Typhoid fever

Typhoid fever is an acute anthroponous infectious disease with a fecal-oral transmission mechanism, characterized by cyclic flow, intoxication, bacteremia and ulcerative lesions of the small intestine lymphatic system.

Typhoid fever is a systemic disease caused by S. Typhi. Symptoms include high fever, prostration, abdominal pain and a pink rash. Diagnosis is based on the clinic of the disease and is confirmed by culture research. Treatment is given by ceftriaxone and ciprofloxacin.

ICD-10 code

A01.0. Typhoid fever.

Epidemiology of typhoid fever

Typhoid fever is classified as a group of intestinal infections and typical anthroponosis. The source of infection is only a person - a patient or a bacterio-exciter, from which the pathogens are excreted into the external environment, mainly with feces, less often - with urine. With feces, the pathogen is excreted from the first days of the disease, but a massive discharge begins after the seventh day, reaches a maximum at the height of the disease, and decreases during the period of convalescence. Bacteriovirus in most cases lasts no more than 3 months (acute bacterial excretion), but 3-5% form chronic intestinal or, more rarely, urinary bacterial excretion. The most dangerous epidemiologically, urinary carriers due to the massive bacterial release.

For typhoid fever is characterized by fecal-oral mechanism of transmission of the pathogen, which can be carried out by water, food and contact-household ways. The transmission of the pathogen through water, which prevailed in the past, plays an important role even now. Water epidemics grow violently, but quickly end when they stop using an infected source of water. If epidemics are associated with drinking water from a contaminated well, the diseases are usually focal.

Sporadic diseases are now often caused by the use of water from open reservoirs and industrial water used in various industrial enterprises. Possible outbreaks associated with the use of foods in which typhoid bacteria can persist and multiply (milk) for a long time. Infection can also occur in a contact-household way, in which environmental factors become transmission factors. The susceptibility is considerable.

The index of contagiosity is 0.4. People who are between the ages of 15 and 40 are most likely to fall ill.

After the transferred disease, a stable, usually lifelong immunity is produced, however, in recent years, due to antibiotic therapy of patients and its immunosuppressive effect, the intensity and duration of acquired immunity appeared to be less, as a result, the incidence of repeated diseases with typhoid fever increased.

For typhoid fever, epidemic spread is characterized by summer-autumn seasonality.

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What causes typhoid fever?

About 400-500 cases of typhoid are detected in the US annually. Typhoid bacilli are excreted with the feces of asymptomatic carriers and people with active cases of the disease. Inadequate hygiene after defecation can spread S. Typhi to public food and water supply systems. In endemic regions where sanitation is usually inadequate, S. Typhi is transmitted more to water than to food. In developed countries, the main mode of transmission is food, while microorganisms are ingested during its preparation from healthy carriers. Flies can carry the pathogen from the feces to food. Sometimes typhoid fever is transmitted directly (fecal-oral route). This can occur in children during games and in adults during sex. Occasionally, hospital staff, who do not follow adequate precautions, receive the disease during the change of dirty bed linen.

The causative agent enters the human body through the gastrointestinal tract. Further, it penetrates into the blood through the lymphatic canal system. In acute cases, ulceration, bleeding and intestinal perforation may occur.

About 3% of untreated patients become chronic carriers. The microorganism is in their gallbladder and is excreted with feces for more than 1 year. Some carriers do not have an anamnesis of a clinical disease. Most of the 2000 carriers in the US are elderly women with chronic biliary pathology. Obstructive uropathy associated with schistosomiasis may become a predisposing factor in certain patients with typhoid fever to become urinary carriers. Epidemiological data indicate that carriers are more likely to develop hepatobiliary cancer than the general population.

What are the symptoms of typhoid fever?

