16/10/2025
Rabies
( source: The 5-Minute Clinical Consult 2023)
Rabies is a nearly universally fatal viral encephalitis caused by a neurotropic RNA virus (genus Lyssavirus) transmitted via saliva of infected animals, most commonly through bites or scratches .
Initial symptoms are nonspecific: fever, malaise, headache, and paresthesias near the bite site. As it progresses:
• Neurologic phase: agitation, hydrophobia, aerophobia, confusion, seizures, coma
• Paralytic form: ascending flaccid paralysis
Diagnosis is mainly clinical but supported by:
• RT-PCR or immunofluorescence on saliva, corneal smears, or nape-of-neck skin biopsy
• Antibody titers in serum or CSF
• MRI/CT: nonspecific or normal in early stages
• Negri bodies (postmortem) in Ammon horn or cerebellar Purkinje cells 
Diagnosis
Includes rapidly progressive encephalitis and neuromuscular conditions:
• HSV, Japanese encephalitis, West Nile virus
• Botulism, tetanus
• Guillain-Barré syndrome
• Substance intoxication 
• Postexposure prophylaxis (PEP) is effective before symptom onset:
• Wound cleansing with soap and virucidal agents
• Rabies immune globulin (RIG)
• Rabies vaccine (HDCV or PCEC) on days 0, 3, 7, 14, and 28 
• Preexposure vaccination for high-risk individuals
• After symptom onset: treatment is palliative
• Experimental protocols (e.g., Milwaukee protocol) have very limited success 
-Up & Prognosis
• Fatality rate approaches 100% once symptoms appear
• Less than 20 documented survivors—most received some form of immunization
• Survivors may have long-term neurologic impairments
• Animal testing via direct fluorescent antibody on brain tissue is important post-exposure