Chlamydial pneumonia is an infectious and inflammatory process in the lungs caused by obligate intracellular bacteria of the genus Chlamydia and Chlamydophila. Chlamydial pneumonia is characterized by respiratory manifestations (rhinitis, tracheobronchitis), unproductive cough, subfebrile and febrile fever, extrapulmonary symptoms (arthralgia, myalgia). When making a diagnosis, auscultative and radiological data are taken into account, but the decisive role belongs to laboratory diagnostics (ELISA, MIFR, PCR, etc.). Antimicrobial agents (macrolides, tetracyclines, fluoroquinolones), immunomodulators, physiotherapy are used for the treatment of chlamydial pneumonia.
Chlamydial pneumonia is an etiological type of atypical pneumonia that occurs when the respiratory tract is infected with various types of chlamydia – Ch. rpeimopiae, Ch. psittaci and Ch. trachomatis. It is believed that 5 to 15% of cases of community-acquired pneumonia are caused by chlamydia annually; during epidemic outbreaks, this figure may be 25%. Most often adults get sick, cases of chlamydial pneumonia in newborns are associated with infection from mothers with urogenital chlamydia.
Asymptomatic carriage of chlamydia in the nasopharynx is determined in more than half of adults and 5-7% of children, therefore, the probability of transmission of infection with respiratory secretions is very high. Intrafamily outbreaks of chlamydial pneumonia, as well as cases of mass morbidity in isolated collectives are described.
Causes of chlamydial pneumonia
Characteristics of the pathogen
Of all the variety of representatives of the Chlamydiaceae family, three types of chlamydia are of etiological interest for pulmonology: Chlamydophila pneumoniae, Chlamydia trachomatis and Chlamydophila psittaci.
- Ch. pneumoniae is the most common causative agent of respiratory chlamydia (including chlamydial pharyngitis, sinusitis, bronchitis, pneumonia) in patients of all ages.
- The incidence of trachoma, genitourinary chlamydia, venereal lymphogranuloma, as well as chlamydial pneumonia among newborns and infants up to 6 months is associated with Ch. trachomatis. Pneumonia is also associated with this type of chlamydia in immunocompromised individuals and laboratory staff.
- Ch. psittaci is considered as the causative agent of ornithosis (psittacosis), often occurring in the form of severe interstitial pneumonia.
The ways of infection with each variety of chlamydia are different, but all types can spread hematogenically. Transmission of Ch. pneumoniae from person to person is carried out mainly by airborne and household contact routes. Infection with the Ch. psittaci strain occurs by air-dust or fecal-oral route when inhaling dust or eating food containing the biological secrets of birds carrying infection (parrots, canaries, chickens, ducks, pigeons, sparrows, etc.).
Infection of newborns with Ch. trachomatis occurs during childbirth from mothers with urogenital chlamydia infection. With intranatal infection, 15-25% of infants develop chlamydial nasopharyngitis and conjunctivitis, which are often complicated by pneumonia.
All chlamydia are obligate gram-negative microorganisms that parasitize inside the host cells. In the macroorganism, chlamydia can exist in an infectious form (elementary corpuscles) and a vegetative form (reticular corpuscles). Elementary corpuscles penetrate into the cell by stimulating endocytosis, where they are transformed into reticular corpuscles. The latter have high metabolic activity and the ability to intracellular binary division.
The reproduction cycle lasts about 48 hours, after which the reticular corpuscles again turn into elementary ones, the membrane of the host cell breaks with the release of elementary corpuscles of a new generation into the extracellular medium. Then the cycle of infection of new cells repeats.
Symptoms of chlamydial pneumonia
Pneumonia caused by Chlamydophila pneumoniae
Chlamydial pneumonia caused by Ch. pneumoniae is more common in children and young people aged 5 to 35 years. Among the causes of community-acquired pneumonia in this age group, chlamydia is second only to Mycoplasma pneumoniae.
The onset of the disease is acute or gradual. In the first case, the symptoms of intoxication and respiratory tract damage reach their maximum severity already on the 3rd day. In the subacute course, chlamydial pneumonia manifests with respiratory syndrome (rhinitis, nasopharyngitis, laryngitis), cognition, subfebrility, and therefore, in the first week of the disease, patients are mistakenly diagnosed with acute respiratory infections. Mainly, patients are concerned about nasal congestion, nasal breathing disorders, moderate mucous discharge from the nose, hoarseness of the voice.
Pneumonia itself can develop in terms of 1 to 4 weeks after the onset of respiratory symptoms. The body temperature rises to 38-39 ° C, weakness increases, myalgia worries, headache. In all cases, dry or wet paroxysmal cough and chest pain appear simultaneously with fever. The course of chlamydial pneumonia is prolonged; a painful cough and malaise can persist for up to several months. Of the complications, otitis media, sinusitis, and reactive arthritis are the most frequent.
