Measles pneumonitis

To investigate the finding of increased alveolar-arterial (A-a) gradient in adult patients with measles who have normal results on both pulmonary auscultation and chest radiography.

Retrospective, descriptive case series.

An urban county teaching hospital in southern California.

Consecutive adult patients with the clinical diagnosis of measles seen in the emergency department.

Patients were considered to have pneumonitis if they had any of the following: ED diagnosis of pneumonia; an A-a gradient of more than 30 mm Hg; one or more infiltrates on chest radiograph.

Seventy-five patients, including 44 men and 31 women (median age, 25 years; 25% to 75% interquartile range [IQR], 20 to 28 years) were seen during the 36-month study period. Forty-three patients (57%; 95% confidence interval [CI], 45% to 69%) had pneumonitis, with a median A-a gradient of 42 mm Hg (IQR, 34 to 48 mm Hg). Twenty-seven of the 43 patients with pneumonitis (63%; CI, 48% to 77%) had both normal pulmonary auscultation findings and normal chest radiographs; this represented 36% of the study population (CI, 25% to 50%). Thirty-eight of the 43 patients with pneumonitis were admitted; one patient was later intubated after respiratory failure developed. Two of the 5 patients with pneumonitis who were sent home were admitted the following day for worsening symptoms. All 75 patients eventually did well.

A significant percentage of adult patients with measles presenting to an ED with both normal pulmonary auscultation and normal chest radiographs have increased A-a gradients. These patients warrant close follow-up and perhaps hospital admission.