Poliomyelitis

Snapshot

• A 26-year-old man presents to the emergency department with worsening muscle weakness over the course of 3 days. Prior to developing muscle weakness, he reports acquiring flu-like symptoms, such as a sore throat, myalgias, and headache. Social history is significant for recently emigrating from Pakistan. He does not believe to ever being vaccinated. On physical examination, there is asymmetric proximal muscle weakness of the lower extremities. After extensive workup, his PCR was positive for poliovirus.

Introduction

• Clinical definition
  • flaccid paralysis secondary to poliovirus infection 
• Epidemiology
  • incidence
    • due to mass vaccination, the virus has been eradicated in most of the world
  • risk factors
    • lack of vaccination
• Pathogenesis 
  • this (+) ssRNA virus is spread via the fecal-oral route and
    • replicates and disseminates throughout the body
      • which may involve the motor neurons (e.g., anterior horn cells)
• Prognosis
• 2-10% mortality rate in paralytic poliomyelitis

Presentation

• Symptoms
  • asymptomatic (~70% of cases)
  • flu-like syndrome such as
    • myalgias
    • sore throat
    • headache
  • asymmetric weakness
  • fasciculations
• Physical exam
  • decreased muscle tone
  • decreased or absent reflexes
  • proximal > distal and legs > arm weakness
• normal sensory exam

Studies

• Labs
  • polymerase chain reaction (PCR) of poliovirus RNA
• this is the gold standard

Differential

• Other enteroviruses such as
  • coxsackievirus
• Guillain-Barre syndrome 
• Acute intermittent porphyria 

Treatment

• Conservative
  • supportive treatment
    • indication
      • there is no specific treatment available and thus management is aimed at improving symptoms, such as
        • pain and fever control and physical therapy
          • mechanical ventilation may be needed in cases of respiratory failure
• therefore, it is best to prevent development of poliomyelitis via vaccination

Complications

• Postpolio syndrome
  • occurs years after recovery from poliomyelitis
  • patients present with
    • fatigue, weakness, myalgias, arthralgias, and decreasing functional status