Rickettsia rickettsii spotted fever
Introduction
Introduction to the Rickettsia plague fever Rickettsia rash fever is an acute endemic infection caused by the transmission of Rickettsia rickettsia. This disease is also called Rocky Mountain spotted fever, typhus fever, typhusfever, tick-borne Named after the US Centers for Disease Control, Fiebremanchada (named after Mexico), Fiebrepetequial (named Columbia), Febremaculosa or SaoPaulotyphus (named after Brazil), clinical features of fever, headache and rash, severe patients can be life-threatening. basic knowledge The proportion of illness: 0.0005% Susceptible people: no special people Mode of infection: digestive tract spread Complications: shock, deafness, erythema, erythema
Cause
Rickettsia nectar fever
(1) Causes of the disease
The shape of Rickettsia rickettsia is mainly in the shape of a cue, and the size is (0.3m0.6m)×(1.2m2.0m). Gram stain is negative, sensitive to heat and disinfectant, low temperature resistance, Infected cells can survive for a long time below -70 °C. Animal inoculation can cause disease in rabbits, mice, guinea pigs and monkeys. Chicken embryos and Vero cells can be used to isolate Rickettsia.
(two) pathogenesis
Rickettsia has two surface proteins with molecular weights of 1.2×105 and 1.55×105, which are related to pathogenicity. Rickettsia mainly invades arteriovenous endothelial cells and causes increased vascular inflammation and permeability. In severe cases, the coagulation system and the kinin system are activated, causing thrombotic obstruction, vascular myometrial necrosis, and microembolism in the central nervous system, causing damage to major organs such as the heart, lungs, kidneys, and central nervous system. Pathological changes are more common than tsutsugamushi And typhus is severe.
Prevention
Rickettsia rash heat prevention
1. Control the source of infection to kill rats and kill cockroaches.
2. Cut off the route of transmission. Use 2% malathion solution to spray mites in pastures, shrubs, grasslands and sheltered areas.
3. Protect susceptible populations. Wear protective clothing in the field, or use repellents such as acetanilide in exposed parts. Chicken embryo yolk sac vaccine has partial protection, which can prolong the incubation period, shorten the heat history and reduce the disease. However, it is not possible to prevent the onset of disease, and it is necessary to enter the epidemic area temporarily, and oral doxycycline can be prevented.
Complication
Rickettsia rash fever complications Complications, shock, erythema, erythema
The complications of Rickettsia rash fever are shock, heart and kidney failure. Some patients may have deafness, decreased vision, limb paralysis and recurrent episodes of bullous erythema after recovery.
Symptom
Rickettsia ecchymosa fever symptoms common symptoms rash high fever limb weakness joint pain cold pustule fatigue loss of appetite severe headache liver splenomegaly
The incubation period is 2 to 14 days, with an average of 7 days. The greater the infection of Rickettsia, the shorter the incubation period and the more serious the condition. After the incubation period, some patients may have a prodromal period of 1 to 3 days, which is characterized by loss of appetite. , fatigue, limb weakness and chills and other symptoms.
Typical patients suddenly start onset, body temperature rises sharply to 39 ~ 40 ° C, severe patients can have super high fever above 41 ° C, accompanied by chills, severe headache, body muscle and joint pain, photophobia and post-ocular pain, liver, spleen There is swelling, no pathogen treatment, fever does not retreat, the heat course can reach 2 to 3 weeks, and most patients will slowly fade afterwards.
Rickettsia nectar fever is different from other spotted fever in that there is no ulcer or eschar (acne) at the bite, and if there is a bacterial infection at the bite, there may be a purulent inflammatory change or pustule.
80% of the patients in 90% of the patients developed rash 3 to 4 days after fever, began to be located in the wrist and ankle, and later extended to the arms, feet, chest and abdomen and maxillofacial region, the rash form is pink rash, diameter 2 ~ 5mm 2 to 3 days after the rash, the rash is merged and turned into red or purple. During the recovery period, the rash gradually subsides. In the palm, sole, periorbital and axillary folds, the rash becomes a defect, forming a Ricci The characteristic distribution of the skin rash hot rash may have transient pigmentation and molting-like peeling after the rash subsides.
In patients without effective treatment, Rickettsia can aggravate vascular endothelium damage, thrombosis and ischemic gangrene, and the skin at the tip of the nose, earlobe, scrotum and fingertips is prone to occur if aortic thrombosis Formation, limb necrosis and hemiplegia can occur, and severe patients often die from myocarditis and pulmonary edema.
Examine
Rickettsia nectar fever
1. Blood routine examination The peripheral white blood cell count is reduced early, and most of them are in the normal range. If there is severe or secondary bacterial infection, it may increase, and secondary anemia may occur later in the disease.
2. Coagulation mechanism examination in patients with severe fibrinogen reduction, prothrombin time and partial thrombin time prolonged, and even diffuse intravascular coagulation.
3. Cerebrospinal fluid examination in patients with neurological disease, cerebrospinal fluid examination showed increased pressure, monocyte count and protein levels increased slightly.
4. Immunological examination of exo-Fi reaction OX19 and OX2 may have a coagulation reaction, the condensed titer of OX19 and OX2 may be increased by 4 fold at intervals of 2 weeks; while OXk does not appear positive, in addition, indirect immunofluorescent antibody test and A positive reaction can also occur in the complement fixation test. After 2 to 3 weeks, the titer is increased by 4 times. The skin and rash biopsy is tested by immunofluorescence antibody. The ricks rickettsia can be found. The test process only takes 4-6 hours. There are positive results in the 3 to 4 days of the disease course, and there is an early rapid diagnosis.
5. Pathogen examination Rickettsia can only be grown in eukaryotic cells, and the rickettsia can not be isolated in free cell culture. Pathogens can be isolated from rabbits or mice. Positive results have diagnostic significance. .
Abdominal ultrasound examination of hepatosplenomegaly.
Diagnosis
Diagnostic diagnosis of Rickettsia striata
Diagnostic criteria
In a small town or rural area where the media has existed within 2 weeks, there is a history of contact with animals carrying hard cockroaches, or a history of hard bite is a useful reference material for epidemiology. Patients with acute fever, severe headache, and photophobia , after eyeball pain and pink rash on the wrist and ankle, should be highly suspected of this disease, foreign-Fiji reaction and immunological positive results are conducive to clinical diagnosis, skin, rash biopsy specific immunofluorescent antibody positive and animal pathogen isolation positive The significance of diagnosis.
Differential diagnosis
The main differential diagnosis of this disease is measles, which can be identified by the characteristics of measles oral mucosa plaque. Patients with central nervous system symptoms should be differentiated from epidemic cerebrospinal meningitis type, with the help of epidemic cerebrospinal meningitis. The septic type of sputum and ecchymosis appeared early, and the cerebrospinal fluid showed a purulent change.
