An arteriovenous malformation (AVM) is a rare condition where blood flows directly from arteries into veins through a tangle of abnormal blood vessels, bypassing the capillaries that normally buffer the pressure. This high-pressure flow can cause veins to leak or burst, potentially leading to a brain hemorrhage or stroke.
While most AVMs are caused by genetic changes affecting blood vessel growth, recent research suggests that repeated exposure to blast waves from firing heavy weapons may alter genes in the brain, potentially contributing to AVMs. Both Wilcox and Lozano experienced repeated blast exposures during their military service, which may have damaged their blood vessels.
Both veterans experienced severe headaches, memory problems, and cognitive difficulties. Wilcox suffered a brain hemorrhage in 2014, leading to emergency surgery, while Lozano's AVM caused forgetfulness and emotional struggles, including PTSD and anger issues. Both men also faced long-term challenges, such as epilepsy (Wilcox) and memory loss (Lozano).
Research indicates that blast waves from powerful weapons can cause concussion-like symptoms, including headaches and memory problems. Studies also suggest that repeated blasts may damage blood vessels in the brain, potentially leading to conditions like AVMs. Animal studies have shown malformed blood vessels resembling AVMs after repeated blast exposure.
Wilcox lives with epilepsy, memory lapses, and a reliance on medication, while Lozano focuses on equine therapy at his War Horse Ranch, helping other veterans recover from trauma. Both men have found ways to manage their disabilities, with Lozano using horses to provide emotional support and Wilcox adjusting to his cognitive and physical limitations.
The military has implemented measures to minimize blast exposure, particularly during training. However, these changes do not help veterans like Wilcox and Lozano, who were exposed to repeated blasts before such precautions were in place.
Some weapons used by the U.S. military are so powerful they can pose a threat to the people who fire them. Today, we meet two Marines, William Wilcox and Michael Lozano, who spent years firing missiles and rockets, then developed the same rare brain condition: arteriovenous malformation, or AVM. The condition sends high pressure blood from a tangle of abnormal blood vessels directly into fragile veins, which can leak or burst. Most AVMs are caused by genetic changes that affect the growth of blood vessels, so the connection between weapon blasts and AVM isn't always immediately clear. But NPR's brain correspondent Jon Hamilton reports that recent research suggests that blast waves can alter genes in the brain — and that the evidence is even stronger for less extreme blood vessel changes.*Have questions or story ideas? Let us know by emailing [email protected])!Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave).*Learn more about sponsor message choices: podcastchoices.com/adchoices)NPR Privacy Policy)