Pneumocystis pneumonia ( Pneumocystosis ) - Causes, Symptoms and Treatment .MF .

August 12, 2017 17:52 | Infectious Diseases

Pneumocystosis malopatogennymi caused by microorganisms, so among healthy people there is no disease symptoms in the presence of antibodies in the blood.Symptomatic form of the disease can only be formed in the body with immune deficiencies, which makes up 45-50% of all patients with immune deficiency.Among HIV-infected patients, the share is 70%, resulting in pneumocystis is indikatornymili AIDS opportunistic infection.

Pneumocystis pneumonia - it anthroponotic infectious disease caused by protozoan Pneumocystisjiroveci (previously Pn carini.), With air-borne transmission occurs on the background of immune deficiency and exhibit a bland infectious-toxic syndrome and the defeat of the respiratory system - the lungs and bronchial tubes withthe possibility of respiratory failure.

Pneumocystiscarinii first described in 1909 and separated in 1912, at the time the pathogen is not considered a human pathogen.It was in 1942 byly Pneumocystis is indicated as the cause of interstitial pneumonia during an outbr

eak in newborn infants and in children with defects of the immune system.Since 1980, previously referred to simplest Pneumocystis was classified in the class, which occupies an intermediate position between fagomitsetami fungi and higher fungi, as evidenced by the overall biochemical properties and morphology.

Pneumocystis

Causes of PCP

The causative agent - the average between the protozoa and fungi Pneumocystisjiroveci by Czech scientist Otto Yirovitsa surname, first described the causative agent of pulmonary form of the disease (the previous name of the genus Pneumocystiscarinii).It malopatogenny for healthy people pathogen, therefore, the disease can occur in immunocompromised individuals.Pneumocystis tropic exclusively to the lung tissue, that is, the main symptoms are the symptoms of lung disease.During the multiplication of pathogen exchange highlights the different products with weak pathogenic properties, so infectious-toxic syndrome (fever and intoxication) do not pronounced at PCP.

cycle of Pneumocystis. Pneumocystisjiroveci (carinii) is an extracellular parasite and has its development cycle, flowing inside the alveoli - lung structural element.The cycle includes four stages: trophozoite, pretsista, cyst, circumsporozoite.

cycle of Pneumocystis

During the multiplication of Pneumocystis formed vegetative forms of pathogen - trophozoites (single-celled organisms that are the core of 2hsloynuyu membrane, with diameter up to 5 mm).Trophozoites attach themselves to the cells of the epithelium - ACs and begins to evolve: it becomes oval, and its membrane thickens (formed pretsista).Further development continues in cyst diameter of 8 microns having a thick wall consisting of 3 layers.Cyst wall contains glycoproteins, one of which is necessary for p120 binding ACs lung epithelium.Inside the cysts are small vnutritsistnye to 3 microns education - sporozoites, the amount of which may vary from 5 to 8 pieces.If study found mature cysts sporozoites with a large number, it is evidence of active infection.

There are 2 phases of development: sexual and asexual.The difference is that the sexual phase mature cysts destroyed allocated sporozoites which merge in pairs, form trophozoites and further in stages.In asexual phase the trophozoites divide and each turns into a cyst.

cysts

source of infection - a sick person or carrier: it may be family members, workers organized children's groups, medical institutions.Bearers of Pneumocystis can be and animals - rats, mice, cats, dogs, pigs, rabbits.Among the 10% of healthy carriers of Pneumocystis.

infection mechanism - aerogenic and path - airborne.Pneumocystis apply with particles of mucus, sputum by coughing, sneezing.It is also possible airborne dust transmission path.An additional mechanism - transplacental (from mother to the fetus), and evidence of intrauterine infection is the occurrence of PCP during the 1st month of life.

Susceptibility general population, however, in the total group of patients with male-dominated.The incidence of recorded sporadically (ie identified isolated cases of pneumocystis pneumonia person).The distinct seasonality is not typical, but is traced increase in the number of patients in the spring-summer period.The majority of patients with pneumocystis - are persons with immunodeficiency.

Examples of immunodeficiency in humans:

1) physiological age failure (young children, the elderly);
2) babies under 1 year born with signs of prematurity, asphyxia, congenital lung development, the heart;
3) older children and adults who have any chronic or serious illness or forced to take cytotoxic drugs, steroids, radiation therapy (oncological diseases, blood diseases);
4) patients with chronic diseases (rheumatoid arthritis, systemic lupus erythematosus, chronic nonspecific lung diseases, cirrhosis of the liver and other conditions);
5) HIV (up to 70% of patients with pneumocystis).

