Pseudotuberculosis is a yersiniosis infection characterized by the development of toxic, allergic and polyococcal organ symptoms. The course of pseudotuberculosis is accompanied by polymorphic manifestations: fever, intoxication, intestinal disorders, catarrhal phenomena, scarlet fever-like rash, arthralgia and swelling of the joints. A crucial role in the diagnosis of pseudotuberculosis belongs to bacteriological research, serological methods, PCR. Antibiotics (tetracycline, chloramphenicol, cephalosporins, etc.) are prescribed as etiotropic therapy for pseudotuberculosis.; additionally – antihistamines, infusion solutions.
General information
Pseudotuberculosis (extraintestinal yersiniosis, Far Eastern scarlet fever) is an infectious pathology of the yersiniosis group, occurring with intoxication–febrile syndrome, damage to the gastrointestinal tract, skin, joints. The incidence of pseudotuberculosis is registered in all countries of the world; in the USA, extraintestinal yersiniosis is diagnosed annually in 10 thousand people. The incidence rate is higher in economically developed countries, where food epidemic outbreaks are noted along with sporadic cases. Pseudotuberculosis occurs in all age groups, mainly among children under 14 years of age. Reducing the incidence of pseudotuberculosis is an urgent task of practical infectious diseases, gastroenterology, pediatrics.
Causes
Pseudotuberculous infection is caused by the gram-negative bacterium Yersiniae pseudotuberculosis, belonging to the Enterobacteriaceae family. Currently, there are 21 serotypes of pseudotuberculosis yersinia within the group. The bacterium is sensitive to boiling, drying, exposure to ultraviolet light and disinfectant solutions. At the same time, Y. Pseudotuberculosis is able to grow and multiply at the temperature regime of the refrigerator (1-4 ° C) – under these conditions, the microorganism can persist for a long time on vegetables and other food products.
Pseudotuberculosis yersinia are found in many species of mammals and birds, but the main reservoir of infection are mouse-like rodents. Small animals infect soil, water, root crops and vegetables in fields and vegetable gardens with their secretions. With further storage of agricultural products in refrigerators and vegetable storages, the contamination increases. Under favorable conditions, Y. Pseudotuberculosis remain viable in water for 2-8 months, in soil for about a year. Infection of a person with pseudotuberculosis is carried out in an alimentary way, during the consumption of water or vegetable dishes (salads, vinaigrettes, fruits, etc.), dairy products that have not undergone preliminary heat treatment. The maximum increase in the incidence of pseudotuberculosis among the population is registered in February–March, which is associated with the widespread consumption of vegetables and fruits of last year’s harvest coming from vegetable stores.
In the pathogenesis of pseudotuberculosis, there is a phase of infection, an intestinal (enteral) phase, a phase of regional infection, a phase of generalization of infection, a phase of parenchymal infection and convalescence. Getting into the gastrointestinal tract with infected products, pseudotuberculosis yersinia enter the ileum, where they are introduced into enterocytes, causing inflammation – terminal ileitis. The further spread of yersinia into the regional mesenteric lymph nodes leads to the development of mesadenitis. In the phase of regional infection, the vermiform process and the caecum may be involved in the pathological process.
Generalization of yersiniosis infection is associated with the release of microorganisms and their toxins into the blood, the development of bacteremia and toxemia. This phase corresponds to the maximum severity of the clinical symptoms of pseudotuberculosis. With the progression of the process, the cells of the reticuloendothelial system are affected with the predominant fixation of the pathogen in the liver and spleen. The parenchymal phase of pseudotuberculosis is accompanied by hepatosplenomegaly, a violation of liver function. Activation of cellular immunity and the production of specific antibodies marks the elimination of the pathogen and clinical recovery.
Classification
Pseudotuberculosis can occur in various clinical forms with the development of isolated or mixed syndromes. Based on this principle, the are:
- abdominal form is distinguished – it proceeds with intense, paroxysmal or constant pain in the right iliac region, fever, signs of enterocolitis and, due to the similarity of symptoms, it is often diagnosed as acute appendicitis.
- the scarlet fever–like form is the main, and sometimes the only symptom is a skin rash resembling that of scarlet fever.
- arthralgic form – characterized by fever, myalgia and polyarthritis with swelling of the joints.
- a mixed form – combines dyspeptic syndrome, scarlet fever-like rash, arthralgia, permanent or wave-like fever.
- septic variant – accompanied by the development of infectious and toxic shock.
Some authors supplement the classification of pseudotuberculosis with forms of acute appendicitis, mesenteric lymphadenitis, terminal ileitis and secondary focal form (enterocolitis, erythema nodosum and Reiter’s syndrome). In typical cases, pseudotuberculosis occurs with a partial or complete combination of symptoms of various clinical forms. The severity of pseudotuberculosis (mild, moderate and severe) is assessed by the severity of intoxication and changes in the internal organs.
