Childhood exanthmas Flashcards
Measels
Paramyxoviridae. –ssRNA, enveloped (frgile), Helical. nonsegmented,
- Fusion peplomer (syncytia giant cells)
- Heamaglutinin glycoprotein spike binds to CD46
- Intracellular repication epithelial cells, spread local lymph node then blood.
- Infected B/Tcells induce switch Th1 to Th2 (Ab production verses intracellular)
Human only. Respiratory droplets inhalled (contagious)
PATIENT: young children, unvaccinated, malnourished
- Prodromal fever, cough, corzya, conjunctivitis, photophobia
- T+2d: Kaplik spots buccal/throat
- T+3d: Maculopapular Rash confluent spots (T.CD8 kill infected epithelial cells) begin neck to body including soles/palms
- bacterial super infection pneumonia
- post measel encephalitis
- giant cell pneumonia without rash in patient lacking Tcell response.
DX: clinical, DFA, RT-PCR, acute phase IgM
TX. Supportive (vitA, antipyretics and fluids)
Vaccine. Live attenuated (MMR)
Atypical Measels
Paramyxoviridae. –ssRNA, enveloped (frgile), Helical. nonsegmented,
- Fusion peplomer (syncytia giant cells)
- Heamaglutinin glycoprotein spike binds to CD46
- Intracellular repication epithelial cells, spread local lymph node then blood.
- Infected B/Tcells induce switch Th1 to Th2 (Ab production verses intracellular)
Human only. Respiratory droplets inhalled (contagious)
PATIENT: killed vaccine (KMV) 1963-1967 sensititzed without immunity
- Fever,
- pleural effusions, pneumonia,
- sweling of extremities.
- acute, more intense rash, petechia, purpura, utricarial hives (ankle/wrists first)
DX: clinical, DFA, RT-PCR, acute phase IgM
TX. Supportive (vitA, antipyretics and fluids)
Vaccine. Live attenuated (MMR) should be administered prophylaxtially
Post Measels Encephalitis
Subacute Sclerosing Panencephalitis (SSPE). Paramyxoviridae. –ssRNA, enveloped (frgile), Helical. nonsegmented,
- Fusion peplomer (syncytia giant cells)
- Heamaglutinin glycoprotein spike binds to CD46
- Intracellular repication epithelial cells, spread local lymph node then blood.
- Infected B/Tcells induce switch Th1 to Th2 (Ab production verses intracellular)
PATIENT: previously (1-10yrs) diagnosed with measels usually at <2yrs age.
- Fatal CNS or permanent mental/physical impairment
- defective measels virus form persists in brain. replication slowly from cell to cell, nerver released.
Rubella Virus
German Measels.
Toga.viridae (Rubivirus genus) icosahedral, envelopped, +ssRNA linear (no viral polymerases)
Human only. only one serotype. respiratory infectious prodromal and post symptomatic. transplacental. “eliminated 2005”
- not cytolytic
- cell mediated immunity and HSR responsible for disease
- Rash associated with HSR III complex. less intence than rubeola-measels and rarely coalesce.
- enters resp replicate localy and spread to lymph nodes. dissminates hematogenously.
PATIENT: low fever, maculopapular rash from face to trunk, lymphadenopathy. (more severe in adult, arthralgia, arthritis, and post infective encephalopathy)
Gx: RT-PCR, IgM or 4xIgG
TX: antipyretic and fluid (tylenol/Reye)
PX: live attenuated vaccine MMR.
Congenital Rubella virus
- German Measels.*
- Toga.viridae (Rubivirus genus) icosahedral, envelopped, +ssRNA linear (no viral polymerases)*
- Human only. only one serotype. respiratory infectious prodromal and post symptomatic. transplacental. “eliminated 2005”*
first trimester infection of mother.
- PDA
- Cataracts, glaucoma, blindness
- CNS. microcephaly. mental retardation and deafness
Baby with IgM at birth.
Parvovirus B19
5th. Erythema Infectiosum (slap cheek)
Icosahedral, naked, -/+ linear ssDNA (smallest)
Humans only (65% sero+). respiratory, oral secretions, blood, transplancental Hydrops fetalis. (Risk in chronic anemics) infectious during incubation time.
- infects mitotic cells for replication enzymes
- immature erythroid progenitor bone marrow or leukemic erythroid cells
- aplastic anemia caution sickle cell patient
- binds to P antigen
- kill cells and susequent HSR III complex (rash arthralgia)
Biphasic infection.
- (8-11days) lytic infectious phase with predromal flue like symptoms including fever
- (2-5 days) non-infectious/immunological phase
- rash face - slap cheek
- rash extremities -lace like
- arthralgia usually to adult women
DX: PDR, IgM (4xIgG)
TX. supportive (blood tx in severe)
Varicella-Zoster Virus
chickenpox / shingles
Herpes.viridae. alpha genus (epithelial). Icosahedral, envelopped, dsDNA
Human (life long latent 90% sero+). respiratory droplest, direct/indirect mucosa from skin lesions. (reactivation in elderly and primary more ssevere in adults)
- lytic, persistent, latent, transforming infections
- infects epithelial cells, fibroblasts, Tcells, neurons
- lytic and latent infections of neurons: dorsal root and cranial nerve ganglia
- produce viral thymidine kinase
PATIENT
- prodrome flu like symptoms
- Rash skin and mucosal
- itchy, papulo-vesicualr, appear in crops and cform crusts. Face then truck moving outward (replication of virus)
- blisters of differing stages.
- interstitial pneumonia and encephalitis (immnocompromised - can be fatal)
Shingles reactivation
- painful (burning/tingling) vesicular skin lesions within dermatomes
- small bumps in clusters blister and bust crusting (damage to nerves)
- post herpetic neuralgia lasting weeks-years without rash
DgX: microscopi tzanck smear multinucleated cells (syncitia) with cowdry type A intanuclear inclusion bodies
Ag detection (direct imunofluorescnet), PCR
TX: supportive children. Adult: acyclovir/famiciclovir (inhibit viral DNA polymerase) OR passive immunity and pain control.
PX: live attenuated vaccine (oka strain) varivax for children and **zontavax ** for audult reactivation. Passive for immunocompromized.
Roseola - exanthema subitum
6th. Herpes lymphotropic virus HHV 6 and 7
Herpes.viridae. alpha genus (epithelial). Icosahedral, envelopped, dsDNA
Human (100% sero+, latent T cell infectio). replication in salivary glands tx saliva. infection infants, reactivation i immunocompromised.
PATIENT 6-24 month old.
- abrupt high fever (epileptic babies)
- post fever rash starting on trunk
- recovery in a few days
