Whooping cough is an acute infectious disease of bacterial nature, manifested in the form of attacks of spasmodic cough accompanying catarrhal symptoms. Infection with whooping cough occurs by aerosol in close contact with a sick person. The incubation period is 3-14 days. The catarrhal period of whooping cough resembles the symptoms of acute pharyngitis, then characteristic attacks of spasmodic cough develop. In vaccinated patients, the erased clinical picture of whooping cough is more often observed. Diagnosis is based on the detection of pertussis bacillus in smears from the pharynx and sputum. Antibacterial therapy (aminoglycosides, macrolides), antihistamines with sedative effect, inhalations are effective against whooping cough.
A37 Whooping cough
Whooping cough causes Bordetella pertussis – a small stationary aerobic gram-negative coccus (although traditionally the bacterium is called “whooping stick”). The microorganism is similar in its morphological features to the causative agent of paracoccussis (infections with similar but less pronounced symptoms) – Bordetella parapertussis. Pertussis bacillus produces thermolabile dermatonecrotoxin, thermostable endotoxin, and tracheal cytotoxin. The microorganism is little resistant to the external environment, retains viability under the action of direct sunlight for no more than 1 hour, dies after 15-30 minutes at a temperature of 56 ° C, easily destroyed by disinfectants. They retain their viability in dry sputum for several hours.
The reservoir and source of pertussis infection is a sick person. The contagious period includes the last days of incubation and 5-6 days after the onset of the disease. The peak of contagion occurs at the time of the most pronounced clinic. Epidemiological danger is posed by persons suffering from erased, clinically poorly expressed forms of infection. The carriage of whooping cough does not happen for a long time and is not epidemiologically significant.
Whooping cough is transmitted using an aerosol mechanism mainly by airborne droplets. Copious release of the pathogen occurs when coughing and sneezing. Due to its specificity, the aerosol with the pathogen spreads over an insignificant distance (no more than 2 meters), so infection is possible only in case of close contact with the patient. Since the pathogen does not persist for a long time in the external environment, the contact transmission path is not implemented.
People have a high susceptibility to whooping cough. Most often, children get sick (whooping cough is attributed to childhood infections). After the infection is transferred, a stable lifelong immunity is formed, but the antibodies received by the child from the mother transplacentally do not provide sufficient immune protection. In old age, cases of recurrent whooping cough are sometimes noted.
Pertussis bacillus enters the mucous membrane of the upper respiratory tract and inhabits the ciliated epithelium covering the larynx and bronchi. Bacteria do not penetrate into deep tissues and do not spread through the body. Bacterial toxins provoke a local inflammatory reaction.
After the death of bacteria, endotoxin is released, which causes a spasmodic cough characteristic of whooping cough. With progression, the cough acquires a central genesis – a focus of excitement is formed in the respiratory center of the medulla oblongata. Cough reflexively occurs in response to various stimuli (touch, pain, laughter, conversation, etc.). The excitation of the nerve center can contribute to the initiation of similar processes in neighboring areas of the medulla oblongata, causing reflex vomiting, vascular dystonia (increased blood pressure, vascular spasm) after a cough attack. Children may have seizures (tonic or clonic).
Pertussis endotoxin, together with the enzyme produced by bacteria – adenylate cyclase, helps to reduce the protective properties of the body, which increases the likelihood of secondary infection, as well as the spread of the pathogen, and in some cases, long-term carrier.
Whooping cough symptoms
The incubation period of whooping cough can last from 3 days to two weeks. The disease proceeds with a sequential change of the following periods: catarrhal, spasmodic cough and resolution. The catarrhal period begins gradually, moderate dry cough and runny nose appear (rhinorrhea can be quite pronounced in children). Rhinitis is accompanied by a viscous mucosal discharge. Intoxication and fever are usually absent, body temperature can rise to subfebrile values, the general condition of patients is recognized as satisfactory. Over time, the cough becomes frequent, persistent, and its attacks may occur (especially at night). This period can last from several days to two weeks. In children, it is usually short-term.
Gradually, the catarrhal period turns into a period of spasmodic cough (otherwise – convulsive). Coughing attacks become more frequent, become more intense, the cough acquires a convulsive spastic character. Patients may note the precursors of an attack – sore throat, chest discomfort, anxiety. Due to the spastic narrowing of the glottis, a whistling sound (reprise) is noted before inhalation. A coughing fit is an alternation of such whistling breaths and, in fact, coughing jerks. The severity of the course of whooping cough is determined by the frequency and duration of coughing attacks.
Seizures become more frequent at night and in the morning. Frequent tension contributes to the fact that the patient’s face becomes hyperemic, edematous, small hemorrhages may occur on the skin of the face and oropharyngeal mucosa, conjunctiva. The body temperature remains within normal limits. Fever with whooping cough is a sign of the addition of a secondary infection.