Accordingly, high-risk groups for infection Pneumocystis are:

• children - pupils of children's homes.
• Elderly people who are in nursing homes.
• Cancer patients receiving immunosuppressants.
• Patients with diseases of the blood (leukemia, and others).
• Patients with tuberculosis, HIV, cytomegalovirus and other infections.
• Patients who are treated with glucocorticosteroids.

Immunity after past infection is not stable, there may be recurrent infection related to infection by a new genotype of the pathogen.In immunocompromised persons undergoing PCP, relapses are possible in 10% of cases, patients with HIV infection at the stage of AIDS - in each case 4m.

pathogenic effects on the body

1) Pneumocystis enter the body through the respiratory tract and are in the lumen of small bronchi, alveoli, where the breed is active (as a result of longitudinal division formed oocyst, which subsequently turns out to be surrounded by a mucous capsule).During this period, the patient lumen of small bronchi and alveoli is filled almost completely with mucus.All this leads to the difficulty of air promoting the airway of the patient - severe respiratory failure.

2) During the multiplication of Pneumocystis formed metabolic products, which enter the bloodstream and cause sensitization and formation of specific antibodies.In parallel metabolic products are irritating to the phagocytic cells that are attracted to the lesion.All this leads to infiltration of inflammatory lung alveoli walls and disruption of the diffusion of gases (oxygen - carbon dioxide), which is another cause of respiratory failure.

3) in advanced process - the protracted nature of the disease - formed fibroblasts and
other words pulmonary fibrosis.Complications can arise (emphysema, closed pneumothorax).

Symptoms PCP

incubation period for PCP from a week to 10 days, an average of 6-7 days.Pneumocystis can occur in the form of acute respiratory infections, laryngitis, exacerbations of chronic bronchitis, but most often in the form of Pneumocystis pneumonia interstitial.

There are 3 stages of the disease:
1) edematous (7-10 days);
2) atelektaticheskaya (up to 4 weeks);
3) emphysematous (1-3 weeks or more).

Stage 1 - edematous.
symptoms of intoxication and fever are not leading.The temperature may be normal, and low grade (less than 38º).Patients may be concerned about the weakness, increased fatigue, decreased performance, loss of appetite, body weight may be normal or reduced.Respiratory syndrome is weak - can be a rare cough with viscous sputum difficult to be separated.When listening to the lungs (auscultation) hard breathing, no wheezing.Percussion (for rapping the lungs) - a shortening of percussion sound in the interscapular region.

Stage 2 - atelektaticheskaya.
accrues respiratory syndrome - patients and there is increasing breathlessness (60-80 breaths per minute in adults), with the participation of auxiliary muscles, there is cyanosis (bluish tinge of the skin) may develop cardiopulmonary diseases.The cough becomes frequent and intrusive, sputum thick, transparent and hard othodimaya.Auskultativno - listened small- and medium-bubble wheezing.Percussion - shortening of the sound in the interscapular region, sometimes over large centers, the growing "tipmanit" (loud music sound like the sound of the drum, box sound) in the anterior-upper lungs.
In this step may develop complications - Crescent pneumothorax without threatening the patient's life, self-limited for 1-2 days.

Stage 3 - emphysematous.
At this stage, the improvement of health - decreased cough, shortness of breath docked.Long preserved box sound with light percussion and auscultation dry rales.

The most common process when PCP is limited to lung tissue, but in severe immunodeficiency and lymphogenous possible hematogenous spread with the emergence of extrapulmonary manifestations: liver, spleen, thyroid gland, adrenal glands, heart and others.It is rarely possible to ENT pathology (sinusitis, otitis, sinusitis).

Peculiarities of pneumocystosis:

1) Most of the patients with atypical disease: some patients resemble patients with acute respiratory infections, followed by obstructive bronchitis, responds poorly to therapy;in some patients the disease has abortifacient for (sudden interruption of disease symptoms).
2) Pneumocystis pneumonia tends to retsidiviruyuschmu flow, contributes to the development of chronic fibrosing processes in the lungs.

Peculiarities of PCP children:

1) Time of occurrence - often by 5-6 months of age groups at risk (premature babies, patients with rickets, CNS disorders, IUI, HIV, oncology).
2) The gradual onset of the disease - poor appetite, poorly gaining weight, then do not add, low-grade fever, cough similar to the cough in whooping cough is accompanied by shortness of breath (70 or more breaths per minute), pale skin with cyanotic (cyanotic) tinge.When weighting symptoms may develop complications - pulmonary edema with a fatal outcome.
3) When X-ray - patchy shadows "cloud-" easy.The KLA - an increase of eosinophils, ESR, white blood cells.

features in HIV-infected patients (especially at the stage of AIDS):

Pneumocystis pneumonia - a leading opportunistic disease in HIV infection.
1) Due to the frequent combination of PCP with other bacterial infections and symptoms can be expressed by an infectious-toxic syndrome (fever, intoxication), cough and shortness of breath may act in the background.In some patients, the disease is "under the guise of" acute respiratory disease.
2) The tendency to a prolonged and chronic course of the disease.
3) is difficult diagnosis of infection due to the combined nature of the bacterial lesions.

