INFECTIOUS DISEASES : TYPHUS (TYPHUS EXANTHEMATICUS) - etiology, pathogenesis, symptoms and course of, recognition, prediction and prevention
Included in the group of rickettsioses diseases that are common in different parts of the world, transmitted by blood-sucking parasites and flowing pronounced temperature reaction and the formation of specific changes in small blood vessels.
Etiology. There are the following basic forms ricketsiosis:
1) European typhus pathogen Rickettsia Prawaczeki;
2) krysinyy typhus pathogen Rickettsia typhi (IRickettsia Prawaczeki var. mooseri);
3) tick-borne typhus - Dermacentroxenus rlckettsii. Serum of patients with each of the forms ricketsiosis agglutinated O-form of a particular strain of Proteus: X19, x2 and Xk ;
Epidemiology. Most important is the European form of typhus, properly called epidemic unlike other endemic forms. The only reservoir of infection is a sick man. His blood pathogen circulates throughout the febrile period and the first days of convalescence. The preservation of the pathogen in megapotamicum time occurs due to some sporadic, sometimes recognized and registered diseases. Vector European typhus is a louse. From wswa, parasitic on the human head, and a crab lice, the role of a lice is overwhelming. While infecting the blood of the patient typhus louse becomes infectious only after 5 to 7 days. As an active carrier of typhus, louse tolerate this kind of disease, shorten its life (desquamation of the walls of the stomach, their porosity with seepage of blood from the stomach into the hemolymph). Infected lice allocate rickettsiae with bowel movements. Human infection occurs through; 1) rubbing the feces of lice and 2) rubbed into the skin itches crushed infected lice. While sucking blood louse does not emit rickettsiae with saliva (this is only possible with great destruction of the stomach in the last days of life of the infected fleas), but by piercing the skin with contaminated by ispareniya lice, louse can mechanically be entered rickettsiae in the capillaries of man. Pogodno to be aware that on linen and clothing contaminated with feces of lice, rickettsiae can be kept for long (up to 2 - 3 weeks) and to infect humans, used the clothes of the sick or dead from typhus, when all the lice that were on the dress already died (Weigl). This kind of infection is possible only where control measures are low and where there is processing and decontamination centers. Not being the cause of typhus, lice is a necessary condition for the spread of epidemic typhus. The susceptibility of people to typhus, typhoid depends largely on social conditions, which is having a huge impact on the breadth of the dispersion of the infection. The least susceptible are children, easy to carry typhus. This is Bolshoe epidemiological importance, as it is in children typhoid fever can often remain unrecognized due to the light within. The highest incidence falls on the young age of 20 - 25 years. A sharp decline in incidence during the summer associated with reduced lice infection; the disease is increasing from October, reaching a peak between February and April. In the spring increases and the severity of typhus. Moved typhus leaves immunity, but cases of recurrent disease often observed. In contrast to European forms of typhus others are endemic.
American rat typhus (Mexican, or cabanilla, Malay urban typhus, Manchurian typhus) is mostly of the nature of natural-focal zoonoses. The reservoir of the virus are rats and mice. Carriers of infection among animals are the rat lice and fleas. Infection from rats to humans is transmitted by fleas that produce rickettsiae with bowel movements. Human diseases occur mainly in the cities; they occur among a limited circle of persons - most of the workers in the food warehouses and businesses, usually densely infested by rats. Endemic foci of rat typhus exist in many parts of America, Asia, in the port cities of North Africa, in Europe - in France (Toulon), Turkey (Constantinople). Some of the endemic foci (Mexico, China) represent the peculiarity that in them there was a further transfer of infection from person to person clothing lice.
Tick-borne typhus is zoonotic diseases in rural areas. The reservoir of the virus are various wild rodents. Vectors - ticks of the genus Dermacentor and krasnoselka. Ticks from infected rodents, firmly retain and rickettsiae can transmit them to their posterity transovarially way. This fact forces us to consider ticks not only as vectors, but also as reservoirs of the virus. In some centers there is a very malignant course (Rocky mountain spotted fever, Brazilian fever), other benign (Marseilles fever). Vector Marseilles fever is the dog tick Rhipicephalus sanquineus. In some endemic foci found certain reservoirs of the virus - field mouse, Eastern vole, gopher, rat and vectors: ticks Dermacentor nutalli, D. silvarum, D. marginatus, D. pictus, Haemaphysalis concinna and H. punctata (they are also reservoirs of the virus). For tick-borne forms of typhus is characterized by the formation of necrotic lesion at the site of the tick bite with the development of regional lymphadenitis.
