The use of steroids, a broad class of hormones, is associated with an increased risk of developing blood clots (thrombosis). These clots often form in deep veins (Deep Vein Thrombosis or DVT) or travel to the lungs, resulting in a life-threatening Pulmonary Embolism (PE). Understanding this risk involves looking at how steroids interact with the body’s complex blood clotting and vascular systems. This risk is present whether the steroid is used therapeutically or for performance enhancement.
Which Types of Steroids Carry This Risk
The increased risk of blood clots is primarily linked to two major categories: Anabolic Androgenic Steroids (AAS) and Corticosteroids. AAS are synthetic variants of testosterone, often misused for performance enhancement and muscle building. AAS use is associated with both venous (veins) and arterial (arteries) thromboses.
Corticosteroids, such as prednisone or dexamethasone, are prescribed to treat inflammation, autoimmune diseases, and allergic reactions. Glucocorticoids, a type of corticosteroid, increase the risk of venous thromboembolism (VTE). This risk appears to be dose-dependent and can occur even with short-term oral use. While both types of steroids raise the overall risk, they often do so through different biological pathways.
The Biological Mechanism of Clot Formation
Steroids promote clot formation by disrupting the delicate balance of the hemostatic system, the body’s natural process for stopping bleeding. This disruption involves three main areas: changes in blood composition, damage to blood vessel walls, and increased platelet activity. These effects contribute to hypercoagulability, meaning the blood is more prone to clotting.
Hypercoagulability
Anabolic steroids contribute to clotting by causing polycythemia, an increase in red blood cell count that thickens the blood and slows its flow. Corticosteroids primarily increase the production of pro-coagulant factors, which are proteins necessary for clotting, such as Factor VIII and von Willebrand factor. They also impair the body’s ability to break down existing clots (fibrinolysis) by elevating levels of plasminogen activator inhibitor 1 (PAI-1). This combination of increased clot-forming proteins and reduced clot-dissolving capacity creates a prothrombotic environment.
Endothelial Dysfunction
The inner lining of blood vessels, the endothelium, is normally a smooth surface that prevents clots from forming. Both types of steroids can damage this lining, creating rough areas where platelets and clotting factors aggregate. Glucocorticoids can induce endothelial cell apoptosis (programmed cell death), which promotes thrombus formation. This damage also contributes to inflammation and creates a surface prone to platelet adhesion.
Platelet Activity
Steroids directly affect platelets, the blood cells that form the initial plug in a clot. Anabolic steroids are known to increase platelet aggregation and stickiness, making them hyper-aggregable. Corticosteroids may also make platelets more likely to clump together and interfere with normal blood vessel function. The combined impact on blood viscosity, clotting factors, and vessel integrity compromises the body’s natural protection against unwanted clot formation.
Warning Signs and Risk Mitigation
Recognizing the signs of a blood clot is important for anyone using steroids. Deep Vein Thrombosis (DVT), which typically occurs in the legs, commonly presents with symptoms like swelling in one limb, pain or tenderness, and skin that is red or discolored and warm to the touch.
A Pulmonary Embolism (PE) occurs when a clot travels to the lungs and is a medical emergency. Signs of a PE include sudden shortness of breath, sharp chest pain that worsens with deep breathing or coughing, and a rapid heart rate. If any of these symptoms appear, immediate medical attention is necessary.
Risk Mitigation
Patients can take practical steps to lower their risk when using prescribed steroids. Maintaining adequate hydration and avoiding long periods of immobility are simple methods to reduce the risk of stasis, which contributes to clotting. If a steroid is being used, discussing all pre-existing conditions and other risk factors with a physician is necessary to balance the benefits of the medication against the potential for a serious thromboembolic event. Minimizing the dose and duration of steroid exposure is a key preventive strategy recommended by healthcare professionals to reduce overall risk.