Sarah Bassra's leg pain and swelling were initially attributed to plantar fasciitis, a common foot condition. However, these symptoms were the first indicators of antiphospholipid syndrome (APS), a rare autoimmune disorder that significantly increases the risk of blood clots.
Bassra's experience highlights a critical diagnostic challenge: the subtle and varied presentation of APS, which can lead to dangerous delays in treatment. "About 80 percent of deep vein thromboses don’t present as the big, swollen leg we were taught about, so people with unexplained leg pain or swollen ankles and toes are often sent away until the clot reaches their lungs," explained Professor Beverley Hunt, an expert in APS and founder of Thrombosis UK. "Our research shows people with deep vein thrombosis often see doctors several times before anyone recognizes the clot, simply because healthcare professionals aren’t aware of how varied and subtle the symptoms can be."
In June 2022, Bassra, then 34, first noticed her toes were red and hot. The symptoms progressed to her ankle, which became swollen and inflamed. Despite two doctor visits, her condition was misdiagnosed. One physician suggested an allergic reaction to nail polish, while another diagnosed it as plantar fasciitis, advising orthopedic trainers and sending her home without further tests. "I think [doctors] thought I was being overdramatic when I went to them with my swollen ankle," Bassra recalled.
As the pain spread up her calf and thigh, Bassra experienced chest pains and shortness of breath during a music festival outing. She collapsed, initially fearing a heart attack. Emergency department tests revealed deep vein thrombosis (DVT) in her leg and a pulmonary embolism, a life-threatening blockage in a lung artery caused by a clot that had traveled from her leg. "Now, looking back and knowing it was a blood clot, I could literally feel it travelling up my leg," she said.
After five days in the hospital and a course of blood thinners, Bassra eventually received an APS diagnosis months later. APS is an immune system disorder that makes blood abnormally sticky, elevating the risk of clots and pregnancy complications such as recurrent miscarriages. According to the APS Foundation of America, it is thought to affect approximately one in 2,000 Americans, with 70-to-90 percent of those affected being women. Many individuals with APS experience no symptoms until a clot or pregnancy complication occurs.
Experts estimate that APS contributes to about one in six cases of strokes, DVTs, and heart attacks in individuals under 50. However, a 2023 study indicated that nearly 15 percent of APS patients face delayed or incorrect diagnoses, often waiting over seven years for the correct one. This diagnostic delay can have severe consequences, as Bassra experienced when her untreated condition led to a pulmonary embolism.
While DVT symptoms can include swelling, tenderness, warmth, or redness in an affected limb, these signs are frequently overlooked, particularly in younger patients. When a clot reaches the lungs, symptoms can rapidly escalate to sudden breathlessness, sharp chest pain, rapid heartbeat, or coughing up blood, signifying a medical emergency.
APS can have a genetic component, and lifestyle factors such as poor diet, lack of exercise, and smoking may increase an individual's risk. Certain medications, including the combined contraceptive pill, can also trigger the condition in susceptible individuals. Unmanaged APS can also lead to pregnancy complications, including miscarriages and stillbirths, by restricting blood flow to the placenta.
Early diagnosis allows for effective management through daily blood-thinning medication. Bassra, who will likely require lifelong blood thinners, noted the significant side effects of her treatment, including hair loss and heavier periods. She also experienced breathlessness during moderate exercise for about three years and worried about clots during flights. "If I had got a second opinion and diagnosis sooner, it would have never spread to my lungs and I wouldn’t have permanent damage," she stated.
Bassra hopes her experience emphasizes the importance of seeking a second opinion when symptoms are not properly addressed, especially as blood clots can affect people of all ages. "There is an assumption that blood clots are things that happen to old people – but I was in my early 30s when this happened," she said. Professor Hunt advises that unexplained leg pain, new swelling or color changes in the foot or ankle, and chest pain should always be taken seriously, as these subtle signs can indicate the early stages of a dangerous clot.
