Bilateral thalamic lesion presenting as Broca's type subcortical aphasia in cerebral venous thrombosis: index case report

Abstract

A 35-year-old man with a history of multiple substances abuse (alcohol, tobacco and cannabis) presented with acute, severe, holocranial headache associated with nausea and few episodes of vomiting followed by acute onset Broca-type aphasia with intact comprehension from next day, without any other focal neurodeficits, seizure or altered sensorium. Neurological examination was marked by Broca-type aphasia and failure in convergence reaction bilaterally, rest unremarkable. Brain imaging revealed lesions in bilateral thalamus, while magnetic resonance venography showed multiple flow voids in posterior part of superior sagittal sinus and bilateral transverse sinus. A diagnosis of cerebral venous sinus thrombosis was made. Subsequent investigations revealed decreased levels of protein C, protein S and antithrombin III. The patient was started on anticoagulation to which his headache and aphasia recovered completely after 8 and 12 days of therapy, respectively. He is being continued on anticoagulation and is following-up with us for past 4 months uneventfully.

Keywords: neuroimaging; stroke; venous thromboembolism; warfarin therapy.

Figure 1

MRI of the brain T1-weighted image showing bilateral thalamic hypointensities (A) with faint rim enhancement with contrast (B), Diffusion-weighted imaging (DWI) showing restrictions in bilateral thalamus (C), Manetic resonance angiogram (MRA) showing apparently normal anterior and posterior cerebral circulation (D).

Figure 2

MRI of the brain T2-weighted image (A) and T2 fluid-attenuated inverse recovery (B) showing bilateral thalamic hyperintensities without any blooming in gradient recalled echo sequence (C).

Figure 3

Magnetic resonance venography revealed multiple flow voids in posterior part of superior sagittal sinus and bilateral transverse sinus suggestive of venous sinus thrombosis (A, B) and recanalisation following anticoagulation therapy (C).

Figure 4

Schematic representation of role of thalamus in dysphasia: Circuit 1: Thalamus of dominant hemisphere has direct connections with lexical-semantic system, the predominant circuit, disruption leads to fluent aphasia (Wernicke-like aphasia) with semantic paraphasias. Circuit 2: The ventro-anterior and dorso-medial nuclei has reciprocal connections with the frontal cortex via thalamo-cortical and cortico-thalamic connections, disruption of which leads to Broca-type aphasia. Circuit 3: Phonological input can directly lead to lexical output without having to relay to thalamus, thus is least impaired in thalamic lesions and repetition is usually preserved.