Chronic Cough

FeNO testing helped guide an appropriate workup and diagnosis of this patient and helped avoid an expensive immunodeficiency workup that would not have been useful.

• Referred for possible immunodeficiency
• Patient presented with a worsening shortness of breath, chest tightness, and coughing, especially in the previous 2 weeks
• Frequent bronchitis, sinusitis, and strep throat over the previous 6 months
• Previous pulmonary function tests were reportedly normal
• No previous known history of allergy or asthma
• No past or current medications for her condition

• Her fractional exhaled nitric oxide (FeNO) measurement was 52 ppb suggesting significant airway inflammation
• Chest x-ray was normal, pulmonary function tests were 68% of predicted
• Allergy test results were positive for cats, dogs, trees, grasses, and weeds

• Treated for asthma aggressively with oral steroids for 5 days
• Started a short-acting bronchodialator as needed, and combination inhaled corticosteroid and long-acting beta agonist

• Continuously improving, patient had a resolution of asthma symptoms and has been well controlled since starting appropriate treatment
• Repeat FeNO was 16 ppb