The pathogenesis. The basis of pathogenesis of typhus is the ability rickettsiae to exist and reproduce in the endothelial cells of the arterioles and precapillaries. In the overflow by Rickettsia is death and desquamation of endothelial cells, which, on the one hand, leads and supports the admission of rickets in the bloodstream, and on the other, leads to the formation of specific changes in the vascular walls (see below). When typhus occur morphological and functional changes on the part of almost all internal organs and systems, but most sharply is mutually associated pathology of the cardiovascular, nervous and endocrine systems. Clinical manifestations the most early encounters a lesion of the adrenal glands with a sharp decline in the production of adrenaline and intoxication. Hypoadrenalism leads to a progressive decrease of tonus of the sympathetic nervous system, causing vascular hypotension (sudden flushing of the face). Falling blood pressure could be leveled increased pressure forces the heart, but at last typhus occurs in the most adverse conditions; the narrowing of the coronary vessels in connection with a reduction in the amount of adrenaline; the result is the ability of the muscles of the heart muscle and the heart stops in systole; weakening and the perversion of the contractility of the vessels; the flow of blood in the abdominal cavity (collapse) due to paresis or paralysis n. splanchnici; impaired innervation of the heart; degenerative changes in the heart muscle due to intoxication and malnutrition; the expenditure of the reserve power of the heart. These phenomena can be expressed more or less sharply depending on the degree of intoxication and regulatory abilities of the body; accordingly will act and circulatory disturbances (hypotension, cyanosis, congestion in the liver, lungs and brain). The walls of blood vessels, mainly precapillaries, are undergoing profound changes. These changes, I. C. Davydov, start with desquamation of endothelial education warty parietal thrombus (trombovasculitis verrucosa); this can be appended to the proliferation of lymphoid and plasma cells with education around the vessel so-called coupling. If you are involved in the process not only intima and media, and adventitia is thrombosis of the vessel and destructive changes reach various degrees of necrosis inclusive (trombovasculitis destructiva). Inversely destructive changes develops cell proliferation with the formation around the vessel motoblaze granulomas. Most dramatically vascular changes are expressed in the brain and in the skin. In connection with vascular changes occurs: 1) the porosity of the vascular wall with the subsequent extravasate (petechial rash) and easier penetration of microbes in the vascular bed; 2) malnutrition tissues of various organs; 3) the involvement of cells of these organs, especially the brain. In the brain, in particular, in oblong, there are numerous granulomas involving glia cells and degenerative changes in the ganglion cells (encephalitis). The Pia mater is usually swollen, destructive processes are from blood vessels and lymphatic spaces; intracranial pressure is greatly increased due to the porosity of the vascular plexus (serous meningitis). Currently proved the presence of Rickettsia particular toxic substances, which confirms the views of clinicians about intoxication with typhus. The Central nervous system is connected, apparently, not only with the morphological changes, but also with intoxication. Reverse the progression of brain begins only with the 4th week of the disease, i.e., much later clinical recovery. Delay of sodium chloride and water are expressed so dramatically that in the course of typhus weight of the patient is reduced very little, despite the increased burning. After the crisis is striking a dramatic loss of weight of the patient, with knitted with copious critical and postcritical by diuresis.
Pathological changes of the rest Organon associated with vascular lesions, blood circulation and nervous trophism, with the richness of the blood by various microorganisms and ease of eviction in various places because of the reduced resistance of the tissues. Important role in the pathology of typhus plays the development of acidosis.
Symptoms. Acute onset with rapid rise in temperature without the Express chills, severe headache, General fatigue. Sudden redness and puffiness of the face, a strong injection of scleral vessels, early drying of the language. On the 4th day you receive enanthema - 2 - 3 vishnevogorsky hemorrhage at the base of the hyperemic and edematous uvula. From the 5th day of the disease is the appearance of the skin roseolous, papular, and later, petechial rash, which is located on the lateral surfaces of the thorax, abdomen and elbow; positive endothelial symptom with the 4th day of illness. Early happy crazy state.
For. Incubation 10 - 14, an average of 11 days, only in rare cases is reduced to 5 or lengthened to 21 days. The clinical course can be divided into four periods, with an average duration of each of them is 4 days: the first period is the increased proliferation of parasites in the endothelium, the second period - the flood parasites in the blood stream, the third period is the emergence of immune bodies and the most strong interaction between micro - and macroorganism; it is the "biological recovery" (N. K. Rosenberg) is accompanied by the most serious clinical symptoms; the fourth period, clinical recovery, which is a consequence of the previous period. The first period is preceded by a prodromal period characterized by subjective malaise, increased respiration and game vasomotion (light change color of the face).