Typhoid fever has an incubation period (usually 8-14 days), which is inversely related to the number of microorganisms in the body. Typhoid fever usually has a gradual onset. At the same time, fever, headache, arthralgia, pharyngitis, constipation, anorexia and abdominal pain and tenderness occur in the palpation of the abdomen. Less frequent symptoms of typhoid fever include dysuria, an unproductive cough and nasal bleeding.

If typhoid fever is not treated, then the body temperature rises stepwise for 2-3 days, remains elevated (usually 39.4-40 ° C) for the next 10-14 days, begins to gradually decrease by the end of the 3rd week and returns to normal values during the 4th week. Long-term fever is usually accompanied by a relative bradycardia and prostration. In acute cases of the disease there are symptoms from the side of the central nervous system, such as delirium, stupor and coma. Approximately 10% of patients on the surfaces of the chest and abdomen have a discrete pink pale rash (pink spots). These lesions appear on the 2nd week of the disease and disappear within 2-5 days. Frequent splenomegaly, leukopenia, impaired liver function, proteinuria and moderate consumption coagulopathy. There may be acute cholecystitis and hepatitis.

In later stages of the disease, when gastrointestinal damage comes to the fore, bloody diarrhea may appear, and the feces may contain an admixture of blood (20% hidden blood and 10% obvious). Approximately 2% of patients develop acute bleeding at week 3 of the disease, which is accompanied by a mortality rate of about 25%. The picture of an acute abdomen and leukocytosis during the 3rd week of the disease suggest an intestinal perforation. In this case, the distal part of the ileum is usually damaged. This occurs in 1-2% of patients. Pneumonia can develop during the 2-3 weeks of the disease. It is usually due to a secondary pneumococcal infection, but S. Typhi can also cause the formation of pulmonary infiltrates. Bacteremia sometimes leads to the development of focal infections such as osteomyelitis, endocarditis, meningitis, soft tissue abscesses, glomerulitis or the involvement of the genito-urinary tract. Untypical manifestations of infection, such as pneumonitis, fever without other symptoms or symptoms persistent for urinary infections, can cause late diagnosis. Recovery may last several months.

In 8-10% of untreated patients, the symptoms of typhoid fever, similar to the initial clinical syndrome, disappear after the 2 nd week of temperature drop. For unknown reasons, treatment of typhoid with antibiotics at the onset of the disease increases the incidence of recurrence of fever by 15-20%. In contrast to a slow drop in temperature with an initial disease with a relapse of fever, if antibiotics are again prescribed, the temperature quickly decreases. In some cases, relapses of fever occur.

How is typhoid diagnosed?

Typhoid fever must be differentiated with the following diseases: other infections caused by Salmonella, major rickettsiosis, leptospirosis, disseminated tuberculosis, malaria, brucellosis, tularemia, infectious hepatitis, psittacosis, infection caused by Yersinia enterocolitica, and lymphoma. In the early stages of the disease can resemble the flu, viral infections of the upper respiratory tract or urinary tract.

It is necessary to take away for examination the culture of blood, feces and urine. Blood cultures are usually positive only during the first 2 weeks of the disease, but stool cultures are usually positive for 3-5 weeks. If these cultures are negative, and there is every reason to suspect typhoid fever, the MO can detect a culture of a biopsy specimen of bone tissue.

Typhoid bacilli contain antigens (O and H), which stimulate the formation of antibodies. A fourfold increase in antibody titers to these antigens in paired samples taken at intervals of 2 weeks suggests an infection due to S. Typhi. Be that as it may, this test has only a moderate sensitivity (70%), and it lacks specificity. Many non-tofoid salmonellae react cross-over, and cirrhosis can produce false positive results.

How is typhoid treated?

Without prescribing antibiotics, the mortality rate is about 12%. Timely treatment allows you to reduce the death rate to 1%. Most deaths occur among impaired patients, infants and elderly people. Stupor, coma and shock reflect a serious illness, with their prognosis unfavorable. Complications mostly occur in those patients who do not receive typhoid fever, or treatment is belated.

