emDOCs Podcast – Episode 37: Cerebral Venous Thrombosis
- Sep 14th, 2021
- Brit Long
Introduction: CVT is an uncommon neurologic emergency that can lead to stroke, seizures, and death. CVT is defined by thrombosis of the intracranial veins and dural sinuses and has an estimated annual incidence of 0.3-1.5 cases/100,000 person-years, accounting for up to 1% of all strokes worldwide. This incidence approaches that of meningitis. Delays in diagnosis are associated with worse morbidity.
Pathophysiology: An obstruction within the dural venous system leads to increased venous pressure and reduced capillary perfusion pressure, which can result in ischemia, edema, elevated intracranial pressure (ICP), and even hemorrhagic infarction.
Epidemiology: There is a female predominance to CVT, and the typical age is less than 50 years old (commonly 33 years). Less than 10% are over age 60 years. Most patients with CVT will have at least one risk factor for thrombosis which includes peripartum states, hypercoagulability, inflammatory conditions, neurosurgery, and infections.
Table 1. Risk Factors Associated with CVT.
Presentation: Headache is the most common presenting complaint of CVT, occurring in 81-95% of patients, while focal neurologic deficits, seizures ,and altered mental status can be additional features of CVT.
Table 2. Clinical Presentations Suggestive of CVT.
While headache is common in ED patients, several distinguishing factors may suggest CVT. The headache of CVT is most often subacute, lasting for 4 days to 2 weeks prior to presentation. A combination of headache and seizure or headache and papilledema have a high sensitivity but low specificity for CVT.
Focal neurological deficits, including cranial nerve palsies and extremity weakness occur in 31-68% of cases. Seizures occur in 23-44% of patients with CVT. The location of the clot can be related to the symptoms that the patient will manifest.
Table 3. CVT Locations.
Laboratory Testing: Laboratory evaluation cannot be used to rule in or rule out CVT. D-dimer is classically thought to be elevated in CVT, but the false negative rate ranges from 24-40%. A recent prospective multicenter study proposes a predictive clinical score for the diagnosis of CVT.
Table 4. CVT Clinical Score.
Imaging: The most common initial imaging modality obtained in the emergency department in patients with suspected high-risk headaches is non-contrast head CT. Unfortunately, this test is poorly sensitive for CVT and can be normal in up to 30% of patients. CT venography has an overall sensitivity of 95% for CVT. MRI findings alone are dependent on the age of thrombus. MRV highly sensitive and should be considered in those with suspected involvement of the deep venous system (altered mental status).
Management: The overall goals of treatment of CVT are to treat the sequela/complications of CVT, prevent propagation of the clot, recanalize the occluded vessel, and prevent thrombosis elsewhere in the body.
- Seizures: Patients actively seizing should be treated first with benzodiazepines. A retrospective study of seizures in CVT reported that lorazepam was the most commonly used medication to treat acute seizures from CVT
- ICP: There is no evidence to support the use of steroids or acetazolamide for increased ICP in CVT. Recommendations for elevating the head of bead to 30 degrees, hyperventilation to 30-35mmHg PaCO2, and either hypertonic saline or mannitol to lower ICP are based on expert opinion. Decompressive surgery should be considered in patients with CVT and signs of impending herniation as small case series have shown that decompressive craniotomy can be life-saving, but there are little data to guide patient selection.
- Anticoagulation: Anticoagulation is the mainstay of ED treatment of CVT. Intracerebral hemorrhage is not a contraindication to starting anticoagulation. Initial anticoagulation with low molecular weight heparin is recommended. European guidelines currently do not recommend systemic thrombolysis. A recent RCT of endovascular therapy showed no difference in mortality when compared with standard of care.
- CVT is a rare and difficult diagnosis to make due to a wide variety of signs and symptoms.
- Patients are commonly under 50 years of age.
- Scenarios warranting CVT investigation include headache that is atypical and persistent, stroke with no typical risk factors or in the setting of seizure, intracranial hypertension with no explanation, multiple hemorrhagic infarcts, hemorrhagic infarcts not in a specific arterial distribution, or objective neurologic symptoms in a patient with risk factors for CVT.
- Patients can present with four major syndromes, the most common of which is headache from intracranial hypertension.
- Do not rely on labs such as D-dimer for ruling out or ruling in. Imaging is required, including CT with venography or MRI/MRV.
- Treatment includes stabilizing immediate condition, anticoagulation, and managing underlying condition.