It wasn't until a couple of weeks later that Lanthier — who had spent 31 years as a firefighter with the city of Palo Alto and now works in the emergency room of El Camino Hospital — began to suspect he had suffered another injury.
It started with a terrible headache. And then he noticed he was having trouble forming words. He couldn't whistle for the dog the way he'd always done. Looking in the mirror he could see the left side of his face was sagging. That's when he knew he needed to get to the hospital right away.
Dr. Amy Lee, a neurologist with ECH saw him immediately and gave him a CT scan. It revealed that Lanthier had a small cut on the inside of his carotid artery, which carries blood to the brain and head. A clot had formed as a result of the injury, known as a "carotid artery dissection," and the clot had since broken off and was blocking blood flow to his brain.
Lanthier, an otherwise healthy and physically fit man, was having a stroke.
Lee and her team put him on blood thinning medication to help break up the clot, and in two weeks Lanthier had regained most of his normal function.
"I'm a lucky guy," Lanthier said, reflecting on the incident. Having worked as a firefighter and in the ER, the Los Altos man said, he was "very sensitive to the issue" and knew all the signs as symptoms of stroke.
His ability to recognize what was happening likely saved his life, according to Dr. Peter Fung, another ECH neurologist, who said that when it comes to strokes "time lost is brain lost."
"If you have any stroke symptoms at all, even if it's a remote possibility, make sure you come to the hospital as soon as possible," Fung said. After all, not everyone can be as lucky as Lanthier — and it's probable that no one is as lucky as another of Fung's patients, Alex Myers.
A tale of two strokes
Like Lanthier, Myers suffered a stroke caused by a carotid artery dissection. Unlike Lanthier, however, the 50-year-old lawyer had not hurt himself in any way in the run-up to his stroke. In fact, the only thing Myers had been doing differently from his daily routines was running.
A carotid artery dissection occurs when a small tear develops in the innermost layer of the carotid artery, Fung explained. These tears can sometimes lead to buildup of "blood elements," such as cholesterol and platelets, which may become lodged in the small tear. If enough of these blood elements build up, the artery may become blocked, or a clot may form, become dislodged and travel farther up into the brain.
The tear often results from trauma to the neck, Fung said. This can happen to people who have been in a car accident or taken a nasty fall, or even those who have had a neck adjustment by a chiropractor — any violent twisting or whipping motion has the potential to result in a tear.
Sometimes, however, as in Myers' case, a tear can occur ostensibly out of the blue. He had suffered from what is known as a "spontaneous" carotid artery dissection, according to Fung; in such cases, doctors can't be sure what caused the arterial wall to tear.
A tricky diagnosis
Three years ago, Myers was training for a marathon. He had just come back from a 5-mile run, and was sitting on the couch watching TV when he was struck with a terrible headache.
"It was like someone had hit me in the back of a head with a baseball bat," he recalled.
He assumed the pain would eventually go away. But it didn't. Not much later, while sitting at his desk, he suddenly couldn't see his computer screen.
Myers decided to go to an eye doctor, who told him he was either having a stroke or a migraine. Given that Myers had not recently experienced any trauma, and that he otherwise seemed healthy — with no slurred speech or lack of motor function — the eye specialist told him he was most likely having a migraine and sent him home.
Three days later Myers was in the emergency room with a splitting headache, which he had been attempting to block with prescription painkillers to little avail. He was given a CT scan, which didn't reveal anything. He was again told it must be a migraine and was given morphine to numb his pain. On his way out of the hospital he set up an appointment to see a neurologist — two weeks later.
But the next day, with the morphine wearing off, it was clear to Myers and his wife that he could not wait. Once more, Myers returned to the hospital and once again he was told that it was either a migraine or a stroke — though all signs continued to point to migraine, according to the specialists.
An MRI was ordered; halfway through the procedure, his opiate-based painkillers began wearing off, and when the hospital refused to give him more after the scan, he and his wife went home to fetch more. Once there, his wife checked her cell phone and discovered a deluge of calls from the hospital: The doctors had realized that Myers had a carotid artery dissection, and had chased after their car as they pulled away.
"Stay at the house," they told his wife. "We're sending an ambulance."
Awareness is key
A representative from El Camino Hospital said that the delay in Myers' diagnosis shouldn't be attributed to carelessness, but rather to the fact that it was a difficult diagnosis to make.
That is why it's important for people to familiarize themselves with all the potential symptoms of stroke, Fung said.
Lanthier recognized his stroke symptoms — slurred speech, the inability to whistle, a drooping face. But symptoms might also include dizziness, double-vision, problems swallowing, and paralysis of limbs, Fung said.
When strokes are caused by high cholesterol, hypertension and heart disease — all of which are more common in older people — headache is less common, he said. But with a carotid artery dissection stroke, a headache can be an indicator. Myers' inability to see his computer screen is a commonly seen symptom of such a stroke, he said.
Dodging a bullet
Myers, a regular runner before his stroke, said he is convinced that if he weren't in such great shape physically it would have been the end for him. He also credits the hospital staff for keeping him calm and safe after he was finally correctly diagnosed.
"They did a great job at El Camino," he said. "I've made pretty darn near a full recovery."
A few weeks after his MRI, Myers returned for a follow-up scan to make sure everything was still OK. "Oh my God, it's you," the MRI technician said before bursting into tears. "You know, I did you're MRI. I thought you died."
That's when the gravity of what he had been through really hit him, Myers said. Until then, he hadn't realized how close he was to slipping away.
Myers now wears a bullet dangling from a chain around his neck as a reminder of his ordeal, he said. "That's the bullet that missed."