Case
The patient’s past medical history included one miscarriage, as well as a papillary thyroid carcinoma with resection, which was discovered a few months before her presentation to the ED and after diagnosis of the initial SSS thrombosis.
Physical examination revealed a well-developed, mildly obese female. On arrival at the ED, the patient’s National Institutes of Health Stroke Scale score was 0. Her vital signs and ocular, neurological, and psychiatric examinations were all normal. The social history was negative for tobacco or alcohol use, and she had no family history of deep vein thrombosis (DVT) or pulmonary embolism.
A noncontrast computed tomography (CT) of the head demonstrated a hemorrhagic venous infarction involving the posterior right parietal lobe. Intracranial magnetic resonance venography (MRV) and brain magnetic resonance imaging (MRI) revealed thrombosis of the posterior third of the SSS as the source of the infarction. This sinus had been patent during the patient’s previous hospital admissions.
The patient’s international normalized ratio (INR) was therapeutic on presentation. Warfarin was discontinued, and she was started on an intravenous (IV) heparin drip. For anticoagulation, she was prescribed 20 mg rivaroxaban daily and 2,000 mg levetiracetam daily.
One week after discharge, the patient again presented to the ED with a recurrence of symptoms, including confusion, slurred speech, and headache, which she rated a “5” on a pain scale of 0 to 10. Similar to the previous ED visit, the slurred speech had resolved by the time of examination. The patient did not exhibit facial asymmetry but did complain of bilateral numbness and tingling in both hands. A noncontrast CT of the head showed no changes in the right parietal hemorrhagic venous infarct and intraparenchymal hemorrhage; however, there was an interval increase in edema compared to the prior CT. Rivaroxaban and levetiracetam were continued, and 20 mg simvastatin daily was prescribed.
Overview
Cerebral venous sinus thrombosis is a rare condition with an often varied clinical presentation—the symptoms of which can take hours to weeks to evolve, thus making the diagnosis challenging. In 70% of cases, the SSS and lateral sinuses are individually involved, and in 30% of cases, both regions are affected simultaneously.1 Only recently have clinicians been able to diagnose this condition antemortem.
Risk Factors and Etiology
Inherited and Acquired hypercoagulable states
Cerebral venous sinus thrombosis (CVST) and cerebrovascular accident (CVA) often result from a hypercoagulable state (HCS), and both acquired and inherited factors place patients at risk. Inherited factors are the most common cause of venous thromboembolism in patients younger than age 40 years. Acquired factors have a combined effect with inherited ones, leading to increased risk of CVST or CVA.2
The patient in this case possessed both acquired and inherited factors of an HCS. Inherited factors can be found through a thrombophilia evaluation. In general, acquired factors of thrombophilia include obesity, a prior history of thrombosis, pregnancy, and cancer and its treatment. A thrombophilia evaluation revealed the patient was homozygous for the 4G allele, which has been shown to increase concentration of plasminogen activator inhibitor (PAI-1) by 30%. An inhibitor to the pathway of fibrinolysis, PAI-1 is a major factor preventing the excessive presence and magnitude of blood clots.3
Pregnancy and the Puerperium
Cerebral vascular sinus thrombosis is most commonly seen in young to middle-aged women. High risk factors include pregnancy and the puerperium due to increased HCS during these periods.4 The incidence of CVST in this population is approximately 10 per 100,000 women.4
Oral Hormonal Contraceptives
In approximately 10% of CVST cases, oral hormonal contraceptive use in the presence of a coagulation disorder are frequently the cause—as observed in the incidence of DVT in this patient population.
Septic Cerebral Venous Sinus Thrombosis
Septic CVST occurs mainly in children and up to 18% of adult cases in developing countries. It is associated with localized infections (eg, mastoiditis, otitis media, sinusitis, meningitis).
Other Causes
Although rare, other causes of CVST include intracranial hypotension, hydrocephalus, and the use of certain drugs and supplements (eg, corticosteroids, high doses of vitamin A). Each of these potential causes also should be considered when evaluating for CVST.4