RABIES

Question 1

• rapidly progressive, acute infectious disease of the central nervous system (CNS) in humans and animal
• infection normally transmitted from animal vectors
• encephalitic and paralytic forms that progress to death

Answer 1

RABIES

Question 2

• single-strand RNA virus
• nonsegmented, negative-sense (antisense) genome that consists of 11,932 nucleotides
• encodes 5 proteins: nucleocapsid protein, phosphoprotein, matrix protein, glycoprotein, and a large polymerase protein.

Answer 2

Rabies

Question 3

Transmission of Rabies

Answer 3

Bite of an infected animal

Question 4

Location where human disease of rabies is usually associated with transmission from bats

Answer 4

North America

Question 5

incubation period of rabies

Answer 5

20-90 days, but in rare cases is either as short as a few days or >1 year.

Question 6

• most characteristic pathologic finding in rabies

- are not observed in all cases of rabies

Answer 6

Negri bodies

Question 7

has led to the concept that neuronal dysfunction—rather than neuronal death—is responsible for clinical disease in rabies

Answer 7

lack of prominent degenerative neuronal changes

Question 8

GENERAL CLINICAL MANIFESTATIONS OF RABIES

Answer 8

atypical encephalitis with relative preservation of

consciousness

Question 9

Clinical Stages of Rabies

• 20-90 days
• NO Ssx

Answer 9

Incubation period

Question 10

Clinical Stages of Rabies

• 2-10 days
• Fever, malaise, anorexia, nausea, vomiting; paresthesias, pain, or pruritus at the wound site

Answer 10

Prodrome

Question 11

Acute Neurologic Disease

• 2-7 days
• Anxiety,
• agitation,
• hyperactivity,
• bizarre behavior,
• hallucinations,
• autonomic dysfunction,
• hydrophobia

Answer 11

Encephalitic (80%)

Question 12

Acute Neurologic Disease
- 2-10 days
- Flaccid paralysis in limb(s) progressing to quadriparesis
with facial paralysis

Answer 12

Paralytic (20%)

Question 13

Acute Neurologic Disease

Coma, death Duration

Answer 13

0-14 days

Question 14

• distinguished by earty brainstem involvement,
  = results in the classic features of hydrophobia and aerophobia
• Autonomic dysfunction is common and may result in hypersalivation, gooseflesh, cardiac arrhythmia, and priapism.
• episodes of hyperexcitability are typically followed by periods of complete lucidity that become shorter as the disease progresses
• These symptoms are probably due to dysfunction of infected brainstem neurons that normally inhibit inspiratory neurons near the nucteus ambiguus, resulting in exaggerated defense reflexes that protect the respiratory tract.

Answer 14

ENCEPHALITIC RABIES

Question 15

• About 20% of patients have
  = muscle weakness predominates and cardinal features of encephalitic rabies (hyperexcitability, hydrophobia, and aerophobia) are lacking.
• early and prominent flaccid muscle weakness, often beginning in the bitten extremity and spreading to produce quadriparesis and facial weakness

Answer 15

PARALYTIC RABIES

Question 16

LAB INVESTIGATION

Answer 16

• ANIMAL TESTING
• LUMBAR PUNCTURE
• SKIN BIOPSY
• BLOOD TEST
• HEAD MRI or CT Scan

Question 17

Diagnostically useful specimens

Answer 17

• serum,
• CSF,
• fresh saliva,
• skin biopsy samples from the neck, and brain tissue (rarely obtained before death).

Question 18

tests never exclude a diagnosis of rabies, and tests may need to be repeated after an interval for diagnostic confirmation

Answer 18

Negative antemortem rabies-specific laboratory tests

Question 19

In a previously unimmunized patient, ___ to rabies virus

are diagnostic.

Answer 19

serum neutralizing antibodies

Question 20

The presence of rabies virus-specific neutralizing antibodies in the CSF suggests ___, regardless of immunization status.

Answer 20

rabies encephalitis

Question 21

A diagnosis of rabies is ___ in patients who recover from their illness without developing serum neutralizing antibodies to rabies virus

Answer 21

questionable

Question 22

• Detection of rabies virus RNA by RT-PCR is highly sensitive and specific.
• can detect virus in fresh saliva samples, skin biopsy specimens, CSF, and brain tissues
• RT-PCR with genetic sequencing can distinguish among rabies virus variants, permitting identification of the probable source of an infection

Answer 22

RT-PCR AMPLIFICATION

Question 23

• highly sensitive and specific for the detection of rabies virus antigen in tissues;
• the test can be performed quickly and applied to skin biopsy and brain tissue samples
• In skin biopsy samples, rabies virus antigen may be detected in cutaneous nerves at the base of hair follicles.

Answer 23

DIRECT FLUORESCENT ANTIBODY TESTING

Question 24

treatment for rabies

Answer 24

• no established treatment
• ## Aggressive management with supportive care in critical care units has resulted in the survival of more than 15 patients with rabies.

Question 25

If RIG is not immediately available, it should be administered no later than ___ after the first vaccine dose.

Answer 25

7 days

Question 26

• ____ 1-mL doses of rabies vaccine should be given IM in the deltoid area
• Ideally, the first dose should be given as soon as possible after exposure; failing that, it should be given without further delay.
• The three additional doses should be given on days _____; a fifth dose on day __ is no longer recommended

Answer 26

• Four
• 3, 7, and 14
• 28

Question 27

may interfere with the development of active immunity and should not be administered during PEP unless they are essential.

Answer 27

Glucocorticoids and other immunosuppressive medications

Question 28

If human RIG is unavailable, ___ can be used in the same manner at a dose of 40 IU/kg.

Answer 28

purified equine RIG

Question 29

The primary schedule consists of three doses of rabies vaccine given on days

Answer 29

O, 7, and 21 or 28

Question 30

help determine the need for subsequent booster doses

Answer 30

Serum neutralizing antibody tests

Question 31

When a previously immunized individual is exposed to rabies, two booster doses of vaccine should be administered on days

Answer 31

0 & 3

Question 32

RIG should not be administered to previously

Answer 32

vaccinated persons.