Hereditary thrombophilias
From IDWiki
Differential Diagnosis
- Antithrombin III deficiency
- Protein C deficiency
- Protein S deficiency
- PTGM 20210A
- FV Leiden (heterozygous/homozygous)
- Hyperhomocysteinemia, maybe
- Elevated Factor VII
Risk of recurrence
- RR 2.5 for ATIII/Protein C/Protein S deficiencies
- RR 1.3-1.4 for Factor V Leiden
Investigations
- Not very predictive of recurrence with most testable thrombophilias
- Diagnosis does not (or at least should not) change management
- Do not test in
- First unprovoked
- Provoked
- Upper extremity DVT
- On anticoagulation regardless
- After first cerebral vein thrombosis or intra-abdominal thrombus
- Retinal venous or arterial thrombus
- Only test if it will change management
- In a patient with unprovoked clots who are less than 40 years old and more than two first-degree relatives
- If skin necrosis on warfarin, test for protein C and S deficiency
- Test for APLA if there's a plan to stop anticoagulation
- Do not test while acute VTE
- APLA need at least two tests
Further Reading
- Smith TW, Pi D, Hudoba M, Lee AY. Reducing inpatient heritable thrombophilia testing using a clinical decision-making tool.. J Clin Pathol. 2014;67(4):345-9.
