Parvovirus Case

Front 1

genus of B19?

Back 1

erythrovirus

Front 2

cells in which B19 can propagate?

Back 2

erythropoietin stimulated erythropoietic cells from bone marrow, umbilical cord blood, or primary fetal liver culture

Front 3

describe B19's niche for age of infection and seasonality.

Back 3

bw 5 and 15. late winter and spring

Front 4

describe seroprevalence of B19.

Back 4

increases with age, 40 to 60% of adults have Ab's

Front 5

transmission?

Back 5

respiratory; schools, hospitals, and parents are susceptable

Front 6

B19 infects and lyses RBC precursors, why are neutropenia and thrombocytopenia observed clinically?

Back 6

no one knows...........

Front 7

describe the biphasic pathogenesis of this bad boy.

Back 7

7 to 11 days after exposure, pts get flu like symptoms with rhinorrhea during which they are infective via nasopharyngeal shedding. Reticulocyte counts drop but only result in a mild Hb drop. But this is when a ttransient aplastic crisis can occur. Then the immune system kicks in and pts may experience a rash with arthralgia. This is due to the immune response.

Front 8

what part of the immunity plays a huge role in controlling infection, leading to a restoration of reticulocytosis and a rise in serum Hb?

Back 8

humoral immunity, B19 IgM appears in 2 days followed by IgG.

Front 9

who is at risk for chronic B19 infections.

Back 9

those with impaired humoral immunity such as children on chemo, congenital immunodeficiency states, transplant patients, and those with AIDS

Front 10

describe B19 in fetuses and neonates.

Back 10

nonimmune fetal hydrops and still birth usually from CHF is most serious case, but most infections during pregnancy result in normal deliveries and asymptomatic children with no teratogenic effects

Front 11

symptoms of B19 infection in children? adults?

Back 11

kids get erythemia infectiosum while adults, esp. women, get acute arthropathy with or without the slapped cheeks

Front 12

describe the three phases of the rash in 5ths disease.

Back 12

initial is facial flushing with typical slapped cheeks. then spreads to trunk and proximal extremities as a diffuse macular erythema. central clearing occurs promptle giving it a lacy appearance and the palms and soles are spared

Front 13

what are some types of chronic hemolysis that are susceptable to transient aplastic crisis from B19?

Back 13

sickle cell, thalassemia, hereditary spherocytosis, and pyruvate kinase deficienct.

Front 14

signs and symptoms of profound anemia?

Back 14

pallor, tachycardia, and tachypnea (hyperventillation). note sickle cell patients may have a pain crisis

Front 15

B19 induced myocarditis is seen in what populations?

Back 15

all ages but it is rare, note that infants are known to have the viral receptor on their myocardial cells.

Front 16

describe the dermatologic syndrome sometimes associated with B19 infection.

Back 16

papular-purpuric glove and socks syndrome. fever, pruritus, and painful edema and erythema localized to the distal extremities in a distinct glove and sock distribution followed by acral petechiae and oral lesions.

Front 17

describe how B19 is diagnosed in all populations.

Back 17

usually the presence of rash or transient aplastic crisis in a sickle cell patient is diagnostic. Serology can be performed (IgM for acute and IgG for past infection). Immunocompromised patients need PCR or hybridization as serology is not accurate in them. fetal hydrops caused by B19 can be confirmed by PCR or hybridization from fetal blood

Front 18

differentials?

Back 18

rash: rubella, measles, enteroviral infections, and drug rxns. Rash and arthritis in older children: RA, SLE, and other connective tissue disorders

Front 19

treatments?

Back 19

no specefic treatments, symptomatic. Immunocompromised should quit being immunocompromised if they can (like stop the chemo for a bit or quit the steroids), IgG infusions may help in AIDS or inherited immune deficiencies. diagnosis of fetal hydrops should be reffered to fetal therapy centers, some can be treated with a intrauterine transfusion but serious complications can arise

Front 20

should anyone be isolated when 5ths disease is about?

Back 20

once the rash appears, the virus is not contagious, but if it is going around at school, pregnant women should lay low. those with transient aplastic crises ARE contagious (get symptoms with viremia) and thus should be isolated.

Front 21

can the rash re-appear?

Back 21

yes, for weeks to months, it can fluctuate its intensity and is recur with changes like temperature and sunlight

Front 22

brief description of the parvovirus structure and morphology...

Back 22

nonenveloped, ssDNA, replicates only in human erythrocyte precursors

Front 23

modes of transmission?

Back 23

resp tract secretions, blood exposure, vertical transmission

Front 24

in what stage of infection is papulopurpuric gloves and socks syndrome seen?

Back 24

during viremia, thus they are infectious when symptomatic

Front 25

how long should aplastic crisis patients be isolated?

Back 25

til one week after symptoms go away

Front 26

incubation period?

Back 26

4 to 21 days (usually around 15)

Front 27

random fact\discrecpancy between articles:

Back 27

the red book says that bc EI is common in the community and not just isolated to something like a school outbreak and that fetal complications if infected are slim, pregnant women should not be excluded from the work\school environment.

Front 28

how "hardy" is the virion.

Back 28

pretty tough bc it is not enveloped thus it can remain in the environement for a while

Front 29

describe the possible outcomes of an aplastic crisis.

Back 29

usually self limiting but can cause severe, occasionally fatal, anemia that preceipitates CHF, CVAs, and acute splenic sequestration

Front 30

what specefic part of the immune response is probably responsible for the rash in 5th disease?

Back 30

Ag-antibody complexes

Front 31

what does the marrow look like in infected individuals?

Back 31

no mature erythroid precursors but giant pronormoblasts are present

Front 32

why does parvovirus infect the fetal liver?

Back 32

it is the site of early erythrocyte production

Front 33

what is the risk of infection during pregnancy and the following risk of fetal loss?

Back 33

30% chance of infection with a 5 to 9% risk of fetal loss

Front 34

what is the cell receptor for B19?

Back 34

globoside (erythrocyte P antigen), found on erythrocyte precursors, placenta, and fetal myocardial cells

Front 35

infection incurs what kind of immunity?

Back 35

life long immunity