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12 notes available
1 Last Minute Review 2 Cerebrovascular Anatomy 3 Stroke Syndromes 4 Acute Stroke Management 5 Stroke Workup 6 Secondary Prevention 7 Intracerebral Hemorrhage 8 SAH & Aneurysms 9 SDH & EDH 10 Venous Thrombosis 11 Vascular Malformations 12 Special Vascular Topics
Clinical › Vascular

Venous Thrombosis

Cerebral Venous Thrombosis

What You'll Learn

  • Cerebral venous anatomy — dural sinuses, superficial cortical veins, and deep venous system drainage patterns
  • Risk factors: prothrombotic states, OCPs, pregnancy/postpartum, infections, malignancy — and how to work them up
  • Two mechanisms of injury: venous outflow obstruction with vasogenic edema/hemorrhage AND impaired CSF absorption causing raised ICP
  • Clinical syndromes by location — SSS (bilateral parasagittal), transverse/sigmoid (pseudotumor pattern), cavernous sinus (painful ophthalmoplegia), deep venous (bilateral thalamic involvement, coma)
  • Imaging: dense triangle sign, cord sign, empty delta sign on contrast CT; MRV/CTV as confirmatory studies; MRI signal changes vary with thrombus age
  • Treatment: anticoagulation with heparin EVEN with hemorrhagic infarction (critical board point), duration of anticoagulation, and role of endovascular therapy
  • Special scenarios: CVT in pregnancy (LMWH), VITT (avoid heparin, use non-heparin anticoagulants), and infectious cavernous sinus thrombosis
  • Prognosis is generally favorable (mortality 5–10%), but deep venous system involvement, coma, and malignancy predict poor outcomes
HighYield Pearls
  • Anticoagulate even with hemorrhagic infarction: LMWH or UFH is first-line acute therapy in CVT — hemorrhagic venous infarction is NOT a contraindication (ISCVT, RE-SPECT CVT); withholding heparin is the classic wrong answer
  • Bilateral thalamic edema/infarction → deep cerebral vein / straight sinus / vein of Galen thrombosis: top-of-the-basilar embolism is the arterial mimic — get MRV
  • Bilateral parasagittal motor deficits (legs > arms): superior sagittal sinus thrombosis with cortical vein involvement — classic board vignette
  • Isolated intracranial hypertension picture (headache + papilledema + normal parenchyma) in a young woman on OCPs: do NOT diagnose IIH until MRV excludes transverse/sigmoid sinus thrombosis
  • Painful ophthalmoplegia + chemosis + proptosis + fever after sinusitis/dental/facial infection: septic cavernous sinus thrombosis — IV broad-spectrum antibiotics ± surgical source control; CN VI palsy is the earliest sign
  • CVT after recent ChAdOx1/Ad26 COVID-19 vaccine + thrombocytopenia (<150K) + elevated D-dimer: VITT — send anti-PF4 ELISA, AVOID heparin, use argatroban / bivalirudin / fondaparinux + IVIG
  • Empty delta sign on contrast CT, dense cord/triangle sign on non-contrast CT: highest-yield CT findings — CT venography and MR venography are the optimal confirmatory studies; DSA is typically reserved for invasive treatment or equivocal cases.
  • Hemorrhagic infarct that does NOT respect an arterial territory (often bilateral parasagittal or temporal-occipital crossing boundaries) → think venous, not arterial
  • Targeted thrombophilia workup (unprovoked / recurrent / young / persistent risk factors) — protein C/S/antithrombin should NOT be interpreted during acute thrombosis or while anticoagulated; JAK2 V617F + genetic markers can be sent any time; APS testing requires repeat positivity at ≥12 weeks.
  • Decompressive hemicraniectomy is the rescue for malignant venous infarction with impending herniation — lifesaving and gives surprisingly good functional outcomes in CVT
🔍 Quick ReferenceClinical · Imaging · Etiology / treatment
Clinical presentation
  • Young woman on OCPs with subacute progressive headache + papilledema → transverse/sigmoid or superior sagittal sinus thrombosis (IIH mimic)
  • Bilateral lower-extremity weakness (parasagittal motor cortex) → superior sagittal sinus thrombosis
  • Bilateral thalamic syndrome + coma + vertical gaze palsy → deep cerebral vein / straight sinus / vein of Galen thrombosis
  • Chemosis + proptosis + painful ophthalmoplegia + fever after sinusitis/dental infection → septic cavernous sinus thrombosis
  • Otitis media / mastoiditis → headache + CN VI palsy (Gradenigo) → lateral (transverse/sigmoid) sinus thrombosis
  • Postpartum (first 4 weeks) headache with seizures → peripartum CVT (also consider PRES, eclampsia, RCVS)
  • Focal seizure + cortical hemorrhage NOT respecting an arterial territory → cortical vein thrombosis (vein of Trolard or Labbé)
Imaging signs
  • Empty delta sign (contrast CT, posterior SSS) → superior sagittal sinus thrombosis
  • Dense triangle / dense sinus sign (non-contrast CT) → acute clot in dural sinus
  • Cord sign (linear hyperdensity on non-contrast CT) → cortical vein thrombosis
  • Bilateral symmetric thalamic T2/FLAIR hyperintensity ± hemorrhage → deep venous thrombosis (basilar tip embolism is the DDx)
  • T2* / SWI “blooming” in a sinus or cortical vein → thrombus / petechial hemorrhage
  • Hemorrhagic infarct crossing arterial boundaries (bilateral parasagittal, temporal-occipital) → venous infarction
  • MRV / CTV showing absent flow / filling defect → optimal confirmatory test for CVT (DSA reserved for treatment or equivocal cases)
  • Vasogenic edema > cytotoxic on DWI → venous (not arterial) infarction pattern
Etiology / treatment
  • OCP + smoking in a young woman → most common acquired CVT risk combination
  • JAK2 V617F mutation → occult myeloproliferative neoplasm — screen in unprovoked CVT
  • Anti-PF4 antibodies + thrombocytopenia after ChAdOx1/Ad26 vaccine → VITT — argatroban/bivalirudin/fondaparinux + IVIG, AVOID heparin
  • Antiphospholipid syndrome (lupus anticoagulant, anti-β2-GP1, anticardiolipin) → lifelong warfarin (NOT DOACs) for recurrent thrombosis
  • Dabigatran noninferior to warfarin → RE-SPECT CVT trial
  • Endovascular thrombectomy → TO-ACT (no overall benefit) — reserve for clinical deterioration on anticoagulation
  • Decompressive hemicraniectomy → lifesaving for malignant venous infarction with herniation (good functional outcome)
  • Future pregnancy after CVT → prophylactic LMWH antepartum and postpartum (pregnancy is NOT contraindicated)
Cerebral Venous Anatomy

