D68.51

Clinical Causes: Genetic mutation of the Factor V gene (Factor V Leiden mutation) which makes the Factor V protein resistant to inactivation by activated protein C. Inheritance of the mutation from one or both parents, making the condition hereditary. Additional risk factors such as prolonged immobilization, surgery, hormone therapy, pregnancy, obesity, smoking, and certain cancers can exacerbate the risk of clot formation in individuals with APCR.

Key Symptoms: Swelling, typically in one leg or arm Pain or tenderness in the affected limb Redness or discoloration of the skin around the affected area Warmth in the area affected by swelling Shortness of breath or chest pain if a clot travels to the lungs (pulmonary embolism) No symptoms in some cases, especially if the clot is small or develops gradually

Diagnosis Path: Diagnosis of activated protein C resistance is usually made through blood tests that measure the clotting ability of the blood. The most common test is the Activated Protein C Resistance (APCR) screening test, which evaluates how well the blood responds to activated protein C. If the initial test indicates resistance, genetic testing can confirm the presence of the Factor V Leiden mutation. Additional assessments may include Doppler ultrasound for suspected deep vein thrombosis and other blood tests to check for inherited clotting disorders.

Treatment Protocols: Anticoagulant medications, such as warfarin or direct oral anticoagulants (DOACs), to reduce blood clotting risk during high-risk periods or after a clot has occurred Lifestyle modifications, including maintaining a healthy weight, staying physically active, and avoiding prolonged immobility Managing other risk factors like smoking cessation and controlling hormonal therapy if applicable Regular medical follow-up to reassess risk levels and adjust treatment as needed