Cerebral venous sinus thrombosis and rarer stroke causes

• Cerebral venous sinus thrombosis (CVT) is a clot in the dural venous sinuses or cerebral veins; it is uncommon but is treatable and often reversible, and it can present with anything from an isolated headache to coma.
• It is the classic "stroke of the young": about 1.2 to 1.6 cases per 100,000 person-years, up to three times more common in women, and often linked to pregnancy, oral contraceptives, infection or thrombophilia.
• Headache is severe in about 90% of patients; roughly half develop a parenchymal lesion (oedema or haemorrhage) that can cause seizures, focal deficits or raised pressure inside the skull.
• The diagnosis is confirmed with MR venography or CT venography, and the first treatment is heparin, even when imaging already shows bleeding.
• A cervical artery dissection, CADASIL, primary CNS vasculitis or a thrombophilia can also cause stroke in a young adult, so a "cryptogenic" stroke in an under-50 patient deserves a methodical work-up.

By the end of this page you should be able to:

1. Recognise the varied presentations of cerebral venous sinus thrombosis and choose the right imaging to confirm it.
2. Treat acute CVT with heparin and plan the switch to oral anticoagulation, stating where guidelines disagree.
3. Describe arterial dissection, CADASIL and primary CNS vasculitis as causes of stroke, and their distinguishing features.
4. Work through a young-stroke evaluation for dissection, patent foramen ovale, thrombophilia and vasculitis, in the right order.
5. Know the special situations (pregnancy, children, recent adenoviral vaccine) and the red flags that change management.

CVT splits into two broad groups. A first group is provoked, with a transient or a clear risk factor (pregnancy, the puerperium, oral contraceptives, recent infection, dehydration, head trauma, a drug with prothrombotic effects). A second group is unprovoked or linked to a permanent prothrombotic state (genetic thrombophilia, antiphospholipid syndrome, myeloproliferative disease, active cancer). In roughly one in seven adults no risk factor is found. ^[2] Acute, subacute and chronic forms are recognised clinically; the timing matters because an acute presentation suggests a parenchymal lesion, while a chronic one more often means isolated raised intracranial pressure.

The rarer arterial causes discussed on this page are separate diseases that share the same endpoint, a stroke, in a younger patient:

• Cervical (extracranial) and intracranial arterial dissection: a haematoma in the wall of a neck or head artery, causing stenosis, occlusion, or a dissecting aneurysm.
• CADASIL: an inherited small-vessel arteriopathy from heterozygous pathogenic variants in NOTCH3, causing lacunar infarcts, migraine with aura and vascular dementia. ^[5]
• Primary angiitis of the central nervous system (PACNS): vasculitis confined to vessels of the brain and spinal cord, needing immunosuppression rather than antithrombotics.
• Hypercoagulable states and paradoxical embolism, usually worked out together with dissection and patent foramen ovale in a young-stroke protocol.

CVT is uncommon: 1.2 to 1.6 cases per 100,000 person-years overall, and 1.32 per 100,000 per year in Western Europe, with higher rates in developing regions and in low- and middle-income settings. ^[3][2] It accounts for 0.5 to 3% of all strokes in the AHA 2024 statement and for 0.5 to 1.0% of stroke admissions in Canadian guidance. ^[1][8] It is proportionally more common in the young because it is a disease of people under 55: two-thirds of patients are women. ^[1] Women are affected up to three times more often than men, largely because oestrogen-bearing contraceptives and pregnancy are major risk factors. ^[3] The incidence appears to be rising, partly from wider use of venous imaging and partly from real change in risk factors. ^{[3] [7]}

Outcomes have improved markedly. Mortality of CVT fell from historical highs to between 3 and 15% in contemporary series, and in the Western world it is now under 5%, with roughly four out of five patients recovering completely. ^[3][2] Death, when it occurs, is usually from herniation after a large haemorrhagic venous infarct, or from the underlying disease. ^[2]

The other causes also concentrate in the young. Cervical artery dissection is a leading cause of stroke in young adults, with an incidence of 2.6 to 3.0 per 100,000 per year; the mean age at extracranial dissection is 44 years and for intracranial dissection 50 years. ^[4] Dissection accounts for about 2% of all ischaemic strokes but a substantially larger share before age 50. ^[7] PACNS is rarer still: 2.4 cases per million people per year, with a median age at diagnosis of 50 years and an equal sex ratio. ^[6] About one in ten patients with any stroke is under 50 years, and an estimated 10% of stroke patients are younger than 50 years. ^{[7] [1]}

CVT risk factors are prothrombotic and can be split into transient and permanent.

