Typhoid fever - Causes, symptoms and treatment. MF.

Typhus abdominalis is an acute anthroponous infectious disease of a bacterial nature, characterized by prolonged fever and intoxication, as well as damage to the lymphoid apparatus( especially the intestine, with the formation of ulcers).

The name "Typhos", which means "fog / smoke", it came to us from a long time ago, because earlier all diseases with fever and periodic loss of consciousness were called so.

The causative agent of typhoid fever

The causative agent of typhoid fever - Salmonella typhi, is a bacillus, of medium forms, has the following structure, the characteristics of which allow identifying the pathogen among other pathogenic Salmonella, and this structure predetermines the features of vital activity and the ways of interaction with the macroorganism:

-antigen( determines the viability, i.e., how long the pathogen can survive under adverse conditions);
• H-antigen( flagellate - determines the mobility of bacteria);
• Vi-antigen( is a specific antigen of virulence, i.e., a high degree of ability to infect);

• Endotoxin( a toxin that is contained within the pathogen and released after its death, causing damage);
• Vorsinki are the formations by which the pathogen is anchored and introduced into enterocytes( intestinal cells);
• Tropism( the most common lesion) to neural tissue;
• Ability to proliferate in cells of the immune system( CMF cells - a system of monocytic phagocytes that can either be fixed in the lymphoid organs or move freely)
• R-plasmids( genes that determine the synthesis of enzymes that destroy antibacterial drugs), due to thisfactor, which causes drug resistance, as well as due to the ability of the causative agent to persist for a long time( to be) in the body, new drug resistant strains are created;This is also facilitated by improper use of antibacterial drugs.

Salmonella typh causative agent of typhoid

Salmonella typh in the intestine

Unlike some other bacilli, this causative agent does not form spores and capsules, but this does not detract from its stability in the external environment, because it is relatively stable and dies only at high temperaturesboiling, autoclaving, etc.) 60 ˚ С - 30 minutes, boiling causes death instantly. Also kills under the action of disinfectants( phenol, chlorine, lezole) for several minutes. Low temperatures for him are not fatal;It reproduces well and lasts for a long time in milk products( milk, sour cream, jelly) - it can stay there for several months, it can spend about the same amount of time in the soil and water bodies( in running water up to several days).

Causes of typhoid infection

Disease is common everywhere, without territorial, age and sex restrictions. Summer-autumn seasonality is characteristic, because it is during this period that favorable conditions are created for the fecal-oral transmission mechanism.

Source of infection - a sick person or carrier( especially for 2-3 weeks of the disease, when there is a massive excretion of the pathogen).Ways of infection - contact-household, water, food( with the use of dairy products).

Symptoms of typhoid

1. The incubation period is from 3-50 days, but on average 10-14.Characterized by the period from the moment of introduction to the first clinical manifestations. The organism receives the infectious dose of the causative agent necessary for the development of the disease( 10⁷ bacterial cells).Penetrating through the upper parts of the digestive tract, bypassing all protective mechanisms, the pathogen reaches the small intestine and is introduced into its lymphoid system → along the lymphocytes reaches the nearest regional nodes( mesenteric, possibly inguinal), where it multiplies to a critical level, after which a breakthrough occurs in the bloodstreamand there is bacteremia( Salmonella typhi in the blood), characterized by an initial period of the disease. Before the breakthrough into the circulatory system, there are no symptoms except for an increase in the inguinal lymph nodes( this may not be)

2. The initial period lasts for 7 days and is characterized not only by the spread of the pathogen along the bloodstream, but also by the immune response - macrophages beginabsorb the pathogen, as a result, endotoxin is released, toxemia is added to the already existing bacteremia, which is accompanied by:

• acute / subacute development of intoxication in the form of persistent headache, rising temperature to 39-40 ° C for 5-7 days( can hold up to 2 weeks), inhibition, adynamia, decreased appetite.

• The gastrointestinal tract is affected not only by the mucous membrane, but also by the intestinal nervous tissue. As a result, cramping and persistent abdominal pain, flatulence, constipation and diarrhea( in the form of "pea puree" with acidic odor)The tongue is gray-white and the tongue is thickened. The gastrointestinal tract is affected so much, with untimely diagnosis and treatment, that the connective tissue carcass of the intestine is practically destroyed, resulting in a high risk of perforating ulcers and peritonitis.

• Due to the tropism to the nervous tissue, the damage to the nervous apparatus of the intestine is not limited to symptoms, there are lesions from the peripheral nerves in the form of cooling / pallor and numbness of the extremities.

• Due to the spread of the pathogen and its penetration into the skin, a roseolous rash appears on the abdomen and lateral surfaces of the chest in the form of small dots up to 3 mm in diameter, sometimes rises above the skin, when pressed they disappear and after a few seconds reappear.

3. Phase of parenchymal dissemination. Lasts for the next 7 days. As the blood stream circulates, the pathogen is absorbed by the cells of the monocytic phagocyte system( including the parenchymal organs), but the pathogen can not only continue to exist in these cells, but also multiply in them, and also pass into L-forms( this precedes the carrier).As a result, this leads to IDS( immunodeficiency state), as well as parenchymal dissemination - excretion of the pathogen from the parenchymal organs( due to the fact that a lot of macrophages / phagocytes are concentrated there + by means of a drift from the intestine via communicating vessels, the pathogen passes to these parenchymal organs).

