Study guide
21.3 Cerebral Venous Sinus Thrombosis (03.F)
ABIM Neurocritical Care Subspecialty Certification Exam
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility, Practice Pathway, and the IM Training Route 1.3 Format, Scoring, Pearson VUE, and Score Reports 1.4 How to Use This Independent Study Guide
2 ICU Neurologic Exam, Cerebral Physiology, and CSF
2.1 Neurological Examination in the ICU 2.2 Cerebral Physiology, ICP, CBF, and Autoregulation 2.3 CSF Physiology
3 Core Neuropharmacology
3.1 Osmotic Agents 3.2 Anti-Seizure Drugs 3.3 Anesthetics, Sedatives, Analgesia, and Paralytics 3.4 Antihypertensives, Vasopressors, and Inotropes
4 Reperfusion Drugs, Airway, and Ventilation
4.1 Thrombolytics, Anticoagulants, and Antiplatelets 4.2 Reversal of Anticoagulation After Acute Hemorrhage 4.3 Airway Management and Tracheostomy 4.4 Mechanical Ventilation
5 Hemodynamics and Shock
5.1 Hemodynamic Monitoring 5.2 IABP, Temporary VADs, LVAD, and ECMO 5.3 Diagnosis and Management of Shock
6 Nutrition, Temperature, and ICU Prophylaxis
6.1 Nutrition (01.J) 6.2 Temperature Control (01.K) 6.3 ICU Prophylaxis, Delirium, and Early Mobility (01.L)
7 General Trauma
7.1 Emergency Evaluation of Polytrauma, Chest, and Abdominal Trauma 7.2 Long-Bone Fractures and Fat Embolism 7.3 Burns, Electrical Injury, and Hanging/Strangulation
8 Pulmonary Critical Care
8.1 Pulmonary Physiology and ARDS (01.N.1–2) 8.2 PE, Pneumonia, and Pulmonary Edema (01.N.3, 7–8) 8.3 COPD, Asthma, PAH, and Bronchoscopy Basics (01.N.4–6, 9)
9 Cardiovascular Critical Care
9.1 Cardiovascular Physiology, Stress Cardiomyopathy, ACS, and Valves 9.2 Arrhythmias and Pacing 9.3 Acute Aortic Dissection and Cardiac Ultrasound
10 Renal and Infectious Disease
10.1 AKI, RRT, and Renal Drug Dosing 10.2 Acid-Base and Electrolyte Disorders 10.3 Severe Sepsis, Septic Shock, and Infective Endocarditis 10.4 Antimicrobial Use and Infection in the Immunosuppressed
11 Endocrine and Salt-Water Disorders
11.1 Pituitary Apoplexy, DI, and Panhypopituitarism (01.R.1–4) 11.2 SIADH and Cerebral Salt Wasting (01.R.5–6) 11.3 Thyrotoxicosis, Myxedema, Adrenal Crisis, and Dysglycemia (01.R.7–9)
12 Gastrointestinal Critical Care
12.1 GI Physiology, Acute Abdomen, Bleed, Ileus, and Perforation (01.S.1–5) 12.2 Mesenteric Ischemia and Abdominal Compartment Syndrome (01.S.6–7) 12.3 Fulminant Liver Failure, Cirrhosis Decompensation, and Hepatic Dosing (01.S.8–10)
13 Hematologic Disorders
13.1 Anemia, Transfusion, Thrombocytopenia, Coagulopathy, and DIC (01.T.1–4) 13.2 VTE in the Neuro ICU (01.T.5) 13.3 Chemo/Immune, SCT, CAR-T, Sickle Cell, and TMA (01.T.6–10)
14 Neuroimaging
14.1 CT of Brain and Spine 14.2 MRI and CT/MR Perfusion 14.3 Noninvasive Angiography and Catheter Angiography
15 EEG, EMG, and CSF Analysis
15.1 EEG, Standard and Processed (02.B) 15.2 Basic EMG Interpretation (02.G) 15.3 CSF Analysis (02.H)
16 ICP, TCD, and Multimodality Monitoring
16.1 ICP Monitoring (02.C) 16.2 Transcranial Doppler (02.D) 16.3 Brain-Tissue Oxygen and Multimodality Monitoring (02.E–F)
17 Brain Death and Bedside Procedures
17.1 Brain Death Prerequisites and Clinical Exam (02.I) 17.2 Apnea Testing and Ancillary Studies (02.I) 17.3 Vascular Access, Thoracic Echo, and Lung Ultrasound (02.J–L)
18 Coma, Anoxia, and Intracranial Hypertension
