Structure, life cycle, symptoms of diseases caused by Mycoplasma pneumoniae

A dangerous inflammatory lung disease caused by a pathogenic agent is mycoplasma pneumonia. Let's consider the features of the disease and methods of its treatment.

Atypical damage to the mucous membrane and all structural elements of the respiratory system caused by the bacterium mycoplasma occurs in 10% of all inflammations. The pathogenic microorganism spreads by airborne droplets. The infectious process formed under its influence is characterized by a long course from 2-3 weeks to several months.

According to the International Classification of Diseases, 10th revision ICD-10, Mycoplasma pneumoniae belongs to category X Diseases of the respiratory system (J00-J99):

J09-J18 Influenza and pneumonia.

• J15 Bacterial pneumonia, not elsewhere classified.
  • J15.7 Pneumonia due to Mycoplasma pneumoniae.

Also in category J20.0 Acute bronchitis due to mycoplasma pneumoniae.

Anthroponotic disease is accompanied by catarrhal and respiratory symptoms, severe intoxication, dyspepsia and other pathologies. This type of pneumonia manifests itself both in the form of sporadic cases and epidemic outbreaks. It has seasonal fluctuations with a peak in the autumn-winter period.

Why is mycoplasma pneumonia dangerous?

Atypical form of pneumonia very often leads to serious consequences, worsening the functioning of the whole organism. Let's consider in more detail, what is dangerous mycoplasma pneumonia:

• Intoxication of the body with decay products of pathogenic microorganisms.
• Impaired lung function and oxygen metabolism.
• Pathologies of the cardiovascular system.
• Severe respiratory failure.
• Bronchial asthma.
• Fibrosis, lung abscess.
• Central nervous system disorders.

In addition to the above problems, the patient may experience side effects of varying severity to the medications used. With a properly designed therapy plan, recovery and rehabilitation take about 6 months.

Structure mycoplasma pneumoniae

Mycoplasmas are microbes that live in the epithelium of the respiratory tissues. The structure of this pathogen is similar to chlamydia. Bacteria do not have strong cell membranes and the ability to create energy bonds. For their existence and reproduction, nutrients from the human body are necessary.

This structure of bacteria has its advantages:

• Due to their small size of 0.3 to 0.8 microns, they easily penetrate into healthy cells of the lungs, trachea and bronchi.
• They move quickly, so when the cell in which they were parasitizing dies, they find a new one and destroy it.
• They hold tightly to cell membranes, so pneumonia develops even with a small number of pathogens.
• After penetrating the mucous membranes of the respiratory organs, they quickly increase their population and disrupt the functioning of the affected tissues.
• They are inaccessible to immune cells and antibodies, as they are similar to some healthy cells of the body. Because of this, the pathogen may not cause an immune response in the affected organism for a long time.

In the structure of community-acquired pneumonia, respiratory mycoplasmosis accounts for 5-50%. The disease has an intermediate position between bacteria, viruses, and protozoa.

The main causes of pulmonary mycoplasmosis are infection with the Mycoplasma pneumoniae bacterium from a sick person. Normally, this type of pathogenic microorganism is present in every healthy person, but under the influence of certain factors it is activated. Most often, the disease occurs due to the following reasons:

• Immunodeficiency states.
• Bad habits: smoking, alcoholism, drug addiction.
• Decompensated diabetes mellitus.
• Chronic obstructive pulmonary disease.
• Seasonal flu epidemics.
• Bronchitis.
• Local bronchial obstruction.
• Cystic fibrosis.
• Bronchiectasis.

Highly virulent strains of anaerobic bacteria are small organisms without cell walls. Mycoplasmas are absorbed by the cells of the bronchi and alveoli, parasitizing on their membranes. Due to their introduction into the body, an autoimmune reaction with a number of painful symptoms is formed.

In addition to pneumonia, bacteria can cause the following diseases:

• Acute inflammation of the upper respiratory tract.
• Bronchial asthma.
• Exacerbation of chronic obstructive bronchitis.
• Various non-respiratory pathologies: otitis, encephalitis, pericarditis, meningitis, hemolytic anemia.

