Infection is transmitted by airborne droplets with droplets of mucus and saliva when coughing. The main cause of the development of pertussis symptoms are toxins excreted by pertussis. The pathogen itself is retained in the mucous membrane of the respiratory tract. All details about this disease you will find in the article on the topic "Whooping cough: signs, symptoms, treatment".
Reproduction of bacteria
The infection is accompanied by hyperproduction of mucus and swelling of the mucous membrane of the respiratory tract. As the multiplication of bacteria, these phenomena progress. A sharp increase in mucus may lead to a blockage in the lumen of the bronchi and the collapse of the lungs. In addition, against the background of pertussis may develop a secondary infection with the onset of pneumonia.
Epidemiology
Pertussis is widely spread all over the world. Individual cases of this disease are regularly recorded, but it can take the nature of epidemics. The incubation period is usually about 7 days from the time of infection. In places where people live in a compact environment, the risk of contracting susceptible people is very high. After World War II, there was a significant reduction in pertussis incidence in Western countries due to changes in the socioeconomic sphere and, later, mass vaccination.
There are three stages in the development of infection:
- catarrhal - lasts about a week and is manifested by subfebrile temperature, nasal congestion and sneezing. Symptoms observed in this period are no different from the symptoms of any cold;
- paroxysmal - lasts from 2 to 4 weeks and is characterized by attacks of convulsive cough, which can last up to 20-30 seconds. During an attack the child does not have time to take a breath, therefore at the end of it a characteristic convulsive breath (reprise) is heard;
- the stage of convalescence - can last several weeks, during which the coughing episodes gradually disappear. A long period of persistent cough explains the name of this disease in China - "a hundred-day cough".
The most severe course of whooping cough is observed in young children. They are most often hospitalized for this disease. In infants, the clinical picture of pertussis may differ from the classical one. Coughing attacks are often not accompanied by reprises, characterized by periods of apnea (temporary stop breathing) and choking. Breast children with whooping cough often require probe feeding. Pertussis often causes serious complications, especially in children in the first months of life.
Pneumonia is the most common complication of whooping cough caused by a pertussis or a secondary bacterial infection. Defeat of the brain - persistent severe disorders develop due to increased intracranial pressure in combination with hypoxia during coughing attacks. They can manifest as a spasm or inflammation of the brain (encephalitis). Long-term effects include paralysis, neurosensory visual and hearing impairment, as well as decreased learning ability. Conjunctival hemorrhage - an increase in intrathoracic pressure when coughing can lead to rupture of small blood vessels of the eye. Nasal bleeding - associated with rupture of small vessels in the nasal cavity. Lesion of the lungs - long-term pneumonia, which has developed against pertussis, can lead to bronchiectasis (pathological expansion of the airways). For whooping cough is characterized by a sharp increase in the level of lymphocytes in the general blood test, but this is observed with virtually any infection and is not a specific sign. The exact diagnosis is made on the basis of the culture of the pathogen from the nasopharynx.
Identification of the pathogen
The difficulty of this type of diagnosis is that a positive result can often be obtained only at the early (catarrhal) stage of the disease, when the clinical picture does not give grounds to suspect pertussis. By the time the suspicion becomes more apparent, the chances of identifying the pathogen are less than 50%. In addition, the smear should be taken from the nasopharynx (and not from the nasal cavity) and delivered to the laboratory as soon as possible, otherwise the microorganisms contained in it may die. Determination of DNA sequences of pertussis with PCR (polymerase chain reaction) is a more sensitive method than the isolation of living bacteria. Such a test can become a standard method for diagnosing whooping cough in the future.
Antibiotic therapy does not affect the clinical symptoms of pertussis, since they are caused not by the bacteria themselves, but by the toxins they release. However, the course of erythromycin helps to shorten the period during which the patient is contagious to others. With a confirmed diagnosis of whooping cough, everyone who was in contact with the patient (especially children of the first year of life) is shown a preventive course of erythromycin.
Supportive treatment
General supportive measures are carried out, for example, ensuring normal nutrition. To identify episodes of apnea or oxygen desaguration (reducing blood oxygen levels), careful monitoring of breathing is necessary. When the children with pertussis are hospitalized, complete respiratory isolation is provided. If suspected of secondary infection, an additional course of the appropriate antibiotic is prescribed. Active immunization of young children can significantly reduce the incidence. In most countries, pertussis vaccine is part of the combined triple DTP vaccine (against pertussis, diphtheria and tetanus) administered three times. It was found that the anticoagulant component of this vaccine can cause side effects (from moderate to severe). Post-vaccination complications can vary from subfebrile and hyperemia at the injection site to severe neurologic reactions with brain damage (in rare cases). In the 1970s, fears about possible risks of vaccination led to a massive rejection of vaccinations. Simultaneously, there was an increase in the incidence of whooping cough in children with a proportional increase in the incidence of complications caused by it. Now we know what pertussis, signs, symptoms, treatment of this disease.