18.1 Coma and Other States of Altered Consciousness (03.A) 18.2 Global Anoxia-Ischemia and Post-Resuscitation Encephalopathy (03.A.1) 18.3 Toxidromes, ICU Delirium, and Hypertensive Encephalopathy (03.A.2–4) 18.4 Intracranial Hypertension as a Disease State (03.B)
19 Acute Ischemic Stroke
19.1 IV Reperfusion Therapy (03.C.3) 19.2 Mechanical Thrombectomy Windows and Imaging Selection (03.C.3) 19.3 Malignant Hemispheric Infarction and Basilar Artery Occlusion (03.C.1–2)
20 Intraparenchymal Hemorrhage
20.1 Intracerebral Hematoma (03.D.1) 20.2 Cerebellar Hematoma (03.D.2) 20.3 Intraventricular Hemorrhage (03.D.3)
21 SAH, CVST, and Spinal Cord Infarction
21.1 Aneurysmal Subarachnoid Hemorrhage (03.E.1) 21.2 Non-Aneurysmal SAH (03.E.2) 21.3 Cerebral Venous Sinus Thrombosis (03.F) 21.4 Spinal Cord Infarction (03.G)
22 Vascular Anomalies and Traumatic Brain Injury
22.1 Unruptured Aneurysm, Cavernoma, AVM, and Dural AVF (03.H) 22.2 Diffuse Axonal Injury and Cerebral Contusions (03.I.1–2) 22.3 Epidural Hematoma, Subdural Hematoma, and Penetrating Injury (03.I.3–4, 7) 22.4 Arterial Dissection and Carotid-Cavernous Fistula (03.I.5–6)
23 Spine, Hydrocephalus, and CNS Infection
23.1 Spinal Cord Injury, Central Cord, and Neurogenic Shock (03.J) 23.2 Unstable Spine Fractures (03.K) 23.3 Hydrocephalus and CSF Diversion (03.L) 23.4 Acute CNS Infections (03.M)
24 Seizures and Neuromuscular Emergencies
24.1 Status Epilepticus and Seizures (03.N) 24.2 Guillain-Barré Syndrome (03.O.1) 24.3 Myasthenic Crisis (03.O.2) 24.4 Motor Neuron Disease, Acute Myopathies, Rhabdomyolysis, and CINM (03.O.3–6)
25 Inflammatory Disease, Neuro-Oncology, and Special Populations
25.1 Fulminant Demyelinating Diseases (03.P) 25.2 Autoimmune Encephalitis and Acute Autonomic Hyperactivity (03.Q–R) 25.3 Neuro-Oncology and Treatment Complications (03.S) 25.4 Pregnancy/Post-Partum, Post-Transplant, and Pediatric Patients (03.T–U)
26 Neurosurgical and Perioperative Complications
26.1 Postoperative Seizures, Hemorrhage, Ischemia, and Hyperperfusion (04.A, C, D, H) 26.2 Infection, CSF Leak, and Pneumocephalus (04.B, E, F) 26.3 Complications of EVD and Lumbar Drain (04.G, I)
27 Ethics, Prognostication, and Organ Donation
27.1 Communication, Decision-Makers, Advance Directives, and DNR (05.A, B, G) 27.2 Uncertainties of Prognostication and the Self-Fulfilling Prophecy (05.C) 27.3 Palliative Care, Withdrawal, Withholding, and Futility (05.D–F) 27.4 Donation After Cardiac Death and Care of the Organ Donor (05.H–I)
21.3 Cerebral Venous Sinus Thrombosis (03.F)
Key Takeaways Explain This Topic AI
CVT presents with headache, seizure, papilledema, or a venous infarct that does not match an arterial territory and is often hemorrhagic — anticoagulation is still first-line.
Risk factors that appear on exams include combined oral contraceptives, pregnancy and the puerperium, inherited or acquired thrombophilia, and parameningeal infection such as mastoiditis (transverse sinus).
Diagnose with MR venography or CT venography; noncontrast CT can be normal or show only the dense-triangle/empty-delta signs.
The 2024 AHA scientific statement on cerebral venous thrombosis continues parenteral heparin (UFH or LMWH) even when some intracranial hemorrhage is present; DOACs are an option in the oral phase for selected patients.
Endovascular thrombectomy or lysis is rescue therapy for selected patients who deteriorate despite anticoagulation, not routine first-line treatment (TO-ACT did not support routine endovascular therapy).
