Head trauma, neurosurgical procedures, severe dehydration (especially in neonates/pediatrics).
Clinical Features
History:
Headache (>90%): Most common initial symptom; gradual, progressive, worsens with recumbency, coughing, or Valsalva (signs of ↑ ICP). Rarely presents as a “thunderclap” headache. c
Seizures (~40%): Focal or generalized (significantly higher frequency than in arterial ischemic stroke).
Altered Mental Status (AMS): Lethargy, confusion, encephalopathy, or coma in severe cases.
Physical Examination:
Papilledema and visual obscurations secondary to elevated ICP.
Focal Neurologic Deficits (FND): Hemiparesis, aphasia, or bilateral/alternating motor deficits (due to parasagittal cortex involvement from superior sagittal sinus occlusion).
Cranial Nerve Palsies:
CN VI palsy (false localizing sign of ↑ ICP).
Cavernous Sinus Thrombosis: Chemosis, proptosis, ptosis, painful ophthalmoplegia involving CN III, IV, V1, V2, and VI.
Diagnosis
Initial Imaging:
Non-contrast CT Head: Often normal (~30%); may show hyperdense cord sign, non-arterial territory edema, or hemorrhagic infarction.
Confirmatory / Gold Standard Imaging:
MR Venography (MRV) or CT Venography (CTV): MRV is the preferred test; demonstrates lack of flow void and intraluminal filling defect.
Contrast-enhanced CT/MRI: “Empty delta sign” (contrast enhancement of collateral dural vessels outlining a non-enhancing clot in the superior sagittal sinus).
Key Labs:
D-dimer: Elevated in acute phase (normal D-dimer does not completely exclude CVST if suspicion is high).
Baseline CBC, PT/INR, PTT, renal/hepatic panels.
Hypercoagulability workup (best drawn after acute phase and anticoagulation completion).
Blood cultures (if septic cavernous sinus thrombosis or infectious etiology is suspected).
Lumbar Puncture (LP):
Indicated if meningitis/idiopathic intracranial hypertension suspected (perform only after imaging rules out mass effect/herniation risk). Shows elevated opening pressure (>20–25 cm H2O).
Diff by normal MRV/CTV without venous sinus thrombosis or parenchymal infarction; typically seen in obese females of reproductive age.
Arterial Ischemic Stroke:
Diff by sudden maximal deficit restricted to a specific single arterial vascular territory (e.g., MCA), absence of severe early headache, and lower incidence of early seizures.
Subarachnoid Hemorrhage (SAH):
Diff by hyperacute “worst headache of life”, blood localized to subarachnoid cisterns/sulci on non-contrast CT, and xanthochromia on LP.
Bacterial / Viral Meningitis:
Diff by prominent fever, marked nuchal rigidity (Kernig/Brudzinski signs), and CSF pleocytosis with positive Gram stain/microbiology.
Brain Abscess / Neoplasm:
Diff by ring-enhancing lesion or discrete intraparenchymal mass on contrast imaging with surrounding vasogenic edema.
Management
First-line / Acute Phase:
Therapeutic Anticoagulation: Immediate initiation of LMWH (subcutaneous) or UFH (IV).
High-Yield Step 2 Rule: Anticoagulation is indicated even in the presence of hemorrhagic venous infarction.
Transition to oral anticoagulation (DOACs or Warfarin target INR 2.0–3.0) once clinically stabilized.
Duration:
3–6 months for provoked/transient risk factors (e.g., infection, OCPs).
6–12 months or lifelong for unprovoked CVST, recurrent thrombosis, or severe thrombophilia (e.g., APS, homozygous Factor V Leiden).
Supportive & Symptom Management:
Seizure Management: Antiseizure medications (e.g., Levetiracetam) if seizures occur. Routine primary prophylaxis without seizures is not recommended unless focal supratentorial cortical lesions are present.
Elevated ICP Management: Head-of-bed elevation (30°), hypertonic saline or IV Mannitol for impending herniation. Acetazolamide or therapeutic LP if persistent elevated ICP without herniation risk.