W20 - Opportunistic viral infections Flashcards
Define endogenous and exogenous opportunistic infections. Give 1 example of each
Endogenous = latent virus that reactivates in immunosuppressed
i.e. varicella zoster
Exogenous = new viral infection with increased severity in immunosuppressed
i.e. influenza
What is baltimore classification system of viruses?
It’s a system of classifying viruses based on their manner of mRNA synthesis
Define indirect and direct detection of viruses?
Indirect detection = response of immune system to virus (i.e. abs)
Direct detection = fragments of actual virus (i.e. viral protein via LFTs, viral genes via PCR)
How useful is serology testing once someone is immunocompromised?
Useless as their immune system is now non-functional!
If you are to induce immunosuppression in a patient (i.e. unergoing BM transplant), what should you do in terms of monitoring/treating viral infections?
- Screen prior to immunosuppression
- Identify previous viral exposure that may reactivate
- Guide the use of antiviral prophylaxis - Monitor using PCR
- Identify viral reactivation (i.e. CMV, EBV, HSV) promptly → Treatment
- Detect infection
A 51-year-old with a recent HSCT is unwell. Which is the most appropriate test?
ALT = 800 IU/mL
A) EBV IgG/IgM
B) HBV sAb
C) Parvovirus PCR
D) HEV PCR
E) CMV IgG/IgM
Serology is useless in immunosuppressed patients
Parvovirus – rare cause of hepatitis
Correct ans = D (Parvovius PCR)
List the patients from highest to lowest risk of opportunistic viral infection
- Solid organ transplant
- Advanced HIV infection (CD4 depleted)
- Cytotoxic chemotheapy
- Allogeneic Stem cell transplant
- Various monoclonal ab therapies
- DMARDs and steroids
Allogeneic stem cell transplant > Advanced HIV > solid organ transplant > various monoclonal ab therapies > cytotoxic chemotherapy > DMARDs and steroids
What are the sources of viral infections in transplant recipients?
- Viruses acquired from the graft
- Viral reactivation from the host
- Novel infection from close contact with infected individual
Which type of immunosuppression carries the greatest relative risk of developing a viral infection?
A. Steroids
B. Solid organ transplant
C. Allogeneic stem cell transplant
D. Monoclonal antibody therapies
E. Cytotoxic chemotherapy
C. Allogeneic stem cell transplant
Herpes Simplex Type 1 and 2 infection in immunosuprressed - what are 4 issues?
- Increased freqeuncy of infection
- Increased severity of infection (i.e. risk of dissemination)
- More organs involved (esophagitis, pneumonitis, hepatitis)
- Increased risk of acyclovir resistance
Varicella zoster (VZV) infection - what are some complications of varicella in immunosuppressed? zoster in immunosuppressed?
Varicella (chicken-pox) in immunosuppressed:
- Pneumonitis
- Encephalitis
- Hepatitis
- Purpur fulminans in neonte
Zoster (shingles) in immunosuppressed:
- Multi-dermatomal/disseminated
A patient who received a stem cell transplant 2 weeks ago presents with mouth ulcers.
Which of the following viruses would you test for on the mouth swab?
A.Enterovirus
B.Adenovirus
C. Herpes simplex type 1
D. Human herpesvirus 6
E. Human gammaherpesvirus 8,
C. Herpes simplex type 1 => HSV PCR
Describe how EBV can cause post-transplant lymphoproliferative disease (PTLD)
latently infected B cells => no immune regulation due to immunosuppression => polyclonal activation => predisposes to lymphoma
NB: should be suspicious on ribing EBV viral load
How should EBV monitoring be done in those immunosuppressed?
- Monitor EBV levels
- Investigate for lymphoma (i..e LN biopsies) as needed
- Treat with rituximab if needed, reduce immunosuppression if possible
Describe CMV infections (4) in HIV/IDS CD4 <50
- Retinitis (AIDS-defining)
- Polyradiculopathy
- Pneumonitis
- Gastroenteritis
Describe how CMV could be seen in SOT vs HSCT
SOT (i.e. renal transplant) => Donor + / recipient - => immunosuppressed patients get given some CMV for the first time
HSCT (i.e. BM transplant) => Donor - / recipient + => patient with CMVD has immune system replaced with one that hasn’t seen CMV
Which of these is NOT an antiviral?
A.Sotrovimab
B.Valganciclovir
C.Foscarnet
D.Rituximab
E.Tenofovir
D.Rituximab
Progressive multifocal leukoencephalopathy (PML) - symptoms (3)
- Cognitive disturbance
- personality change
- motor deficits
- other focal neurological signs
NB: demyelination of white matter => neurological deficits
JC virus - John Cunningham
what does it cause in HIV+ patients?
In HIV patients it causes a CNS infection called PML (progressive multifocal leukoencephalopathy)
What complication can BK virus cause post-SCT?
BK cystitis
Hepatitis viruses - describe what happens in immunosupressed
- Hep A
- Hep B
- Hep C
- Hep E
- Hep A = more severe, vaccinate
- Hep B = re-activation, vaccinate/prophylaxis
- Hep C = increased fibrosis(?), Tx with direct-acting antivirls
- Hep E = chronic infection, reduce immunosuppression
Hep B in the immunocompromised - name 2 things that could happen:
- Carriers may have flare of disease
- Those who have had past infection can reactivate
Hepatitis B - name serological markers of disease (3) and serological markers of immunity (3)
serological markers of disease:
sAg (circulating virus)
cAb+ IgM (acute immune response)
eAg (circulating virus)
serological markers of immunity:
sAb (generated from virus or vaccine)
cAb IgG/total (prior infection)
eAb (generated from virus)
If there is a risk (high, moderate, low) of HBV reactivation due to immunosuppression, what can be done?
high risk (i.e. chemotherapy, anti-CD20) = prophylactic antiviral therapy
moderate risk (i.e. anti-TNF treatment, low-dose steroids) = prophylactic antiviral therapy or on-demand (monitor)
low risk (i.e. steroids alone for a few days) = no prophylaxis
