Asthma, airway hyperactivity, upper airway disorder should be tested post-deployment

Among military personnel, post-deployment pulmonary evaluation should target asthma and airway hyperactivity as well as include upper airway disorder testing, according to a prospective study published in Chest.

“Understanding that symptoms may be multifactorial in nature and not necessarily related to deployment exposures, patients should be first evaluated for evidence of asthma, airway hyperreactivity and upper airway disorders,” Michael J. Morris, MD, of the pulmonary/critical care service in the department of medicine at Fort Belvoir Community Hospital in Fort Belvoir, Virginia, and colleagues wrote.

For the study, 380 active-duty and retired military personnel (87.9% men; mean age, 38.5 years) with at least a 6-month deployment to Iraq, Afghanistan, Kuwait or Qatar were recruited at the Brooke Army Medical Center or Walter Reed National Military Medical Center. All participants underwent a physical and a medical history examination. They also completed a deployment questionnaire and answered questions from the Department of Veterans Affairs Burn Pit Registry.

Pulmonary function assessment included spirometry, lung volumes, diffusing capacity, impulse oscillometry and bronchodilator testing. Methacholine challenge, exercise laryngoscopy, high-resolution CT, electrocardiogram and transthoracic echocardiography were also conducted. The participants reported frequency of airborne exposures on a scale of 0 to 3, with 0 meaning no exposure and 3 meaning continuous exposure. They also reported severity of exposure on a scale of 0 to 3, with 0 meaning none and 3 meaning severe.
Most participants had served in Iraq and Afghanistan, with an average of 1.7 total deployments per participant. The frequency (average, 2.03) and severity (average, 1.63) of airborne exposure were highest for dust and sand and were comparable to the frequency (average, 2.04) and severity (average, 1.47) of burn pit exposure. The average duration of post-deployment symptoms was 4.6 years and included exertional dyspnea (75.1%), decreased exercise tolerance (72.6%), cough (55.2%), wheeze (42.1%) and sputum production (33.3%).

Of 380 participants, 32.1% were classified as undiagnosed exertional dyspnea with normal pulmonary function testing, imaging and endoscopy. The most common diagnosis based on spirometry, abnormal impulse oscillometry or both was asthma (22.9%) and 15% had reactivity with normal spirometry. Additionally, among the 10.8% of participants with airway disorders, 6.6% were identified with laryngeal disorders and 4.2% had excessive dynamic airway collapse. Only 1.6% of participants had interstitial lung disease, 2.9% had fixed obstructive lung disorders such as COPD, 10.5% had isolated pulmonary function abnormalities and 4.2% had miscellaneous disorders.

Significant comorbidities in the cohort included elevated BMI (34.2%), smoking (36.4%), positive allergy testing (43.7%), sleep apnea (38.5%), esophageal reflux (13.6%), diagnosed mental health disorders (51%) and PTSD or mild traumatic brain injury (51%).

Despite the association between deployment and development of respiratory symptoms, there are limited data linking deployment to respiratory diseases other than asthma, according to the researchers.

“Further evaluation to include chest imaging, exercise testing and fiberoptic bronchoscopy may be pursued per guidelines when the diagnosis remains elusive,” they wrote. “But there is little evidence for diffuse lung disease, interstitial or bronchiolar diseases.” – by Erin T. Welsh

Disclosures: Morris reports he is on the speakers bureau for Janssen Pharmaceuticals and GlaxoSmithKline. Please see the study for all other authors’ relevant financial disclosures.