Pertussis - Causes, Symptoms and Treatment .MF .
Pertussis (Pertusis) - acute bacterial infection anthroponotic with airborne transmission mechanism, and is characterized by long-lasting paroxysmal spasmodic cough.
This disease has been known to 1578g, in describing the outbreak in Paris.After that, only in 1906, the pathogen was isolated from sputum of the patient, and much later was created a vaccine to reduce the risk of morbidity and eliminate outbreaks.
pertussis - Bordetella pertusis (there are more pathogens that cause similar symptoms of pertussis - Bordetella parapertusis and bronchiseptica).
Bordetella pertusis airway
causative agent is small, with rounded edges stick, which has structural features that predetermine the mechanism of the disease isimptomy development:
• filamentous hemagglutinin (surface protein, which formed the basis for the creation of a new vaccineInfanrix) - it is attached only to the taphole ciliated airway epithelia, especially in the bronchi and less pronounced in the process of the trachea / la
• In the body forms a capsule - it provides protection against phagocytosis.
• Pertussis exotoxin responsible for specific symptoms, by the neurotoxic effects (cough receptors selectively affects how nerve endings located in the bronchi, also acts directly on the cough / respiratory center in the medulla oblongata - formed a vicious circle of pathological cough).
also produces exotoxin gistaminsensebiliziruyuschee and limfotsitozstimuliruyuschee action.
• Tracheal cytotoxin is a "right hand" of pertussis toxin, because it helps him to form this vicious circle by exhausting cough damage the ciliated epithelium of the respiratory tract - this leads to a stop ciliary movement and stagnation of bronchial fluid, and the place of introduction of the pathogen is formed and bleedingnecrosis in ioge cough receptors are stimulated even more.
• Dermonekrotoksin has neurotropic, ie selectively excites neurons in the medulla oblongata, but not only the cough center, but also vasomotor, as a consequence, there are vascular disorders.
• Endotoxin is released only after the death of the originator and has a toxic-pyrogenic action (this explains the general clinical symptoms of catarrhal period).Pathogen
• produces urease - an enzyme which provides the decomposition of uric acid into ammonia (toxic) and carbon dioxide.
• The presence of enzymes pathogenicity provides penetration of the pathogen in the respiratory department glublezhaschie tissue.These include: hyaluronidase - separates intercellular connections, Lecithinase - splits the phospholipid membrane layer, coagulase - provides plasma coagulation.
• Ability to pathogenic (harmful) properties marked variability that leads to the formation of resistance to infection post-vaccination.But after the disease-resistant forms, busy almost lifelong immunity.
causative agent is very sensitive to environmental factors: UV radiation, desiccation, the action of disinfectants, in the external environment is stable for a few hours and fly at a distance of 2.5m.
Susceptibility pervasive, without sex and age restrictions.As such, there is no principle of seasonality, because the pathogen circulates throughout the year, but like all respiratory infections, outbreaks often recorded in the autumn-winter period.The possibility of disease is reduced, with good intensity of post-vaccination immunity and low infective dose of the pathogen.In recent decades, the incidence of recorded trend growth due to:
• variability pathogenic properties (antigenic drift), to post-vaccination immunity;
• reduce the efficiency of the old vaccines;
• low-level graft;
• postprivivochnogo weakening immunity due to defects immunization.
Causes of pertussis infection
source - the sick person.The most dangerous from the atypical and peeling off the course, also those who are in the last days of the incubation period (including the rest of the clinical stages) ≈ 25-30 days.The difficulty of preventing infection from the source is that the incubation period can not be noticed, and catarrhal period of whooping cough is held in the form of light, and it does not pay attention, even in the event of cough (since he begins gradually, with the increase).As a result, the insulation is often the afterthought.
infection Path - aerogenic (due to droplet transmission mechanism in close and prolonged contact).Also recorded infection of domestic and wild animals, but not pertussis, whooping and disease (Bordetella bronchiseptica).
Symptoms of pertussis
incubation period lasts 3-14 days (usually 5-7), this period begins from the moment of introduction of the pathogen to the first clinical manifestation.By the airborne pathogen penetrates through the upper respiratory tract and is attached to the ciliary epithelium.As we reach the critical number of the pathogen begins next period - catarrhal.From the last days of this period, the patient is contagious.
Catarrhal period lasts 10-14 days, no different than any features (ie ↑ t ° to 39, a runny nose, malaise).The only difference is the nature of cough: it is dry, haunting, often begins in the evening or at night, not facilitated reception of symptomatic drugs.Every day cough becomes stronger due to this action of toxins - pertussis and tracheal.Pertussis toxin, as mentioned above, forms a vicious circle - irritating cough bronchi receptors on nerve fibers goes impulses to the cough center of the medulla oblongata, where forming pathological focus of constant excitation (also due to the direct action of the toxin on the center), followed by feedbackcommunication, this center gives impulses to the cough receptors of the bronchi (the impulses from which came originally) - the so-formed feeding each other pathological lesions.While the cough center in the medulla becomes excitable to such an extent that reacts almost any stimulus (light, sound, emotsionalney), causing coughing.Action tracheal toxin like pertussis, but only through mechanical stimulation - it causes stagnation mucociliary liquid bronchi, which is also an irritant cough receptors (they are mechanical and pressure receptors), and then poured into this vicious circle.
period of spasmodic cough lasts from 2-8 weeks or more.During this period, people become martyrs, because every cough is a struggle for breath.It appears bright specific symptoms, and in the foreground paroxysmal (epileptic) cough, preceded by a kind of aura in the form of sore and tickling in the throat (or sneezing), then followed by cough: cough shocks following one another without the possibility of inhalation.Cough "barking", dry, with very thick and trudnoothodyaschey sputum (consistency as construction selekon).During such periods of apnea may have bouts of kids (cessation of breathing).
cough occurs in the evening / night and is not stopped by conventional means protikashlevymi.Once manages to breathe, the air whistling rushes through the glottis spasm, which explains the formation of the "whistling breaths" or "reprise".