Typhoid fever is treated with the following antibiotics: ceftriaxone 1 g / kg intramuscularly or intravenously 2 times a day (25-37.5 mg / kg for children) for 7-10 days and various fluoroquinolones (eg, ciprofloxacin 500 mg orally twice a day for 10-14 days, gatifloxacin 400 mg orally or intravenously once a day for 14 days, moxifloxacin 400 mg orally or intravenously for 14 days). Chloramphenicol in a dose of 500 mg orally or intravenously every 6 hours, is still widely used, but resistance to it is increasing. Fluoroquinolones can be used in the treatment of children. Alternative drugs, the purpose of which depends on the results of the in vitro sensitivity test, include amoxicillin 25 mg / kg orally 4 times a day, trimethoprim-sulfamethoxazole 320/1600 mg 2 times a day or 10 mg / kg 2 times a day (trimethoprim component ) and azithromycin 1.00 g on the first day of treatment and 500 mg once a day for 6 days.

In addition to antibiotics, glucocorticoids can be used to treat acute intoxication. After such treatment, a drop in temperature and an improvement in the clinical state usually follow. Prednisolone in a dose of 20-40 mg once a day inside (or an equivalent glucocorticoid) is prescribed for 3 days, usually this is enough for treatment. Higher doses of glucocorticoids (dexamethasone 3 mg / kg intravenously prescribed at the beginning of therapy and subsequently 1 mg / kg every 6 hours for 48 hours) are used for patients with severe delirium, coma and shock.

The food should be frequent and fractional. Until the fever falls below the febrile values, patients should adhere to bed rest. It is necessary to avoid the appointment of salicylates, which can cause hypothermia, hypotension and swelling. Diarrhea can be reduced to a minimum, with the appointment of only a liquid diet; for some time may require the appointment of parenteral nutrition. It may be necessary to administer liquid and electrolyte therapy, as well as blood replacement therapy.

Intestinal perforation and associated peritonitis require surgical intervention and expansion of antibiotic coverage of gram-negative flora, as well as bacteroides.

Relapses of the disease are subject to the same treatment, but treatment with antibiotics in cases of relapse rarely lasts more than 5 days.

If the patient is suspected of typhoid fever, the local health department should be notified, and patients should be removed from cooking until evidence of lack of MO is obtained. Typhoid bacilli can be detected within 3-6 months after the acute disease, even in those who do not become carriers later. Therefore, after this period, it is necessary to obtain 3 negative culture stool studies performed at weekly intervals to exclude carrier.

Carriers that do not have pathology from the biliary tract should receive antibiotics. The frequency of recovery with amoxicillin at a dose of 2 grams orally 3 times a day for 4 weeks is about 60%. Some carriers with gallbladder disease manage to achieve eradication by using trimethoprim-sulfamethoxazole and rifampin. In other cases, cholecystectomy is effective. Before it is carried out, the patient should receive antibiotics within 1-2 days. After the operation, antibiotics are also administered within 2-3 days.

How to prevent typhoid fever?

Typhoid fever can be prevented if drinking water is cleaned, pasteurized milk, chronic carriers are not allowed to cook, and sick people should be adequately insulated. Particular attention should be paid to precautions for the spread of intestinal infections. Travelers in endemic regions should avoid eating raw vegetables, food stored and served on the table at room temperature, and uninfected water. Water must be boiled or chlorinated before use, except when it is reliably known that the water is safe to consume.

There is a live attenuated oral protivotifoznaya vaccine (strain Tu21a). This inoculation against typhoid fever has approximately 70% efficacy. It is appointed every second day. A total of 4 doses are prescribed. Since this vaccine contains live microorganisms, it is contraindicated in immunocompromised patients. In the US, this vaccine is most often used in children under 6 years of age. An alternative vaccine is the Vi polysaccharide vaccine. It is prescribed by a single dose, intramuscularly, has an efficiency of 64-72% and is well tolerated.