ABDUCENS NERVE PALSY AND THROMBOSIS OF THE CEREBRAL VEINS AND SINUSES - A DIAGNOSTIC PITFALL

Thrombosis of the cerebral veins and sinuses is an infrequent cerebrovascular disorder. Because the highly variable symptoms, recent neuroimaging plays a key role in the diagnosis. Abducens nerve palsy as a focal neurological deficit is a rare clinical manifestation in these patients. We present two cases with sudden onset of diplopia and headache. Case 1: A 3-year old girl with B cell lymphoblastic leukemia developed bilateral abducens deficit and bilateral optic disc edema after treatment including L-asparaginase. Thrombosis of the right jugular vein, sagittal and right sigmoid sinuses was visualized on magnetic resonance imaging (MRI) and magnetic resonance venography (MRV). Symptoms gradually resolved after treatment with enoxiparine and MRV demonstrated recanalization. Case 2: A 75-year old female with medical history of arterial hypertension presented with headache and sudden left abduction deficit. Computerized tomography (CT) scan was normal. MRI and MRV revealed aging brain and disruption of venous flow at the left internal jugular vein, suspecting thrombosis. Extracranial colour duplex sonography and CT angiography proved haemodinamic equivalent of left internal jugular vein thrombosis due to sclerotic pathology of aortic arch. Our first case illustrates the role of improved neuroimaging techniques as the best method for diagnosis of cerebral veins and sinuses thrombosis, presenting with abducens nerve palsy. With second case the potential neuroimaging pitfalls concerning the accurate diagnosis of these cerebrovascular disorders with neuro-ophthalmologic manifestation are discussed.