Cardiovascular abnormalities are one of many uncommon causes of wheezing in children Small airway edema in the setting of congestive heart failure or airway impingement by enlarged cardiovascular structures is the usual pathophysiologic mechanism Most cardiac conditions are associated with other abnormal physical findings, including cyanosis, murmurs, abnormal pulses, poor perfusion, or signs consistent with congestive heart failure Though abnormal cardiac physical findings are generally absent in patients with a vascular ring or sling, these structural abnormalities may cause wheezing and dysphagia due to esophageal compression; and a right-sided aortic arch is often noted on chest radiograph Pulmonary disease, including wheezing, is the hallmark of cystic fibrosis (CF) In addition to wheezing and other adventitious sounds, individuals with CF will often also exhibit steatorrhea and failure to thrive because of pancreatic insufficiency and malabsorption (see Chapter 99 Pulmonary Emergencies ) Similar to CF, patients with primary ciliary dyskinesia also develop repeated respiratory tract infections, sinusitis, and otitis media, often in association with situs inversus viscerum and bronchiectasis (Kartagener syndrome) Wheezing may result from pulmonary edema, which may be caused by congenital or acquired heart disease with congestive heart failure However, pulmonary edema may also be caused by other disease processes, such as pneumonia, acute respiratory distress syndrome, and hypoalbuminemic states, such as nephrotic syndrome and liver failure Hydrocarbon aspiration, leading to a chemical pneumonitis, may also cause pulmonary edema Pulmonary hemorrhage can also cause wheezing Etiologies include airway trauma, systemic vasculitis, or infection such as tuberculosis or aspergilloma Acute idiopathic pulmonary hemorrhage of infancy and idiopathic pulmonary hemosiderosis are other rare causes of pulmonary hemorrhage An adolescent patient may present with moderate to severe respiratory distress that is unresponsive to β-agonist therapy Consideration should be given to precipitating factors and the diagnosis of psychogenic wheezing (also called vocal cord dysfunction) These patients may generate wheezing noises in their larynx, often best appreciated by auscultating the neck Children with cell-mediated or humoral immune deficiency syndromes often present with recurrent wheezing and bacterial pulmonary infections These patients can have opportunistic infections or repeated extrapulmonary infections, including meningitis, otitis media, otitis externa, furunculosis, and mucocutaneous candidiasis Other uncommon causes of wheezing include extrinsic tracheobronchial compression by an enlarged lymph node or tumor (see Chapter 98 Oncologic