Rabies Vaccination
Hey all,
I’m mostly going to be doing POTD’s on topics I’ve accumulated throughout the year that I wanted to look into but never actually did. So, prepare for quite a few fast track complaints (unless I get a request for a topic – just e-mail/text me!).
Anyways, let’s talk about rabies. I’m sure everyone has heard or experienced a great rabies case in their career. No? That’s because since 1980 there has only been about 2-3 reported cases a year in the US, with ~30% of them related to US travelers returning abroad. It is an almost universally fatal disease if contracted but is also 100% preventable if an exposure is identified and given the proper prophylaxis.
So…briefly about rabies…
Epidemiology
- Estimates 59,000 deaths worldwide, mostly due to inadequate control of rabies in domesticated animals
- Transmission usually through exposure from saliva from an animal bite
o No history of transmission from infected patients to healthcare personnel (though personally I look forward to the coming zombie apocalypse)
- Normal reservoirs: ?dogs/cats to some extent, mostly bats, foxes, skunks, and raccoons
- Incubation period: 1-3 months on average, though can occur several years later
Clinical Manifestations
- Prodromal phase (~1 week): Non-specific low grade fever, chills, myalgias, malaise, fatigue, anorexia, sore throat, nausea, vomiting (COVID is that you?)
- Clinical rabies: Encephalitic (80%) vs. Paralytic
o Encephalitic = “classic” rabies
Fever
Hydrophobia
Autonomic instability – hyperthermia, lacrimation, hypersalivation
Pharyngeal spasms and hyperactivity stupor, coma, and death
Agitation, aggression, combativeness
o Paralytic = Less than 20%
Ascending paralysis not unlike Guillain-Barre Syndrome
As paralysis ascends, respiratory muscles lose tone and respiratory failure and death occurs
After learning more about this, it’s possible some of us HAVE seen rabies and it’s never diagnosed…….. (I’ll definitely be putting it in my MDM from now on)
Diagnosis
- As always, a good history and physical is paramount any of the above symptoms surrounding an animal bite is suggestive of rabies
- Lab diagnosis – requires multiple samples from saliva, skin, serum, or CSF using multiple modalities (sensitivity of a single test not that high) likely unimportant in the ED
- Post-mortem – examining brainstem or other neural tissue directly
Differential – aka all of these are 1000% more likely than rabies
- ANY OTHER CAUSE OF ENCEPHALITIS (West Nile, herpes, autoimmune, etc.)
- Tetanus (another very common disease that we see frequently)
Treatment – almost universally ends in death. 29 well-documented cases of survival. Survival usually still causes severe neurological sequelae
- The treatment is always proper prophylaxis
- Palliation (not joking)
- Supportive care/ICU level care and strategies = no good evidence/way above our level of care in the ED.
Hopefully you’ve learned a little more than you already did about rabies (although the key clinical symptom does appear to be hydrophobia). I, for one, will be splashing Mak with a little bit of water every day until he becomes agitated and then send him to the ED to be treated for rabies.