Infectious agents are easily transmitted by airborne droplets from both infected individuals with pronounced symptoms and asymptomatic carriers. Bacteria do not grow when the nutrient medium is not moist enough, so they cause a runny nose and cough with phlegm. They are not very resistant to the external environment, do not tolerate drying, heating and ultrasound. The main feature of the infection is the periodic chronicity of the disease with generalization of the infection.

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Life cycle mycoplasma pneumoniae

Mycoplasma respiratory tract infection is characterized by smooth and gradual development. The life cycle of the bacteria is 12-14 days, but can last more than a month. During this period, the infected person may not even suspect that he is sick.

The infection is characterized by a gradual progression:

• The tide lasts about 80 hours, characterized by a sharp influx of blood into the lung tissue and the release of exudate. Against this background, the organ edema and inflammation occur.
• Red hepatization – lasts no more than 70 hours. Lung tissues become denser and increase in volume. The exudate contains an increased concentration of red blood cells.
• Gray hepatization – lasts about 5-7 days. Erythrocytes gradually disappear from the exudate and the level of leukocytes increases. The lung tissue becomes gray.
• Resolution – takes 10-12 days. Fibrin is resorbed and leukocytes disintegrate. The lungs are restored.

The upper respiratory tract is affected, causing dryness and nasal congestion, nasopharyngitis, laryngitis. The temperature rises and sweating increases, general well-being worsens. Bacteria provoke paroxysmal coughing, which can last more than a month. During coughing, there is discharge of thick, in some cases purulent sputum. Without proper treatment, mycoplasmas actively multiply, constantly repeating their life cycle, affecting a weakened organism and causing progression of painful symptoms.

Risk factors

Atypical pneumonia has certain risk factors that contribute to its occurrence. Predisposition to the disease is based on age criteria:

Early childhood patients:

• Birth injuries.
• Malformations of the lungs and heart.
• Pneumopathy of the newborn.
• Intrauterine hypoxia.
• Asphyxia.
• Cystic fibrosis.
• Hypovitaminosis.
• Hereditary immunodeficiencies.

School age children:

• Immunodeficiency states.
• Bronchitis.
• Chronic infectious lesions of the nasopharynx.
• Acquired defects of the cardiovascular system.

Adult patients:

• Chronic lung diseases.
• Immunodeficiency states.
• Smoking.
• Bronchitis.
• Heart failure.
• Surgical operations of the abdominal cavity and chest.
• Diseases of the endocrine system.

Recent medical research has established a link between dental pathologies and bacterial pneumonia. People with problematic teeth have an 86% higher risk of developing respiratory mycoplasmosis.

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Pathogenesis

The mechanism of development of atypical pneumonia is associated with infection with Mycoplasma pneumoniae. The pathogenesis of the disease is based on the penetration of the infectious agent into the mucous membranes of the respiratory tract. Bacteria penetrate the mucociliary barrier, attaching to the membranes of epithelial cells. Mycoplasmas are embedded in healthy cells, gradually destroying them.

There are several ways for pathogens to penetrate into the parenchyma of lung tissue:

• Bronchogenic – bacteria enter the body with inhaled air. The infection process is significantly accelerated by inflammatory lesions of the nasal cavity. The swollen mucous membrane with inflamed cilia of the epithelium is unable to retain microbes. The infectious focus can be caused by chronic processes in the pharynx, tonsils or lower respiratory tract. The occurrence of the disease is facilitated by aspiration and various medical manipulations.
• Hematogenous – microbes enter the body with the bloodstream. Infection occurs during a septic condition, intrauterine infection or intravenous drug use.
• Lymphogenous – bacteria enter the lymphatic system and are carried throughout the body by the lymph flow.

Using one of the above-described routes, pathogenic microorganisms penetrate the body, settling on the tissues of the lungs and bronchioles. Because of this, not only pneumonia can develop, but also bronchitis, bronchiolitis and a number of other diseases.

