What is thrombosis?

A thrombosis is a type of dangerous blood clot. A thrombosis may develop anywhere in a child’s body, but are most often found in the calf or lungs. Left untreated, a thrombosis can cause serious problems, including damage to internal organs.


The symptoms of a thrombosis can vary depending on its location and size. A thrombosis in the calf may cause:

  • swelling
  • redness and warmth
  • pain
  • low-grade fever

A thrombosis in the lungs may cause:

  • shortness of breath
  • chest pain


A thrombosis is diagnosed using imaging tests, such as an ultrasound, magnetic resonance imaging (MRI) or computerized tomography (CT or CAT) scan.


The most common treatment for thrombosis is anticoagulation medication (“blood thinners”) to prevent the clot from growing and decrease the risk of further complications.

Your child’s doctor may also suggest home treatments such as remaining active, applying heat to reduce swelling and wearing compression stockings.

Learn more about Pediatric Hematology, Oncology and Stem Cell Transplant services at Boston Children’s Health Physicians.