The disease begins a rapid rise of temperature; from the first days of the patient strongly weakens, the face reddens and becomes puffy, eyes become extraordinary Shine; scleral vessels iniciirovanii. Headache is the main complaint of patients; however, patients in the early days of the disease are in a kind of excitation (euphoria) and vividly respond to questions of the doctor (the difference from typhoid fever, in which early advocate of the phenomenon of oppression). The liver swells with 2 - 3 days, the spleen was increased in 50% of cases to the 4 th day of the disease. By this time, appears enanthema (see Symptoms) and if a tourniquet on his shoulder, you can detect the emergence of Rosey in the elbow bend (with imposed harness the pulse must produmyvatsya!). On the 5th day of normal temperature remission with little urine output. On the same day the rash appears in the form of Rosey or soft papules located, as described above. The patient's health is somewhat improved, and the headache subsides. Rash undergoes a metamorphosis: there are petechial haemorrhages - petechiae - on unmodified skin (primary petechiae) or in the centre previously appeared roseolous-papular elements (secondary petechiae). Localization of petechiae at the time of their initial appearance - designated physiological injury to the skin bends (elbows); in the future they can be distributed on the chest, stomach, and upper extremities. The lower limbs and face are not normally covered in a rash. The more skin hemorrhages, the sooner they are and what they are bigger, the heavier the forecast. Bad symptom is cyanosis of the skin. With the disappearance of the rash leaves pigmentation. The skin is usually dry ("dry heat" Botkin). During the second period, the tongue becomes dry, salivation almost stops, the frequency of the pulse corresponds to the temperature, breathing the same casino throughout the disease, even in the absence of complications from lung, up to 30 per minute and more. At night, insomnia, and delirium, On the 8 - 9th day - new remission temperature diuresis. General condition usually worsens: brad not only nocio, but in the afternoon, unconscious. Often the hyperesthesia of the skin. Muscle fatigue is expressed sharply: the jaw, mouth, tongue while trying to protrusion "stumbles" on the lower incisors. Blood pressure to 10 - 11 th day reaches the greatest fall (of orientirovka feeling the pulse often provides a false sense of completeness vsledstvii relaxation of the tone of the vascular wall). Heart expanding to the right, on top presistolic noise, which disappears with increasing weakness of the heart muscle. Bad signs include: sudden sharp drop in blood pressure due to pulse pressure (reflux of blood into the abdominal cavity) with decreasing temperature, the expansion of cardiac dullness to the right and up (enlargement of the right atrium and appendage), arrhythmia, three-stage tone at the top and increased heart rate when the temperature drops. The crisis is preceded by the moisture of the tongue, slow pulse with dicrotism and diuresis. The temperature rarely occurs during the day, most often occurs 2 to 3 ledges and is accompanied by profuse sweat, urination and even diarrhea (critical diarrhea"). At this time especially, there is often a drop in cardiac activity. After the crisis, breakdown, prolonged sleep and subnormal temperature.
Complications. Pneumonia is often hypostatically as pneumonia associated secondary infection is delayed and after the end of typhus. Often there are fibrinous, serous and purulent pleurisy, less heart attacks, and lung abscesses. Pulmonary edema is often precedes death from progressive heart failure. Meningo-encephalitis is closely connected with typical typhus changes in the brain (see Pathogenesis). Usually develops in severely ill with 8 - to 10-day illness. Occurs with loss of consciousness, with fibrillar twitching of facial muscles, restless arm movements, rigidity of the neck, symptoms of Cernica, Babinski. Eyes narrowed, eyes moist, eyes looking in the same place, motionless. Often, an additional precipitation with a bluish color. Face more pale, but sometimes saves hyperemia with cyanotic hue (red cyanosis). Cardiac activity sharply oppressed. Neuralgia often appear early in the disease, dimming the diagnosis; they are frequent in the period wisdo-recovery. Psychosis appears or in the midst of illness, or after the temperature drop, but not often. Their nature is very diverse and is associated with the individual characteristics of patients. Purulent partity and peripherality can develop under the most careful care of the oral cavity as a consequence of secondary hematogenous infection and oppression functions gl. parotis. The most frequent outcome in suppuration. Kidneys undergo predominantly degenerative changes. In septic preinfection frequent multiple small abscesses. Retention of urine in the bladder are often paradoxical nature; with a small discharge of urine its main mass is retained in the stretched bubble (be sure to mercutioatc lower abdomen!). Urinary retention causes high standing of the diaphragm and the inflection of the aorta and pulmonary artery. In the renal pelvis numerous small hemorrhages. Pilit observed in 3 - 4%. The sores often develop by the end of the first week. Their education associated with trophic disorders, lesions of the vascular walls and weakening the pressure force of the heart. In severe cases they appear not only on the rump, but on the heels, the back of the head, bone protrusions and on the ears. A plurality of pressure sores gives a very poor prognosis. Endarteritis and physiotherapists do not differ from abdominal typhoid. Subcutaneous abscesses after injection, especially camphor, are observed frequently. Preinfection when typhus develop due to increased permeability of the wallsof the OK blood vessels. Most often detected in the blood sticks Rabinovich or anaerobic wand Ploetz. For preinfection of sepsis is very heavy, especially in anaerobic infections. Atypical erased fomy of typhus occur shortened (abortive) or at relatively low temperatures (about 38 ° ). In some cases, rash or missing, or seen a doctor because of the pallor and the quick disappearance. The reaction of the Weil-Felix, generally positive, with a clear increase in titre; often seen in children; when there is rampant erased form become a source of limited subnational flash.
