Which form of poliomyelitis is most likely to cause respiratory failure?

• A. Abortive poliomyelitis
• B. Nonparalytic aseptic meningitis
• C. Paralytic poliomyelitis with bulbar involvement
• D. Subclinical poliovirus infection

Answer: (C)

Respiratory failure in poliomyelitis is most likely when the virus invades the brainstem, specifically the bulbar region, because that area contains the respiratory centers and the cranial nerves that control breathing and airway protection. When paralytic poliomyelitis involves the bulbar area, these centers and nerves can fail, leading to inability to breathe effectively and requiring ventilatory support.

Other forms do not typically cause this level of respiratory impairment: abortive poliomyelitis is a mild illness with no CNS involvement; nonparalytic aseptic meningitis involves meninges but preserves motor function; subclinical infection shows no symptoms at all. Therefore, bulbar involvement represents the form most associated with respiratory failure.