Cerebral Venous Thrombosis

Authors:

Manish KC,

Junaid Siddiquie, MD, MRCP

Introduction

• Thrombosis of cerebral veins and sinuses

• Relatively rare and frequently unrecognized condition

• Potentially severe and fatal condition

Epidemiology

• 0.5% of all strokes

• Prevalence: 5/1,000,000 people

• Common in Asia and the Middle East due to increased rates of pregnancy and infection in these nations

• Important cause of stroke in young people

• Common in 20-50 years age group, less common after age 65

• More common in females (2.9:1) due to estrogen changes, hormone replacement therapy, and pregnancy

• Superior sagittal sinus thrombosis
• most common type
• Frequently presents with bilateral deficits

Etiology

• Risk Factors: related to factors affecting Virchow’s triad (hypercoagulability, endothelial injury and venous stasis)

• Both hereditary and acquired prothrombotic conditions predispose to CVT

• Causes and risk factors
• Hereditary coagulopathies
• Antithrombin III deficiency
• Protein C and S deficiency
• Factor V leiden
• Factor II gene mutations
• Methylenetetrahydrofolate reductase gene mutation
• Von willebrand disease.
• Acquired coagulopathies
• Nephrotic syndrome
• Antiphospholipid antibody syndrome
• Hyperhomocysteinemia
• Prothrombotic condition
• Pregnancy
• Puerperium
• Infectious causes
• Otitis media
• Sinusitis
• Meningitis
• Mastoiditis
• Drugs
• Oral contraceptive pills
• L-asparaginase
• Corticosteroids
• Androgens
• Inflammatory conditions
• Systemic Lupus erythematosus
• Sarcoidosis
• Granulomatosis with polyangiitis
• Inflammatory bowel disease
• Hematological disorders
• Paroxysmal nocturnal hemoglobinuria
• Primary polycythemia
• Sickle cell disease
• Disseminated intravascular coagulation
• Thrombocythemia
• Leukemia
• Trauma
• Neoplasms
• Idiopathic

Pathophysiology

• Cortical vein thrombosis
• Raised venous and capillary pressure
• Disruption of blood brain barrier
• Formation of cerebral edema that develops into hemorrhagic venous infarction
• Venous infarction causes focal neurological deficits and seizures

• Cerebral sinus thrombosis
• CSF outflow obstruction
• Development of intracranial hypertension
• Headache and vision problems

Clinical Features

• 4 prominent clinical syndromes present
• Isolated intracranial hypertension
• Focal syndrome
• Diffuse encephalopathy
• Cavernous sinus syndrome

• Headache: Most common

• Seizures

• Focal neurological deficit
• Aphasia
• Hemiparesis

• Altered consciousness

• Loss of vision

Differential Diagnosis

• Idiopathic intracranial hypertension (pseudotumor cerebri)

• Arterial ischemic stroke

• Primary intracerebral hemorrhage

• Hemorrhagic stroke due to a vascular malformation

• Meningitis/encephalitis

• Brain abscess

• Systemic lupus erythematosus

• Sarcoidosis

• Antiphospholipid syndrome

Figure 1: Cerebral Sinus Thrombosis on CT Brain

Diagnosis

• Combined MRI of brain and Magnetic resonance venography: Gold standard for diagnosis

• MRI of brain
• Identifies thrombosed blood vessels
• Early thrombus formation: Hypodense from deoxyhemoglobin
• Late thrombus formation: Hyperdense from methemoglobin

• MR venography
• empty delta sign (triangular filling defect due to thrombus in sagittal sinus)

• CT scan of Head and CT venography
• Inferior to MRI due to bone infarct and radiation exposure
• Non-contrast CT head: hyperdense cortical veins or dural sinus
• CT venography: Ideal for subacute or chronic thrombosis due to difference in density of thrombosed sinus

• Catheter angiography
• Associated with complications
• Used only
• When MRI and CT are inconclusive
• Endovascular procedure is required

• D-dimer Test: Increased in current patients with cerebral venous thrombosis. Hence, negative d-dimer in such patients rules out CVT. This does not apply in case of a patient with CVT with a current isolated headache where d-dimer can be normal

Treatment

• Admit patients to the stroke unit

• Correct underlying causes like infection and dehydration

• Antithrombotic treatment
• Subcutaneous Low molecular weight heparin or
• IV heparin

• Worsening of medical condition despite adequate anticoagulation and ruling out other causes of worsening of condition
• Local IV thrombolysis or
• Mechanical thrombectomy

• Prevention of recurrent/future thrombotic events
• Oral anticoagulation
• 3-6months: for brief risk factors
• 6-12 months: idiopathic CVT/mild hereditary thrombophilia
• Indefinite: recurrent CVT/ severe hereditary thrombophilia

• Symptomatic treatment
• Treatment of raised ICP
• Monitor ICP
• Elevate head of bed
• Hyperventilation
• Sedation
• Treat with glycerol and mannitol
• Lumbar puncture in presence of vision threatening papilloedema, drain CSF before initiating heparin
• Surgery: VP shunt, Lumboperitoneal shunt, optic nerve fenestration surgery
• Impending herniation: Decompressive hemicraniectomy
• Antiepileptics in patients with seizures

Complications

• Hydrocephalus
• 15% of patients
• Obstructive type due to basal ganglia and thalamus edema
• Associated with worse prognosis

• Intracranial hypertension
• Headache with or without papilloedema
• Vision threatening: treat with immediate lumbar puncture, Shunt surgery

• Transtentorial herniation
• Major cause of immediate mortality
• Treatment: Decompressive hemicraniectomy

Prognosis

• Death rate: 8-10%

• 80% recover without any sequelae

• Overall good clinical outcome when compared to arterial stroke

• Poor prognostic factors
• Brain infection
• Presence of any neoplasms
• Deep vein thrombosis
• Intracerebral hemorrhage
• GCS>9 at the time of admission
• Male gender
• Age>37 years
• Altered mental status

• Death prognostic factors at 30 days
• Decreased consciousness
• Deep venous thrombosis
• Right sided intracranial bleeding
• Injury at the posterior fossa

• Major cause of acute mortality
• Herniation of the brain (transtentorial)
• Increase in size of hematoma
• Widespread cerebral edema
• Pulmonary embolism
• Status epilepticus

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