Concussions from bomb blasts and post-traumatic stress disorder — the two signature wounds of the wars in Afghanistan and Iraq — can be difficult to distinguish from each other. Cognitive problems, sleep trouble and irritability are common symptoms of both.
Up to 44% of veterans who suffered concussions involving a loss of consciousness also meet criteria for PTSD, military researchers have found.
But a new study raises the possibility that at least some of the veterans may not actually have the stress disorder but instead hormonal irregularities due to pituitary gland damage incurred during their concussions.
Researchers at Saint Louis University analyzed brain scans from dozens of military and civilian patients. Comparing patients with concussions to patients with both concussions and PTSD, the scientists found significant differences in the metabolic activity in their pituitary glands.
FOR THE RECORD
Dec. 3, 12:06 p.m.: An earlier version of this post said the researchers were from the University of St. Louis. They were from Saint Louis University.
The findings were presented Monday in Chicago at the annual meeting of the Radiological Society of North America.
Thomas Malone, who led the research, said higher levels of metabolic activity in patients with concussions and PTSD may be due to the gland working harder to produce hormones.
"It's analogous to having your car stuck in the snow and you keep flooring the gas pedal but you don't go anywhere," he said.
Though the PET/CT scans were able to distinguish between the groups, they could not diagnose pituitary damage at the individual level.
The pea-sized pituitary gland secretes nine hormones that help regulate stress response, mood and energy expenditure. It hangs from the base of the brain by a strand of neurons and blood vessels — a connection that makes it vulnerable to damage in certain kinds of trauma.
While pituitary problems have long been associated with the most serious head injuries, a growing body of evidence suggests that concussion-level forces may also be enough to damage the gland. (The Los Angeles Times wrote about the issue last year.)
Over the last decade, more than 200,000 U.S. service members are thought to have withstood explosions from roadside bombs and other artillery.
Most patients with concussions get better in a few days. For reasons that largely remain a mystery, up to 15% do not recover quickly or develop new symptoms later. The Pentagon has issued guidelines to its doctors to screen for hormone irregularities when that happens.