A Mysterious Blood Clot Revealed My Genetic Blood Condition at Age 38

But my discomfort was only worsening, and it was especially bad in the mornings.

When even driving became uncomfortable, I knew it was time to go to the orthopedic urgent care clinic for a same-day appointment.

“How’s your insurance?” the physician’s assistant asked me after a brief exam. “Good… Why?” I countered. Because my injury was lingering and I couldn’t pinpoint a cause, he suspected a blood clot and ordered an ultrasound.

I bristled at the idea. I didn’t have any of the common symptoms of a blood clot, like redness, swelling, heaviness, or heat. Plus, in my mind, blood clots happened to people who were older (I was only 38 at the time), less active, and living in bigger bodies than mine. I couldn’t possibly have a blood clot.

Three hours later, after a thorough ultrasound all the way up to my bikini line, I was diagnosed with a deep vein thrombosis, or DVT—a blood clot that develops in one of the body’s deeper, larger veins, most commonly in the legs, per the Mayo Clinic.

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By that evening, I had a prescription for blood thinners—the same ones my 80-something-year-old grandmother takes—and a follow-up appointment scheduled with a hematologist (aka, a doctor who specializes in blood disorders). But mostly, I had lots of questions and very few answers.

Playing "medical whack-a-mole"

Then the pandemic hit, and I went into “stay home, stay safe” mode with the rest of the world. All my non-urgent medical appointments were put on hold, so when worries about my condition kept me awake at night, I'd badger a doctor friend over on the West Coast. I even turned to “Dr. Google” instead of my trusted primary-care doctor when I had burning questions.

Could this DVT travel to my lungs, like I’d seen on an episode of Grey’s Anatomy? What’s the difference between a vascular specialist and a hematologist? Was it safe to run and do yoga while taking anticoagulants?

My questions felt like medical whack-a-mole. As soon as one was answered, more appeared. My blood clot finally dissolved over the next three months, which relieved my physical discomfort, but my fear surrounding my health only grew. In the fall of 2020, I finally got in to see a hematologist, who dismissed most of my questions as needless anxiety (which is an all-too-common experience BTW, called medical gaslighting).

Through all this uncertainty, I learned one reassuring fact: A clot like mine that forms below the knee is not likely to break off and travel to my lungs, where it can cause a serious and potentially fatal block called pulmonary embolism (PE), according to a December 2017 review in Cardiovascular Diagnosis & Therapy.

But I also learned that DVT and PE are not uncommon, and can reoccur. Further research led me to statistics from the CDC that, even as a health writer, I had only peripheral awareness of:

• An estimated 900,000 Americans have a DVT or PE every year
• Between 60,000 and 100,000 Americans die each year of DVT or PE
• 1 in 3 people with a DVT or PE will have another within a decade
• The first sign of a PE in 25 percent of people is sudden death

I was shocked. Why was no one talking about these numbers, let alone vascular health in general?! Why don’t we have a clever acronym for blood clot warning signs—like FAST to spot a stroke?

This societal lack of awareness was reflected in my personal circles. My mom and grandmother had gotten clots after surgery, but I didn't know anyone my age aware of their risk, or who shared a similar experience. I felt alone, and the isolation of the pandemic didn't make finding support any easier.

"There's an awareness needed. We need to know about DVT and PE just like we know about heart attacks."—Michael Streiff, MD, hematologist

Finding community

Like many people, I went online. I joined a Facebook group that’s part of the National Blood Clot Alliance—a nonprofit focused on awareness and community for those affected by or at risk for blood clots. Reading about other people’s experiences, and perusing the group’s free resources and curated scientific literature, helped me feel less alone and better informed.

“People know about stroke, heart attacks, and cancer, but they don't know anything about blood clots,” says Michael Streiff, MD, a board-certified hematologist, professor of medicine and pathology, and medical director at The Johns Hopkins Hospital Special Coagulation Laboratory. But DVT and PE are really common—the third most common thrombotic disease, he adds. The first two are heart attack and stroke.

“There’s an awareness needed,” says Dr. Streiff. “We need to know about DVT and PE just like we know about heart attacks.”

Dr. Streiff agreed with my previous self-assessment: I didn’t fit the profile of most blood clot patients. “If you look at epidemiological studies across all age groups, the risk of blood clots is very low when we’re young,” he says. “As we age, our risk goes up.” Other factors that increase your risk include the following, per the CDC:

• Surgery
• Hospitalization
• Hormonal birth control
• Cancer
• Family history (aka, genetic thrombophilia)
• Infections (including COVID-19)
• Pregnancy
• Obesity
• Long-distance travel (by car or plane)

When I was diagnosed, I was an active 38-year-old woman in a straight-size body who had no prior surgeries or hospitalizations. And I hadn’t used hormonal birth control in over a decade.

But I had recently endured a hellacious travel day in Mexico, starting with a three-hour taxi ride from Tulum to Cancun (with no stops and no water), lengthy weather-related flight delays, two bumpy flights where the “fasten seatbelt” sign never turned off, and, after the flight crew timed out, a night spent sleeping curled up in a chair at the Atlanta airport.

Not coincidentally, my calf pain started a few days later.

Sure, the average person’s vascular system can handle all that travel (and sitting still for hours) without issue, maintaining “a steady state of normal bleeding and clotting, a teeter-totter that’s balanced,” explains Dr. Streiff. Not mine, it turns out. But why?