The period of spasmodic cough lasts from three weeks to a month, after which the disease enters the recovery phase (resolution): when coughing, the mucous sputum begins to expectorate, the attacks become less frequent, lose their spasmodic character and gradually stop. The duration of the resolution period may take from several days to several months (despite the subsiding of the main symptoms, nervous excitability, coughing and general asthenia may occur in patients for a long time).
The erased form of whooping cough is sometimes noted in vaccinated individuals. At the same time, spasmodic attacks are less pronounced, but the cough may be more prolonged and difficult to respond to therapy. There are no reprises, vomiting, vascular spasms. The subclinical form is sometimes found in the focus of pertussis infection during the examination of contact persons. Subjectively, patients do not notice any pathological symptoms, but it is often possible to note a periodic cough. The abortive form is characterized by the cessation of the disease at the stage of catarrhal signs or in the first days of the convulsive period and rapid regression of the clinic.
Specific diagnostics of whooping cough are performed by bacteriological methods: isolation of the pathogen from sputum and smears of the mucous membrane of the upper respiratory tract (bacposev on a nutrient medium). Pertussis bacillus is sown on a Borde-Zhangu medium. Serological diagnostics using RA, RSC, RNGA is performed to confirm the clinical diagnosis, since the reactions become positive no earlier than the second week of the convulsive period of the disease (and in some cases may give a negative result at a later date).
Nonspecific diagnostic techniques indicate signs of infection (lymphocytic leukocytosis in the blood), characterized by a slight increase in ESR. With the development of respiratory complications, patients with whooping cough are recommended to consult a pulmonologist and perform lung radiography.
Whooping cough most often causes complications associated with the addition of a secondary infection, especially frequent diseases of the respiratory system: bronchitis, pneumonia, pleurisy. As a result of the destructive activity of pertussis bacteria, emphysema may develop. Severe course in rare cases leads to atelectasis of the lungs, pneumothorax. In addition, whooping cough can contribute to the occurrence of purulent otitis media. There is a possibility (with frequent intense attacks) of stroke, rupture of abdominal wall muscles, eardrums, rectal prolapse, hemorrhoids. In young children, whooping cough can contribute to the development of bronchiectatic disease.
Whooping cough treatment
Whooping cough is treated on an outpatient basis, it is advisable for patients to breathe moistened air, rich in oxygen, at room temperature. Full-fledged, fractional meals are recommended (often in small portions). It is recommended to limit the impact on the nervous system (intense visual, auditory impressions). If the temperature remains within the normal range, it is advisable to walk more outdoors (however, at an air temperature of at least -10 ° C).
In the catarrhal period, it is effective to prescribe antibiotics (macrolides, aminoglycosides, ampicillin or levomycetin) in medium therapeutic dosages for courses of 6-7 days. In combination with antibiotics, in the first days, the administration of a specific anti-pertussis gammaglobulin is often prescribed. As a pathogenetic agent, patients are prescribed antihistamines with sedative effect (promethazine, mebhydroline). During the convulsive period, antispasmodics can be prescribed to relieve seizures, and in severe cases, neuroleptics.
Antitussive, expectorant agents and mucolytics for whooping cough are ineffective, antitussive agents with a central mechanism of action are contraindicated. Oxygenotherapy is recommended for patients, a good effect is noted with oxygenobarotherapy. Physiotherapy techniques, inhalation of proteolytic enzymes are successfully used.
The prognosis is favorable. It ends fatally in exceptional cases in elderly people. With the development of complications, it is possible to preserve long-term consequences, chronic lung diseases.
Vaccination against whooping cough in the absence of medical contraindications is carried out for children at the age of 3 months; the second time – at 4.5 months; the third time – at 6 months. The first revaccination is carried out at 1.5 years; the second and third – at 6-7 and 14 years; then every 10 years.
The vaccines Pentaxime (France), Infanrix and Infanrix Hexa (Belgium), Tetraxime (France) are allowed. For the revaccination of older children, adults, pregnant women in the 3rd trimester of pregnancy, the Adacel vaccine (Canada) can be used. Family members of a pregnant woman should also be vaccinated before the birth of a child.
General preventive measures include early detection of patients and monitoring of the health of contact persons, preventive examination of children in organized children’s groups, as well as adults working in medical and preventive and in preschool institutions and schools, if a prolonged cough is detected (more than 5-7 days).
Children (and adults from the above groups) with whooping cough are isolated for 25 days from the onset of the disease, contact persons are suspended from work and visits to the children’s collective for 14 days from the moment of contact, undergoing a double bacteriological test. Thorough disinfection is carried out in the focus of infection, appropriate quarantine measures are carried out. Emergency prevention is carried out by the administration of immunoglobulin. It is received by children of the first year of life, as well as unvaccinated persons who have had contact with a whooping cough patient. Immunoglobulin (3 ml) is administered once, regardless of the time elapsed from the moment of contact.