Study Identifies Airway Anomaly Possibly Indicative of Autism

   There appears to be a correlation between autistic spectrum disorder and airway anatomy, according to a small study presented at CHEST 2011, the 77th annual meeting of the American College of Chest Physicians, in Honolulu.

   As known, autism and autistic spectrum disorders are currently diagnosed primarily through subjective observation of autistic behaviors. However, new research, by Barbara Stewart, MD, of Nemours Children’s Clinic in Pensacola, Florida, suggests that a physical abnormality in the airway may be a prominent indicator for autism and autistic spectrum disorders, making it a possible diagnostic marker for this panoply of conditions.

   She performed a retrospective evaluation of 49 patients <18 years with a diagnosis of autism or autistic spectrum disorder. The patients were seen, in her institution's pulmonary clinic, with a diagnosis of cough that was unresponsive to therapy and who required further pulmonary workup. Bronchoscopic evaluation of the airway was included as part of it.

   The bronchoscopy revealed the presence of initial normal anatomy followed by what Dr. Stewart referred to as "double take-offs" or "doublets" in the lower airway found in 100% of the autistic population studied.

   “Another way to think of this is “symmetric doubling” of airways in the lower airways," she explained. "When airways divide beyond the first generation, they typically branch like a tree, with one branch on one side and one on the other. A 'doublet' occurs when there are twin branches that come off together instead of one, which are exactly symmetrical, in each of the lower locations that can be seen.”

   Patients who have “doublets” in the lower airways may have higher airway resistance, which, as Dr. Stewart explained, “might be why the population of children with autistic spectrum disorder are not truly athletic people.”

   Although bronchoscopy can help identify the structure of the airway, Dr. Stewart cautions that it is not yet ready to be a screening or diagnostic tool for autism. “Bronchoscopy is a useful tool, but it is still an invasive surgical procedure and one that should not be undertaken lightly. The practitioner should consider the root cause for this embryologic anomaly, asking the deeper question concerning the genetic link of the doubling,” said Dr. Stewart. “However, if there is a medical reason to perform bronchoscopic evaluation of the airway, one should obtain the maximum amount of information during that procedure.”