DD- COMMON VIRAL PATHOGENS Flashcards Preview

BL/DD USMLE and Basics > DD- COMMON VIRAL PATHOGENS > Flashcards

Flashcards in DD- COMMON VIRAL PATHOGENS Deck (64):
1

8 herpesviruses which infect humans

-Herpes simplex virus, type 1 and type 2 (HSV1, HSV2)

– Varicella-zoster virus (VZV)

– Cytomegalovirus (CMV)

– Epstein-Barr virus (EBV)

– Human herpesvirus 6 (HHV6)

– Human herpesvirus 7 (HHV7)

– Human herpesvirus 8 (HHV8)/KSHV

2

Herpesviridae: Following primary infection, the virus establishes a______ in the host (location depends on subfamily) and may reactivate at a later time

latent infection

3

Human herpesvirus 8 (HHV8)/KSHV

herpesviruses which infect humans

4

Herpesvirus structure

Enveloped
- Derived from host membrane

-Virally-encoded glycoproteins are important for binding to host cells

5

Human herpesvirus 6 (HHV6)

herpesviruses which infect humans

6

Herpesvirus structure- Tegument

Contains proteins that are fully formed and active and control viral entry, gene expression, and immune evasion

7

Epstein-Barr virus (EBV)

herpesviruses which infect humans

8

HSV1 and HSV2
Both viruses cause painful vesicles on the ______ at the site of inoculation

skin

9

Cytomegalovirus (CMV)

herpesviruses which infect humans

10

HSV1 is usually associated with _____ lesions

orofacial

11

Varicella-zoster virus (VZV)

herpesviruses which infect humans

12

HSV2 is usually associated with

genital lesions (genital herpes)

13

Herpes simplex virus, type 1 and type 2 (HSV1, HSV2)

herpesviruses which infect humans

14

Transmission of HSV usually occurs through close contact with a person who is shedding virus at

a mucosal surface
in genital/oral secretions

15

Clinical Patterns of HSV Disease

Most primary infections with HSV are silent

Primary HSV-1 infection usually occurs during childhood

16

Primary HSV-1 infection usually occurs during______

childhood

17

Gingivostomatitis

common infection of the mouth and gums

Most common symptomatic infection

Clinical Patterns of HSV Disease

18

Herpetic whitlow

a lesion (whitlow) on a finger or thumb caused by the herpes simplex virus.

Occupational hazard for doctors, dentists, nurses

Clinical Patterns of HSV Disease

19

Encephalitis

Inflammation of the brain, often due to infection

20

_____most common cause of encephalitis in US

HSV

21

Herpes keratitis

Inflammation/infection of the cornea, leading to pain absence of trauma

22

HSV reaches the cornea via the ophthalmic branch of the ______

trigeminal nerve

23

Genital Herpes

Lesions last 10-14 days; usually very painful

Distinct from ulcers caused by syphilis (single hard painless
ulcer) and chancroid (soft painful ulcers associated with swollen inguinal lymph nodes)

24

Neonatal HSV

Serious disease transmitted to a newborn

3 forms:
- Skin, eye and mucous membrane disease (SEM)
- CNS
- Disseminated

25

Following primary infection, HSV enters sensory nerve
endings and travels up the axon and establishes a latent
infection in:

sensory ganglia (alphaherpesvirus)

26

Reactivated lesions are infectious and people often continue to shed virus for a period of time_____ the lesions are healed

after

27

Definitive diagnosis of herpes can be obtained by:

– Viral culture of lesions
– Direct IFA of lesions
– PCR of lesions

28

Oral antiviral therapy (______ or a related antiviral) can be used for oral or genital HSV outbreaks

acyclovir

29

_____ is recommended for pregnant women with active
genital lesions at time of delivery

C-section

30

Prophylactic antiviral suppressive therapy has been shown to decrease outbreaks and viral shedding so is used in some patients, particularly with ______

genital herpes

31

Varicella-Zoster Virus

Varicella or chickenpox
highly contagious

32

acyclovir

Oral antiviral therapy can be used for oral or genital HSV outbreaks

33

Varicella-Zoster Virus
Transmission: highly contagious

– Primarily respiratory via droplet or aerosolized
secretions (coughing, sneezing)

