every day and at the last time.

Contacts of the patient need to monitor throat mucus implantation. Carriers of erythromycin take erythromycin 7-10 days.

Specific disease prevention: Diphtheria toxin vaccination according to the National Immunization Program, usually in combination with whooping cough and tetanus vaccine.