infectious diseases
Poliomyelitis
Symptoms and Signs of Poliomyelitis
Most (70 to 75%) poliovirus infections cause no symptoms (seeCenters for Disease Control and Prevention: Epidemiology and Prevention of Vaccine-Preventable Diseases, Poliomyelitis). Symptomatic disease is classified as Abortive poliomyelitis Paralytic or nonparalytic poliomyelitis Most symptomatic infections, particularly in young children, are minor, with 1 to 3 days of slight fever, malaise, headache, sore throat, and vomiting, which develop 3 to 5 days after exposure. There are no neurologic symptoms or signs, and physical examination is unremarkable except for the presence of fever. About 1 to 5% of patients with poliovirus infection develop nonparalytic central nervous system involvement with Aseptic meningitis (see Paralytic poliomyelitis occurs in < 1% of all poliovirus infections. It can manifest as a biphasic illness in infants and young children with a paralytic phase occurring several days after resolution of abortive poliomyelitis symptoms. Incubation is usually 7 to 21 days. Common manifestations of paralytic poliomyelitis in addition to Aseptic meningitis include deep muscle pain, hyperesthesias, paresthesias, and, during active myelitis, urinary retention and muscle spasms. Asymmetric flaccid paralysis may develop and progress over 2 to 3 days. Encephalitic signs occasionally predominate. Dysphagia, nasal regurgitation, and nasal voice are usually the earliest signs of bulbar involvement, but some patients have pharyngeal paralysis and cannot control oral secretions. As with skeletal muscle paralysis, bulbar involvement may worsen over 2 to 3 days and, in some patients, affects the respiratory and circulatory centers of the brain stem, leading to respiratory compromise. Infrequently, respiratory failure develops when the diaphragm or intercostal muscles are affected. Some patients develop Postpoliomyelitis Syndrome years or decades after paralytic poliomyelitis. This syndrome is characterized by muscle fatigue and decreased endurance, often with weakness, fasciculations, and atrophy. 