Poliomyelitis

(Redirected from Poliovirus)

Background

  • Neurotropic enterovirus
  • Extremely rare in developed world, targeted for global eradication by WHO
  • Still endemic in Pakistan, Afghanistan, and Nigeria
  • Fecal-oral transmission, virus enters through GI tract then reproduces in GI lymphoid tissues
  • If virus reaches critical concentration, can spread to motor nuclei of spinal cord, brainstem, and reticular formation → loss of infected neurons→ cycle of muscle denervation/reinnervation→ loss of muscle function

Clinical Features

  • >90% of infections are asymptomatic
  • Minor (abortive) polio:
  • Non-paralytic polio:
  • Paralytic (spinal) polio (~1-2% of polio infections)
    • Neuro symptoms may manifest after resolution of initial febrile illness
    • Maximal paralysis at around 5 days, muscle wasting after several weeks, with most patients' paralysis resolving after about 1 year
    • Flaccid muscle weakness/paralysis
    • Fasciculations
    • Absent or decreased reflexes
    • Autonomic dysfunction (e.g. sweating disturbances, urinary retention, constipation
    • Neuropathic pain, paresthesias, though usually no sensory deficits on exam
    • Bulbar dysfunction in about 20% of spinal polio (dysphagia, dysarthria, facial weakness)
    • Encephalitis: can cause reticular formation disturbances, resulting in dysrhythmias, BP lability, hypoxia, and hypercarbia
  • Post-polio syndrome
    • Occurs sometime after complete resolution of initial acute symptoms
    • Can involve same muscle groups affected during patient's acute illness, as well as those not affected during initial viral infection
    • Symptoms include muscle weakness, atrophy, fasciculations, fatigue, insomnia, joint pain, bulbar dysfunction, respiratory dysfunction

Differential Diagnosis

Evaluation

  • Evaluate for other causes of symptoms
  • PCR: virus can be identified in throat washings (early), CSF (early), and stool/rectal swab (highest yield)
  • CSF: Pleocytosis (PMN predominance initially, then mostly lymphocytes), usually ~normal opening pressure, protein, and glucose.

Management

  • Protect airway, support respiration if bulbar or respiratory muscle weakness
  • Supportive care, symptomatic treatment

Disposition

  • Admit

See Also

External Links

References

Authors:

Claire