Cerebral Venous Thrombosis (CVT)

Related Subjects: Thrombophilia testing |Antiphospholipid syndrome |Protein C Deficiency |Protein S Deficiency |Prothrombin 20210A mutation |Factor V Leiden Deficiency |Antithrombin III deficiency (AT3) |Cerebral Venous Sinus thrombosis |Budd-Chiari syndrome

🧠 Cerebral Venous Thrombosis (CVT) is an under-recognised cause of stroke, especially in young adults, postpartum women, and patients with prothrombotic conditions. ⚠️ Postpartum period is a major risk factor, and CVST has also been reported rarely in association with COVID-19 vaccination + thrombocytopenia. Clues: persistent headache, papilloedema, seizures, or infarcts not in arterial territories.

📖 About

• Likely underdiagnosed; many cases are missed or treated late.
• Headache + papilloedema + normal CT should raise suspicion.
• Think of CVST in pregnant/postpartum women or patients with prothrombotic risk factors.

⚙️ Aetiology (Causes)

• 💊 OCP use, pregnancy, postpartum period.
• 💉 Procoagulant states: Factor V Leiden, protein C/S deficiency, antithrombin deficiency, prothrombin mutation, hyperhomocysteinaemia.
• 🩸 Haematological: polycythaemia, thrombocythaemia, leukaemia, sickle cell disease.
• 🦠 Infections: mastoiditis, otitis media, sinusitis, bacterial meningitis.
• 🧬 Systemic conditions: Behçet’s, SLE, ulcerative colitis, Crohn’s, APS, Graves’ disease.
• ⚡ Drugs: Ecstasy (MDMA), chemotherapy.
• 🦴 Trauma/neurosurgery near venous sinuses.
• 🦠 Malignancy: adenocarcinomas, haematological cancers.
• 💉 Post-COVID-19 vaccine (rare): CVST with thrombocytopenia/VITT.

🧭 Venous Anatomy

CVST can affect any venous sinus or cortical vein, leading to raised ICP and venous infarction.

🩸 Common Sites & Clinical Patterns

• Superior sagittal sinus: raised ICP, headache, papilloedema.
• Lateral/straight sinus, vein of Galen: bilateral thalamic infarcts → akinetic mutism.
• Small cortical veins: focal cortical signs, seizures.
• Cavernous sinus: cranial neuropathies, proptosis, cavernous sinus syndrome.

🔬 Pathophysiology

• Obstruction of venous outflow → venous congestion, cytotoxic + vasogenic oedema.
• Haemorrhagic venous infarction due to capillary rupture.
• ↓ CSF absorption via arachnoid granulations → raised ICP.
• Subarachnoid haemorrhage may occasionally occur.

🩺 Clinical Presentation

• 💢 Headache in ~90% (often progressive, worse lying down).
• 🌡️ Raised ICP: papilloedema, nausea, vomiting, sixth nerve palsy.
• ⚡ Seizures: focal or generalised (much more common than in arterial stroke).
• 🧑‍⚕️ Focal neurology: hemiparesis, aphasia, cortical signs.
• 🤒 Cavernous sinus thrombosis: ophthalmoplegia, cranial nerve palsies, facial pain.
• 🌀 Atypical: psychosis, encephalopathy, TIA-like symptoms, migraine-like headache.

🧾 Differential Diagnosis

• Idiopathic intracranial hypertension (IIH): important mimic, especially in young obese women. ➡️ If male or non-obese, always exclude CVST.

🔍 Investigations

• 🩸 FBC: Look for thrombocytopenia (consider VITT, HIT, leukaemia).
• 🧪 D-dimer: Usually raised but not fully sensitive.
• 🖼️ CT (plain): May be normal; may show haemorrhagic infarcts not in arterial territories. "Cord sign" (fresh clot), SAH possible.
• 🩻 CT venography: "Empty delta sign" (contrast around clot in sagittal sinus).
• 🧲 MRI/MRV: Best modality. Detects venous clot, oedema, infarction, haemorrhage.
• 💉 CSF: ↑ opening pressure, ↑ protein; WCC mildly raised.
• 🧬 Thrombophilia screen: Factor V Leiden, prothrombin G20210, protein C/S deficiency, antithrombin deficiency, homocystinuria.

📉 Prognosis Factors

• Deep venous involvement → poor prognosis (bilateral thalamic infarcts).
• Male sex associated with worse outcomes.
• Right lateral sinus thrombosis carries higher risk.

🧬 Inherited Procoagulant Conditions (approx. prevalence)

• Factor V Leiden: 3–7%.
• Prothrombin G20210 mutation: 1–2%.
• Protein C deficiency: 0.3%.
• Protein S deficiency: 0.1%.
• Antithrombin deficiency: 0.02%.

⚖️ Management

• 💉 Anticoagulation is the cornerstone: LMWH preferred (BID dosing). UFH if renal failure or rapid reversal required.
• 🩸 Even with haemorrhagic venous infarcts, anticoagulation is not contraindicated.
• 🔄 Oral anticoagulation (warfarin, INR 2–3) for 3–12 months; longer if recurrent or idiopathic.
• ⚡ Endovascular thrombolysis/thrombectomy: for severe/refractory cases in expert centres.
• 📉 COVID-19 related (VITT): avoid heparin, use IVIG + non-heparin anticoagulants (e.g., argatroban, fondaparinux) per guidelines.
• 🧑‍⚕️ Supportive: ICP management (acetazolamide, CSF drainage if needed), seizure prophylaxis if recurrent.

📚 References

• Cerebral venous thrombosis: a practical guide. Pract Neurol 2020.
• Imaging Approach to CVST – CAR.
• Piazza G. Circulation 2012;125:1704–1709.
• ACC: CVST with Vaccine-Induced Thrombocytopenia.

💡 Exam Pearls:
– CVST = young woman + headache + seizures + haemorrhagic infarct not in arterial territory.
– Always request CT/MR venography if suspicion is high.
– Anticoagulation is safe, even with haemorrhage.