Table Of Contents
Rabies
Rabies is caused by the Rabies virus (genus Lyssavirus), which commonly inhabits the salivary glands and brain. It is spread through bites or licks on injured tissue, typically from infected animals (dogs, bats, etc.). Rabies has an unpredictable incubation period, occurring days to months after inoculation (shorter onset if the bite is to the head and neck). Diagnosis is clinical. Only a few humans exposed develop the disease. However, once symptoms develop, rabies is almost certainly fatal.
Phases of rabies
| Phase | Feautres |
|---|---|
| Prodrome (2 – 10 days) | Fever, malaise, headache, paraesthesia at bite site |
| Acute neurologic phase | |
| Furious (80%) | Hydrophobia, aerophobia, hyperactivity, hypersalivation, sweating |
| Paralytic (20%) | Flaccid paralysis (like Guillain-Barre syndrome) |
| Coma and death | Within 7-10 days of symptom onset. 100% fatal once symptomatic. |
- Pathogenesis
- Virus enters peripheral nerves and travels retrograde to the CNS
- Spreads centrifugally to the salivary glands, skin and cornea
- Early signs and symptoms
- Anxiety
- Hydrophobia (violent contractions of the diaphragm and respiratory muscles on sight or attempt to drink water)
- Late signs and symptoms
- Hallucinations
- Mania
- Spitting
- Biting
- Lucid intervals
- Focal neurological deficitis
- Generalised paralysis
- Treatment of rabies (post-exposure prophylaxis)
- Wound debridement
- Human rabies immune globulin (safest) or Equine rabies immune globulin
- Rabies vaccine
- 4 doses (day 0, 3, 7, 14) if immune-competent
- 5 doses (day 0, 3, 7, 14, 28) if immune-compromised
- Induce therapeutic coma using the Milwauke protocol: Ketamine + ribavirin
- Prevention of rabies
- PEP vaccine for high-risk group (vets and travellers): human diploi cell strain at 0, 3, 7, 14, 30 and 90 days
