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MononucleosisMumps
lecture 6 gill
Question | Answer |
---|---|
alpha herpes family | herpes simplex viruses 1 & 2 (HHV-1 & 2), varicella zoster and herpes simiae. infect mucoepithelial cells and exhibit latency in neurons |
beta herpes family | CMV (HHV-5) infects monocytes, T cells and some epithelial cells. latency in monocytes and lymphocytes |
gamma herpes family | EBV (HHV-4) and Kaposi sarcoma-related virus. infect lymphocytes and epithelial cells with latency in B cells |
Herpes virus family | DS DNA viruses that establish LIFE-LONG LATENT infections |
EBV infection | transmission through saliva, viruses uses CD21/MHC II as receptor for entry. replicates lytically in OP epithelial cells. infects B cells by viremia or direct spread. once latent EBV replicates as episome |
EBV and B cells | up to 20% of all B cells can be infected with EBV, become immortalized and activated to secrete lots of random Ig that incites NK and T cell response - this kills B cells and causes mono sx |
pharmacologic tx of EBV | most tx is ineffective b/c drugs target the lytic cycle of the virus which occurs while pt is asymptomatic. once sx start almost no virus is in lytic cycle but latent |
Monospot test | detects heterophile Ab secreted by EBV-infected B cells by mixing pt serum with horse RBCs to see agglutination. not as specific for kids < 5 y/o |
EBV: early antigens | encode viral polymerase and thymidine kinase (target for drugs), expressed early and in lytic phase of |
EBV: viral capsid antigens | late structural genes required for production of mature virion, produced in lytic phase // IgG will be expressed for life while presence of IgM indicates acute infection or reactivation |
Epstein-Barr nuclear antigens | required for maintenance of latency i.e. after resolution of acute infection |
EBV: latent membrane proteins | LMP1 is oncogenic, can stimulate B cells via CD40. LMP2 nonspecifically binds BCR to stimulate proliferation |
clinical presentation of infective mononucleosis | incubation period of 15-45 days. cause acute exudative tonsillitis and sore throat, fever from 38-40, malaise, diffuse myalgias, H/A, generalized lymphadenopathy and HSM. fatigue may persist for months |
lab dx of infective mononuclosis | WBC may be elevated, marked abs inc in lymphocytes (may be > 50% of all WBCs and atypical), heterophile Abs make Monospot (+). IgM EBV VCA (+) |
complications of infective mononucleosis | splenic rupture either spontaneous or from minor trauma, airway obstruction by tonsillitis, encephalitis, meningitis, myelitis, myocarditis and conduction abnormalities, blood cell abnormalities, Duncan syndrome |
dz that can cause similar presentation to infective mononucleosis | CMV mono, acute HIV retroviral syndrome, adenovirus or streptococcal pharyngitis, false Monospot (if young child) |
other EBV associated dz | endemic Burkitt's lymphoma (Africa), nasopharyngeal carcinoma (China, SE Asia), Hodgkin's lymphoma, non-Hodgkins in HIV pts, CNS lymphoma in AIDS, post-transplant lymphoproliferative disorders |
EBV X-linked Lymphoproliferative Syndrome | male pts with a very specific and exclusive immunodeficiency towards EBV, defect in T cell signaling, life-threatening condition with mortality rate of 66% |
CMV infection | lytic and productive infection in many cell types. latent in T cells and macrophages for life. acquired through any type of bodily fluid even resp droplets and saliva. doesn't immortalize cells, cleared by cell-mediate immunity |
clinical presentation of CMV infection | most always asymptomatic. if there are sx, appears just like infective mono, clinically indistinguishable except Monospot is (-) for CMV infections |
complications of CMV infection | congenital infection via placental transfer of CMV, CMV chorioretinitis in AIDS pts, GI ulcerative dz, esophageal ulcers, transplant organ failure, encephalitis, myelitis, meningitis and neuritis |
congenital CMV infection | causes microcephaly, deafness, sz disorders, MR, thrombocytopenia, HSM, hepatitis and jaundice or death. intracerebral calcifications are characteristic |
dx of CMV infection | may suspsect if viral syndrome but EBV IgM and Monospot (-), look for intranuclear/cytoplasmic inclusions in infected cells, CMV IgM (+), (+) blood culture/PCR |
pharmacologic tx of CMV infection | ganciclovir, valganciclovir, Foscarnet as 2nd line, cidofovir as 3rd line |
paramyxovirus | neg and SS RNA viruses. morbillivirus subgroup - measles; parainfluenza subgroup - mumps; pneumovirus subgroup - RSV |
mumps | paramyxovirus spread by resp droplets or saliva. infects parotid gland via viremia or direct contact. incubates 14-18d. replicates in epithelium of nose, NO LATENCY |
clinical presentation of mumps | pt asymptomatic contagious carrier up to 6d then H/A, malaise, low-grade fever the higher fever and large parotitis uni or bilaterally |
complications of mumps | meningitis most commonly with viral particles in CSF, encephalitis, sensorineural deafness, orchitis, oophoritis, pancreatitis |
dx of mumps | use clinical picture, mumps specific IgM acutely (cross-rxn with lupus pts) |