Dural Venous Sinuses

The dural venous sinuses in sagittal section
The dural venous sinuses — the superior sagittal and straight sinuses converge at the confluence (torcular Herophili), draining through the transverse then sigmoid sinuses to the internal jugular veins; the inferior sagittal sinus joins the vein of Galen to form the straight sinus. These are the channels occluded in CVST.© HighYieldNeuro
  • Superior Sagittal Sinus (SSS): Runs along the superior margin of the falx cerebri from the crista galli to the confluence of sinuses (torcular Herophili) → receives drainage from superficial cortical veins and arachnoid granulations (site of CSF absorption)
  • Inferior Sagittal Sinus (ISS): Runs along the inferior free edge of the falx cerebri → joins the vein of Galen to form the straight sinus
  • Straight Sinus: Formed by the junction of the ISS and the vein of Galen → runs posteriorly along the junction of the falx and tentorium → drains into the confluence of sinuses
  • Transverse Sinuses: Paired sinuses running laterally from the confluence along the attachment of the tentorium → the right transverse sinus is typically dominant (receives most SSS flow); the left receives most straight sinus flow
  • Sigmoid Sinuses: S-shaped continuation of the transverse sinuses → course inferiorly along the posterior petrous bone → drain into the internal jugular veins at the jugular foramen
  • Cavernous Sinuses: Paired sinuses flanking the sella turcica → contain the internal carotid artery and CN VI within the sinus; CN III, IV, V1, V2 course through the lateral wall → receive drainage from the superior and inferior ophthalmic veins, superficial middle cerebral vein, and sphenoparietal sinus → drain posteriorly into the superior and inferior petrosal sinuses
  • Confluence of Sinuses (Torcular Herophili): Junction of SSS, straight sinus, and occipital sinus near the internal occipital protuberance → highly variable anatomy; true symmetric confluence occurs in only ~25% of individuals

Superficial Cortical Veins

  • Superficial middle cerebral vein (vein of Sylvius): Runs along the Sylvian fissure → drains into the cavernous sinus or sphenoparietal sinus
  • Vein of Trolard (superior anastomotic vein): Connects the superficial middle cerebral vein to the SSS → runs over the parietal convexity — largest of the anastomotic veins
  • Vein of Labbé (inferior anastomotic vein): Connects the superficial middle cerebral vein to the transverse sinus → runs over the temporal lobe
  • Superficial cortical veins drain the cortical surface and empty into the SSS, transverse sinus, or cavernous sinus — variable anatomy with extensive anastomoses explains why isolated cortical vein thrombosis may be clinically silent

Deep Venous System

  • Internal cerebral veins (paired): Run in the roof of the third ventricle → drain the deep white matter, basal ganglia, and thalami
  • Basal vein of Rosenthal (paired): Courses around the midbrain from anteromedial (near the anterior perforated substance) to posterosuperior → drains the medial temporal lobe, basal ganglia, and midbrain
  • Vein of Galen (great cerebral vein): Formed by the union of the two internal cerebral veins (and receives the basal veins of Rosenthal) beneath the splenium of the corpus callosum → drains into the straight sinus
  • Deep venous system thrombosis produces bilateral thalamic involvement — a critical imaging and clinical clue
💎 Board Pearl

The SSS is the most commonly thrombosed sinus (~60–70%). Arachnoid granulations along the SSS are the primary site of CSF absorption — SSS thrombosis impairs CSF reabsorption, causing raised ICP that mimics idiopathic intracranial hypertension. Deep venous system thrombosis (internal cerebral veins, vein of Galen, straight sinus) produces bilateral thalamic edema/infarction and carries the worst prognosis.

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