Last updated: September 2026
Cerebral venous thrombosis (CVT) — also called cerebral venous sinus thrombosis (CVST) when the large sinuses are involved — is a clot in the cerebral veins or dural sinuses. Arterial stroke algorithms miss it because the infarct is often hemorrhagic, bilateral, or in a territory no named artery owns. Incidence is on the order of 1–2 per 100,000 per year in adults, with a strong tilt toward women of childbearing age. The International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT) taught the modern natural history: most patients are young, headache is nearly universal, seizures are common (~40%), and about 80% regain independence — if you anticoagulate and treat intracranial hypertension instead of withholding heparin because the CT already shows blood.
The 2011 AHA/ASA scientific statement (Saposnik and colleagues) established heparin-despite-hemorrhage as standard teaching. The 2024 AHA scientific statement (Saposnik G et al., Stroke 2024;55:e77–e90) updates diagnosis and the oral-anticoagulant era, including direct oral anticoagulants (DOACs) as an option after the acute parenteral phase in selected patients. European Stroke Organization 2017 guidance and Canadian 2024 best-practice recommendations agree on the hemorrhage point: intracranial or subarachnoid blood is not a contraindication to anticoagulation.
Independent ExamFinch coverage of this ABIM Neurocritical Care disease should stay concrete: recognize the syndrome, pick the venogram, start heparin, hunt the cause, and reserve endovascular therapy for true rescue.
Clinical picture that is not an MCA occlusion
Headache is the dominant symptom and may be thunderclap, subacute, or chronic and papilledema-like. Seizure — including status epilepticus — is far more common than in arterial ischemic stroke. Focal deficits follow the occluded sinus:
Structure Typical clinical/imaging footprint
Superior sagittal sinus Bilateral or parasagittal venous infarcts, often hemorrhagic; headache, paraparesis, seizures
Transverse / sigmoid sinus Temporal or occipital hemorrhage; may follow mastoiditis or otitis
Deep venous system (internal cerebral veins, vein of Galen, straight sinus) Bithalamic edema or infarct, coma, high mortality if untreated
- Cortical vein (including vein of Labbé) Isolated lobar hemorrhage or seizure with a small cortical infarct
- Cavernous sinus Chemosis, painful ophthalmoplegia; often infectious
Papilledema and a high opening pressure on lumbar puncture (once imaging has excluded a mass that forbids LP) mark the isolated-intracranial-hypertension phenotype, which can mimic idiopathic intracranial hypertension. A venous infarct that crosses arterial territories , is hemorrhagic from the start , or sits in the parasagittal or bithalamic regions is CVT until venography says otherwise.
Risk factors the exam expects you to name
Category Examples
Hormonal Combined estrogen-progestin oral contraceptives; pregnancy, especially third trimester and puerperium; hormone-replacement therapy
Thrombophilia Factor V Leiden, prothrombin G20210A, protein C/S or antithrombin deficiency, antiphospholipid syndrome
- Infection Mastoiditis, otitis, sinusitis, meningitis (parameningeal spread into adjacent sinus)
- Systemic Malignancy, inflammatory bowel disease, nephrotic syndrome, severe dehydration
Hematologic / iatrogenic Myeloproliferative neoplasms, PNH, L-asparaginase, COVID-19 and vaccine-induced thrombotic thrombocytopenia (HIT-like, rare but historically tested)
Local Head trauma, neurosurgery, jugular catheter
A young woman with a new combined oral contraceptive, a week of headache, and a left temporal hematoma is a CVT stem, not a hypertensive ICH stem. Mastoiditis plus a transverse-sinus clot is infection plus thrombosis: drain the ear, culture, antibiotics, and anticoagulate.
Imaging: CTV, MRV, and the traps of noncontrast CT
Noncontrast CT is often the first scan and is frequently normal or nonspecific. Clues, when present:
- Hyperdense triangle (acute clot in the superior sagittal sinus)
- Empty delta sign on contrast CT (enhancing dura around a nonenhancing clot)
- Hemorrhagic infarct that is not wedge-shaped in an arterial map
Definitive noninvasive tests are CT venography (CTV) and MR venography (MRV) . MRI also shows the parenchyma: DWI/ADC of venous infarction, blooming on susceptibility-weighted images in a cortical vein, and edema that looks "too much" for the amount of hypodensity. Time-of-flight MRV can overcall hypoplastic transverse sinuses; contrast-enhanced MRV or CTV helps. Catheter cerebral venography is reserved for diagnosis that remains uncertain or for endovascular treatment.