• Transient: combined oral contraceptives, pregnancy and the puerperium, dehydration (including in children), recent infection (especially of the ear, mastoid, sinuses or central nervous system), recent head trauma, and drugs with prothrombotic effects.
• Permanent: inherited thrombophilia (factor V Leiden, prothrombin gene mutation, protein C or S or antithrombin deficiency), antiphospholipid syndrome, myeloproliferative disease and malignancy.

Active cancer is found in around 7 to 15% of patients with CVT, and in a quarter of those aged 55 or older. ^[3] Obesity and infection with SARS-CoV-2 have been added to the list of predisposing conditions since the 2011 statement. ^[1] Roughly 13% of adults with CVT have no identifiable risk factor at all. ^[2]

Local infection can spread directly to adjacent sinuses. Otogenic lateral sinus thrombosis and septic cavernous sinus thrombosis are now rare but remain important in children and in low-resource settings, where they still tip the balance toward poor outcome.

Arterial dissection has its own risk profile. Hypertension and migraine are reported risk factors, minor trauma (even coughing, sneezing, vomiting or a recent infection) is a frequent trigger, and some patients have an underlying connective-tissue arteriopathy or fibromuscular dysplasia; inherited connective-tissue disease is a rare but important cause. ^[4] CADASIL is a single-gene disease: autosomal dominant inheritance of a heterozygous NOTCH3 pathogenic variant. ^[5] PACNS is a disease of unknown cause, isolated to the central nervous system. ^[6]

Young stroke is also where the conventional list of risk factors reappears with a vengeance: in a large Finnish registry, 39% of patients aged 15 to 49 years with ischaemic stroke were hypertensive, 60% dyslipidaemic and 44% smokers. ^[7] Under-50 stroke is therefore not simply "rare causes": it is common risk factors plus the rare causes that are listed here.

In CVT, thrombosis is in the venous outflow. Raising pressure in the territory drained by the blocked sinus produces a clinical spectrum determined by two variables: how much of the venous territory is affected, and how well collateral veins compensate. Partial obstruction with good collaterals gives a benign picture (often an isolated headache or papilloedema from raised pressure). Near-total obstruction with poor collaterals gives a venous infarct, which is frequently haemorrhagic because the arterial inflow is still present while venous drainage is blocked. Obstruction of the deep cerebral veins or the straight sinus is particularly dangerous, because it produces bilateral, basal-ganglia and thalamic damage, coma and a poor outcome.

This mechanism explains the four clinical pictures that recur in CVT: raised intracranial hypertension, focal neurological deficit from a venous infarct, seizure from cortical irritation, and diffuse encephalopathy or coma from deep or bilateral disease.

Dissection begins with blood entering the arterial wall (an intimal tear, or less commonly a primary intramural haematoma), creating a false lumen that narrows or occludes the true lumen, or bulges outward as a dissecting aneurysm. Emboli from the damaged wall or fresh thrombus produce stroke in the territory downstream. Intracranial arteries have thinner, less elastic walls than cervical ones, which is why intracranial dissection is more likely to cause subarachnoid haemorrhage. ^[4]

CADASIL begins with the NOTCH3 protein accumulating in the wall of small penetrating arteries, producing progressive stenosis of the vessels that supply the deep white matter and basal ganglia. ^[5] The result is recurrent lacunar infarcts and a stepwise vascular cognitive decline on the background of migraine with aura. There is no treatment that reverses the arteriopathy itself. ^[5]

PACNS is inflammatory: immune cells infiltrate the vessel wall and produce stenosis, occlusion and sometimes rupture, giving a vasculitic picture that can span any part of the central nervous system. ^[6]

CVT pathology is venous congestion, with thrombus in sinus or vein, venous infarction that may be haemorrhagic, oedema, and, when pressure is sustained, herniation. There are usually no atherosclerotic risk factors, which is why the entity can be mistaken for "a stroke that does not fit."

