USMLE

Measles

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Viruses - RNA Viruses
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Summary

Measles is a paramyxovirus that can present with a variety of symptoms. Prodromal symptoms include the 4 C’s of measles - a cough, coryza, conjunctivitis, and Koplik Spots, which are blue-grey spots visible on the oral mucosa. Measles is transmitted via respiratory droplets or contact and is highly contagious. A few days after onset, patients usually experience a downward-spreading maculopapular rash. In some rare cases, patients experience acute encephalitis. Late stage complications include the feared SSPE or Subacute Sclerosing Panencephalitis, which is usually fatal To treat a severe measles infection, vitamin A supplements are used and have been proven to reduce morbidity and mortality in malnourished children. Finally, prophylaxis for measles include the live-attenuated MMR vaccine, which is administered in children between 12-15 months of age.

Key Points

  • Measles virus
    • Transmission
      • Respiratory droplets or contact
      • Highly contagious
    • Presentation: Measles
      • Prodromal fever with cough, coryza (runny nose), conjunctivitis
        • 4 Cs of measles: cough, coryza, conjunctivitis, “Coplik” spots
      • Koplik spots
        • Bright red spots with blue white center on buccal mucosa
      • Followed 1-2 days later by maculopapular rash
        • Starts at head/neck and spreads downwards
      • Possible sequelae
        • SSPE (subacute sclerosing panencephalitis)
          • Occurs years after initial infection and apparent recovery
          • personality changes, dementia, autonomic dysfunction, death
          • High titers of measles antibodies in serum and CSF
        • Acute Encephalitis (1:1000)
          • Symptoms occur within a few days of rash
        • Acute Cerebellitis (post-viral cerebellar ataxia)
          • Occurs 2-3 weeks after infection with cerebellar symptoms (ataxia, nystagmus)
        • Giant cell pneumonia
          • rare except in immunosuppressed
        • Pneumonia
          • Most common cause of measles-associated death in kids
    • Diagnosis
      • Biopsy of lymph nodes shows Warthin-Finkeldey giant cells (fused lymphocytes) in background of paracortical hyperplasia
      • Acute rise in anti-measles IgM, IgG, or RT-PCR used to confirm diagnosis
    • Treatment
      • Vitamin A → reduces morbidity and mortality, esp. In malnourished children
    • Prophylaxis
      • MMR (Measles, Mumps, Rubella) vaccine - live attenuated
        • Administered at 12-15 months of age