"I’m doing all I can to build a strong body today, to help offset the potential future effects of a genetic issue I can’t control."

A "unicorn" diagnosis

Months later, my primary-care doctor decided to order genetic blood testing, seeing that my DVT was a mystery given my health and age. I learned I have Factor V Leiden (FVL)—a genetic mutation that predisposes me to blood clots.

FVL is the most common inherited form of blood clotting mutation. About 3 to 8 percent of people with European ancestry carry at least one copy of this gene mutation—called heterozygous FVL, per the National Library of Medicine (NLM). But the risk for clots with this type isn’t much more than the general population: “about a four- to five-fold increase,” says Dr. Streiff.

Homozygous FVL "unicorns" like myself carry two copies of the mutation, which is rare: only about 1 in 5,000 people have this type, per the NLM. And it makes the risk of clots significantly higher—anywhere between a nine-fold to 80-fold increase— estimates that are “much less precise,” adds Dr. Streiff. (We’re so rare even an expert in venous thromboembolisms can’t give an exact figure!)

Under healthy conditions, our bodies form blood clots as a means of protection, Dr. Streiff says. For example, if you get a cut, a series of blood proteins and platelets work to "glue" it back together. One of those proteins is called Factor V. When you have a FVL gene mutation, your body's anti-clotting proteins are disrupted, making you more susceptible to clots.

Dr. Streiff says the FVL mutation likely formed over 25,000 years ago as a survival mechanism before modern medicine. One example? Back then, “pregnancy and delivery were times of great risk to women,” he adds. “Some women would bleed to death, but others with FVL were less likely to have that happen.”

Before my genetic testing, I had no idea my likelihood for potentially fatal blood clots was much higher than the average person—and that it’ll only go up with age. Today and for the rest of my life, I have to be mindful of my vascular health, a part of the cardiovascular system many people overlook.

This means every strained muscle requires a new level of scrutiny and care, and any future injury that prevents me from walking will likely require blood thinners. I still see a hematologist who specializes in genetic thrombophilia as needed, and I take injectable blood thinners before any long flights.

How I'm managing my FVL

Nearly four years later, I have no lingering physical issues, but that blood clot changed the way I approach my fitness and wellness. I’m doing all I can to build a strong body today, to help offset the potential future effects of a genetic issue I can’t control.

Some lifestyle habits I’ve implemented to prevent blood clots include the following (which are backed up by The National Blood Clot Alliance):

• I wear compression socks anytime I travel. On flights and trains, I also get up every hour, drink plenty of water, and choose an aisle seat to move more freely. I alert flight attendants to my condition so they know I’m not trying to be annoying by standing so often. On road trips, I stop to walk around and stretch every 90 minutes.
• When I can’t get up, I move my feet and ankles often, to prevent blood from pooling in my lower legs.
• I view my daily workouts as an investment in my future, as well as a boost for my mental and cardiovascular health.
• I’ve prioritized strength training in my fitness routine, to help keep my cardiovascular system healthy, prevent falls, and protect me from injuries that may require surgery as I age.
• I get up every hour when I work, and I never sit with my legs crossed for lengths of time (to avoid restricting blood flow).
• I’m diligent about warming up, cooling down, and recovery after working out, and I immediately deal with any pain or discomfort in my joints and muscles. I focus more on stabilizing my muscles and incorporate extra unilateral and balance training. Given my risk factors, I need to do everything in my power to avoid being immobilized or having surgery. (I’m also clumsy and hypermobile, so this one is a big job!)

What I want everyone to know about blood health

Many people don’t know they’re FVL carriers until after they’ve had a painful (and in the U.S., potentially expensive) clot. Despite this risk, Dr. Streiff does not recommend that everyone get tested for genetic thrombophilia, or worry about whether they’re a carrier. Instead, it’s more important to know the signs, symptoms, and risk factors for DVT and PE, and to treat them accordingly.

A pulled muscle will usually heal in a couple of days, but pain from DVT only gets worse, so try not to write off lingering pain (or other DVT symptoms) as a part of aging, says Dr. Streiff. This is especially true if you feel DVT symptoms along with shortness of breath, chest pain, tightness or pain in the chest or back when taking a deep breath, coughing blood, an unexplained cough, or feeling faint—which could mean PE.

“If you have those symptoms, it’s a medical emergency,” says Dr. Streiff. “Call your doctor, and go to the ER or urgent care immediately.” Thankfully when you catch a clot early, there are plenty of effective treatments available like oral, injected, and intravenous blood thinners, surgery, and stents to help keep veins open.

Blood clots (and vascular issues in general) are often seen as problems only older adults face. But they don’t discriminate.

“[Blood clots] can happen to healthy people, including athletes,” says Alok A. Khorana, MD, FACP, FASCO, medical and scientific advisory board chair of the National Blood Clot Alliance. “Please be aware of signs and symptoms and seek medical attention, particularly in high-risk settings like after a knee, hip, or ankle injury or operation, in the hospital, or if you have cancer.”

Vascular health is important for everyone, no matter your blood clot risk. If you've had a clot before without other risk factors, ask your doctor if it's worth getting tested for genetic mutations like FVL.

—reviewed by Jennifer Logan, MD, MPH