Poliomyelitis is a disease of the anterior horn motor neurons of the spinal cord and brainstem caused by the poliovirus.
-Anterior horn cells control the skeletal muscle cells of the trunk and limbs
-In up to 95% of cases, poliovirus infection is asymptomatic
-the viral transmission is oral to oral or fecal to oral
-Acutely, the polio virus enters the body through the GI tract, reproduces in the GI lymphoid tissue, and then spreads to the large motor nuclei of the spinal cord, the brainstem, reticular formation, hypothalamus, thalamus, cerebellum and cerebral cortex.
Symptoms & Signs
Thankfully, not every polio infection results in paralysis. It can be divided into following types based on the severity.
Abortive poliomyelitis: fever, headache, vomiting, diarrhea, constipation, and sore throat lasting 2–3 days.
Nonparalytic poliomyelitis: Above symptoms plus meningeal irritation and muscle spasm but no frank paralysis
Paralytic poliomyelitis:
Asymmetrical paralysis; Proximal limb muscles are more often involved than distal, and lower limb involvement is more common than upper.
1.Spinal poliomyelitis: involves the muscles innervated by the spinal nerves, flaccid and weak muscles, absent tendon reflexes and fasciculations
- Bulbar poliomyelitis: involves the muscles innervated by the cranial nerves IX and X; seen in up to 20 percent of polio patients with paralysis; affects swallowing, speech, facial muscles
Post-poliomyelitis syndrome: Fatigue, pain, respiratory problems, sleep problems, increased risk of falls
Guillain-Barré syndrome: Always think of GBS in the differential diagnosis of polio paralysis. GBS is distinguished from polio by its symmetry, disturbances in sensation, lack of preceding aseptic meningitis, absence of a CSF pleocytosis, presence of multifocal demyelination on electrodiagnostic testing
Diagnosis
Virus isolated and typed from throat swabs and rectal swabs; PCR amplification of poliovirus RNA from the CSF
Treatment
Treatment of poliomyelitis is supportive
-Pain relief, physical therapy
-Mechanical ventilation for respiratory failure
–Intubation or tracheostomy for secretion control
Prevention
the trivalent live OPV, the inactive (Salk) parenteral vaccine is currently used in the United States for all four recommended doses (at ages 2 months, 4 months, 6–18 months, and at 4–6 years).