Isolated lateral sinus thrombosis: 43 cases
Background and Objective: Since the preantibiotic era, where isolated lateral sinus thrombosis (isolated LST) was known as “otitic hydrocephalus”, little attention has been paid to this variety of cerebral venous thrombosis (CVT). We therefore reviewed all cases of isolated LST prospectively collected in our center over 25 years. Methods: Among 185 patients with CVT examined between 1975 and April 2000, we identified 135 patients with LST and among them 43 patients with isolated LST. Diagnosis was based on conventional angiography and/or magnetic resonance imaging and/or helical cerebral CT venography. Clinical, etiologic and prognostic features were studied and compared with those of the other 142 CVT cases. Results: 43 patients (23%; 28 female, 15 male) had isolated LST: right in 17, left in 25, bilateral in 1. The main clinical symptoms were headache (88%), papilledema (44%), seizures (28%), motor or sensory deficit (19%), multiple cranial nerves palsy (19%), altered consciousness (9%), dysphasia (9%). The single common pattern of presentation was isolated intracranial hypertension in 20 patients (47%). Four patients had isolated headaches (9%) and 19 (44%) had at least one focal sign (deficits and/or partial seizures). Compared with the other 142 CVT cases, presentation with isolated headaches or intracranial hypertension was more frequent (p=0.02) and altered consciousness or partial seizure less common (p=0.01; p=0.004). Numerous causes or predisposing factors were identified among them septic and local causes represented respectively 14% and 19%. The association of both was significantly more frequently found that in other CVT patients (p=0.01). Treatment consisted of anticoagulation in 32 patients (74%). Complete recovery occurred in 37 patients (86%), 5 patients had sequelea (12%) and 1 died of a carcinoma (2%), compared with respectively 71.5%, 24% and 4.5% for the other 142 CVT cases (no significant difference). Conclusion: The isolated LST is a frequent variety of CVT, presenting in a majority of cases with isolated intracranial hypertension or headache. Septic and local causes are more frequent that in other variety of CVT and require specific treatment. Its prognosis is usually good.