Cerebral Venous Thrombosis Mimicking Limbic Encephalitis

Abstract

Cerebral venous thrombosis (CVT) is challenging to diagnose, as it presents with variable symptoms. We encountered a complicated case of CVT that mimicked limbic encephalitis due to sensory aphasia. Based on the characteristic magnetic resonance imaging findings, this 72-year-old Japanese man was later confirmed to have CVT, the cause of which was periodontitis due to Eikenella corrodens, a Gram-negative facultative anaerobic that is part of the mouth's normal flora. The symptoms improved without sequelae following anticoagulation treatment and antibiotics. Clinicians should consider CVT as a differential diagnosis when unexplainable neurological symptoms suggesting limbic encephalitis are observed.

Keywords: cerebral venous thrombosis; infectious disease; limbic encephalitis; periodontal infection.

Figure.

The characteristic radiological findings of CVT. A: Head CT showed a high-density area in the straight sinus, suggesting cerebral venous sinus thrombosis (yellow arrowhead). B, C: Brain MRI identified a high signal intensity in the superior sagittal sinus on DWI (yellow arrowhead), and the corresponding area on a T2-weight image was missing the signal void (yellow arrowhead). D: On DWI-MRI, a low signal intensity in the bilateral cerebellar hemisphere was observed, reflecting decreased perfusion in the affected area (yellow arrowheads). E: The ADC values were high in the bilateral cerebellar region (yellow arrowheads). F: On an intracranial 4D-CT venogram, thrombotic occlusion was detected within the left sigmoid, transverse, superior sagittal, and straight sinuses (yellow arrowheads). G: After treatment for a week, the low-DWI-intensity signal in the bilateral cerebellar hemisphere disappeared. H: After treatment for one month, the thrombi in the transverse sinus disappeared on DWI-MRI. I: On MR venography, the thrombi improved, recanalizing the cerebral venous sinus, and collateral circulation emerged in the cerebral venous system.