Acute bronchiolitis in children

Bronchiolitis is an acute infectious disease of the viral etiology with the defeat of the lower respiratory tract, which occurs in children under 18 months of age and is characterized by respiratory failure, wheezing and various wheezing. The diagnosis is suspected in the history, including an epidemic history; an etiological agent, a respiratory syncytial virus, can be identified using an express test. Treatment of bronchiolitis in children is oxygen and hydration.

Bronchiolitis often occurs in the epidemic primarily in children under the age of 18 months with a peak incidence in infants less than 6 months old. Annually, the incidence of children of the first year of life is approximately 11 cases / 100 children. Most cases occur between November and April with a peak incidence during January and February.

[1], [2], [3], [4], [5], [6], [7], [8]

What causes acute bronchiolitis in children?

Most of the cases are caused by respiratory syncytial virus and parainfluenza virus type 3; Influenza A and B viruses, parainfluenza type 1 and 2, metapneumovirus and adenoviruses are less common. Rare causes are rhinoviruses, enteroviruses, measles virus and Mycoplasma pneumoniae.

The virus spreads from the upper respiratory tract to the middle and small bronchi and bronchioles, causing necrosis of the epithelium. Developing edema and exudation lead to partial obstruction, most pronounced during exhalation and leading to the formation of an air trap. Complete obstruction and absorption of air from the alveoli lead to the formation of multiple sites of atelectasis.

Symptoms of acute bronchiolitis

Usually, the child has symptoms of an acute upper respiratory tract infection with a progressive development of respiratory failure characterized by tachypnea, an entrainment of pliable areas of the chest and coughing. In young children, the disease may manifest as recurrent episodes of apnea, more characteristic symptoms of bronchiolitis appear after 24-48 hours. Signs of respiratory failure may include perioral cyanosis, increased entrainment of pliable areas of the chest and wheezing. Fever is noted as a rule, but not always. The child at the beginning of the disease is in a satisfactory condition without signs of respiratory failure, with the exception of tachypnea and the retraction of the pliable areas of the chest, but his condition can quickly deteriorate with the development of the infectious process down to lethargy. Dehydration may develop due to vomiting and decreased intake and fluid. With the progression of weakness, breathing can become more superficial and ineffective, which leads to respiratory acidosis. At auscultation wheezing, wheezing, and often small bubbling wet wheezing are audible. Many children develop acute otitis media in parallel.

Diagnosis of acute bronchiolitis

The diagnosis is suspected on the basis of anamnesis, examination, manifestations of the disease and its transition to the epidemic. Symptoms similar to bronchiolitis can occur with asthma, which is more common in children older than 18 months, especially if there is a history of wheezing and a family history of asthma. Gastroesophageal reflux with aspiration of gastric contents can also cause a clinical picture of bronchiolitis; multiple episodes in a baby can be the key to this diagnosis. Aspiration of a foreign body is rarely manifested by wheezing, it should be thought of if there is a sudden onset that is not associated with manifestations of an acute infection of the upper respiratory tract.

Patients suspected of bronchiolitis should be pulsoximetry to assess oxygenation. Further examination in mild cases with normal oxygenation is not required, but in the case of hypoxemia, a chest x-ray is required to confirm the diagnosis. On the roentgenogram, as a rule, flattening of the diaphragm, increased transparency of the lung fields, a noticeable reaction of the roots are found. There may be infiltrative shadows due to atelectasis or RSV pneumonia, which are relatively common in children with RSV bronchiolitis. An express test to detect RSV antigen, which is performed in a smear or wash from the nose, is diagnostic, but not always necessary; It can be left for patients with a condition that is severe enough for the child to need hospitalization. Other laboratory tests are nonspecific; approximately 2/3 of the children have leukocytosis 10 000-15 000 / μL. Most of them have 50-70% of lymphocytes in the leukocyte formula.

[9], [10], [11], [12], [13]

Treatment of acute bronchiolitis

Treatment of acute bronchiolitis is supportive, most of the children can be treated at home, providing them with comfortable conditions and adequate hydration. Indications for hospitalization include increased respiratory failure, severity of the disease (cyanosis, weakness, lethargy), history of apnea and the presence of atelectasis on the radiograph. Children with background conditions, such as heart disease, immunodeficiency, bronchopulmonary dysplasia, which increase the course of the disease and the risk of complications, should also be considered as candidates for hospitalization. In hospitalized children, 30-40% of O is given by an oxygen tent or mask. This is usually sufficient to maintain oxygen saturation of more than 90%. Intubation of the trachea is indicated in severe repeated apnea, hypoxemia that does not respond to the use of oxygen, or delayed CO2, or if the child can not remove the secret from the bronchi.

Hydration should be maintained by frequent small portions of drinking. Children in a more serious condition are shown with infusion therapy, the level of hydration should be assessed by controlling diuresis and specific gravity of urine, as well as blood electrolytes.

There is evidence that the systemic administration of glucocorticoids can be effective at their early administration or in patients with diseases that are sensitive to glucocorticoid therapy (bronchopulmonary dysplasia, bronchial asthma), but for most hospitalized children the effect is not proven.

Prescribing antibiotics should be avoided, except when a secondary bacterial infection joins (a rare complication). Bronchodilators are not always equally effective, but a significant proportion of children experience a short-term improvement. This is especially true for children who have already had a wheezing breath in their history. The length of stay in the hospital is most likely not reduced.

Ribavirin, an antiviral drug with in vitro activity against RSV, influenza and measles virus is not effective in the clinic and is no longer recommended for use; It is also potentially toxic to hospital staff. There have been attempts to use anti-RSV immunoglobulin, but it is not reliably effective.

How to prevent acute bronchiolitis in children?

Prevention of respiratory syncytial infection is carried out by passive immunoprophylaxis with monoclonal antibodies to RSV (palivizumab). This reduces the frequency of hospitalizations, but this is an expensive method, and it is shown to children from the high-risk group.

What prognosis does acute bronchiolitis have in children?

Acute bronchiolitis in children has a favorable prognosis; most of the children recover after 3-5 days without consequences, lethality less than 1% with adequate medical care. Children who have had bronchiolitis in early childhood are expected to have a higher incidence of bronchial asthma, but this relationship is controversial.