Pediatrics: Causes of Wheezing in Infants and Toddlers

Viral bronchiolitis
Asthma
Foreign body aspiration
Gastroesophageal (GE) reflux
Tracheomalacia
Extrinsic compression (e.g. due to adenopathy, mass, vascular ring or sling or other anatomic airway lesion)
Cystic fibrosis

Ask about:
- Timing of the wheeze
- Association of symptoms with feeding
- Change of symptoms with position or activity
- Other exacerbating factors
Past history of wheezing episodes and response to treatment with bronchodilators or steroids

Paradoxical breathing (thoracoabdominal dissociation): almost always a sign of severe respiratory distress due to respiratory muscle fatigue
Tachypnea: mild, moderate, or severe depending on the severity of the underlying process
Retractions: use of accessory muscles to augment breathing during respiratory distress
- Suprasternal, supraclavicular, and intercostal retractions
- Subcostal retractions
Nasal flaring: seen in younger children with significant respiratory distress, indicating use of accessory muscles
Grunting: forced expiration against a partially closed glottis, helping infants generate positive pressure to stent airways open
Head bobbing: use of accessory muscles of respiration (neck strap muscles) in young infants

Viral upper respiratory tract illnesses
Pneumonia
Post-nasal drip due to allergies and/or sinusitis
Foreign body aspiration
Gastroesophageal reflux
Cough can be dry or wet/junky, with different implications for diagnosis and treatment

Bordetella Pertussis (Whooping Cough)
- Triphasic course: catarrhal stage, paroxysmal stage, and convalescent stage
- Complications: difficulty feeding, central nervous system complications such as apnea
- Immunization: acellular pertussis vaccine, but even with full immunization, vaccine efficacy is only 70-90%
Epiglottitis
- Life-threatening emergency, rare due to widespread immunization
- Etiology: Haemophilus influenzae type b (Hib), staphylococcal or streptococcal organisms
- Signs and symptoms: fever, stridor, drooling, dysphonia, dysphagia, respiratory distress
- Emergent intervention: prompt intervention in a controlled environment to secure the airway

Pathophysiology: airway obstruction due to inflammation, mucus hypersecretion, and mucosal edema
Signs and symptoms:
- Acute exacerbations: cough, wheezing, tachypnea, dyspnea
- Chronic symptoms: recurrent episodes of dyspnea and/or cough
Radiographic findings: hyperinflation due to air trapping, increased interstitial markings, patchy atelectasis
Treatment:
- Acute exacerbations: anti-inflammatory therapy with corticosteroids, bronchodilation with beta-2 agonists
- Maintenance therapy: daily controller medication (inhaled corticosteroid), with an inhaled beta-agonist as needed for breakthrough symptoms

Acute viral disease of the lower respiratory tract, most common cause of wheezing in infants
Pathophysiology: bronchiolar obstruction due to edema, mucus, and cellular debris
Signs and symptoms: wide spectrum of disease, including mild upper respiratory tract symptoms, fever, cough, wheezing, dyspnea
Radiographic findings: hyperinflation, increased interstitial markings, peribronchial cuffing, scattered atelectasis
Treatment: supportive, aimed at maintaining adequate oxygenation and hydration### Choking in Children
Choking is a significant injury risk in children, particularly in older infants and toddlers who explore the world by putting things in their mouths.
The risk of choking is greatest in this age group, and parents should be advised on methods to reduce this risk.

When evaluating a pediatric patient, it's essential to assess the stability of their condition to initiate urgent interventions or treatments.
Vital signs vary by age in children; for example, a respiratory rate of 55 may be normal in a newborn, but not in a 10-month-old.

When taking a family history, ask about heritable conditions that affect the respiratory tract, such as asthma, environmental allergies, and cystic fibrosis.
Explore social and environmental history, including:
- Exposure to sick contacts, which increases the likelihood of an infectious process.
- Childcare, which increases the risk of sick contacts.
- Tobacco smoke exposure, which can cause or contribute to a chronic cough.

Adjust your approach to the child according to their age.
Infants (9-10 months) may develop stranger anxiety and cry when approached by strangers; having the parent hold the patient can reduce anxiety.
Older infants, toddlers, and some preschoolers can also become frightened when approached; use a calm and unhurried approach to examine them.

After treating a child for an incident involving their safety at home, provide anticipatory guidance to prevent future events.
Counsel the family on how to prevent future events in a gentle, non-accusatory manner.

In foreign object aspiration, radiographic findings may include:
- Flattened right hemidiaphragm on PA film, suggesting unilateral hyperexpansion on the right.
- Fixed hyperinflation of the right lung on right decubitus.
- Hyperinflation and air trapping with each breath, causing an expiratory wheeze.

Asymmetric wheezing is key to diagnosing foreign body aspiration, but it can also be caused by mucus plugging from asthma or bronchiolitis.
Radiography is necessary to further evaluate the etiology of wheezing, including inspiratory and expiratory films to demonstrate unilateral air trapping.