Dissection pathology is an intramural haematoma, a intimal flap, or a double lumen in the affected artery, sometimes with a dissecting aneurysm. The pattern and whether multiple arteries are involved depends on the underlying arteriopathy. ^[4][7]

CADASIL pathology is granular osmiophilic material (GOM) in the media of small arteries on electron microscopy, with characteristic NOTCH3 immunostaining, and confluent white-matter hyperintensities crossing into the anterior temporal lobes and external capsules. ^[5]

PACNS pathology is a transmural lymphocytic, granulomatous or necrotising infiltrate of the vessel wall; the histological pattern is the only proof, and the gold standard for diagnosis is biopsy or autopsy. ^[6]

There is no single syndrome. The presentation is set by the sinus involved, the speed of occlusion and the collateral veins.

Symptoms in the patient's words

• A severe headache in about 90% of patients, often described as different from anything before, sometimes thunderclap-like, and worse with coughing or Valsalva. ^[3]
• Focal deficits (weakness, aphasia, visual loss) from a venous infarct; these do not respect an arterial territory and may be bilateral.
• Seizures, focal or generalised, in a substantial minority.
• Encephalopathy, confusion or coma with deep venous thrombosis.
• Visual symptoms from raised intracranial pressure: transient visual obscurations, diplopia from a sixth nerve palsy, pulsatile tinnitus.
• In a slower course, only a chronic headache or papilloedema may be present.

Signs on examination

• Papilloedema and signs of raised intracranial pressure are common; intracranial hypertension is present in roughly 80% in the acute phase. ^[3]
• Focal neurological signs (hemiparesis, aphasia, cranial nerve palsy) when there is a parenchymal lesion, which develops in 50 to 60% of patients. ^[3] (Intracranial haemorrhage is reported in 30 to 40% of patients in some cohorts. ^[8])
• Fever or local evidence of infection if the CVT is septic.
• Mental-status change; coma suggests deep venous or bilateral involvement.

A vignette: a 24-year-old woman on a combined oral contraceptive presents with a two-week headache worse in the morning, papilloedema on fundoscopy, and a brief generalised seizure; she has a mild right hemiparesis. Arterial imaging is normal. This pattern points to CVT.

Local symptoms come before the stroke in many cases, by hours to weeks. ^[4]

• Cervical internal carotid dissection: ipsilateral Horner syndrome, neck or facial pain, pulsatile tinnitus, and cranial nerve palsies of the lower nerves; about two-thirds to three-quarters of patients go on to have cerebral or retinal ischaemia. ^[4]
• Vertebral dissection: posterior neck pain or headache, cervical root pain, and posterior-circulation brainstem features.
• Intracranial dissection: prodromal headache in about 80% of patients, then either subarachnoid haemorrhage in 50 to 60% or cerebral ischaemia in 30 to 78%, rarely both. ^{[4] [2]}
• Multiple cervical arteries are affected in 15 to 20% of patients. ^[4]

The sudden onset of a severe neck or head pain with an ipsilateral Horner syndrome in a young adult is the classic prompt to image the neck arteries.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) usually presents in mid-adult life. ^[5]

• Migraine with aura is often the first symptom, beginning in early adult life; the reported prevalence of migraine (most often with aura) in CADASIL varies between cohorts. Auras can be atypical (prolonged, basilar, hemiplegic) and be confused with transient ischaemic attacks. ^[5]
• Recurrent lacunar stroke and TIA, causing stepwise deficits, with progressive executive and cognitive decline toward vascular dementia.
• Mood disturbance and apathy are common.
• Family history: one affected parent is usual, autosomal dominant, with a 50% risk for each child. ^[5]

