CHICAGO – , explained Erik Hysinger, MD, MS, of the division of pulmonary medicine at Cincinnati Children’s Hospital.
Localized wheezing is not consistent with asthmatic or viral wheezing, which is typically diffuse and polyphonic, Dr. Hysinger emphasized at the annual meeting of the American Academy of Pediatrics.
“Localized wheezing is less common than diffuse wheezing and typically has a homophonous sound,” Dr. Hysinger said. It also usually arises from a central airway pathology. “High flow rates create loud amplitude sounds.”
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Dr. Hysinger also covered management strategies for focal wheezing, starting with an initial trial of bronchodilators. Any wheezing resulting from a central airway problem, however, isn’t likely to respond to bronchodilators. Standard work-up for any of these causes is usually a chest x-ray, often paired with a bronchoscopy. Persistent wheezing likely needs a chest CT, and many of these conditions will require referral to a subspecialist.
Airway occlusion diagnoses
Four potential causes of an airway blockage are a foreign body, a bronchial cast, mucous plugs, or airway tumors.
A foreign body typically occurs with a cough, wheezing, stridor, and respiratory distress. It is most common in children under age 4 years, usually in those without a history of aspiration, yet providers initially misdiagnose more than 20% of patients with a foreign body. The foreign object – often coins, food, or batteries – frequently ends up in the right main bronchus and may go undetected up to a month, potentially leading to pneumonia, abscess, atelectasis, bronchiectasis, or airway erosion.
Dr. Erik Hysinger
An endobronchial cast is rarer than a foreign body, but can be large enough to completely fill a lung with branching mucin, fibrin, and inflammatory cells. The wheezing sounds homophonous, with a barky or brassy cough accompanied by atelectasis. Dr. Hysinger recommended ordering chest x-ray, echocardiogram, and bronchoscopy. Although often idiopathic, these casts also can result from asthma or another disease: neutrophilic inflammation typically indicates a heart condition whereas asthma or influenza leads to eosinophilic inflammation.
Treatment should involve clearing the airway, followed by hypertonic saline, an inhaled tissue plasminogen activator, and a bronchoscopy for extraction.
Although distinct from endobronchial casts, a mucus plug also presents with wheezing, a cough, and atelectasis, and potentially respiratory distress or failure, and hypoxemia. Mucus plugs are diagnosed with a chest x-ray and flexible bronchoscopy, and then treated by removing the plug and clearing the airway, hypertonic saline, and mucolytics.
The rarest cause of an airway blockage is an airway tumor, often mistaken for asthma. Benign causes include papillomatosis, hemangioma, and hamartomas, while potentially malignant causes include a carcinoid, mucoepidermoid carcinoma, inflammatory myofibromas, and granular cell tumors.
In addition to a chest x-ray and bronchoscopy, a chest CT scan plus a biopsy and resection are necessary to diagnose airway tumors. Treatment will depend on the specific type of tumor identified.
“Overall survival is excellent,” Dr. Hysinger said of children with airway tumors.
Airway narrowing diagnoses
Two possible diagnoses for an intrinsic airway narrowing include bronchomalacia, occurring in only 1 of 2,100 children, and bronchial stenosis.
In bronchomalacia – diagnosed primarily with bronchoscopy – the airway collapses from weakening of the cartilage and posterior membrane. Bronchomalacia sounds like homophonous wheezing with a barky or brassy cough, and it’s frequently accompanied by recurrent bronchitis and/or pneumonia. Intervention is rarely necessary when occurring on its own, but severe cases may require endobronchial stents. Dr. Hysinger also recommended considering ipratroprium instead of albuterol.
Bronchial stenosis involves a fixed narrowing of the bronchi and can be congenital – typically occurring with heart disease – or acquired after an intubation and suction trauma or bronchiolitis obliterans (“popcorn lung”). A chest x-ray and bronchoscopy again are standard, but MRI may be necessary as well. Aside from helping the patient clear the airway, bronchial stenosis typically needs limited management unless the patient is symptomatic. In that case, options include balloon dilation, endobronchial stents, or a slide bronchoplasty.