Six weeks after a stroke causing dense numbness of the right side, a 62-year-old woman reports severe burning, stabbing pain on the right, triggered by light touch of clothing, with exaggerated emotional response to the discomfort. Examination shows right-sided hypersensitivity to pinprick. This syndrome results from involvement of:

• A Postcentral gyrus, areas 3, 1 and 2
• B Ventroposterolateral and posteromedial nuclei of the thalamus ✓
• C Spinothalamic tract in the midbrain tegmentum
• D Medial lemniscus in the pons

Explanation

Dejerine-Roussy thalamic pain syndrome follows infarction of the ventroposterolateral and posteromedial nuclei. Initial contralateral hemianaesthesia evolves into spontaneous burning pain with allodynia and hyperpathia. B cortical postcentral gyrus lesion produces loss of discrimination without this severe affective allodynia because cortical sensory loss does not recruit the thalamic-cingulate pain network responsible for the emotional amplification characteristic of the syndrome.

Reference: Gray's Anatomy for Students, 4th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.