Symptoms
The incubation stage of pseudotuberculosis lasts from 3 to 18 days. This is followed by an acute (less often – subacute or gradual) rise in temperature to 38-40 ° C, accompanied by a general intoxication syndrome (weakness, chills, poor appetite, muscle and joint pain, insomnia, headache, injection of sclera). In the initial period, catarrhal changes may occur: sore throat, nasal congestion, cough, sometimes tonsillitis. In the future, the clinical picture of pseudotuberculosis is supplemented by pain in the epigastrium and right iliac region, nausea, vomiting, relaxation and increased stool up to 2-3 or more times a day.
From the 3rd-4th day, against the background of increased symptoms of pseudotuberculous intoxication, a small-point or spotty-papular rash appears, sometimes accompanied by itching and peeling of the skin. The typical location of the rash in pseudotuberculosis is the lower abdomen, axillary areas, and lateral surfaces of the trunk. Rashes around the joints are larger and more intense, up to continuous erythema. Cyanotic hyperemia of the skin of the face and neck (“hood symptom”), hands (“glove symptom”), feet (“sock symptom”) is characteristic. Like scarlet fever, white dermographism, “crimson tongue”, pallor of the nasolabial triangle are detected. The duration of the period of skin rashes is 3-7 days.
During the height of pseudotuberculosis, arthralgias, swelling of the interphalangeal, wrist, ankle and knee joints occur. Often there is an increase in the liver and spleen, jaundice of the skin and sclera, an increase in biochemical liver samples; in some cases, a picture of acute cholecystitis develops. Changes from the cardiovascular system may include bradycardia or tachycardia, moderate arterial hypotension, and less often – arrhythmia. Signs of infectious and toxic kidney damage in pseudotuberculosis are lower back pain, decreased diuresis; changes in the general analysis of urine (microhematuria, cylindruria, albuminuria, pyuria). Diffuse glomerulonephritis may develop.
With a favorable course of pseudotuberculosis, improvement occurs on the 5th-7th day: there is a gradual decrease in temperature, signs of intoxication disappear, rash and signs of damage to internal organs disappear. Full recovery occurs by the 15th day from the onset of the disease. In more severe cases, the duration of the disease can reach 1-1.5 months; with relapses and exacerbations of pseudotuberculosis, convalescence is delayed up to 2-3 months. Relatively rare complications of pseudotuberculosis can be myocarditis, pneumonia, meningitis, polyneuritis, acute renal failure.
Diagnostics
When conducting clinical diagnostics, the combination of fever, scarlet fever-like rash, signs of gastrointestinal and joint damage is of the greatest importance. The epidemiological history of pseudotuberculosis often indicates the group nature of the incidence, the consumption of vegetables, winter-spring seasonality. A decisive role in the diagnosis of pseudotuberculosis belongs to laboratory (bacteriological, serological, molecular genetic) research methods. To isolate the bacterial culture, blood, urine, sputum, feces, and a smear from the pharynx are seeded on nutrient media. From serological studies, the agglutination reaction, precipitation reaction (PR), complement binding reaction, passive hemagglutination reaction, immuno-enzyme assay are used to confirm pseudotuberculosis. For emergency diagnostics, the PCR method is used, with the help of which the DNA of yersinia is detected not only in biological material, but also in water and food.
Sometimes, in order to exclude an acute abdomen, it is necessary to resort to diagnostic laparoscopy or laparotomy. Due to the polymorphism of the clinical picture, pseudotuberculosis has to be differentiated with measles, scarlet fever, rubella, acute intestinal infections, enterovirus infection, hemorrhagic fevers, rheumatism, typhus, etc.
Treatment
During the fever period, bed rest and a gentle diet are prescribed. Mild forms of pseudotuberculosis usually do not require antibiotic therapy. With moderate and severe course of infection, chloramphenicol, cephalosporin antibiotics, tetracycline, doxycycline, gentamicin sulfate, streptomycin sulfate are the most effective of etiotropic drugs. The course of antimicrobial therapy is 7-10 days; in the generalized form – 14 days. With severe intoxication and dehydration, infusion therapy is performed – intravenous administration of glucose-electrolyte and polyionic solutions. The complex therapy of pseudotuberculosis includes desensitizing agents, NSAIDs, corticosteroids, enterosorbents, immunocorrectors, multivitamins. The criteria for recovery are normalization of well-being and two-fold negative results of bacteriological examination.
Prognosis and prevention
Usually pseudotuberculosis proceeds benign and ends with recovery. Deaths due to possible complications are rare. The main place in the system of preventive measures is occupied by rodent control, proper organization of food storage in warehouses and at home, sanitary control over water supply, storage and sale of vegetables, food production technology and catering establishments.