In the pathogenesis of mycoplasmosis, immunopathological reactions are of great importance. Respiratory lesions are characterized by cold agglutinins. That is, mycoplasma pneumoniae affects the antigens of erythrocytes I, turning them into immunogenomes. Because of this, cold IgM antibodies to the antigen of erythrocytes I appear. Bacteria induce an immune response of the body, which is accompanied by the production of secretory IgA and circulating IgG antibodies.

How is mycoplasma pneumonia transmitted?

Pneumonia occurs due to many reasons. Faced with an atypical form of the disease, many patients wonder how mycoplasma pneumonia is transmitted.

Main routes of infection:

• Airborne – infection occurs through contact with a sick person. When he coughs or sneezes, pathogenic microorganisms enter a healthy body. The infection penetrates the mucous membranes of the nasal and oral cavity. For prevention, you should wear protective masks during the epidemiological period and adhere to personal hygiene rules.
• Airborne dust – mycoplasma bacteria can be found in rooms with poor ventilation and poor cleaning.

To date, about 12 different forms of mycoplasma have been identified, which have been found in the nasopharynx and urinary tract. But only three types can function in the human body. Outbreaks of infection occur no more than once a year. The risk of infection increases significantly in densely populated cities. The disease is transmitted very slowly, indicating its viral nature.

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Epidemiology

About 10% of lower respiratory tract infections are caused by Mycoplasma pneumoniae. The disease is common among patients aged 5 to 35 years and over 65.

Statistics of the disease state indicate its annual progression. At the same time, cases of infection of school-age and younger children have become more frequent. Epidemics caused by the bacteria occur in large cities with a frequency of 3-7 years. The risk of infection is associated not only with age characteristics, but also with the level of protective properties of the immune system.

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Symptoms

An atypical form of inflammation caused by mycoplasmas develops in the upper respiratory tract with various pathological manifestations. The symptoms of the disease are conditionally divided into two groups:

Respiratory:

• Bronchitis.
• Tracheitis.
• Pleurisy.
• Lung abscesses.
• Pharyngitis.

Non-respiratory (arise due to damage to internal organs or body systems):

• Anemia.
• Hepatitis.
• Pancreatitis.
• Dermatological reactions.
• Myocarditis.
• Pericarditis.
• Thrombocytopenia.
• Polyarthritis.
• Arthralgia.

The disease has a subacute onset of respiratory syndrome. Subfebrile body temperature, unproductive and painful cough, and discharge of non-purulent sputum gradually appear. Various extrapulmonary signs of infection are also observed.

The rapid increase in painful symptoms is due to the fact that pathogenic microorganisms are little affected by the human immune system. In addition, bacteria are insensitive to most antibacterial drugs.

First signs

The causative agent of anthroponotic infectious disease occupies an intermediate position between bacteria and viruses. This is due to the fact that mycoplasma parasitizes on the cell membranes of the ciliated epithelium of the bronchi and can penetrate into the cells.

Infection usually occurs by airborne droplets, which resembles acute respiratory viral infections or flu, but with a slower spread. The incubation period is 2-3 weeks, after which the first signs of mycoplasma pneumonia appear:

• Deterioration of general well-being and increased weakness.
• Subfebrile body temperature.
• Sore throat, dryness in the throat, hoarseness.
• Headaches.
• Redness of the soft palate and pharynx.
• Dry paroxysmal cough.
• Pain in the ears and eyes.
• Muscle pain.
• Increased sweating.
• Joint pain.
• Dyspnea.
• Enlargement and soreness of the cervical lymph nodes.

In addition to respiratory symptoms, the disease is characterized by other symptoms: gastrointestinal tract lesions, dermatological rashes, various neurological symptoms. Laboratory tests show elevated ESR values and no leukocytosis.

The above symptoms increase over 5-7 days. The patient is dangerous to others for 20 days. During the examination, the doctor detects fine-bubble wheezing, shortening of the percussion sound, which is a reason for laboratory diagnostics and radiography.

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Mycoplasma pneumonia in adults

A fairly common disease diagnosed in the autumn-winter period is mycoplasma pneumonia. In adults, this pathology is less common than in children and is usually combined with parainfluenza.

