Legionnaires Disease in Children

What is Legionnaire Disease in Children?

Legionnaires disease is also known as legionellosis and Pontiac fever. It is an acute infectious disease caused by bacteria and leads to fever, lung damage, respiratory syndrome, and often to the GIT, kidneys, and the central nervous system.

According to the International Classification, legionnaires’ disease and Pontiac fever (legionnaires disease without pneumonia) are distinguished.

Epidemiology. The causative agent of the disease lives and multiplies in warm open ponds covered with algae. Legionella may be associated with certain types of algae and protozoa. Also, the pathogen can “live” for a long time in water supply and air conditioning systems, shower installations, cooling towers, medical equipment for inhalation and artificial respiration, baths for balneological procedures.

Presumably, the only mode of transmission is airborne dust. Air and water play a role in the spread of infection, which condenses in air conditioners. Also among the mediators of transmission of the Legionnaires’ disease is the dust raised during the excavation, the shower head, the soil in the endemic foci.

It is believed that the infection is not transmitted from person to person. Children can become infected in schools and kindergartens, nurseries, orphanages, and in any rooms that have faulty or uncleaned air conditioners.

In medical practice there have been outbreaks of legionellosis inside hospitals; therefore, some authors regard this disease as a nosocomial infection.

Legionnaire disease in children can occur in the form of epidemic outbreaks or sporadic cases. The greatest number of cases is recorded in summer and autumn. Diseases are subject to adults and children, even infants.

Causes of Legionnaire Diseases in Children

The causative agent of Legionnaires disease belongs to the genus Legionella, the family of Legionellaceae. These are gram-negative rods, the length of which is 2-50 microns, and the width 0.3-0.7 microns.

There are more than twenty species in the genus Legionella: L. bozemanii, L. pneumophila, L. Miedadei. The most numerous species is L. pneumophila, which is divided into 15 serotypes – they all cause illness in children.

The microorganisms in question are pathogenic for laboratory animals such as guinea pigs and non-pathogenic for mice. Legionella contain endotoxins. In the external environment, they are stable. Legionella can be destroyed with the help of disinfectants: formalin, alcohol, phenol solution. Also, the pathogen is destroyed by using antibiotics: ampicillin, erythromycin, rifampicin, chloramphenicol, etc. Legionella are located in the affected tissues inside and outside the cells.

Pathogenesis during Legionnaires Disease in Children

The infection is initially localized on the mucous membrane of the upper respiratory tract or in the tissues of the lung. There the pathogen accumulates, due to which an inflammatory process occurs. The development of the disease further depends on the pathogenicity of the pathogen and the dose that has entered the body, as well as on the local and general resistance of the organism.

The disease is severe in children who have been treated for a long time by immunosuppressants with concomitant diseases, as well as in nosocomial infections.

In the mild form of legionary disease in children, the pathological process affects mainly the mucous membranes of the upper respiratory tract. In such cases, the disease passes, as is the ARD, there are no signs of generalization of infection. Severe forms of leginellosis in children affect the lung tissue, lobar or total pneumonia appears. There are general toxic phenomena up to infectious-toxic shock and. disseminated intravascular coagulation syndrome.

In severe cases, multiple heart attacks in the internal organs are fixed, hemorrhagic syndrome is growing in the form of nasal, uterine and stomach bleeding, hemoptysis, hematuria. Renal failure in most cases progresses, as does the phenomenon of encephalopathy. Infectious toxic shock can occur, as a result of which a fatal outcome occurs.

Pathomorphology. Maximum changes are fixed in the lungs. Macroscopic examination reveals foci of compaction and fibrinous pleurisy phenomena in a light grayish tissue.

In the alveoli, a histological examination detects an exudate with a large number of neutrophils, macrophages and fibrin.

Immunity. The infectious process leads to the fact that the body produces specific antibodies. The maximum falls on the 3-6th week of the disease, the amount gradually decreases. It is not precisely known how long the action of humoral immunity is. Some researchers say that lifelong immunity. In the literature, there are no cases of recurrent diseases of legionnaires in children, as well as relapses.

Symptoms Diseases of Legionnaires in Сhildren

When infected with leginellosis in children, the incubation period lasts 2-10 days. The disease usually occurs in pneumonic form, which is designated in the international classification as legionnaire’s disease. If it is of the type ORZ, it is called Pontiac fever. In recent years, began to allocate a third form – acute febrile illness with exanthema.

The most typical symptoms are in the pneumonic form of legionnaires’ disease in a child. In such cases, the disease has an acute onset, the body temperature rises, the child is shivering, muscle pains and headaches are noted. From the first days of the disease, a dry cough is heard, reemerging behind the sternum, and a runny nose appears.

The above symptoms progress quite quickly – in 3-5 days. Body temperature reaches 39-40 ° C, symptoms of intoxication are pronounced. Cough instead of dry becomes wet, sputum departs, shortness of breath increases.

Percussion methods reveal in the lungs foci of shortening the percussion sound, and during auscultation in the projection of these foci on the background of weakened breathing crepitus and finely moist moist rales are heard.