The recognition is based on the complex of symptoms: high fever, redness and puffiness of the face, glitter eyes with scleral injection vessels, early inhibition with a bad headache, or, conversely, euphoria, enanthema. The blood leukocytosis with neutrophilia and cells irritation Turk; urobilin urine, urobilinogen, positive desireable. Artificial obtaining blemishes by using a harness on his shoulder. The reaction of the Weil-Felix appears on the 5 - 6th day of illness and grows in the course of the disease and in the first days after the crisis (bet again!). Positive reactions in the feverish of reciprocity possible, but they quickly fade away. More specific reaction Weigle with specific rickettsiosis antigen. The diagnosis of mild forms somewhat more difficult, but certainly possible, as the main symptoms persist (need hard to find a rash!); it is based on the mapping of clinical symptoms and increase the reaction Weil-Felix. During epidemics every febrile disease in which there is no data to explain the temperature, should be considered suspicious by typhus, typhoid. You can mix with typhoid fever, sepsis, with eritem, scarlet fever with toxic flu.
During epidemics is correct and early detection of all forms of typhus liquidation rampant in areas of infection. For full admission obvious and suspicious patients it is necessary to use not only clinical, but also epidemiologicheskii indicators (probability of contact, lice or suspicions about the lousiness of the environment and the patient). Fever for 4 days, no explanation for the clinical symptoms, the presence of the epidemic should be suspected typhus, typhoid. Face surrounding the patient should be examined for lice. In the apartment of the patient after his hospitalization is simultaneously handling (people in a sanitary point is, things in the camera, indoors - wet disinfection). The monitoring center is within 71 days of the disease the last patient. The period of isolation of patient - not less than 12 days after the fall of temperature. Before discharge, the patient must re-examination of his place of residence and in the presence of lice or unsanitary conditions - repeated sanitization. The main preventive measure is the systematic fight against lice and raise the cultural level of the population. The latest achievement in the prevention of typhus is active immunization. The vaccine of the Rickettsia is produced by three main methods: (a) Krotovskoe from the lungs of mice infected intranasally b) of Weigle-Wheat - from the intestines infected with typhus and lice) Coke from cultures of rickets in chicken embryos. The most experienced is the vaccine Krotovskoe; its dosage is 0.5 - 1 ml - 1 with intervals of 7 days. As shown by the experience of the great Patriotic war, in vaccinated reduces the incidence and diseased typhus is very easy, with no deaths.
In the application of therapeutic serum (Cool) 50-100 ml a few days in a row quickly disappear phenomena of intoxication and the disease usually ends with the recovery in normal times. When symptomatic treatment requires sufficient volume of air at a temperature no higher than 17 to 17.5 ° . On the head of the bladder with ice for 1 hour with half-hour break, which is used to cool the heart. Cool baths (35 - 37 ° ) to improve skin and brain blood circulation and strengthen the respiratory excursions; if you cannot give baths - cold wraps, rubbing the skin camphor alcohol. The bed is soft,with a padding all around; to frequently change the position of the patient (prevention of bedsores and hypostatic pneumonia). Diet dairy-vegetable, fruit, vitamins, white meat, enough drinking (Borjomi). Thorough cleaning of the tongue and the mouth, rinse the mouth after eating, smearing language glycerin, and lip - cocoa butter. With declining blood pressure intramuscular injection of adrenaline (not to be used for hypertension). Heart drugs are used depending on the activity of the heart - camphor, caffeine, Adonis, digitalis and its preparations. You should not pile cardiac funds and apply them without sufficient evidence. The most delicate effects camphor and Adonis; pre-preparations of digitalis should not be given to elderly and hypertensive patients. In cases of collapse intravenous infusion gitalin and adrenaline with 200 ml of physiological solution. Injection technique: in the syringe gaining 0.2 - 0.3 ml of epinephrine and 1 ml Vitalina; begin with the intravenous infusion of saline; the needle of the syringe with epinephrine injected into the rubber tube, which enters the vein of the salt solution, the plunger of the syringe pressure very slowly. During the introduction appears pale face and coughing. With the dramatic expansion of the heart to the right, especially with the expansion of the Atria, intravenous administration of large quantities of liquid is contraindicated (risk of pulmonary edema); in such cases, it operates a massive bloodletting (200 - 300 ml), mechanical unloading of the right heart and reflex increase in blood pressure. When the initial phenomena meningo-encephalitis is necessary to perform a lumbar puncture.