This explains the following symptoms:

• hepatosplenomegaly( enlargement of the liver and spleen), their painfulness is possible, as well as icteric staining of the palms and soles due to a violation of keratin metabolism of the liver.

• Kidney damage can be accompanied by a decrease in excretory function.

• from the lungs - hard breathing and scattered rales. Because the excretory function of the organs presented above does not practically suffer, the pathogen in them begins to be allocated again. Isolation occurs with bile / breast milk in nursing mothers / feces / urine / sweat and salivary glands.

4. Continuation of excretory excretion and formation of allergic reactions. Continues for the next 7 days. But these reactions are not with the standard manifestations of allergy, but they are characterized by the restoration of the reserves of the immune system and the emergence of specific and nonspecific complications.

5. The recovery phase occurs at the end of 4 weeks of illness, and clinical recovery, that is, after the disappearance of symptoms, is not always accompanied by bacteriological clearance from the pathogen. It is characterized by a decrease in body t,null, restoration of appetite, moistening of the tongue and disappearance of plaque from it. But carriage is not excluded, because among those who have recovered 2-3% become carriers, therefore, after recovery, a three-time study with an interval of 5 days is necessary.

The above symptoms can be very variable, both with the abortive / erased clinic, and in various combinations among themselves.

Diagnosis of typhoid

Depending on the stage of the infectious process, different materials are taken at different times for the study and carried out by various diagnostic methods.

• There are no symptoms during the incubation period, so the disease itself is difficult to suspect.

• At the first clinical manifestations corresponding to 1 week( stage of the initial period), the following materials are taken for the study using the following methods:
- Bacteriological method with blood / urine / feces sowing, on nutrient media;The faster the method is wired, the more likely it is that reliable results will be obtained. Preliminary results are obtained in 2-3 days, and the final results for 10 days.
- The serological method is used at the end of the first week - the beginning of the second and until the recovery, the sera of the patient with
& gt;RA( agglutination reaction) according to Vidal with O and H antigens: O-antigens appear on day 4 and decrease during recovery, H-antigens appear on days 8-10 and persist for 3 months after recovery, they can also indicate vaccination;
& gt;PGNA( indirect hemagglutination reaction) is carried out with O, H and Vi antigens;This method is preferred more often than others, because it is the most specific and highly sensitive, aimed at determining specific antibodies.
& gt;RIF, IFA, RNF, PHA, IRA - these methods are also very specific and informative, but they are rarely resorted to, because RNGA is quite enough.
- UAC: ↓ Lc and Nf, ESR normal, there are no eosinophils( "E").

Treatment of typhoid

Treatment is continuously associated with nutrition and is performed only in the hospital with strict pastel regimen up to 11 days from the drop in temperature( from 8 days from the normalization of temperature it is allowed to sit, from 11 days - to walk).

Partially the patient is transferred to parenteral( through intravenous administration of nutrient media) food, so as not to provoke perforation of the intestinal walls.

The diet is the most mechanically and chemically sparing, but it is quite caloric( table 4 and 4b, as you recover the diet can be expanded - 4c and 2).Products that cause increased peristalsis and gas formation( black bread, peas, beans, cabbage dishes) are excluded. The diet includes low-fat cooked varieties of meat and fish, egg dishes, white bread, sour-milk products, crushed vegetables and fruits.

Antibiotics with a specific orientation against S. typhi are used as etiotropic therapy( against the pathogen): Ampicillin, Levomycetin, Amoxiclav, Amoxicillin, Unazine, Rifampicin. They can be combined with each other.

Assign immunomodulators, because they speed up the process of treatment and make it more effective.

General restorative treatment: prebiotics, probiotics, symbiotics, a complex immunoglobulin preparation( KIP), vitamin complexes is possible.

Complications of typhoid

Specific: intestinal bleeding, perforation of the intestinal wall, development of peritonitis.

Nonspecific: pneumonia, parotitis, cholecystitis, thrombophlebitis, etc.

Prevention of typhoid

Specific: According to epidemic indications( if more than 25 people per 100,000 population + exit to countries with high morbidity + constant contact with carriers) - in this case, alcohol dry vaccine Tifivac is prescribed, it can be carried out from 15-55 years. If the age from 3-15 years old is a typhoid vaccine, Vi-polysaccharide liquid viacin( Vianvak), and after 3 years repeat the revaccination.

Nonspecific prevention:

• Compliance with sanepid rules at various levels of the organization( from water supply - wastewater treatment, to personal hygiene);
• Survey of employees of food enterprises( with the help of RNGA, they are not allowed to work until results are obtained);
• For each case of the disease, an emergency notification is sent to the Sanitary and Epidemiological Supervision Authority. The patient is hospitalized, the contact persons are observed for 21 days, and the final disinfection is carried out in the hearth.
• After the transferred disease, no less than 10 days after discharge, 5-fold bacteriological examination of feces and urine is carried out, with an interval of 2 days, then for 2 years, 4 times a year, a 3-fold bacteriological study of feces and urine is carried out. If all the results of the study are negative, people are removed from the register.

Therapist doctor Shabanova I.Е.