Rabies

Background

  • Indication for Prophylaxis
    • Bite or salivary exposure from bat, or mammalian carnivore
    • Close proximity with unknown salivary exposure (e.g. live/dead bat in room)
  • Prophylaxis not needed if non-salivary exposure, or if bird, reptile, or rodent (rare cases)

Clinical Features

Clinical rabies is incredibly rare.
Almost always fatal. Diagnosis frequently made postmortem.
Incubation period ~20-90 days, but may be shorter or longer.

Encephalitic form: hyperexcitability, disorientation, bizarre behavior, hallucinations, autonomic dysfunction (eg, hypersalivation)
Paralytic form: paresis in bitten extremity → quadriparesis, bilateral facial weakness → coma, organ failure
50% of patients may have hydrophobia --> spasms of larynx, pharynx, diaphragm
Death from various complications—eg, pituitary complications, respiratory dysfunction, cardiac dysfunction, autononmic dysfunction.

Differential Diagnosis

Jaw Spasms

Evaluation

Algorithm for Prophylaxis

Animal was captured

Is animal dog or cat?

  • Yes: Observe 10 days, if abnormal, sacrifice and treat patient with the vacc and RIG. Then patient treatment can be discontinued if the animal pathology is negative for rabies
  • No: Sacrifice animal and begin RIG and vaccine. Discontinue if animal negative path for rabies
Animal was not captured

Is Animal dog or cat?

  • Yes: Give vacc and RIG only if rabies risk for species in area
  • No: Treat with full course vacc and RIG

Management

Immunocompetent + NOT Vaccinated

  • Clean the wound (e.g. copious irrigation)
  • Rabies vaccine (human diploid cell vaccine)
    • 1mL IM on days: 0, 3, 7, 14[1]
    • Give in deltoid (not buttock), since Ab not created in fat cells
  • AND, Rabies immune globulin
    • 20 IU/kg subcutaneous
    • Infiltrate around wound if possible
    • place remainder opposite arm of vaccine
    • can administer up to 7 days after the first vaccine dose

Immunocompetent + Vaccinated

  • Clean the wound (e.g. copious irrigation)
  • Rabies vaccine (human diploid cell vaccine)
    • 1mL IM on days: 0 and 3
    • Give in deltoid (not buttock), since Ab not created in fat cells
  • NO rabies immune globulin

Immuno-compromised

  • Clean the wound (e.g. copious irrigation)
  • Rabies vaccine (human diploid cell vaccine)
    • 1mL IM on days: 0, 3, 7, 14, and 28[1]
    • Give in deltoid (not buttock), since Ab not created in fat cells
  • AND, Rabies immune globulin
    • 20 IU/kg subcutaneous
    • Infiltrate around wound if possible, except for digits and the penis
    • Place remainder opposite arm of vaccine
    • Can administer up to 7 days after the first vaccine dose

Disposition

See Also

References

  1. 1.0 1.1 Use of a Reduced (4-Dose) Vaccine Schedule for Postexposure Prophylaxis to Prevent Human Rabies. http://www.cdc.gov/rabies/resources/acip_recommendations.html