Do not wait for a perfect MRI in a seizing, herniating patient: CTV on the way to the ICU is enough to start heparin.
Anticoagulation even when there is blood
The clot is causing venous hypertension; the hemorrhage is often a venous hemorrhagic infarct . Leaving the sinus occluded lets edema and bleeding worsen. Randomized data are old and small (intravenous unfractionated heparin versus placebo; nadroparin versus placebo), but they, plus two decades of observational practice, underpin every major statement:
Start therapeutic heparin — unfractionated heparin (UFH) infusion or low-molecular-weight heparin (LMWH) .
Presence of intracranial hemorrhage or convexity SAH is not a reason to withhold anticoagulation.
UFH is convenient when an EVD, craniectomy, or other procedure is likely (short half-life).
LMWH is reasonable in stable patients who are unlikely to need an immediate operation.
Avoid heparin if there is heparin-induced thrombocytopenia; use an alternative anticoagulant with hematology.
After a parenteral lead-in (often several days to 2 weeks, individualized), transition to oral therapy. Traditional course: vitamin K antagonist with INR target 2–3 for 3–12 months if the trigger was transient, longer or indefinite if the thrombophilia or cancer is permanent. The 2024 AHA statement and subsequent summaries include DOACs as an alternative to warfarin in selected lower-risk patients, supported by small randomized trials (including RE-SPECT CVT with dabigatran) and observational series. DOACs are not first-line in antiphospholipid syndrome (warfarin remains preferred) or in pregnancy (LMWH). There is still insufficient evidence to skip parenteral therapy and start a DOAC as the very first anticoagulant in acute severe CVT.
Endovascular rescue, ICP, and seizures
The TO-ACT randomized trial of endovascular thrombolysis/thrombectomy plus anticoagulation versus anticoagulation alone did not show a benefit that would make catheter therapy routine. AHA 2024-era teaching: endovascular treatment is selected rescue — clinical deterioration from clot propagation or refractory intracranial hypertension despite anticoagulation, or perhaps a comatose deep-venous occlusion at a center that does this work. It is not the opening move for an awake patient with a transverse-sinus clot and a small hematoma.
Mass effect and herniation: osmotherapy as a bridge; decompressive craniectomy can be life-saving in young patients with large venous infarcts and is supported by registry data and European guidance even without a dedicated RCT. That is one of the better craniectomy stories in all of stroke.
Seizures: treat clinical seizures; prophylactic antiseizure drugs in patients who have not seized are not routinely recommended. Acute symptomatic seizures (within 7 days) get treated per usual ICU protocols.
Acetazolamide or therapeutic lumbar puncture may help the isolated-intracranial-hypertension phenotype after imaging clearance. Steroids are not a routine CVT treatment except when the cause is inflammatory disease that independently needs them.
Workup for cause
Once the patient is anticoagulated and the brain is not herniating, find why :
- History of OCP, pregnancy, miscarriage, cancer, IBD, ear infection
- CBC (myeloproliferative disease), pregnancy test
- Antiphospholipid antibodies (can be sent acutely)
Inherited thrombophilia panel: some proteins fall in acute thrombosis, so protein C, protein S, and antithrombin are more reliable later, off anticoagulation, unless you use assays that heparin/DOAC do not wreck
- Blood cultures and ear imaging if fever or mastoid tenderness
- Age-appropriate cancer screening when unprovoked and older
- HIT/VITT testing only when the clinical context fits
Counsel estrogen users to stop combined contraceptives. Future pregnancy is not forbidden after CVT; it is a high-risk hematology/OB collaboration, usually with LMWH prophylaxis in subsequent pregnancies depending on the original trigger.
In practice
A 29-year-old on a combined oral contraceptive has a week of headache, then a seizure. CT shows a left temporal hematoma that does not look like an MCA wedge. CTV shows left transverse- and sigmoid-sinus thrombosis. You start unfractionated heparin despite the hematoma, treat the seizure, obtain MRI, and screen for thrombophilia and mastoid disease. If she later herniates from swelling, you consider decompression, not reversal of heparin as the first and only move. If she is stable after a heparin lead-in and has no antiphospholipid syndrome, a DOAC or warfarin for months is consistent with the 2024 AHA statement. If she deteriorates with expanding thrombosis despite therapeutic heparin, that is the setting for a selected endovascular rescue discussion — not TO-ACT-for-everybody.