infections of CNS - viral encephalitis and atypical conventional viral infections

Question 1

hallmark symptoms of encephalitis in addition to headache and fever

Answer 1

• brain dysfunction including…
• depressed levels of consciousness
• seizures
• behavior changes
• focal neurologic signs

Question 2

6 major causes of viral encephalitis

Answer 2

1) arbovirus
2) picornavirus
3) myxovirus
4) herpes virus
5) pox virus
6) other

Question 3

how is specific cause of viral encephalitis determined

Answer 3

• symptoms tend to all be the same so must use PCR, antigen detection etc.

Question 4

which type of viral encephalitis is usually epidemic?

Answer 4

arbovirus (arthropod borne)

Question 5

what is the most common non epidemic form of viral encephalitis?

Answer 5

herpes (HSE)

Question 6

herpes encephalitis caused by hsv-1 or hsv-2?

Answer 6

hsv-1

Question 7

HSE portal of entry

Answer 7

• nasal mucosa

- trigeminal ganglion

Question 8

HSE where in the brain?

Answer 8

orbitofrontal and anteromedial temporal cortices

Question 9

HSE pathology

Answer 9

• severe

- inflammation, edema, necrosis, hemorrhage

Question 10

HSE neurological symptoms

Answer 10

• personality changes
• memory loss
• loss of smell and olfactory hallucinations
• hemiparesis or aphasia are possible if unilateral

Question 11

HSE lab findings

Answer 11

CT - may show focal abnormality
MRI - may see changes sooner, but none specific to HSE
EEG - bitemporal slowing and sharp activity
PCR - most accurate and reliable

Question 12

treatment of HSE

Answer 12

• treat while waiting for PCR results

- acyclovir, start ASAP, benign medication

Question 13

most common arboviruses in US

Answer 13

• eastern and western equine
• St. Louis
• California
• West Nile

Question 14

arbovirus incubation period

Answer 14

2-18 days after mosquito bite

Question 15

seasonal incidence of arbovirus

Answer 15

late summer, early autumn

Question 16

rabies incubation period

Answer 16

up to one year

Question 17

parts of brain rabies tends to attack

Answer 17

• limbic system
• hypothalamic area
• brain stem nuclei

Question 18

neurological signs of rabies encephalitis

Answer 18

• agitated delirium
• seizures
• painful spasms of throat musculature

Question 19

treatment of rabies encephalitis

Answer 19

• no treatment after neurological damage is done

- there is early immune treatment

Question 20

west nile and polio similarity

Answer 20

• both can attack motor neurons of spinal cord and brain stem

Question 21

what is the primary difference between the atypical viral infections and the typical acute viral infections?

Answer 21

they cause subacute or chronic disease often after long latent period

Question 22

subacute sclerosing panencephalitis (SSPE) affects mainly whom?

Answer 22

children and adolescents

Question 23

SSPE disease progression

Answer 23

1) mental deterioration
2) myoclonic jerks
3) progressive pyramidal and extrapyramidal involvement
4) death within a few years

Question 24

SSPE CSF

Answer 24

• high gamma globulin

- high measles antibody titer

Question 25

who gets progressive multifocal leukoencephalopathy (PML)?

Answer 25

• the debilitated, mostly lymphoma and AIDS

Question 26

cause of PML

Answer 26

two different papovaviruses (one of which is JC virus)

Question 27

PML pathology

Answer 27

• small areas of demyelination

- inclusion bodies seen in oligodendroglia

Question 28

PML disease progression

Answer 28

• starts with focal cortical signs and progresses to diffuse deterioration
• death in one to two years