Opportunistic viral infections Flashcards
Which group of pts are affected by opportunistic viral infections?
Immunodeficient
What are the 2 types of immunodeficiency?
- Innate (primary)
- Acquired (malignancy, HIV, steroids, chemotherapy)
How do more severe viral infections present?
Wider range of systems affected
More varied manifestations
What are the 3 stages of PCR?
1) Denature
2) Primer annealing
3) Chain elongation (with Taq polymerase)
List the 3 origins of opportunistic viral infections post-transplant
- Reactivation of latent infection (eg herpes)
- Graft introduced infection (eg hep B)
- Exogenous opportunistic infection post-transplant (eg measles)
Herpes viruses cause lifelong infection, which cell types do HSV, VZV, CMV and EBV reside in?
HSV/VZV: neurons
CMV/EBV: leucocytes
Name 2 complications VZV can cause in the immunocompromised?
Pneumonitis
Hepatitis
What is the treatment for VZV?
Acyclovir
How can VZV be prevented?
Varicella zoster immunoglobulin
When is there a risk of CMV in solid organ transplant?
Seropositive donor and seronegative recipient (due to recipient virus exposure)
When is there a risk of CMV in bone marrow transplant?
Opposite: risk when seronegative donor but seropositive recipient. (protective antibodies in recipient are removed by chemo/radiotherapy, but not replaced by seronegative donor)
How is CMV diagnosed?
PCR for viral load
What is the treatment for CMV?
Ganciclovir
OR
Foscarnet/cidofovir
What risk is posed by EBV in a transplant situation?
Post-transplant lymphoproliferative disease - control of proliferation of latently infected B cells is lost
What risk is posed by EBV in HIV +ve pts?
Oral hairy leukoplakia
Lymphomas
What is the treatment for opportunistic EBV?
Reduce immunosuppresion
Rituximab (anti-CD20)
What is the major risk of HHV-8 in AIDS pts?
Cancer
- Kaposi’s sarcoma
- Castleman’s disease
What does Kaposi’s sarcoma show when biopsied?
Spindle cells
KSHV (HHV8) proteins
What risk is associated with HHV6 in transplant pts?
Graft rejection
Similar symptoms to CMV
What is the treatment for opportunistic HHV6?
Ganciclovir
Foscarnet/cidovir
Who is at risk of opportunistic adenovirus?
Paediatric pts post-bone marrow transplant
How are paediatric pts post-BMT monitored for adenovirus?
Weekly PCR surveillance
What is the treatment for adenovirus?
Reduce immunosuppression
Ribavirin
How is opportunistic measles prevented in immunocompromised pts?
Human normal Ig
What are 2 complications of opportunistic measles?
Giant cell pneumonia
Encephalitis
