Rabies
Background
- Almost always fatal (diagnosis frequently made postmortem)
- 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.
- Incubation period = ~20-90 days, but may be shorter or longer
Encephalitic form
- Hyperexcitability, disorientation, bizarre behavior, hallucinations
- Autonomic dysfunction (e.g. hypersalivation)
Paralytic form
- Paresis in bitten extremity → quadriparesis, bilateral facial weakness → coma, organ failure
- Hydrophobia (50%) --> spasms of larynx, pharynx, diaphragm
- Aerophobia (9%) --> spasms of larynx, pharynx, diaphragm in response to drafts of air (pathognomonic)[1]
- Death from various complications: pituitary complications, respiratory dysfunction, cardiac dysfunction, autonomic dysfunction.
Differential Diagnosis
Jaw Spasms
- Acute tetanus
- Akathisia
- Conversion disorder
- Drug toxicity (anticholinergic, phenytoin, valproate, carbamazepine)
- Dystonic reaction
- Electrolyte abnormality
- Hypocalcemic tetany
- Magnesium
- Mandible dislocation
- Meningitis
- Peritonsillar abscess
- Rabies
- Seizure
- Strychnine poisoning
- Stroke
- Temporomandibular disorder
- Torticollis
Evaluation
Algorithm for Prophylaxis
Animal was captured
Is animal dog or cat?
- Yes: Observe 10 days, if abnormal, euthanize and treat patient with the vaccine and RIG. Then patient treatment can be discontinued if the animal pathology is negative for rabies
- No: Euthanize animal and treat patient with vaccine and RIG. Discontinue if animal pathology is negative for rabies
Animal was not captured
Is animal dog or cat?
- Yes: Give vaccine and RIG only if rabies risk for species in area
- No: Treat with full course vaccine and RIG
Management
Prophylaxis
Immunocompetent + NOT Vaccinated
- Clean the wound (e.g. copious irrigation)
- Rabies vaccine (human diploid cell vaccine)
- 1mL IM on days: 0, 3, 7, 14[2]
- 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[2]
- 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
- Patient needing prophylaxis: outpatient
- Clinical rabies: admit
See Also
References
- ↑ Petersen BW, Rupprecht CE. Human Rabies Epidemiology and Diagnosis. US Centers for Disease Control and Prevention, 2011. https://www.intechopen.com/books/non-flavivirus-encephalitis/human-rabies-epidemiology-and-diagnosis (Accessed on January 15, 2021).
- ↑ 2.0 2.1 Use of a Reduced (4-Dose) Vaccine Schedule for Postexposure Prophylaxis to Prevent Human Rabies. http://www.cdc.gov/rabies/resources/acip_recommendations.html