– Contact with lesions

34

Varicella

The classic rash consists of lesions in multiple stages of development on any one part of the body (i.e. vesicles, pustules, scabs/crusts)

35

Complications of varicella

Pregnant women and immunocompromised patients are at high risk for morbidity and mortality

36

_____ has been shown to accelerate the
resolution of chickenpox if the patient presents
within 48-72 hours of onset

Acyclovir

37

__________vaccine is currently recommended for prevention of chickenpox

Live attenuated varicella

38

VZV is the only herpes virus in which asymptomatic viral shedding ______-in normal hosts who experience reactivation

does not occur

39

Herpes zoster or shingles:
occurs in 30% of individuals from

Varicella

40

Post-herpetic neuralgia
(PHN)

complication of shingles, which is caused by the chickenpox (herpes zoster) virus

41

Post-herpetic neuralgia
(PHN)

Debilitating neuropathic
pain that can last weeks to
months

42

Immune response to VZV

-Cell mediated immunity to VZV decreases w/ age

– Incidence of shingles much higher in the elderly and
immunocompromised

– Persons with low cell mediated immunity to VZV at higher risk for VZV reactivation (shingles)

43

Cell mediated immunity to VZV is an important determinant
in who is at risk for

shingles

44

Diagnosis, Chickenpox and shingles are diagnosed
clinically or

– Direct IFA
– HSV and VZV PCR
– Viral culture

45

For shingles, acyclovir given within ______ of onset may decrease lesions and pain

48-72 hours

46

Cytomegalovirus

– Almost all are asymptomatic

Primary infection in immunocompromised persons is serious and CMV can infect most organs (CMV retinitis and colitis in HIV patients)

47

Cytomegalovirus Transmission

A person can become infected with CMV when they
come in contact with infected body fluids

48

CMV infects the ___________, resulting in a persistent infection and intermittent viral shedding

epithelial cells of the salivary gland or the genital tract

49

Congenital CMV Syndrome

• Low birth weight
• Microcephaly
• Hearing loss
• Mental impairment
• Hepatosplenomegaly
• Skin rash (blueberry muffin spots)
• Jaundice
• Chorioretinitis

50

Neonate viral syndromes

neonatal HSV, or congenital VZV and
CMV syndromes.

51

Most common symptomatic primary infection that occurs with HSV-1 infection.

Gingivostomatitis

52

condition where HSV infects the cornea of the eye

Herpes keratitis

can be the result of a primary infection or from reactivation

53

Low birth weight
Microcephaly
Hearing loss
Mental impairment
Hepatosplenomegaly
Skin rash (blueberry muffin spots)-due to extramedullary hematopoiesis in the skin
Jaundice
Chorioretinitis

Congenital CMV Syndrome

54

This is an extremely serious manifestation of herpes disease.

Encephalitis

-can be caused by primary disease or reactivation.

55

Herpes encephalitis can occur either through
blood-borne (hematogenous) spread or ___________ of the virus.

neuronal transmission

56

Herpes infection of the brain results in a fulminant and hemorrhagic, ________.
There is a strong predilection for the temporal lobes of the brain.

necrotizing encephalitis

57

Mortality is about 30% with treatment. HSV-1 causes most cases of childhood and adult.

HSV-2 is the more common cause of neonatal herpes, Associated with maternal genital herpes infections.

Encephalitis

58

Gingivostomatitis is common in

HSV-1

59

Herpes Keratitis is occasional in

HSV-1

60

"Other" virus tests (when clinical doesn't work)

Viral culture of lesions

Direct fluorescent antibody stain of lesions

PCR of lesions (most expensive)

61

Chicken pox (varicella) is a highly contagious and common childhood disease, which is now preventable by vaccination. Chickenpox is primarily transmitted by the _____________ via droplet or aerosolized secretions (coughing, sneezing).

respiratory route

62

Incubation period: It takes from ________ after exposure for someone to develop chickenpox.

10-21 days

63

The initial lesions of_______ might be flat and rose
colored, but they quickly mature into the classic “dew drop on a rose petal” which is a vesicle on an erythematosus base

Chicken pox (varicella)

64

Pathogenesis of Chickenpox- The virus gains entry via the respiratory tract and spreads to the regional_______.

lymphoid system