What is the typical distribution pattern of paralysis in poliomyelitis compared with other causes of acute flaccid paralysis?

• A. Polio causes symmetric paralysis
• B. Polio tends to cause asymmetric, focal paralysis; other AFP may be symmetric
• C. Polio affects only the sensory nerves
• D. Other AFP causes always cause symmetrical weakness

Answer: (B)

The key idea is how paralysis is distributed across muscles in poliomyelitis compared with other acute flaccid paralysis causes. Poliomyelitis typically damages anterior horn motor neurons in a limited region of the spinal cord, so weakness shows up in a focal, often asymmetric pattern—one limb or a specific muscle group may be affected, with sensation usually spared. This focal, uneven spread stands in contrast to many other AFP etiologies, such as Guillain-Barré syndrome, which commonly produce symmetric weakness that involves both sides and many muscle groups, often progressing proximally. So the characteristic description for polio is asymmetric, focal paralysis, while other AFP causes are more likely to be symmetric.