Mycoplasmas are microorganisms without cell walls. They are similar in size to viruses and in morphology to L-forms of bacteria. They affect the mucous membrane of the respiratory tract, causing pathological changes. At first, rather non-specific symptoms arise:

• Sore throat.
• Feverish condition.
• Subfebrile body temperature.
• Headaches.
• Pain in the eye sockets.
• Runny nose.
• Dry, hacking cough.
• Chills.

Such signs very often lead to erroneous diagnosis and treatment of bacterial pneumonia. Symptoms characteristic of the disease appear as it progresses, i.e. at its later stages. Because of this, various complications of both pulmonary and extrapulmonary nature arise.

Diagnosis of the pathology consists of a set of various examinations. When performing radiography, an increase in the pulmonary pattern and small focal shadows in the lower parts of one or both lungs are observed. To confirm the diagnosis, a blood test for Ig to Mycoplasma pneumoniae M, A, G is indicated. Treatment in adults consists of antibacterial therapy, vitamin therapy and physiotherapy. Recovery is long and requires a comprehensive approach.

Mycoplasma pneumonia during pregnancy

Any illnesses that occur during pregnancy are dangerous for both the mother and the future baby. Mycoplasma pneumonia during pregnancy is dangerous not only because of its complications, but also because of its latent/blurred course, similar to the symptoms of a cold. Because of this, many women do not seek timely medical help, trying to eliminate the disorder on their own. Such behavior only complicates the pathology and its prognosis.

Home treatment very often leads to secondary infection and purulent complications. Pulmonary mycoplasmosis during pregnancy is dangerous due to the development of respiratory failure, myocarditis, endocarditis, septic conditions, exudative pleurisy, edema and lung abscess. If the atypical form of pneumonia was detected in time, the prognosis is favorable.

Mycoplasma pneumonia in children

In the complex of respiratory diseases, mycoplasma pneumonia in children deserves special attention. This is due to the fact that young patients are more susceptible to infection, and the disease has pronounced symptoms. Most often, the development of inflammation occurs against the background of acute respiratory tract lesions: bronchitis, tonsillitis, tracheobronchitis, and others.

Mycoplasma pneumoniae infection in children is manifested by the following main syndromes:

1. Intoxication

Since inflammation of the lung tissue affects small areas, it is rarely accompanied by pronounced symptoms of intoxication. If several segments of the lungs or its entire lobes are involved in the pathological process, then signs of intoxication come to the fore. In children, the following symptoms are observed:

• Elevated body temperature.
• Chills and fever.
• Rapid pulse.
• Rapid fatigue.
• Paleness of the skin.
• Increased drowsiness.
• Loss of appetite and refusal to eat.
• Increased sweating.
• Nausea and vomiting.

The duration of the above symptoms is 3-4 days. If treatment has not been started during this time, the disease progresses.

2. Inflammation of the lung tissue

The appearance of such signs allows us to suspect a bacterial nature of the lung damage. The main symptoms of specific inflammation:

• Dry cough.
• Poor expectoration.
• Painful sensations behind the breastbone and in the throat.
• Auscultatory changes.
• Radiographic signs.
• Violations of hemoleukogram norms.

The peculiarities of infectious cough are its constant presence, regardless of the time of day. It has a paroxysmal nature and occurs when trying to take a deep breath. Against this background, the release of mucopurulent sputum is possible. Aching pains in the abdomen and chest appear, which intensify with deep breathing.

3. Respiratory failure

Due to damage to the lung tissue, the area of the so-called breathing surface of the organ decreases, and respiratory failure occurs. Moreover, the younger the child, the more pronounced the pathological symptoms:

• Increased respiratory rate.
• Difficulty breathing.
• Cyanosis of the nasolabial triangle.
• Mobility of the wings of the nose during breathing.

Shortness of breath appears from the first days of the disease. Difficulty, irregular breathing causes great anxiety in both children and parents, and leads to sleep disturbances. During breathing, skin retraction is observed in the supraclavicular and subcostal regions, and in the spaces between the ribs. Without timely and proper treatment, painful symptoms quickly increase.

