Causes of Wheezing in Preschool Children

Wheezing or wheezing in children under five can occur for many possible reasons. It is generally considered the first sign of asthma, but a significant proportion of young children with wheezing do not develop asthma. Bronchitis in infancy is the most likely cause of wheezing. As children get older, episodic viral wheezing becomes more common. Atopic wheezing most likely occurs in children with risk factors such as a family history of asthma.
By school age, some of these wheezing children are diagnosed with asthma, while others become increasingly diagnosed without being diagnosed. Therefore, rather than focusing on making a diagnosis when a young child presents with wheezing, it is more important to ensure that the child is properly managing his symptoms and that parents receive advice on education and vaccinations about the treatment of their child.

Not All Wheezing Is Asthma

Causes of Wheezing in Preschool ChildrenHalf of all children will have a wheezing attack before school age. 2 Many will “recover” from their symptoms when they go to school, but a clear pattern of reversible airway obstruction will continue, in some that will be recognized as recurrent respiratory symptoms and asthma. It can be difficult for the clinician to distinguish young children who will have asthma from those who will not.
Wheezing is clinically defined as a continuous musical sound due to intrathoracic airway obstruction. The small physical size of a young child’s respiratory system, a still developing immune system, and high levels of exposure to viral respiratory pathogens make wheezing both more common and difficult to diagnose in young children than in older children. Environmental factors also play an important role in the occurrence and severity of wheezing.
Exposure to tobacco smoking before and after birth significantly increases the likelihood that a child will develop wheezing. Additionally, smoking at home exacerbates respiratory symptoms. There are many other environmental factors that can cause or aggravate wheezing in children, including damp homes, dust mites, pets, food allergies, air pollution, and infections.
The benefit of diagnosing asthma in preschool children is discussed. The signs, symptoms and treatment defined by the terms “episodic viral wheezing” and “atopic wheezing” in preschool children are very similar to “episodic asthma” and “atopic asthma”, respectively. 2 Asthma is also commonly diagnosed in school-age children who have previously experienced recurrent wheezing. Therefore, some clinicians believe that wheezing and asthma are part of the same spectrum, and giving the asthma “tag” leads to more appropriate treatment strategies. Others are reluctant to diagnose asthma in preschool children when the pathology is largely unknown, and the diagnosis of asthma, which later turns out to be temporary, may have unintended social and psychological consequences.
In practice, determining an exact cause of wheezing in preschool children requires a long-term approach, taking into account the possibility of common causes, excluding serious congenital or acquired conditions, and evaluating the child’s response to treatment. The purpose of primary health care should be to provide symptomatic control, manage aggravating factors, and monitor the child, rather than providing a definitive diagnosis, as delivery may change over time.

Causes of Wheezing in Preschool Children

The first step in evaluating wheezing in a young child should be to determine how long symptoms have been present. Consider the possibility of inhaled foreign body if there is a recent sudden onset of wheezing (ie that day or within a few days) and there is no apparent cause, eg viral illness. If wheezing has just begun, but a concomitant upper respiratory tract infection is present, episodic viral wheezing or bronchiolitis should be considered. Consider atopic wheezing if there is wheezing for several weeks / months or if the child has wheezing multiple times. However, symptoms may also be due solely to recurrent upper respiratory tract infections.
Inhaled foreign body

A substance absorbed and attached to the tracheobronchial system can cause acute onset wheezing, dry cough, and decreased lung sounds. The most important finding in a child with an inhaled foreign body is the onset of choking or severe coughing after lying down. However, this phenomenon is not always observed and children may not be willing to learn. If diagnosis is delayed, other symptoms may be present, such as dyspnoea and a wet cough producing sputum.
Serious complications of an inhaled foreign body (including pneumonia, pneumothorax, and subglottic edema) are more likely when diagnosed 24 hours after inhalation. Long-term complications such as recurrent pneumonia, lung abscesses, and bronchiectasis become more likely the longer the diagnosis is delayed. Children suspected of having a foreign body should be referred to a Pediatrician or emergency room immediately.
Causes of Wheezing in Preschool ChildrenBronchiolitis is an acute lower respiratory tract infection that occurs especially in young babies and is most common in winter. It is usually caused by the respiratory syncytial virus (RSV). In a child with bronchiolitis, tachypnea, cough, hyperinflation of the chest and fine inspiratory cracks are possible. 6 It is likely to be a short, firm cough and airway secretions play an important role in obstructing. 6 The child may also have a low-grade fever (<39 ° C). 6 High-grade fever, although wheezing is rare in children with bacterial pneumonia, it may indicate another diagnosis, such as pneumonia. Bronchiolitis is the most common cause of wheezing in 1-6 months old children. The incidence of bronchiolitis is much lower by ten months of age, and it is rare after one year of age.
Episodic viral wheezing
Episodic viral wheezing, also called non-atopic wheezing, is wheezing associated with viral upper respiratory tract infections (URIs). Children with episodic viral wheezing usually do not show respiratory symptoms between episodes of viral infection. The most common causative viruses include rhinovirus, coronavirus, human metapneumovirus, parainfluenza virus, and adenovirus.
Symptoms include acute wheezing and dyspnoea, usually accompanied by cough, shortly after the onset of an upper respiratory tract disease. Children with acute viral wheezing are unlikely to have chest cracks as seen in children with bronchiolitis. In addition, bronchiolitis is usually a single episode of acute illness compared to recurrent infections with viral wheezing.
Episodic viral wheezing is most common in children aged ten months to three years. Children who develop wheezing as a symptom of viral infection usually have fewer episodes over time, 2 and most children with wheezing without concurrent atopy will have symptoms at school age or soon after. However, some children with episodic viral wheezing will continue to receive a confirmed asthma diagnosis.
Atopic hırıltıCauses of Wheezing in Preschool Children
Atopic wheezing or multi-trigger wheezing is recurrent persistent wheezing associated with atopic features and multiple aggravating factors such as cold weather, night time, exercise, or allergen exposure. 2 Symptoms occur when the child does not have a viral illness, and more severe exacerbations occur when the child has a viral illness.
Children with atopic wheezing were typically found to have cough, dyspnoea, prolonged expiration, increased respiratory rate, and chest tightness, as well as bilateral, diffuse wheezing or wheezing, which is most pronounced on exhalation. A child with recurrent wheezing with symptoms of atopy or eczema, positive skin prick tests, or a child with a family history of asthma or atopy may be considered to have atopic wheezing.
Atopic wheezing is unusual in a child under the age of two (although it happens), but it becomes the dominant form of wheezing after the age of three. In practice, it appears that almost all children with atopic wheezing are diagnosed with asthma after reaching school age. Sometimes, a child with wheezing that initially only appears with viral respiratory infections will develop wheezing over time in response to interval symptoms and other triggers, and is later diagnosed with asthma in childhood.
Temporary wheezing
Transient baby wheezing is an epidemiological term for self-limiting wheezing that occurs in children up to the age of three. The clinical utility of the term is limited, but it is widely used in the literature to describe the group of children with recurrent wheezing that grow from their symptoms to the age of three.
Children in this group are usually born with smaller airways, their lung function decreases from birth, there is no family history of atopy or asthma compared to wheezing children, and they are generally exposed to tobacco smoke antenatally. Premature and low birth weight can also be risk factors for temporary baby wheezing. In general, it is not possible to clinically distinguish transient baby wheezing from other types of wheezing.


Author: Ozlem Guvenc Agaoglu

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