viral Dx Dan

Question 1

T/F

maternal herpes zoster puts the foetus at risk

Answer 1

False
varicella does
zoster does not
although if occurs peripartum there is risk of neonatal varicella but transmission rates much lower than with varicella (chickenpox)

Question 2

What is the risk of peripartum maternal VZV infection?

Answer 2

If occurs 4 days before to 2 days after term risk of neonatal varicella (as it is infectious for 2 days before symptoms)
- causes severe primary varicella infection in neonate and mortality of 30%

Question 3

What is management of asymptomatic non-immune woman exposed to varicella in pregnancy?
what if she develops varicella?

Answer 3

If exposed check if truly seronegative - if never tested do the serology test in case she is actually immune already;
if seronegative or testing not possible offer VZIg to start ASAP (ideally within 3 days but effective if given up to 10 days post exposure)
- if there is another exposure >3 weeks later need to give more VZIg
If develops varicella do not give give VZIg as ineffective
- Give Acyclovir if 20 weeks or more and presents within 24hr of rash
- If under 20 weeks discuss acyclovir - highest risk time but drug not approved in pregnancy
- If she has severe varicella e.g. hepatitis, pneumonitis etc must give acyclovir regardless of gestation
If she has peripartum varicella (7 days before to 28 days after delivery) offer acyclovir and give baby VZIg - if baby becomes unwell with varicella give IV acyclovir

Question 4

What is Hutchinsons sign in zoster?

Answer 4

vesicles on tip of nose indicate involvement of nasociliary branch of ophthalmic nerve (CNV1) which innervates nose tip as well as cornea so increased risk of herpetic eye disease

Question 5

what is the risk of maternal VZV infection in pregnancy?

Answer 5

Risk highest in first 20 weeks - 2% risk of foetal infection resulting in Foetal Varicella Syndrome - CLOCK 30
CNS defects
Limb hypoplasia and microcephaly
Occular defects
Cutaneous scars + aplasia cutis congenita
Kgs low - low birth weight
30% mortality in first yr of life

Question 6

What dermatoses are associated with Hep B or C?

Answer 6

Small vessel vasculitis (B, C) 
Serum sickness-like reaction (B, C) 
Urticaria (B, C) 
Porphyria cutanea tarda (B, C) 
Pruritus (B, C) 
Erythema multiforme (B, C)
Erythema nodosum (B>C) 
Polyarteritis nodosa (B [classic]>C) 
Gianotti–Crosti syndrome (B>C) 	
Sarcoidosis (with interferon and/or ribavirin therapy; C>B) 
Cryoglobulinemic vasculitis (C>B) 
Necrolytic acral erythema (C) 
Lichen planus – particularly erosive oral disease (C) 
Livedo reticularis (C)

Question 7

What is Fifth disease?

Answer 7

Erythema infectiosum
Slapped cheek disease
Due to Parvovirus B19
Strong tropism for erythroid progenitor cells and erythrocyte P antigen
- Individuals who lack P antigen are naturally resistant to parvovirus B19 infection
Cheeks first + generla symptoms then morbiliform exanthem
resolves in 3 weeks

Question 8

What is Sixth disease?

Answer 8

Roseola infantum
Exanthem subitum
Due to HHV6
morbiliform exanthem confined to trunk and proximal limbs
Characteristically high fever followed by diffuse exanthem at defervescence (abatement of fever) (i.e. distinguished by onset of rose-pink macules and papules as fever abates)
May get Nagayama’s spots -> red papules n soft palate and uvula
Primarily affects infants + toddlers

Question 9

What is Herpangina?

Answer 9

Viral illness of young children age 1-7 yrs
caused by Coxsackie A virus
Up to 15mm vesicles with vivid red areola develop in pharynx/ tonsils/ uvula & soft palate-> prefer posterior mouth unlike HSV
later they rode leaving ulcers
heal in 5-7 days

Question 10

T/F

Coxsackie B infection has more skin presentations than Coxsackie A

Answer 10

F
Coxsackie B causes myosiits, hepatitis, pancreatitis and non specific viral infection.
Coxsackie A can cause herpangina or hand, foot and mouth disease as well as maculopapular or urticarial viral exanthem

Question 11

What does parvovirus cause?

Answer 11

Mainly parvovirus B19
Gianni Slaps PUPs
Erythema infectiosum (fifth disease, slapped cheek)
Papular-purpuric gloves and socks syndrome and
Unilateral laterothoracic exanthem
Thought to trigger PLEVA
Gianotti-Crosti
Foetal infection can cause hydrops or miscarriage

Question 12

Which viruses are picornoviruses?

Answer 12

Includes

1. enteroviruses (Coxsackie, echovirus, polio virus)
2. rhinoviruses (cold)
3. hepatitis A

Question 13

What causes hand, foot and mouth disease?

Answer 13

Enteroviruses mainly Coxsackie A

Question 14

What are Koplik spots, Forscheimers pots and Nagayama spots?

What other viruses cause oral mucosal lesions?

Answer 14

Koplik spots - Measles - grey-white spots w/ bright red rim on buccal mucosa
Forscheimers pots - Rubella - dull red macules or petechiae on the soft palate
Nagayama spots - Roseoloa infantum - red papules on soft palate and uvula
Others;
Herpangina
Hand, foot and mouth

Question 15

What does HHV6 cause?

What does HHV 7 cause?

Answer 15

HHV6
Roseola infantum
Pit rosea
reactivated in DRESS
HHV7
Unclear - may cause pit rosea, may be reactivated in DRESS

Question 16

What are the triggers of Gianotti-Crosti?

Answer 16

EBV most common aetiology now but was HBV prior to routine vaccination
can also be; coxsackie, echo, paraflu, flu, RSV, HIV, parvo B19, immunization