Bronchiolitis and mycoplasma pneumonia

An inflammatory disease affecting the small bronchi is bronchiolitis. Mycoplasma pneumoniae can be one of the causes of the painful condition. Inflammation of the bronchioles most often occurs due to the following factors:

• Infection of the respiratory system with bacterial or viral agents.
• Inhalation of toxic substances over a long period of time.
• Rheumatoid arthritis.
• History of diseases with connective tissue damage.

Depending on the severity of the pathological process, bronchiolitis has the following classification:

1. Acute – symptoms develop rapidly. The patient’s condition rapidly worsens, signs of intoxication appear.
2. Chronic – the signs of this form appear gradually. At first, the painful condition is not noticeable, but it becomes more pronounced with each passing year.

Bronchiolitis caused by Mycoplasma pneumoniae refers to the obliterating form of the disease. The symptoms of the disorder are varied, but the most pronounced is shortness of breath. As the pathology progresses, cyanosis of the skin, obstructive paroxysmal cough, subfebrile body temperature, and swelling of the upper extremities appear.

Diagnosis of the infectious process may present certain difficulties. The standard research algorithm consists of: chest X-ray, spirography, CT, bronchoscopy and others.

Treatment consists of taking antiviral, antibacterial and anti-inflammatory drugs. To reduce shortness of breath and expand the bronchi, bronchodilators are prescribed, as well as mucolytics to speed up the discharge of sputum. If the disease is severe, oxygen inhalations are indicated. Particular attention is paid to preventive measures, which consist of strengthening the protective properties of the immune system.

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Atypical pneumonia

Infectious and inflammatory lung lesions caused by uncharacteristic pathogens are atypical pneumonia. Most often, the disease occurs due to the following reasons:

• Mycoplasma.
• Chlamydia.
• Influenza viruses A, B.
• Respiratory parainfluenza viruses.
• Coxiella.
• Legionella.
• Epstein-Barr virus and other pathogens.

The above pathogens have different microbiological characteristics, so the diseases differ in epidemiology and pathomorphology. Today, the following forms of atypical pneumonia are distinguished: mycoplasma, chlamydial, Q fever, Legionnaires' disease.

Like most infectious pathologies, the atypical form has the following stages:

1. Incubation period – lasts 7-10 days from the moment of infection.
2. Prodromal – 1-3 days with the appearance of non-specific symptoms of respiratory viral infections (headaches and muscle pain, dry cough, sore throat).
3. The peak is a pronounced infectious and inflammatory process in the lungs.
4. Convalescence – the activity of the disease gradually subsides and the patient’s condition normalizes.

The following general symptoms are characteristic of all types of atypical pneumonia:

• Increased weakness.
• Cough and shortness of breath.
• Profuse sweating.
• Increased body temperature up to 40-41°C.
• Chest pain.

In addition to the above symptoms, the mycoplasma form often occurs with an enlarged liver and spleen. Diagnosis is based on the clinical picture of the disorder. The patient undergoes chest X-ray in two projections to determine the source of inflammation. Bacteriological, microbiological and immunological studies are indicated to identify the pathogen.

Treatment of atypical pneumonia consists of etiotropic and symptomatic therapy. It is necessary to destroy pathogenic microorganisms and conduct concomitant treatment. Without proper and timely treatment, the disease causes many complications that significantly worsen the functioning of the entire body.

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Complications and consequences

Mycoplasma pneumonia is a serious disease with quite severe consequences and complications. Based on this, the following pathological conditions are distinguished:

