A 55-year-old man has bilateral lower limb weakness progressing over 6 months, upper motor neuron signs (brisk reflexes, Babinski), lower motor neuron signs in the upper limbs (wasting, fasciculations), and dysarthria, but intact sensation and sphincters. MRI brain and spine show no compressive lesion. EMG shows widespread denervation. The MOST appropriate disease-modifying drug with proven survival benefit in this condition is:
- A Interferon beta-1a
- B Levodopa-carbidopa
- C Riluzole 50 mg twice daily (glutamate antagonist) ✓
- D Pyridostigmine
Correct answer: C. Riluzole 50 mg twice daily (glutamate antagonist)
Explanation
This presentation is classic amyotrophic lateral sclerosis (ALS/motor neuron disease): combined upper and lower motor neuron signs at multiple levels (brain, brainstem, spinal cord) with preserved sensation. Riluzole (50 mg twice daily) is the only oral disease-modifying treatment with proven survival benefit in ALS, extending median survival by 2–3 months by reducing glutamate-mediated excitotoxicity. Edaravone (IV or oral) may slow functional decline in a subset of early ALS patients. Interferon is for MS; levodopa for Parkinson's; pyridostigmine for MG.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.