RABIES ILLNESS CLINICAL NOTES

Incubation: Several days – 19 yrs

Avg:First 90d (75%)

< 30d (25%)

30 – 90d (50%)

90d – 12mo. (20%)

> 1yr (5%)

Initial Symptoms:

Systemic: As with other viral infections:Fever

(4 – 10 days)H/A

Malaise

Upper respiratory/GI sx’s

Myoedema (mounding of part of muscle after reflex hammer strike, extincting in seconds)

Neuro: Personality/Cognitive Changes

Pain/Paresthesias – exposure site

2 – 14 days to coma

“Furious” Rabies (80% of cases):Hydrophobia

Aerophobia

Delirium

Agitation

Hydrophobia: exaggerated irritant reflex of the respiratory tract (? Nucleus ambiguous)

Description by Sir William Gowers (excerpts),

Discomfort about throat

Choking sensation

Liquid dysphagia (pharynx spasm spreading to muscles)

Short, quick inspiration; a “catch in the breath”

Strong inspiratory effort with accessory respiratory muscles and mouth

angles outward and shoulders raised

Increasing respiratory/pharynx spasm severity and sensitivity (to provoke);

brought on by mere water contact on lips or a draught of air on hyperesthetic skin

Inability to swallow saliva, abundant and viscid (hanging on mouth)

Vomiting common

Attacks very distressing to patient – increasing attacks, such that even

sight of water causes attack

Strong light or visual image (mirror reflection) provoking attacks

Sufferer’s horror/dread of attack becomes intense

Disordered swallowing causes mental disturbance and other extensive

muscle spasms

Spasms first only with muscles of deglutition and respiration, then to other

muscles and finally spasmodic paroxysms (convulsive) at first respiratory,

then general (tetanoid rigidity/opisthotonus)

Delusions/Wild Delirium – mental derangement, worst during paroxysms,

and frenzied patient spits saliva at others and attempts to bite; strange

dog-like barking

Other Episodic Neuro Phenomena: Hyperactivity

Seizures

Aerophobia

Hyperventilation, then periodic/ataxic

breathing, then apnea

SIADH (Syndrome of Inappropriate Anti Diuretic Hormone)

Apnea

Other: Cardiac arrhythmias

Autonomic dysfunction

– piloerection

– sweats

– pupillary dysfunction

– increased salivation

– priapism/ejaculation

Death:   Within 1-2 weeks of coma FR, with strong medical support, passes through PR phase

Paralytic(Dumb) Rabies (PR)

– No hydrophobia, aerophobia, hyperactivity, or seizures

Initial: Ascending paralysis (like Guillain-Barré syndrome) or symmetric quadriparesis

Weakness may be most severe in bitten limb.

Later: Meningeal signs (sometimes prominent)

Confusion

Coma

Death usually due to myocarditis with arrhythmias or CHF

Total time to death from illness onset averages 0 – 14 days