• Pulmonary (affecting the bronchi, pleura and, of course, lung tissue).
  • Pleurisy is an inflammation of the pleural sheets covering the lungs. It can occur in both dry and wet forms. In the first case, fibrin clots accumulate in the pleural cavity, which glue the tissues together. The main sign of this complication is increasing symptoms of respiratory failure and pain behind the breastbone.
  • Empyema is a purulent form of pleurisy in which pus accumulates in the pleural cavity. The symptoms are similar to the exudative form of the disease. The main sign of the pathology is a very high body temperature and a feverish state.
  • Lung abscess – one or more cavities form in the organ, in which purulent contents accumulate. The destructive process is characterized by the destruction of lung tissue and severe intoxication. At the initial stage, the abscess is closed, but gradually breaks through into the pleural cavity or bronchi. The patient develops copious sputum, the body temperature drops. If the abscess breaks through into the pleura, this leads to its empyema.
  • Obstructive syndrome – shortness of breath and frequent attacks of suffocation. Lung tissues lose their functionality and connective tissue forms in their place.
  • Pulmonary edema is the most dangerous complication of bacterial pneumonia. Fluid from the vessels gets into the lungs and alveoli, filling them. Against the background of increased agitation, the patient suffocates. A strong cough appears, the skin is cold and sticky. Without timely resuscitation, a fatal outcome is possible.
• Extrapulmonary (caused by the action of bacteria that have a destructive effect on the internal organs and systems of the body).
  • Toxic shock – toxins released by bacteria and viruses penetrate the blood. Against this background, multiple organ failure increases. At least three body systems are involved in the pathological process: digestive, cardiovascular and renal. The painful condition is accompanied by fever, polymorphic rashes on the body and a sharp decrease in blood pressure.
  • Cardiac complications – myocardial dysfunction is caused by hemolytic anemia, which in its symptoms resembles myocardial infarction. It is also possible to develop pericarditis, myocarditis, hemopericardium, AV block, severe heart failure.
  • Meningitis is an inflammatory lesion of the meningeal membranes of the brain. It develops due to the penetration of harmful microorganisms into the central nervous system. It causes attacks of nausea and vomiting, stiffness of the occipital muscles and photophobia.
  • Hepatitis is a fairly common complication of atypical pneumonia. The lung tissue is affected, which is why the liver cannot cope with its functions. The decay and metabolic products of pathogenic microorganisms are not excreted from the body, but accumulate in it. This leads to an increase in bilirubin levels and jaundice. Patients complain of nausea and vomiting, pain in the right hypochondrium.
  • Nervous system lesions – meningoencephalitis, serous meningitis, ascending paralysis, myelitis, encephalitis. Such complications significantly complicate the recovery process.
  • Lesions of the skin and mucous membranes - most often, patients are diagnosed with maculopapular and vesicular rash, aphthae, and conjunctivitis.
  • Joint pathologies – arthritis and rheumatic attacks.

In addition to the above complications, mycoplasma pneumonia causes dyspeptic disorders of varying severity. The fatality rate from the consequences of pneumonia is 3-5%, and in the presence of chronic diseases it can reach 30%.

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Prevention mycoplasma pneumoniae

There are no specific methods for preventing atypical pneumonia. Prevention is aimed at increasing the immune system's defenses and reducing the risk of complications.

Main methods of prevention:

• Immunization, that is, hardening and vitamin therapy. Such methods stimulate the immune system.
• Timely treatment of any diseases, especially seasonal colds.
• Avoid hypothermia and stress, balanced nutrition.

It is also necessary to eliminate possible contacts with those infected with mycoplasma infection. If preventive measures are followed and timely medical care is sought, the risk of developing a severe form of the disease is minimal.

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Forecast

In case of atypical pneumonia, the prognosis of the disease depends on the following factors:

• Age of the patient.
• Virulence of a pathogenic microorganism.
• Presence of chronic diseases.
• Protective properties of the immune system.
• Timeliness and reliability of the diagnostics performed.
• Adequacy of prescribed therapy.

An unfavorable prognosis with the development of complications is typical for patients with immunodeficiency states and with pronounced resistance of pathogens to antibacterial therapy. The disease is especially dangerous for pediatric patients. In this group of patients, the risk of death is 10-30%.

With timely and correct therapy, the disease ends in recovery. The following changes in the lung tissue after the transferred pathology are distinguished:

• Complete restoration of tissue and organ structure – 70%.
• Local pneumosclerosis – 25-30%.
• Focal carnification – 10%.
• Reduction in the size of a lobe or segment of the lung – 2-5%.
• Shrinkage of part of the lung and development of an infectious process - less than 1% of cases.

Mycoplasma pneumonia has rare cases of fatal outcome, but is characterized by a high risk of developing severe consequences.

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