Parainfluenza in children

Parainfluenza is an acute respiratory disease with moderate intoxication and predominant damage to the mucous membranes of the nose and larynx. Human parainfluenza viruses (HPIVs) are a group (types 1-4) of organisms that cause various respiratory infections (croup, pneumonia, and bronchiolitis).

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Epidemiology

In the overall structure of viral respiratory diseases in children, parainfluenza accounts for 10 to 30%. The proportion of parainfluenza cases depends on the season, incidence of influenza and other acute respiratory viral infections, the age of the children and the completeness of diagnostics. The highest incidence is recorded among children in the first 2 years of life. Sporadic incidence is recorded all year round with an increase in winter. Outbreaks are often observed in children's groups. Almost all children suffer from parainfluenza several times.

The source of infection is only a sick person, who is dangerous during the entire acute period of the disease - up to 7-10 days. The virus is transmitted from person to person by airborne droplets. The most significant in human pathology are viruses of types 1, 2 and 3.

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Causes parainfluenza in a child

The pathogen belongs to the paramyxovirus family. There are 5 known types of human parainfluenza viruses. All of them have hemagglutinating activity. Neuraminidase has been found in all types. They contain RNA, are large in size - 150-200 nm, and are unstable in the environment. They differ from influenza viruses in the stability of the antigen structure and the absence of visible variability of the virion genome.

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Pathogenesis

The virus with droplets of saliva and dust gets on the mucous membranes of the upper respiratory tract and penetrates into the epithelial cells mainly of the nose and larynx. As a result of the cytopathic effect in the epithelial cells, dystrophy and necrobiosis phenomena occur with their complete destruction. Locally, an inflammatory process develops and mucous exudate accumulates, edema appears. Particularly pronounced local changes are found in the larynx, as a result of which croup syndrome often occurs.

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Symptoms parainfluenza in a child

The incubation period is 2-7 days, on average 3-4 days. In most patients, parainfluenza begins acutely with a rise in body temperature, the appearance of mild symptoms of intoxication and catarrhal phenomena. Usually, the temperature reaches its maximum on the 2nd-3rd day of the disease, less often on the 1st day. The general condition of the child at the height of the disease is moderately disturbed. Children complain of weakness, loss of appetite; sleep is disturbed. There is a headache, a single vomiting. In some patients, the body temperature can reach 40 ° C, but there are no pronounced symptoms of intoxication.

Symptoms of parainfluenza begin with catarrhal symptoms, which are quite pronounced from the first day of illness. There is a persistent, rough dry cough, sore throat, runny nose, nasal congestion. Nasal discharge is initially mucous, later it can become mucopurulent. When examining the oropharynx, swelling, moderate hyperemia of the mucous membrane, arches, soft palate, posterior pharyngeal wall are noted, sometimes exudative purulent effusion is found in the lacunae.

Often the first manifestation of parainfluenza infection is croup syndrome, mainly in children aged 2 to 5 years. In these cases, in the midst of complete health, the child suddenly wakes up at night from a rough, barking cough. Hoarseness of voice, noisy breathing quickly join in, and stenosis of the larynx develops. However, with parainfluenza, stenosis rarely reaches grade II and even more rarely grade III.

Parainfluenza croup quickly disappears as the acute symptoms of parainfluenza are eliminated. If secondary microbial flora joins in, the course of croup is longer.

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Forms

There are mild, moderate and severe forms of parainfluenza. In mild forms, body temperature is usually normal or subfebrile. Parainfluenza disease manifests itself as catarrhal symptoms, nasal congestion, and mild malaise. In moderate forms, body temperature reaches 38-39 °C, and intoxication symptoms are moderate. Severe forms are rare.

Symptoms of parainfluenza depend little on the serovar of the parainfluenza virus. However, croup syndrome most often occurs with the disease caused by viruses of types 1 and 2, and pneumonia - by virus of type 3.

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Diagnostics parainfluenza in a child

Suspicion of parainfluenza may arise when a child develops an acute febrile disease with catarrhal symptoms and croup syndrome. Early age and correct assessment of epidemiological data are important for diagnosis.

Isolation of parainfluenza virus from nasopharyngeal swabs has no practical significance due to the difficulty and insufficient sensitivity of cultivation methods.

For serological diagnostics, RSK, RTGA and RN are used. An increase in the titer of specific antibodies in the dynamics of the disease by 4 times or more indicates parainfluenza. As an express diagnostic, an immunofluorescence method of research with labeled sera against parainfluenza viruses of all types is used.

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Differential diagnosis

Parainfluenza is differentiated from acute respiratory viral diseases of other etiologies:

1. flu,
2. adenoviral diseases,
3. respiratory syncytial infection, etc.

Croup syndrome at the onset of the disease with an increase in body temperature with mild symptoms of intoxication gives grounds to assume parainfluenza. However, the etiology of the disease can be finally established after a laboratory examination, since the same symptoms can be seen with influenza and acute respiratory diseases of other viral etiologies.

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Treatment parainfluenza in a child

Symptomatic treatment of parainfluenza is carried out at home. Only children with croup syndrome and severe bacterial complications are subject to hospitalization. Bed rest and symptomatic agents are prescribed. Nutrition should be complete, easily digestible, without significant restrictions on food ingredients. Food is given warm.

Prevention

Specific prevention of parainfluenza has not been developed. General preventive measures are the same as for influenza.

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Forecast

Parainfluenza in children has a favorable prognosis. Fatal outcomes are possible only if severe bacterial complications occur (pneumonia, purulent-necrotic laryngotracheobronchitis, etc.).

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