Pneumocystis pneumonia in HIV-infected, microscopy

Histology pneumocystosis can also be characterized by three stages:

In the initial stage there is no inflammatory changes in the alveoli may identify trofozoidov and cysts.
intermediate stage histology coincides with the clinical manifestations and is characterized by changes in the alveolar epithelium, the abundance of macrophages in the alveoli, the discovery of a large number of cysts.
final stage is characterized by the development of alveolitis, a change in the alveolar epithelium, interstitsionalnoy infiltration of the epithelium.The abundance of cysts detected in the lumen of the alveoli, and within macrophages.

Complications PCP

Complications of Pneumocystis carinii pneumonia can be a lung abscess, spontaneous pneumothorax, exudative pleurisy.
pneumocystosis Outcomes may include: healing, death from 1 to 100% in patients with severe immunosuppression (eg AIDS stage of HIV-infection).The cause of death is respiratory failure with severe disturbance of gas exchange.

Diagnostics pneumocystosis

preliminary diagnosis - clinical and epidemiological.Data are needed on the patient contact, identify groups at risk for HIV or other immunodeficiency.Matter and features of the clinic - the absence of severe intoxication with respiratory syndrome.

Final diagnosis is carried out by means of laboratory and instrumental studies:

1) Complete blood count: marked leukocytosis (20-30 * 109), an increase of lymphocytes,
monocytes, eosinophils, mild anemia - decreased hemoglobin, ESR may be normalor changed to 50 mm / h.

2) Instrumental studies - X-rays, the results of which 1 stage pneumocystosis noted increased pulmonary pattern, the 2nd stage appear patchy shadows, which can be located on the right and left (common and unilateral disease), alternating with areas of increased transparency (the so-called phenomenoncompensatory emphysema) and increased vascular pattern - a syndrome of "veil" or "falling snow flakes."

PCP, X-ray pattern

3) Parasitological studies aimed at identifying Pneumocystis in the lesion.To do this, take
mucus from the airways by bronchoscopy (material - bronchoalveolar lavage), flexible bronchoscopy (prints), biopsy.The material can be obtained using the "method of inducing cough": provisional carried 20minutnaya inhalation of hypertonic salt solution (5% NaCl) through the ultrasonic nebulizer, which leads to increased mucus production;then press down on the root of tongue spatula, a cough, mucus is taken.
Diagnostic value of mucus when "method of inducing cough" - less than 70%, lavage - 70% of prints - 80-90% of biopsy material - 100%.The material stained with Romanovsky-Giemsa and mikroskopiruyut.

4) Serologic studies to detect antibodies to Pneumocystis blood - IFA NRIF.
used paired sera taken with an interval of 10-14 days, in which only the increase in titer of 2 or more times confirms the disease.This is done to avoid the usual carrier, antibodies are usually detected in 70% of the population.

5) PCR diagnostics to identify Pneumocystis antigens in sputum, biopsies, broncho-alveolar lavage.

Treatment of patients with PCP

1. Organizational regime activities, which include the compulsory hospitalization of patients with severe clinical form of the disease.Balanced diet, taking into account the patient's condition.

2. Drug therapy includes etiotropic treatment (exposure to the causative agent), pathogenetic (effect on pathogenic action links Pneumocystis), symptomatic (elimination of symptoms).
- Etiotropic treatment is pentamidine intramuscularly 1 time per day of 4 mg / kg heading
10-14 days (but only required the appointment of a doctor due to the toxicity of the drug);furazolidone 10 mg / kg / day;Trichopolum 25-30mg / kg / day;Biseptol 120 mg / kg / day, first intravenously 3 times a day, followed by oral administration of 2 times per day to the general course of 3 weeks.
- For HIV-infected patients, antiretroviral therapy is appointed as PP
in such patients when there is significant suppression of immunity.
- pathogenetic and symptomatic treatment includes anti-inflammatory drugs,
mucolytics, drugs, facilitating expectoration, expectorants;prevention of respiratory failure and struggle with its consequences.

infectious disease doctor Bykov NI