Acute and Subacute Encephalitis

Question 1

Sxs encephalitis

Answer 1

altered level of consciousness, focal neurologic deficits, seizures (both men and enc), coma

Question 2

Significant portion of EE caused by

Answer 2

autoimmune disorders, postinfectious EE caused by immune response to primary infection

Question 3

Most common pathogen of EE

Answer 3

HSV (1 and 2)

Question 4

Major causes of EE

Answer 4

idiopathic, HSV1, HSV2, VZV, postinfectious, TB, autoimmune, enteroviruses (least likely)

Question 5

Minor causes of EE

Answer 5

Arboviruses - geography
Other herpesviruses - IC
JC virus - IC
Resp. viruses
Rabies - Rare
Mumps, measles (primary)
Bacteria (listeria, coxiella, mycoplasma)

Question 6

Differential Dx EE

Answer 6

alphaherpesviruses (HSV, VZV)
Postinfectious immune
TB
Autoimmune
Enteroviruses
Other minor/rare causes

Question 7

Dx EE - suspicious when see

Answer 7

Altered level of consciousness, w/ unexplained fever, seizures, new focal neurological deficits

Question 8

Empiric tx EE

Answer 8

acyclovir for alphaherpesvirus

Question 9

CSF test for EE

Answer 9

WBC count, differential, protein, glucose
also PCR for HSV-1, 2, VZV and enteroviruses, serology
other for more specific testing (IC, geography, etc.)

Question 10

CSF viral EE

Answer 10

WBC high, no banding. Normal protein, normal glucose. PCR and serology.

Question 11

Temporal lobe involvement –>

Answer 11

HSV infection (latent in CN V –> goes back into TL)

Question 12

______ will show neutrophils early in infection

Answer 12

WNV

Question 13

Flaviviruses target

Answer 13

basal ganglia and thalamus

Question 14

Site of latency for alphaherpesviruses

Answer 14

neurons

Question 15

DNA virus - icosahedral nucleocapsid - enveloped - DS DNA linear genome (class I) –>

Answer 15

herpesviridae (HSV1,2 and VZV)

Question 16

Major targets of current antiviral tx for herpesvirus

Answer 16

proteins that are required to promote viral DNA replication (ie viral DNA-dependent DNA polymerase)

Question 17

HSV 1 vs 2 for what they cause and in whom

Answer 17

HSV1 — predominate. encephalitis more in older people.

HSV2 - more common in aseptic meningitis, neonatal

Question 18

Acyclovir spectrum

Answer 18

alpha herpesvirus in reactivation or primary (doesn’t work against latent - need to be replicating)

Question 19

acyclovir prodrug – active

Answer 19

acyclovir = prodrug –> viral thymidine kinase phosphorylates –> cellular GMP kinase phosphorylates –> cellular phosphatase phosphorylates –> active form

Question 20

acyclovir action

Answer 20

block DNA synthesis (picked up by DNA polymerase instead of ddGTP – block synthesis d/t no sugar group off side, no hydroxyl group)

Question 21

Postinfectious EE caused by

Answer 21

measles, mumps, rubella

VZV, influenza

Question 22

ADEM

Answer 22

acute disseminated encephalomyelitis
days to 4 weeks post viral inf
type II hypersensitivity

Question 23

virus - ssRNA- group V - nonsegmented - helical nucleocapsid - enveloped - paramyxovirus - morbillivirus

Answer 23

measles

Question 24

primary measles EE vs ADEM

Answer 24

primary = onset during exanthem
ADEM = weeks to months after measles infection or vaccination - see myelin basic protein in CSF

Question 25

SSPE

Answer 25

subacute sclerosing panencephalitis - slow infection usually in children who contract measles before 2, sx free for 6-15 years, then survive 1-3 years after sxs develop Cannot treat.

Question 26

virus - ssRNA+ group IV - nonsegmented - icosahedral nucelocapsid - nonenveloped

Answer 26

picornavirus ---> enterovirus | * polio, coxsackie, echo, enterovirus