In this period there are changes in the cardiovascular system, but not only because of the violation of compensatory abilities, but also because of the direct impact dermonekrotoksina on the vasomotor center, as a result of the following symptoms are formed: vasospasm, increased arterial and venous pressure, violation of vascular permeability - as a consequence, pale skin, akrotsianoz (cyanosis of nasolabial triangle), haemorrhagic skin manifestations and injected sclera.As a consequence of the above, enhanced load on the heart, which can lead to complications, particularly if it is compromised.
Due to frequent and prolonged oxygen starvation occurs hypoxia (↓ level of oxygen in the blood) and the first to suffer central nervous system: encephalopathy, manifested by general anxiety, physical inactivity, sleep disorders, convulsive readiness.
recovery period lasts for 3 weeks (may take up to 6 months).It is characterized by a gradual decline in coughing (he does not have such a painful and paroxysmal).But even after recovery pathologically dominant center in the cough center of the medulla oblongata leaves your changes (sensitivity threshold is lowered) and, in the most common respiratory diseases, cough still gets pertussoid shade.
there are features of the course in which symptoms do not meet the standards:
• Atypical form of the disease (erased clinic and there is no consistent periods of change)
• Features of motion in young children: the presence srednetyazhёloy and severe forms, in which the symptoms are much brighter + insteadcough appears equivalent in the form of a sneeze, hiccup or cry + in children 1 year of age can be the loss of acquired skills, especially motor and speech + often affected the central nervous system and is formed convulsive readiness.If you have a cough, a bridle on the tongue is formed by small wound as a result of frequent irritation coughing.
• Vaccinated persons may re-disease, but it occurs in mild or atypical form.
• Features of the modern course of the disease - most often occurs as a mixed infection, ie in combination with other viral or bacterial pathogens.
1. Objective assessment is available in the catarrhal and convulsive period in assessing the nature of the cough.
2. KLA: ↑ A ^ and LF, ESR ↑ or normal
3. On radiographs: an increase in the transparency of the lung tissue, and the flattening of the low standing of the dome of the diaphragm, expanding the lung roots, the availability of equity or segmental atelectasis.
4. Laboratory diagnosis:
- Bacteriological method (abjection in the material - sputum or mucus from the upper respiratory tract).Negative results in the presence of appropriate clinical symptoms, does not give the right to exclude a diagnosis!
- Serological method aims to identify antibodies by RA setting (agglutination) and Phragmites (reaction of indirect hemagglutination) - the method of paired sera and looking for increase of antibody titer.
Treatment of pertussis
1. Causal treatment is aimed at destruction of the pathogen.In this disease, prescribe antibiotics against specific pertussis (sumamed), but until bacteriological results can assign shirokospektornyh preparations with change them afterwards needed.Causal therapy is prescribed at all during the catarrhal period, an average of 2 weeks.
2. Pathogenetic and symptomatic:
- for the relief of bronchial obstruction and brnhospazma prescribe aminophylline, as well as inhalation and berodualom berotekom
- agents that suppress the cough reflex (for children up to 3 years - neokodion, kodipront; Sturshe 3 years - stoptussin, sinekod, tusupreks)
- mucolytics, improve sputum discharge - inhalation of drugs ambroxol and bromhexine
- preparations for the restoration of hemodynamic and metabolic processes in the central nervous system - piracetam
- immune preparations: immunomodulators and immunostimulants
- medication metabolic rehabilitation replenish the reserve capacity of the organism -vitamin complexes
in more severe clinical manifestations of the patients hospitalized in the hospital to treatment added: oxygen therapy, corticosteroids, anti-toxic pertussis possible to use human immunoglobulin.
Complications of pertussis
- the part of the respiratory tract (respiratory putёy): emphysema, atelectasis, bronchitis, pneumonia
- Heart and blood vessels: hemorrhage, myocardial dystrophy, cardites
- CNS: encephalopathy, cerebral edema
- ENT organs: otitis andeardrum ruptures
Prevention of pertussis
1. Isolation of patients: up to 7 years - 25 days older than 7 years - until the termination of acute manifestations.After recovery, vaccinations, if they coincide with the calendar vaccination rates, postponed for 1 month or 2 months in the development of complications.For all contact persons set under medical surveillance for 14 days, with 2-fold bacteriological examination.
2. Vaccination is carried out in 4,5mes 3mesyatsa → → → 6 months 18 months (according to the national calendar of vaccinations).The following vaccinations: DTP (domestic), Tetrakokk (French), Infanrix (the latest and most reliable).
therapists Shabanova IE