A rare presentation of trigeminal neuralgia in lateral medullary syndrome

Sir, According to the International Classification of Headache Disorders - 3 (ICHD-3), painful trigeminal neuropathy (PTN) is commonly caused by vascular compression on the trigeminal nerve; however, it may also be caused by a structural lesion or a plaque associated with multiple sclerosis. A 73-year-old lady presented with a history of acute-onset giddiness, vomiting, clumsiness in the left hand and leg, gait unsteadiness, and numbness on the right half of her body. Cranial nerve examination showed a left-sided horizontal gaze evoked nystagmus, left-sided Horner's syndrome, and cerebellar dysarthria; there was no bulbar involvement. Sensory examination revealed impaired sensation to touch and pain on the left side of the face and right half of the body, impaired joint position and vibration sense in the left upper and lower limbs, and cerebellar signs on the left side. [3] She showed a significant decrease in the frequency and intensity of pain with a pain scale score of 2 out of 10, and its frequency was reduced to 1-2 episodes per day at the time of discharge. [6] Classical TN is usually attributed to neurovascular compression by a blood vessel, with demyelinating plaques associated with multiple sclerosis, space occupying lesions in the posterior fossa,...