There is no treatment of proven efficacy for CADASIL; management is supportive, with vascular risk-factor control and symptomatic migraine treatment. ^[5]

PACNS is a rare single-organ vasculitis presenting subacutely after a long prodrome (mean time from onset to diagnosis about 170 days). ^[6] It may affect any part of the central nervous system and produces a varied, non-specific picture: headache, encephalopathy, psychosis and multiple strokes not restricted to one vascular territory. ^[6] The incidence is 2.4 per million per year, with a 1 to 1 sex ratio and a median age at diagnosis of 50 years. ^[6]

A "cryptogenic" stroke in an under-50 patient is not a diagnosis; it is an invitation to look harder. The approach is:

1. Confirm the stroke and image the brain and vessels first (CT, MRI, CTA or MRA of head and neck).
2. Look for large-artery atherosclerosis and cardiac sources (ECG, telemetry, transthoracic and transoesophageal echocardiography).
3. Think dissection, which is the commonest arteriopathy in young adults.
4. Look for patent foramen ovale and a venous source of embolus.
5. Select testing for thrombophilia in high-risk patients rather than screening everyone.
6. Reserve CNS vasculitis testing for the stroke pattern that does not fit (multi-territory, encephalopathy, raised inflammatory markers).
7. Consider inherited small-vessel disease (CADASIL) in small-vessel stroke in a younger adult with a paucity of risk factors or a relevant family history. ^[9]

A stroke in a young adult, or a stroke that looks venous, should be sorted by mechanism. The most useful separator is the imaging: arterial territory versus non-arterial territory, and whether there is venous infarction or sinus thrombosis.

Brain and venous imaging. CT or MRI first, to show the parenchymal consequences and to raise the suspicion. In CVT, non-contrast CT may show a hyperdense sinus or cord sign, but can be normal. ^[1] Confirmation needs CT venography or MR venography. ^[1][2] CT venography and MR venography are alternatives; MR venography is preferred, and gradient-echo or susceptibility-weighted imaging is more sensitive for small cortical vein thrombosis. ^[1] D-dimer is a useful triage tool but is not definitive; in the meta-analyses it has a weighted mean sensitivity of about 89%, and it is least trustworthy with isolated headache, symptom duration over 1 week, or thrombosis of a single sinus, where false negatives are doubled. ^[2] Canadian 2024 guidance, by contrast, considers D-dimer of limited diagnostic utility and does not recommend using it to decide whether neuroimaging is needed. ^[8]

Arterial imaging in dissection and young stroke. CTA or MRA of the head and neck is the reasonable first test; fat-suppressed T1 MRI has the best sensitivity for mural haematoma. Digital subtraction angiography is not first-line, but is used when clinical suspicion remains and non-invasive imaging is negative. ^[4][7] Dissection is not a contraindication to thrombolysis, and outcomes are similar to those of strokes that are not dissection-related. ^[7]

Cardiac and general evaluation. ECG, troponin, transthoracic and transoesophageal echocardiography, and 24-hour to 7-day monitoring for atrial fibrillation, plus basic bloods (blood count, glucose, HbA1c, lipids, renal function, inflammatory markers). ^[7]

Young-stroke specific tests

• Thrombophilia testing (factor V Leiden, prothrombin G20210A, protein S/C, antithrombin, and antiphospholipid antibodies) is reserved for patients with a high pre-test probability (young, undetermined cause, venous thrombosis or miscarriage history, recurrent events, or a thrombotic family history). ^[2][7]
• Testing factor V Leiden and prothrombin mutation in non-white populations is very low-yield. ^[7]
• Protein S, C and antithrombin levels should be repeated a few months after the stroke, ideally after at least 2 weeks off anticoagulation, because acute-phase and drug effects confound the result; about 30% of acute testing is uninterpretable and three-quarters of positive results are not confirmed. ^[7]
• In patients with a right-to-left shunt, perform DVT imaging (compression ultrasound of the legs plus pelvic venography), because the inertial source may be a venous clot. ^[7]
• Antiphospholipid antibody syndrome: screen any stroke patient with a rheumatological disease, and consider it in any stroke under age 45; stroke is its most common arterial manifestation. ^[7]
• Genetic testing for monogenic small-vessel disease (NOTCH3) when there is an early small-vessel stroke with few risk factors or a family history. ^[9]

Imaging the cervical and intracranial veins, the arteries and the heart at the same time is efficient in a young patient and avoids serial testing.

