Which disease is described by an insidious onset of muscle weakness that progresses to muscle atrophy and paralysis?

• A. Bell's Palsy
• B. Encephalitis
• C. Amyotrophic Lateral Sclerosis
• D. Alzheimer's Disease

Answer: (C)

This pattern points to a motor neuron disease where nerve cells controlling voluntary muscles gradually deteriorate, leading from subtle weakness to marked muscle wasting and eventually paralysis. In amyotrophic lateral sclerosis, both upper motor neurons (causing spasticity and hyperreflexia) and lower motor neurons (causing weakness, atrophy, and fasciculations) are affected. The weakness often starts in the limbs and progresses over time, with bulbar involvement (speech, swallowing) and respiratory muscle weakness developing later. This progression to widespread muscle atrophy and paralysis is not typical of Bell’s palsy (sudden facial nerve weakness), encephalitis (fever and altered mental status), or Alzheimer's disease (primarily cognitive decline). So this description best fits amyotrophic lateral sclerosis.