A blood clot can form inside a blood vessel and block the vessel and this keeps blood from getting where it needs to go. When that happens to one of the veins deep within the leg, blood can back up and cause swelling and pain.

Another and usually more life threatening problem with blood clots in veins is that they can travel to other parts of the body and block blood vessels there. Blood clots that form in the legs, for example, can be carried in blood and when these clots reach the lungs where the blood vessels are tinnier, they can get trapped and block these blood vessels in the lungs. This can make it hard to breathe or rapidly lead to death. When blood clots travel to the lungs and clog a blood vessel there, it is medically called "pulmonary embolism” or "PE.”

Common symptoms of a clot in the legs include swelling, pain, warmth and redness in the involved leg although the symptoms can be very vague to recognize. Sometimes clots form in the veins that are closer to the surface of the skin (in other words, not the deep ones). Those blood clots cause a different set of symptoms. Blood clots in the veins near the surface of the skin can cause pain, redness, or infection. These clots sometimes also cause the veins to harden and bulge into ridges that look like cords (often called varicose veins) and this is most common with the veins below the knee. Blood clots in the veins near the surface of the skin are not usually dangerous. But blood clots in the deep veins of the leg can be serious and suspicion of this should warrant seeking immediate health care.

Dislodge of a clot from the legs and its deposition in the blood vessels of the lung can cause sudden onset of symptoms such as; panting or trouble breathing, sharp knife-like chest pain when you breathe in, coughing or coughing up blood, a rapid heartbeat and these are life threatening symptoms which should be taken as emergency.

Certain factors increase the risk of forming a clot than the normal population such as; inherited conditions which lead to increased ability of blood to clot than normal, sedentary lifestyle, pregnancy, obesity, smoking, heart failure, previous clot or PE, increased age, some cancers increase substances in the blood that cause blood to clot, and kidney problems. Certain medications such as certain birth control pills increase the risk of forming a clot. Surgical procedures, especially those involving the hip, pelvis, or knee, increase a person’s risk of developing a blood clot. During the patient’s recovery period, this risk often continues because the person is less active and often such patients are given medicines to prevent clot formation in this period. Inactivity during long trips can also increase a person’s risk of developing a blood clot.

The diagnosis of a clot in the legs is made through proper detailed history taking of the symptoms, physical examination and some investigations are done to confirm the diagnosis to rule out other medical conditions with similar symptoms. Blood lab tests are usually done to assess the likelihood of clot formation in the body, and also an ultrasound scan of the leg is done to look at the blood flow in the blood vessels of the suspected leg. Some other investigations can be done to further locate the clot more precisely.

These blood clots once detected are usually treated with medicines that dissolve them or keep them from getting bigger. Some of these medicines come in shots and others come in pills and these pills are usually taken for a long period of time under close medical monitoring.

Lifestyle modifications can reduce the risk of suffering from a clot and these include; quitting smoking, losing weight, exercising regularly and when going for long trips, always try to stand up and walk around every hour or two, not smoking just before your trip, wearing loose comfortable clothes, shifting your position while seated, and moving your legs and feet often, drinking plenty of fluids, wearing knee-high compression stockings, and avoid alcohol and medicines that make you sleepy, because they can impair your ability to move around.

Dr. Ian Shyaka is a General Practitioner at Rwanda Military Hospital.