There is no single score that diagnoses CVT or young stroke; the diagnosis rests on imaging, and criteria-based diagnosis is mainly for PACNS. Useful concepts:

• CVT "risk score": a pre-treatment score where a value of 38 or above, or any of coma, mental-status disturbance, thrombosis of the deep venous system, or intracerebral haemorrhage, marks high risk and favours close monitoring. ^[2]
• PACNS probable versus definite: a definite diagnosis requires histopathological proof; a probable diagnosis requires a high-probability angiogram plus abnormal MRI and CSF; in PACNS, MRA is not an adequate substitute for digital subtraction angiography, and normal MRA does not exclude the disease. ^[6]
• Young stroke causes split by mechanism (large artery atherosclerosis, cardioembolism, small-vessel disease, other determined aetiology including dissection, cryptogenic or ESUS) which is what guides prevention rather than the age alone.

Immediate phase. The one intervention with evidence is anticoagulation with full-dose heparin for every adult with acute CVT, including patients whose baseline scan shows an intracerebral haemorrhage; the haemorrhage is venous congestion, and anticoagulation does not worsen it. ^[2] A meta-analysis of two small randomised trials (79 patients) showed a non-significant reduction in death or dependence with heparin over placebo (relative risk 0.46). ^[2] Low-molecular-weight heparin is preferred to unfractionated heparin where possible: in a randomised trial of 66 patients, treatment with low-molecular-weight heparin was associated with better 3-month recovery; unfractionated heparin is reserved for situations needing rapid reversal (surgical plans, severe renal failure). ^[2] Anticoagulation continues while the rest of the work-up proceeds.

Transition to oral anticoagulation. After acute stabilisation, transition to an oral agent for 3 to 12 months in transient-risk-factor CVT, and indefinitely where there is a chronic major risk factor or a recurrence. ^[1][3] Vitamin K antagonists are the traditional drug. Direct oral anticoagulants look safe and effective in small and mostly open studies, and the AHA 2024 statement endorses them as a reasonable option, whereas the ESO 2017 guideline advised against direct oral anticoagulants, especially in the acute phase, and favoured vitamin K antagonists. ^[1][2] Where sources differ, the choice between a vitamin K antagonist and a direct oral anticoagulant is best made with local expertise and with attention to pregnancy plans.

Thrombolysis and endovascular therapy. The ESO 2017 panel could not make a recommendation on thrombolysis in CVT. Systematic reviews put major haemorrhagic complications at about 9.8% after endovascular therapy. ^[2] Endovascular thrombolysis or thrombectomy is reserved for patients with impending herniation, progressive deterioration despite maximal medical therapy, or thrombus propagation, and only at centres with the capability. ^[1]

Raised pressure and seizures. Suppressing intracranial pressure is crucial: acetazolamide, therapeutic lumbar puncture for fulminant intracranial hypertension, and, for impending herniation, decompressive hemicraniectomy, which may be life-saving. ^[2] Steroids do not reduce death or dependence and are not recommended; early seizures are treated with antiepileptics, with prophylaxis for patients who have a supratentorial lesion and an early seizure. ^[2] Over 80% of patients are affected by intracranial hypertension in the acute phase, so do not wait for visual loss before acting.

Pregnancy and the puerperium. Future pregnancy is not contraindicated after CVT. During a pregnancy after CVT, prophylactic low-molecular-weight heparin is used throughout pregnancy and the postpartum period; anticoagulation is not a reason to delay conception. ^[2] Hormonal contraceptives containing oestrogen are avoided after CVT for women who had one. ^[2] The AHA 2024 statement gives a more specific postpartum duration than ESO, which is why practice should follow the edition adopted locally. ^[1]

Paediatric CVT. In neonates and children, infection, dehydration, iron-deficiency anaemia and head trauma dominate; parenteral anticoagulation is the first-line treatment, followed by low-molecular-weight heparin, a vitamin K antagonist or rivaroxaban under paediatric guidance.

