A dissociated sensory loss is seen in: (A) Syringomyelia, (B) Vitamin B12 deficiency, (C) Transverse myelitis, (D) Pellagra
Answer is A. Impairment of pinprick and temperature appreciation but relative preservation of light touch, position sense and vibration senseA dissociated sensory loss can reflect spinothalamic tract involvement in the spinal cord, especially if the deficit is unilateral and has an upper level on the torsoBilateral spinothalamic tract involvement occurs with lesions affecting the center of the spinal cord, such as in syringomyeliaRef: Davidson's 21/e p1157