Cerebral Venous Thrombosis
Occlusion of the cortical and subcortical veins causes focal neurologic symptoms and signs, including neuro-ophthalmic findings. Most commonly affected are the cavernous sinus, lateral (transverse) sinus, and superior sagittal sinus; each produces a distinct clinical syndrome. During pregnancy, the lateral and superior sagittal sinuses are more commonly affected. Patients with thrombosis may present with headaches and papilledema, and the thrombosis could be confused with IIH. Thrombosis of the deep veins may cause infarction of the thalamus or basal ganglia, and death can occur in 3%–15% of cases.
Types of cerebral venous thrombosis
Cavernous sinus thrombosis
Cavernous sinus thrombosis (CST) in the septic form results from an infection of the face, oral cavity, or sphenoid or ethmoidal sinuses. Otitis media or orbital cellulitis is a rare cause. Patients experience headache, nausea, vomiting, and somnolence. There may also be fever, chills, tachycardia, evidence of meningitis, or generalized sepsis. Ocular signs from anterior infection (facial, dental, or orbital) are initially unilateral but frequently become bilateral. These signs include orbital congestion, lacrimation, conjunctival edema, eyelid swelling, ptosis, proptosis, and ophthalmoplegia. CN VI palsy is the most consistent early neurologic sign. Corneal anesthesia, facial numbness, Horner syndrome, and venous stasis retinopathy can occur. Septic CST is a medical emergency; it carries a high mortality rate if it is not recognized promptly and if treatment is not initiated immediately. The mainstay of therapy is early and aggressive antibiotic administration. Anticoagulation is often recommended as adjunctive therapy. Corticosteroids may help to reduce inflammation and edema. If feasible, the primary source of infection should be drained.
The signs and symptoms of aseptic CST resemble those of septic CST, but clinical or laboratory examination shows no evidence of infection. Pain around the eye is common, but orbital congestion is typically less severe than with septic CST. Anticoagulation or antiplatelet therapy is often used.
Lateral (transverse) sinus thrombosis
Lateral sinus thrombosis may be septic or spontaneous (see Chapter 2, Fig 2-13). With the widespread use of antibiotics, septic thrombosis has become rare, but it may result from otitis media.
Patients with lateral sinus thrombosis have features of systemic infection as well as neck pain, tenderness of the ipsilateral jugular vein, retroauricular edema, and sometimes, facial weakness. Severe facial pain also may occur; when accompanied by CN VI palsy it is called Gradenigo syndrome. Lateral sinus thrombosis is much more likely to be spontaneous and produce an IIH-like syndrome with increased intracranial pressure. The most common ophthalmic signs are papilledema and CN VI palsy.
Superior sagittal sinus thrombosis
The most commonly involved cerebral venous sinus is the superior sagittal sinus (SSS); symptoms of its thrombosis depend on the extent and location of the occlusion. With thrombosis of the anterior third of the sinus, symptoms are mild or absent. Posterior SSS thrombosis may produce a clinical picture similar to that of IIH, with headaches and papilledema. It is a diagnosis to consider in atypical IIH patients, such as slim women and men. Seizures and motor deficits may occur.
Diagnosis of cerebral venous thrombosis
Neuroimaging is required to diagnose CVT. CT or MRI is often used initially, but a targeted venographic study, such as magnetic resonance venography (MRV) or computed tomography venography (CTV) should also be considered. Cerebral venography may be used in cases in which clinical suspicion is high despite normal CTV or MRV findings.
Laboratory evaluation of cerebral venous thrombosis
Prothrombotic conditions are present in 21%–34% of patients with CVT, most commonly protein C deficiency, protein S deficiency, presence of antiphospholipid and anticardiolipin antibodies, factor V Leiden, presence of prothrombin G20210A mutation, and hyperhomocysteinemia. Other predisposing factors include pregnancy, use of oral contraceptives, and systemic conditions including cancer, facial infections, inflammatory diseases, and hematologic diseases.
Treatment of cerebral venous thrombosis
Treatment of CVT is directed toward the underlying condition. Therapies include use of anticoagulants, fibrinolytic drugs, and treatments to lower intracranial pressure. Antiepileptic drugs are used for patients with seizures. Corticosteroids are typically not used in CVT treatment unless required for management of the underlying inflammatory disease. Endovascular interventional therapy using modern approaches to intracranial recanalization may be needed in symptomatic patients showing resistance to medical treatment.
Patients with CVT may benefit from receiving care in a dedicated hospital stroke unit to ensure adequate treatment and to prevent complications.
Bushnell C, Saposnik G. Evaluation and management of cerebral venous thrombosis. Continuum (Minneap Minn). 2014;20(2):335–351.
Mokin M, Lopes DK, Binning MJ, et al. Endovascular treatment of cerebral venous thrombosis: contemporary multicenter experience. Interv Neuroradiol. 2015;21(4):520–526.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.