Vaccine-induced CVT. Venous thrombosis with thrombocytopenia (VITT) can occur after adenovirus-vector SARS-CoV-2 vaccination, often with new headache and thrombocytopenia, and needs haematologist-led expert care.

Acute stroke from dissection is treated like any acute ischaemic stroke: intravenous thrombolysis with alteplase within 4.5 hours if eligibility criteria are met, and mechanical thrombectomy for large vessel occlusion, because the benefit outweighs the theoretical hazard. ^[4] For prevention, the key concept is that the choice of antithrombotic does not dominate outcome: two small randomised trials in acute extracranial dissection showed no difference between anticoagulation and antiplatelet therapy, and the guideline strongly allows either; for intracranial dissection with subarachnoid haemorrhage, early endovascular or surgical treatment is advised. ^[4] A common clinical plan is an initial course of antithrombotic therapy, often heparin initially for a high-ischaemic-risk patient, then a single antiplatelet if the vessel heals, extending if there is residual stenosis or a dissecting aneurysm. ^[4] and the vessel is re-imaged at 3 to 12 months to check healing. Direct anticoagulants are mentioned in expert consensus as a consideration in dissection, but no randomised data exist. ^[4] Vascular Ehlers-Danlos syndrome is the special case: standard anticoagulation and endovascular work may rupture fragile vessels, so management is cautious and individualised. ^[6]

Stenting is reserved for patients with significant stenosis producing distal hypoperfusion and recurrent ischaemic stroke despite optimal medical therapy.

Follow-up imaging at 3 to 12 months checks for healing: recanalisation of extracranial dissections occurs mostly in the first 12 months, and most dissecting aneurysms stay stable or regress. ^[4][1] Recurrence of ischaemic events is low: 0 to 13% in the first year, higher in the early months and with fibromuscular dysplasia. ^[7] Recurrent dissection, or a dissection in a child or young adult, prompts a search for a connective-tissue disorder.

There is no proven disease-modifying therapy. ^[5] Management is directed at the symptoms and the vascular risk factors:

• Avoid antiplatelet therapy for primary stroke prevention; aspirin monotherapy may be safe for preventing recurrent ischaemic stroke, but efficacy is unproven. ^[5]
• Avoid oral anticoagulants where possible, because they probably raise intracerebral haemorrhage risk. ^[5]
• Tight blood pressure control and no smoking are recommended. ^[5]
• Migraine: treat attacks symptomatically; prophylactic treatment depending on frequency. ^[5]
• Cognitive and psychiatric symptoms: standard treatment. ^[5]
• Avoid smoking, which increases the risk of stroke. ^[5]

Thrombolysis safety is unknown in CADASIL, and it probably raises intracerebral haemorrhage risk, so it should be used only carefully and case by case. ^[5]

PACNS is treated with immunosuppression, not antithrombotics. ^[6]

• Induction: glucocorticoids, with consideration of adding an immunosuppressant (cyclophosphamide orally or intravenously, or mycophenolate mofetil) in most patients, given the relapsing course and the toxicity of long-term steroids. ^[6]
• Maintenance: mycophenolate mofetil is preferred over prolonged cyclophosphamide, continued for at least 2 years before considering cessation in patients without recurrence. ^[6]
• Aspirin is suggested for patients with large or medium vessel involvement. ^[6]
• Acute ischaemic stroke from PACNS is treated like any other: consider intravenous thrombolysis within the time window and mechanical thrombectomy for large vessel occlusion. ^[6]
• Routine long-term anticoagulation is not part of the plan; control of blood pressure and vascular risk remains important.
• Multidisciplinary care in an expert centre is advised because of the low quality of the evidence and the mimics. ^[6]