Pneumonia caused by Chlamydia trachomatis
The onset is often gradual; in children, chlamydial pneumonia is often preceded by conjunctivitis, acute otitis media or bronchitis of the same etiology. An early sign is a dry cough, which, intensifying, becomes paroxysmal. Against the background of coughing attacks, the child has tachypnea, cyanosis and vomiting, but there are no reprises. Gradually, there is an aggravation of shortness of breath, an increase in BH to 50-70 per minute, breathing becomes groaning. At the same time, the general condition usually remains satisfactory, the symptoms of intoxication and respiratory failure are poorly expressed.
Auscultative and radiological picture of bilateral chlamydial pneumonia unfolds by the end of the first – at the beginning of the second week. In the midst of the disease, symptoms of enterocolitis, hepatosplenomegaly may appear. Recovery is often delayed for many weeks and months. In severe forms of chlamydial pneumonia, pneumothorax, pleurisy, abscessing may occur. Of extrapulmonary complications, myocarditis, endocarditis, meningoencephalitis occur. Children who have suffered chlamydial pneumonia caused by Ch. trachomatis, later suffer from bronchial asthma and other chronic obstructive pulmonary diseases more often.
Pneumonia caused by Chlamydophila psittaci (Ornithosis)
The clinical course of ornithosis varies from asymptomatic to severe. The most striking symptom is high (up to 39.5-40 °With and above) body temperature, accompanied by chills and severe intoxication (severe weakness, headache, arthralgia, myalgia). In the absence of other symptoms, this condition is often regarded as a fever of unknown origin.
In the future, in more than half of cases, there is an unproductive cough, chest pain, enlarged liver and spleen. Characteristic signs indicating the chlamydial etiology of pneumonia are signs of neurotoxicosis, spotty rash on the skin, nosebleeds. Digestive disorders often occur: nausea, vomiting, abdominal pain, diarrhea or constipation.
Clinical and radiological changes may persist for 4-6 weeks. Typical complications of ornithosis are hepatitis, DIC syndrome, venous thrombosis, hemolytic anemia, polyneuropathies, myocarditis.
Difficulties in establishing an etiological diagnosis are due to the fact that, unlike bacterial pneumonia, chlamydial pneumonia lacks distinct physical and radiological signs, as well as characteristic changes in peripheral blood. In these conditions, therapists and pulmonologists have to focus mainly on the indications of anamnesis, the features of the clinical picture and confirm their suspicions by laboratory methods (ELISA, PCR, etc.).
- Physical examination. Auscultative data are variable: breathing can be hard, bronchial or weakened vesicular; wheezing in the midst of the disease is more often moist or crepitating. The percussion sound is usually blunted.
- Radiography. Radiography of the lungs reveals focal, segmental or lobar infiltration or interstitial changes.
- Laboratory diagnostics. The most specific and sensitive is the cultural method of isolating the pathogen, however, due to the duration and complexity of diagnosis, in practice they are usually limited to serotyping. The standard today is ELISA and MIFR (microimmunofluorescence reaction). During ELISA, the activity of chlamydia infection is indicated by an increase in the titer of specific IdM, IgG and IdA more than 1:16, 1:512 and 1:256, respectively; MIFR – an increase in the titer of IgG / IdA in paired blood sera by 4 or more times. PCR analysis allows you to quickly and accurately identify the DNA of the pathogen, but does not allow you to distinguish a persistent infection from an active one.
Differential diagnosis of chlamydial pneumonia should be carried out with influenza, whooping cough; viral, mycoplasma, legionella, fungal pneumonia and other atypical lung infections.
Treatment for chlamydial pneumonia
The complexity of effective treatment of chlamydial pneumonia is associated with the fact that chlamydia are present in the body simultaneously in both extracellular and intracellular forms, therefore it is necessary to influence both of these links. In addition, activation of infection, as a rule, occurs against the background of suppression of immunity, which also requires correction of the immune response.
Antimicrobial drugs from the groups of macrolides, fluoroquinolones and tetracyclines are recognized as means of eradication therapy for chlamydial pneumonia. Macrolides are the most preferred among them, because they can be used for the therapy of newborns, children and pregnant women. Of the drugs in this group, clarithromycin, josamycin, erythromycin, and spiramycin have the greatest activity against chlamydia.
Fluoroquinolones and tetracyclines also successfully cope with chlamydia infection, but the latter are excluded during pregnancy and liver failure. The duration of the course of antimicrobial treatment of chlamydial pneumonia is at least 2-3 weeks.
In order to correct immunological disorders, as well as to prevent the recurrence of infection, in addition to antimicrobial agents, immunomodulators, vitamins, probiotics are prescribed. During the period of convalescence, much attention is paid to physiotherapy, respiratory gymnastics.
In young patients with the absence of concomitant pathology, chlamydial pneumonia usually ends in recovery. Among the elderly, deaths occur in 6-10% of cases. Observations of specialists indicate a possible etiological role of Ch. pneumoniae in the development of atherosclerosis, lung sarcoidosis, ischemic stroke, Alzheimer’s disease, therefore, chlamydial pneumonia can have far-reaching consequences. The negative effect of respiratory chlamydia on the course of bronchial asthma and the frequency of its exacerbations has been unequivocally proven.