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Post-partum period is a risk factor of cortical vein and sinus thrombosis. The combination of CVST and thrombocytopenia had been identified very rarely in those receiving COVID vaccination

About

• Likely underdiagnosed and many cases go untreated
• Headache, papilloedema and a normal CT may mean CVST
• Consider in pregnant or recent pregnancy

Aetiology

• Any procoagulant condition or localised infections
• OCP, Pregnancy or postpartum period
• Hyperviscosity syndromes, smokers
• Dehydration, ecstasy tablets,
• Behcet's disease, Ulcerative colitis, Crohn's disease
• Localised mastoid, ear or sinus infections
• Malignancy: Adenocarcinoma
• Haematological: polycythemia vera, thrombocythemia, leukemia, sickle cell disease
• Direct cranial trauma, neurosurgical procedures in the area of a venous sinus
• Bacterial meningitis
• Antiphospholipid antibody syndrome
• Factor V Leiden, protein S and protein C deficiency
• Prothrombin mutation, and hyperhomocysteinemia.

Venous Anatomy

Anatomy of the thrombosis in order of occurrence

• Superior sagittal sinus: raised ICP, headaches
• Lateral sinuses, Straight sinus and galenic system: can cause bilateral massive deep infarction affecting thalami with akinetic mutism
• Thrombosis of small cortical veins (cortical vein thrombosis)
• Cavernous sinus
• Cortical veins: localised venous infarction and focal cortical signs
• These all drain down into the right and left internal jugular veins

Pathophysiology

• Venous thrombosis leads to oedema and infarction
• Reduced CSF drainage with increased ICP
• Congested oedematous haemorrhagic infarcts
• Subarachnoid bleeding may be seen

Clinical

• Isolated headache or increased ICP (present in ~90% of cases)
• Focal neurological presentations, Subacute encephalopathy
• Cavernous sinus syndrome/multiple cranial neuropathies
• Headache, Nausea, Vomiting, Neck stiffness, malaise
• Cortical vein occlusion gives expected localising signs.
• Dural sinuses ? raised ICP, Sudden headache
• Declining consciousness, Coma, Seizure,
• Neurological deficit like stroke, Papilloedema, VI nerve palsy
• Atypical - psychosis, SAH, cranial nerve palsies, TIA and migraine

Differential

• Idiopathic intracranial hypertension need to exclude CVST especially if male or non obese

Investigations

• FBC: Thrombocytopenia consider post COIVD vaccine or other haematological condition ? HITT
• D Dimer is usually elevated as it would be for a DVT
• CT: May be normal or maybe wedge-like (haemorrhagic) infarcts not corresponding to the arterial territory. Increased contrast enhancement of falx and tentorium. Cord sign-on non-contrast CT due to fresh clot along falx. Subarachnoid blood may be seen. Empty ? (delta) sign on CT with contrast identifying clot.
• CT with contrast or MRV can show empty delta sign and absence of flow in lumen of sagittal sinus occluded by a venous clot
• MRI and MRV: Can show the extent of infarcts, haemorrhage and evidence of venous thrombosis
• CSF: Raised pressure and protein. LP may help reduce CSF pressure. May be a rise in CSF WCC
• Thrombophilia screen: polycythemia, sickle cell anaemia, deficiencies of proteins C and S, factor V Leiden mutation (resistance to activated protein C), antithrombin III deficiency, homocysteinemia, and the prothrombin G20210 mutation

Worse Prognosis

• Involvement of the Deep vein thrombosis is worse
• Males
• Right lateral sinus thrombosis also worse

Inherited Procoagulant Conditions

Management

• If recent COVID vaccine see below
• LMWH is the standard of care and may be given in a BD formulation to minimise bleed risk. Unfractionated heparin should be used in patients with renal insufficiency or in patients requiring very rapid reversal of anticoagulation (eg, imminent neurosurgical intervention)
• Although their alarming radiological appearance can cause anxiety, haemorrhagic venous infarction, intracranial haemorrhage or isolated subarachnoid haemorrhage are not contraindications for anticoagulant treatment in CVT. See References below.
• Cortical vein thrombosis is also usually treated with anticoagulation (and is our practice) though there are no randomised controlled trials. In a series of 116 patients, most (80%) were treated with anticoagulation, with good outcomes (6% in-hospital mortality)
• Current guidelines recommend using oral vitamin-K antagonist (usually warfarin in the UK) at standard-intensity (target internationalised normalised ratio (INR) 2.5, range 2.0–3.0) for between 3 and 12 months
• Interventional radiology with thrombolysis or clot removal has been done
• Warfarin for 3-6 months followed by antiplatelets. Prolonged Warfarin course e.g. 12 months if no cause found

References

• Cerebral venous thrombosis: a practical guide
• Imaging for CVST
• Cerebral Venous Thrombosis Gregory Piazza Circulation. 2012;125:1704–1709
• Management of CVST With Vaccine-Induced Thrombocytopenia