A brain biopsy is the gold standard for diagnosis, and the small-vessel form in particular is biopsy-proven; when there is suspicion but a normal angiogram, biopsy of leptomeningeal or targeted enhancing tissue is recommended. ^[6]

Pregnancy. CVT in pregnancy and the puerperium is managed with low-molecular-weight heparin throughout pregnancy, with oral anticoagulation or heparin for at least 6 weeks postpartum (in the AHA 2024 statement; the ESO 2017 guideline phrases it as throughout pregnancy and puerperium). ^[1][2] Future pregnancy is not contraindicated, and prophylactic low-molecular-weight heparin is recommended in later pregnancies. ^[1][2] Oral contraceptives containing oestrogen are avoided after a CVT. ^[2] Treatment of PACNS and CADASIL in pregnancy has no dedicated evidence and proceeds in partnership with obstetrics and neurology. ^[5]

Children. Neonatal CVT is linked to infection, dehydration and iron-deficiency anaemia and is treated with parenteral anticoagulation followed by low-molecular-weight heparin, a vitamin K antagonist or rivaroxaban under paediatric guidance. PACNS also occurs in children and is worked up differently (biopsy rarely, imaging more heavily); a paediatric vasculitis service should lead.

Older adults. CVT is less common with age, but when it occurs, the principal associated condition is cancer, and malignancy screening is otherwise not routine. ^[2][3] CADASIL has no age-specific upper limit; suspicion before 55 in a patient with a paucity of risk factors is the trigger.

Immunocompromised and infection. Septic CVT (otogenic, cavernous sinus) is treated with antibiotics plus anticoagulation after imaging; the source must be treated or the clot recurs.

• CT with CT venography is a fully acceptable substitute for MRI and MR venography in CVT when resources are limited, and is more widely available. ^[1][2]
• A transthoracic echo, even in an emergency department, detects most atrial masses and is the one test that can redirect the diagnosis when a myxoma or cardiac source is suspected.
• D-dimer loses value where CT is unavailable, because the confirmatory scan is still needed when the index of suspicion is high.
• Low-molecular-weight heparin requires refrigeration assurance and weight-based dosing; unfractionated heparin can be used where monitoring of the activated partial thromboplastin time is available.
• Decompressive surgery for CVT or PACNS management requires referral; recognise herniation early and transfer.
• Dissection imaging relies on accessible CT angiography; fat-suppressed MRI improves detection of mural haematoma when available.
• Gene testing and thrombophilia work-ups are low-yield or unavailable; a careful history, family history and accessible imaging matter more than laboratory panels.

• CVT: venous infarct (often haemorrhagic), seizures, intracranial hypertension with papilloedema and visual loss, venous haemorrhage, and herniation. ^[2][3]
• Dissection: ischaemic stroke, dissecting aneurysm formation or growth, subarachnoid haemorrhage (more often intracranial), and, rarely, vessel rupture. ^[4]
• CADASIL: recurrent stroke, vascular dementia, apathy, and a high late disability; intracerebral haemorrhage in a minority. ^[5]
• PACNS: recurrent stroke, relapse on stopping treatment, and steroid-related toxicity. ^[6]
• Long-term after CVT: residual cognitive problems in 40 to 70% of patients, fatigue in 30 to 40%, chronic headache in 20 to 40%, and depression in 20 to 35%; about 30% cannot return to previous work. ^[3]
• Thrombolysis and thrombectomy in dissection or PACNS carry the ordinary haemorrhagic risks of those treatments, discussed above.

CVT has the best prognosis of the group if treated: most patients survive without physical disability, although residual symptoms are common and matter for quality of life. ^[3] Clinical predictors of poor outcome are older age, active cancer, coma at presentation, and intracerebral haemorrhage. ^[1] The residual burden means that "recovery" after CVT should be measured in cognition, fatigue and return to work, not only on a disability scale. ^[3]

Extracranial dissection heals in most patients within months; persistence at 12 months or a new aneurysm changes advice on sport and exertion. Intracranial dissection depends on subtype (ischaemic versus haemorrhagic) and carries the worse outlook for the haemorrhagic forms. ^[4]

CADASIL is progressive; lacunar strokes recur and cognition declines over years. ^[5] PACNS, treated, usually remits, but relapses occur and long immunosuppression carries its own risks.

