Heparin is a drug used to help prevent blood from clotting and can be used to treat blood clots that have formed. Some people develop a reaction to heparin called heparin induced thrombocytopenia. Thrombocytopenia refers to low platelets in the blood. Platelets aid in blood clotting. Heparin induced thrombocytopenia, known as H.I.T., then, is a low level of blood platelets caused by a reaction to the drug heparin. Unexpectedly, the disorder induces a state in which the blood is prone to form clots. In this disorder there are generally no symptoms at all. If symptoms do develop, they are often from blood clots.
Deep Vein Thrombosis
One of the more common places for blood clots to form is in the deep veins. These are most common in the veins of the legs, but can occur elsewhere such as the pelvis or arms. A deep vein thrombosis restricts the flow of blood back to the heart from the limb, and causes pain, swelling and discoloration in the affected extremity.
Pulmonary Embolism
A pulmonary embolism is a complication of a deep vein thrombosis. A blood clot in the deep veins of the legs or elsewhere can become dislodged and travel through the veins, the right side of the heart and out to the lungs. Once there it gets trapped in the blood vessels. This is called a pulmonary embolism. It restricts blood flow to the lungs, potentially causing pain in the chest and shortness of breath, depending on the size of the clot. If it restricts blood flow to both lungs, called a saddle embolus, it can cause death.
Heart Attacks and Strokes
The increased tendency towards clotting can cause blood clots to form in vital organs. If a blood clot forms in a blood vessel supplying blood to the heart, the heart muscle will be deprived of oxygen. If this goes on for more than several minutes, the heart muscle will die--this is called a myocardial infarction, or heart attack. Symptoms may include chest pain that may or may not radiate to the arm and jaw, sweating, nausea, shortness of breath and anxiety.
A similar chain of events in the brain, with a clot blocking blood flow, leads to a stroke. Symptoms may include the inability to feel or move part of the body, an inability to speak or comprehend speech, or other problems with the senses.
Limb Ischemia
LImb ischemia refers to a lack of blood supply to an arm or leg. Unlike a deep vein thrombosis, this is caused by a blood clot in an artery that is supplying blood to the limb rather than returning it to the heart. Symptoms include pallor, or lightening of the color of the skin, pain, numbness, tingling and swelling in the affected extremity.
Skin Lesions
Skin lesions can also develop in some people with heparin induced thrombocytopenia. These typically consist of red dots all over the body, according to the medical reference "Harrison's Principles of Internal Medicine."
Systemic Reactions
Another possible manifestation from H.I.T. is systemic reactions. This refers to a complex of symptoms occurring in the body. Symptoms include fever, chills, increased heart rate and blood pressure, chest pain and shortness of breath.
References
- "Current Medical Diagnosis and Treatment"; Stephen J. McPhee and Maxine Papadakis; 2010
- "Robbins & Cotran Pathologic Basis of Disease"; Vinay Kumar, Abul K. Abbas, Nelson Fausto, and Jon Aster; 2009
- "Harrison's Principles of Internal Medicine"; Anthony S. Fauci et al.; 2008
