Snapshot A 10-year-old boy presents to the emergency room after being bit by an animal in a cave. His parents report that they live near some caves that the boy frequently explores. While they are not sure if it was a bat, they are concerned about rabies. On physical exam, there is a small excoriation on his left leg. Otherwise, physical exam is within normal limits. The boy is given the rabies vaccine and immunoglobulin. Introduction Classification rabies virus linear negative single-stranded RNA virus rhabdovirus helical capsid and bullet-shaped transmission via bites from infected animals developed countries bats > raccoons and skunks > dogs developing countries dogs > others via aerosol transmission (rare) bats Epidemiology demographics more common in children majority of cases are in Asia and Africa risk factors interaction with non-domestic animals Pathogenesis long incubation period (weeks to months) replicates in muscle and binds to the nicotinic acetylcholine receptor retrograde migration to central nervous system via dynein motors Associated conditions encephalitic rabies (more common) paralytic rabies Prevention whole virus inactivated vaccine active immunization rabies immunoglobulin passive immunization Prognosis most cases, without early intervention, lead to coma and death within weeks Presentation Symptoms nonspecific prodrome malaise fever headache Physical exam fever encephalitic rabies hydrophobia muscle spasms when offered water leads to “foaming at the mouth” photophobia autonomic dysfunction excess sweating piloerection hypersalivation agitation seizures paralytic rabies quadriparesis bilateral facial weakness late-stage disease paralysis coma death Studies Labs viral studies reverse transcription polymerase chain reaction (RT-PCR) isolation of virus Histology brain biopsy performed post-mortem Negri bodies eosinophilic inclusion bodies in cerebellar Purkinje cells and hippocampal neurons pathognomonic Making the diagnosis based on clinical presentation Differential Botulism distinguishing factor flaccid paralysis without other signs of encephalopathy Temporal lobe (herpes simplex virus-1) encephalitis distinguishing factor disinhibited behaviors such as hyperphagia, hypersexuality, and hyperorality Treatment Management approach give post-exposure prophylaxis immediately when bitten by rabid animal when bite cannot be ruled out once patients are symptomatic, there is no treatment and patients should receive supportive care pain management sedation Conservative wound cleaning indication post-exposure Medical rabies immunoglobulin indication post-exposure prophylaxis Complications Respiratory failure leading to death