• CVT recurrence and recurrence of venous thromboembolism are prevented by the right duration of anticoagulation; thrombophilia screening after a single unprovoked CVT is not recommended, but it is considered when the pre-test probability of a severe thrombophilia is high (personal or family history, young patient, no transient or permanent risk factor). ^[2]
• Routine screening for occult malignancy after CVT is not recommended. ^[2]
• Secondary prevention of arterial stroke after CVT is not the issue; the matter is the venous thrombosis itself. Where an arterial stroke has also occurred (for example a concomitant dissection), the aetiology found directs prevention.
• Dissection prevention amounts to advice on avoiding trauma-prone sports for a period after diagnosis, vascular risk-factor control, and treatment of migraine; there is no drug that prevents dissection. ^[1]
• CADASIL prevention is vascular risk-factor control and aspirin only when a prior stroke has occurred; family counselling and predictive testing are part of the package. ^[5]
• PACNS prevention is long-term immunosuppression done properly and then stopped, with vigilance for relapse. ^[6]
• Young-stroke prevention is best handled by a cause-specific plan rather than a generic "secondary prevention" bundle: carotid surgery or stenting for severe stenosis, anticoagulation for high-risk atrial fibrillation, antiplatelets for small-vessel and cryptogenic disease, and closure of a patent foramen ovale only in selected patients within a trial setting. ^[7]

• CVT is a venous stroke, usually in young adults and often in women; headache is severe in about 90% of patients and a parenchymal lesion develops in 50 to 60%. ^[3]
• Treatment starts with full-dose heparin for every adult with acute CVT, including those with an intracerebral haemorrhage on the scan, followed by oral anticoagulation for 3 to 12 months. ^[1][2]
• Direct oral anticoagulants and vitamin K antagonists are both used after CVT; guidelines disagree, so local practice and an expert should be followed. ^[1][2]
• CVT needs a high index of suspicion; confirm it with MR or CT venography, and be careful with D-dimer. ^[1][2]
• Cervical and intracranial dissection is the commonest arteriopathy in young adults; local pain and a Horner syndrome are early clues and imaging (CTA/MRA, fat-suppressed MRI) makes the diagnosis. ^[4][7]
• Intracranial dissection causes subarachnoid haemorrhage in about half of cases; intracranial arteries are fragile and the threshold for intervention differs. ^[4]
• CADASIL is a NOTCH3 small-vessel disease presenting with migraine with aura in early mid-life, recurrent lacunar stroke and vascular dementia; there is no disease-modifying treatment and anticoagulation is discouraged. ^[5]
• Primary CNS vasculitis is a rare single-organ vasculitis; biopsy is the gold standard and immunosuppression (steroids plus cyclophosphamide or mycophenolate mofetil, with aspirin for large-vessel disease) is the treatment. ^[6]
• A young-stroke work-up is methodical: confirm stroke, image vessels and heart, exclude dissection and PFO, and select thrombophilia and genetic testing rather than screen.
• One in seven adults with CVT has no identifiable risk factor, and conventional vascular risk factors are common in under-50 stroke, so neither the young nor the "idiopathic" case should be written off. ^[2][7]

Related topics that are relevant when you build the rest of the syllabus:

• Ischaemic stroke and transient ischaemic attack (acute arterial stroke, thrombolysis, secondary prevention)
• Neuroimaging basics (CT, MRI, CTA, MRA, venography)
• Aortic dissection and other arterial diseases (differential for chest/back pain)
• Epilepsy and status epilepticus (seizures in CVT)
• Thrombophilia and coagulation disorders
• Migraine and intracranial hypertension
• Vasculitis and connective tissue disease
• Pregnancy-related neurological disease

This page was written as an educational topic and cites the editions named above; clinical decisions should follow the local adopted guideline and formulary.