Transient infantile wheeze

Transient infantile wheeze is typified by wheeze that is associated with an intercurrent respiratory tract illness within the first 3 years of life. Unlike in children with asthma, children with transient infantile wheeze are non-atopic and generally do not have a family history of asthma. There is no hypoxia or significant morbidity with this condition. The children are generally thriving. After the age of 3 years, children with transient infantile wheeze become less symptomatic and generally are symptom-free by the age of 6 years. The pathophysiology of this condition is thought to be congenitally small, poorly developed, airways. Although the aetiology is uncertain, there is an association with maternal smoking. Bronchodilators are not usually effective in treating the wheeze in children with transient infantile wheeze.

Infections

The common viruses that can infect the respiratory tract of infants and preschool children are respiratory syncytial virus (RSV), metapneumovirus, influenza, parainfluenza and rhinovirus. Children with acute bronchiolitis may present with a short history of coryza, cough and wheeze, together with tachypnoea and a mild fever. On auscultation, coarse crackles are a more common finding than wheeze. See Chapter 14.5 for a detailed review of this topic.

Most children with Mycobacterium tuberculosis infection do not develop clinical disease. Uncommonly, young children with tuberculosis may present with cough, fever, weight loss and wheeze as the constellation of symptoms. These symptoms are more typical of adulthood. Tuberculosis in the young child differs to that in adolescence or adulthood in that it is unlikely to be infective to contacts. The diagnosis can be made with a tuberculin skin test (Mantoux test). Three-quarters of children with a positive tuberculin test have a normal chest radiograph.

Bronchopulmonary dysplasia

Children who are born prematurely with a history of hyaline membrane disease are at risk of developing bronchopulmonary dysplasia (BPD). BPD is defined by the need for supplemental oxygen therapy beyond 28 days of life and is associated with chronic radiological changes. The radiological changes associated with BPD are characterized by areas of fibrotic, thickened markings with cystic changes. Children with BPD may present with an acute viral infection that precipitates a respiratory decompensation. On examination, they may demonstrate signs of increased work of breathing (such as tachypnoea, nasal flare, intercostal muscle recessions and use of accessory muscles of respiration). On auscultation, widespread expiratory wheeze may be present. The long-term prognosis for children with BPD is good in terms of lung function but there is growing evidence of ongoing exercise limitation into adulthood.

Cystic fibrosis

Cystic fibrosis (CF) is a cause of chronic suppurative lung disease with an estimated carrier rate of 1 in 20 in the Caucasian population and an incidence of 1 in 2500 live births. More than 1700 genes are associated with CF. Although newborn screening is now widely performed, a small proportion of infants may fail to be diagnosed if they have uncommon mutations. If symptoms of failure to thrive, recurrent chest infections, cough and wheeze are noted, the clinician should consider CF as a diagnosis. If the child has associated pancreatic insufficiency, steatorrhoea may be present. Chest radiographs may be normal or demonstrate upper lobe bronchiectasis (Fig. 14.4.1). A sweat test may aid in making the diagnosis and should be performed after consultation with a paediatrician.

Fig. 14.4.1 Child with cystic fibrosis demonstrating classical upper lobe bronchiectasis.

Non-cystic fibrosis suppurative lung disease

Recurrent wheeze can be a presenting feature in children with other non-CF causes of suppurative lung disease. Causes of generalized wheeze and crackles would include underlying immune deficiency such as X-linked hypogammaglobulinaemia and immotile cilia syndrome. The latter, also called primary ciliary dyskinesia, is due to absent or abnormally functioning cilia that line the respiratory tract. Children with this condition typically have other upper airway manifestations such as recurrent middle ear infections and sinusitis. In approximately half the children with primary ciliary dyskinesia, there is associated dextrocardia. This constellation is referred to as Kartagener syndrome (Fig. 14.4.2). Management is aimed at achieving good airway clearance with physiotherapy and antibiotics to treat infective exacerbations.

Fig. 14.4.2 Child with primary ciliary dyskinesia with dextrocardia (Kartagener syndrome).

Aspiration pneumonia

Aspiration pneumonia could occur from below the diaphragm due to gastro-oesophageal reflux of gastric contents. It can also occur if a child has a discoordinate oral swallow and aspirates non-particulate matter. The latter presentation is more common in children with neurological impairment. Figure 14.4.3 depicts a child with chronic aspiration who, due to a poor swallowing coordination, had no oral intake and was fed via a gastrostomy button. Underlying anatomical abnormalities such as a tracheo-oesophageal fistula may result in aspiration pneumonia. Clinical presentations may vary, and recurrent wheeze may be a feature. Bronchoscopy, barium studies, pH studies and milk scans may all be needed to confirm this diagnosis, as each of these investigative tools has limitations when used in isolation.

Fig. 14.4.3 Child with neurological impairment and chronic pulmonary aspiration.

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