Haematological Investigations for Suspected Vertebral Thrombosis
Initial Blood Work
For patients with suspected vertebral (cerebral venous) thrombosis, perform routine blood studies consisting of complete blood count, chemistry panel, prothrombin time, and activated partial thromboplastin time immediately 1.
Essential Laboratory Tests
Complete blood count (CBC) to assess for thrombocytosis, polycythemia, or other hematologic abnormalities that may indicate underlying myeloproliferative neoplasms 1, 2.
Prothrombin time (PT) and activated partial thromboplastin time (aPTT) to evaluate baseline coagulation status and identify coagulopathies 1.
Chemistry panel including liver and renal function tests to assess organ function and identify metabolic derangements 1.
Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to screen for underlying inflammatory or infectious processes 1.
White blood cell count with differential to evaluate for infection or hematologic malignancy 1.
D-Dimer Testing
A highly sensitive D-dimer using rapid ELISA methodology should be measured, as it has high sensitivity for cerebral venous thrombosis and can help exclude the diagnosis when negative in low-probability cases 1.
Important Caveats About D-Dimer
D-dimer has poor specificity for cerebral venous thrombosis, with many false positives from other conditions 1.
D-dimer levels decline with time from symptom onset, making false-negative results more likely in patients presenting subacutely or chronically (>48 hours from onset) 1.
Patients with smaller clot burden may have false-negative D-dimer results 1.
If clinical suspicion remains high, a normal D-dimer should not preclude further imaging evaluation 1.
Thrombophilia Screening
Screen for prothrombotic conditions during the initial clinical assessment, including oral contraceptive use, underlying inflammatory diseases, and infectious processes 1.
Specific Thrombophilia Testing
JAK2V617F mutation testing is critical, as approximately 45% of patients with Budd-Chiari syndrome and 34% with portal vein thromboses harbor this mutation, indicating underlying myeloproliferative neoplasm 2.
Testing for inherited thrombophilias (Factor V Leiden, prothrombin gene mutation, protein C/S deficiency, antithrombin deficiency) should be performed, particularly in younger patients without obvious risk factors 1.
Antiphospholipid antibody testing including lupus anticoagulant, anticardiolipin antibodies, and anti-beta-2-glycoprotein I antibodies 1.
Consider testing for brucella or mycobacterium if the patient is from an endemic area 1.
Blood Cultures
Obtain blood cultures if there is any suspicion of septic thrombosis, particularly in cavernous sinus thrombosis where Staphylococcus aureus and Streptococcus species are common pathogens 3.
Critical Pitfalls to Avoid
Approximately 5% of patients with thrombotic complications from myeloproliferative neoplasms present with platelet counts in the normal range, which may subsequently fall due to concurrent hypersplenism, occult GI bleeding, or hemodilution 2.
Do not delay imaging based on awaiting laboratory results if clinical suspicion is high—imaging should proceed urgently while laboratory studies are pending 1, 3.
Fibrinogen levels should be maintained ≥1.5 g/L with cryoprecipitate or fibrinogen concentrate if coagulopathy develops during treatment 3.
Risk Stratification Based on Laboratory Findings
Age >60 years with JAK2 mutation represents a high-risk feature requiring aggressive management 2.
Platelet count ≥1,500 × 10⁹/L is a high-risk feature requiring immediate platelet reduction with hydroxyurea to target <400 × 10⁹/L 2.
Patients with elevated ESR may be at increased risk for epidural abscess in the context of spinal involvement 1.