Clinical Features and Diagnosis of Rabies

Introduction to Rabies

Rabies presents as an acute encephalomyelitis that almost always progresses to coma or death within 10 days after the first symptom, manifesting in two distinct clinical forms: furious (encephalitic) rabies in 80% of cases and paralytic (dumb) rabies in 20% of cases, as reported by the Centers for Disease Control and Prevention (CDC) 1, 2

The incubation period typically lasts 1-3 months but can range from days to over a year, with an average of one to two months, according to the World Health Organization (WHO) 3

Hydrophobia is pathognomonic for rabies: terror and violent spasms of the inspiratory muscles, larynx, and pharynx precipitated by attempts to drink water or even by the sight or sound of running water, as described by the Infectious Diseases Society of America (IDSA) 2, 4
Intermittent episodes of agitation, hyperexcitability, and bizarre behavior alternating with periods of lucidity, as reported by the CDC 2, 4
Disorientation progressing to stupor and coma, according to the IDSA 2, 4

Ascending flaccid paralysis resembling Guillain-Barré syndrome, starting from the bitten extremity, as described by the IDSA 2, 4

Patients become extremely agitated in the presence of stimuli such as loud noises, air currents, and running water during the acute neurologic phase, as reported by the CDC 6
Death typically occurs within 7 days of symptom onset, according to the WHO 6
Rabies is not considered curable once clinical symptoms appear, with only 6 documented human survivors, and 5 of these had received vaccination before symptom onset, as reported by the IDSA 8

MRI may show nonenhancing focal lesions in basal ganglia, thalami, and brainstem, as described by the IDSA 2, 4, 7
When a definitive diagnosis is obtained, primary health considerations should focus on comfort care and adequate sedation in an appropriate medical facility, as recommended by the CDC 6