The roentgenogram shows focal shadows with a tendency to merge and form large areas of darkening. Rarely, pleurisy or slight exudation into the pleural cavity occurs.

At the peak of a severe illness, constant vomiting, abdominal pain, impaired renal function up to renal failure, loose stools, etc., occur. Such a symptom as gastrointestinal bleeding is also likely. If the infection affects the central nervous system, insomnia, dizziness, in some cases, convulsions, loss of consciousness, hallucinations, delusions, incoordination of movements (if the cerebellum is affected) appear.

In the cardiovascular system in the case of legionary disease, a child has such changes as tachycardia, hypotension, and deafness of heart tones. In severe cases, there may be cardiovascular failure, which is fatal.

The blood test shows leukocytosis, neutrophilic shift, a tendency to thrombocytopenia and lymphopenia, a sharp increase in ESR. Also in severe cases, urinalysis reveals protinuria, hematuria. Kidney damage can result in the development of anuria and azotemia.

The disease is considered to be particularly severe if respiratory and cardiovascular insufficiency progresses rapidly, hemorrhagic syndrome increases as a manifestation of disseminated intravascular coagulation syndrome. Also on the severity of the disease Legionnaires indicate the phenomenon of severe encephalopathy and infectious-toxic shock, severe renal failure.

Legionellosis with Qatar of the upper respiratory tract is very similar to ARD. The clinical picture is as follows: temperature 38-39 C, runny nose, cough, easy chills. There is the possibility of vomiting, muscle pain, neurological symptoms and liquid stude. The child recovers 7-10 days after the onset. There is evidence that the number of forms of legionellosis by type of ARD exceeds the number of forms with lung tissue damage dozens of times.

Acute febrile illness with exanthema (Fort Bragg fever) has the following symptoms: respiratory tract catarrh, fever and maculopapular rash on the body.

Complications of legionnaires’ disease in children. There is a possibility of abscess formation in the lungs, the development of multiple thromboembolism, pleural empyema, acute renal failure with azotemia and renal encephalopathy.

Complications with respiratory forms of the disease can only be when the accession of the secondary microbial flora. In the pneumonic form, the percentage of deaths is more than 20%. Often the cause of death are comorbidities. Prgnoz favorable with legionellosis, passing the type of ARD.

Diagnosis Diseases of Legionnaires in Сhildren

The diagnosis of legionary disease in children is made on the basis of a complex of clinical, epidemiological and laboratory data.

Legionellosis is suspected if there are dark areas or spotted interstitial infiltrates in the lungs, which exist for a long time and – in some cases – are progressive, despite active treatment with antibacterial agents from the penicillin group.

Laboratory confirmation of the diagnosis is required, for which bacteriological and serological methods are used. The pathogen is isolated from the pleural fluid, as well as from the blood and sputum.

If express diagnostics are necessary, a direct immunofluorescence method is used, which is used to detect DNA or the pathogen itself in a biomaterial (sputum, bronchial washes, or in biopsy specimens of bronchi and lung obtained by bronchoscopy).

Serological diagnosis is carried out using ELISA, indirect immunofluorescence methods or microagglutination reactions.

The pneumonic form of legionellosis in children is distinguished from severe pneumonia, which are caused by viral-bacterial associations, mycoplasmas and chlamydia. Legionnaires’ disease is indicated by a progressive course of the disease with extensive areas of darkening in the lungs that are difficult to treat with large doses of penicillin.

The same picture can be with chlamydial or mycoplasmal pneumonia. But, unlike these diseases, legionella pneumonia is often combined with signs of encephalopathy, etc.

Accurate diagnostics provide only laboratory research methods.

Treatment of Legionnaire Diseases in Children

Etiotropic therapy is carried out with antibiotics. The maximum effect is possible with azithromycin or erythromycin treatment.

Carried out pathogenetic and symptomatic treatment according to generally accepted rules. Corticosteroid hormones do not justify their appointment. Acute renal failure is treated with diuretics, if they do not give effect, hemodialysis is prescribed.

Prevention of disseminated intravascular coagulation is carried out with the help of anticoagulants, with the control of coagulogram.

Forecast. According to American authors, the percentage of deaths ranges from 15 to 20% in the pneumonic form of the disease. Acute renal failure, hypoxemia and shock, profuse abdominal hemorrhage, disseminated intravascular coagulation syndrome, adrenal hemorrhage, swelling and swelling of the brain substance can be immediate causes of death.

The disease does not end with death in such forms of legionella infection as fever of Fort Brag and Pontiac fever.

Prevention of Legionnaires’ Diseases in Children

Preventive methods are not developed. Since the possibility of transmitting the pathogen from person to person has not been proven, quarantine measures are considered inexpedient.

Conduct a study of water in the air conditioning system and disinfection by increasing the water temperature to 60 ° C, which allows you to clean the system from legionella.

In order to prevent outbreaks of nosocomial disease of legionnaires, thorough cleaning and sterilization of medical equipment, especially devices used for the treatment of respiratory diseases (ventilators, tracheotomy tubes, cannulas) should be carried out.

Active immunization is being developed with vaccines.