Microbiology 13 - Opportunistic viral infection

Question 1

What is the Baltimore classification?

Answer 1

Virus classification system

Question 2

What class of viruses form latent infections?

Answer 2

DNA viruses

Question 3

What do IgM and IgG differentiate?

Answer 3

IgM = active or resolving infection

IgG = past infection >6wks ago

Question 4

How is most viral serology performed?

Answer 4

Indirectc ELISA

immune response to virus

tests if you have ever had infection - measures Ab levels

Question 5

What is the marker of replication and immune response in Hep A?

Answer 5

replication = HAV in stool

immune response - anti-HAV IgM 4-18w

Question 6

What is the marker of replication and immune response in Hep B?

Answer 6

HBsAg

anti HBc IgM starts 12wks → 3-6 months

Question 7

How can you test whether you have infection CURRENTLY?

Answer 7

direct detection - PCR/viral proteins (LFT/Ag test)

Question 8

Why can’t you use serology in immunocompromised, and what is used instead?

Answer 8

cannot use serology as immune system is non functional

1. screen prior to immunosuppression
2. monitor using PCR

Question 9

Recall 3 reasons for immunosuppression

Answer 9

1. Solid organ transplant
2. Human stem cell transplant (short term, or long term if they have significant GVHD)
3. HIV/AIDS

Question 10

Recall 4 types of immunosuppressing drugs

Answer 10

1. Steroids
2. Calcineurin inhibitors
3. Anti-proliferative agent (eg. Azothioprine/ mycophenolate)
4. Antibodies

Question 11

What is the most significant immunosuppressive risk factor for opportunistic viral infection?

Answer 11

ASCT

Question 12

How would you manage HSV 1+2 in immunocompromised?

Answer 12

test HSV IgG prior to immunosuppression

Question 13

What is a common re-activator of latent HSV?

Answer 13

Stressful situations

Question 14

How can VZV manifest?

Answer 14

pneumonitis

encephalitis

hepatitis

purpura fulminans in neonate

shingles

multi dermatomal/disseminated

late presenting

Question 15

What is the treatment for VZV in the immunocompromised?

Answer 15

varicella - antivral for 7-10 days

zoster - antiviral (IV if disseminated) and analgeisa

Ramsey Hunt - + steroids

HZO - topical steroids

Question 16

What is the most common malignancy caused by EBV?

Answer 16

Post-transplant lymphoproliferative disorder

Latent infected B cells have polyclonal activation → predispose to lymphoma

Suspicion on rising EBV viral load (>10^5c/mL) and CT scan

confirm on biopsy of LN

Question 17

Management of PTLD

Answer 17

Reduce immunosuppression

Anti-CD20 monoclonal antibodies (Rituximab) - removes B cells

Question 18

What is the most important opportunistic virus in transplant patients?

Answer 18

CMV

causes allograft disease + GIT (e.g. renal)

Question 19

What is the Pathognomonic histological feature of CMV?

Answer 19

Owl’s eye lung pneumocytes (inclusion bodies)

Question 20

What drug would you give to someone who has CMV AND is immunosuppressed?

Answer 20

ganciclovir (IV) = BM suppression

valganciclovir (oral)

foscarnet (IV) - nephrotoxicity!

cidofovir - nephrotoxicity

IVIg with another drug for pneumonitis

reduce immunosuppression

Question 21

In renal transplants, is risk of CMV transmission when the donor or recipient is positive?

Answer 21

Donor is pos

immunosuppressed pt gets given some CMV for first time

Question 22

In Human Stem Cell Transplants, is risk of CMV transmission when the donor or recipient is positive?

Answer 22

Donor is neg (recipient is pos) as patient with CMV has immune system replaced with one that is CMV-naive

Question 23

How to prevent CMV post transplant?

Answer 23

Question 24

What CMV prophylaxis is offered, and to whom?

Answer 24

Ganciclovir
Given to all transplant patients

Question 25

What virus causes multifocal leukoencephalopathy?

Answer 25

JC virus cognitive disturbance, personality change, motor deficits focal neurological signs caused by demyelination of white matter

Question 26

In which patients does JC virus cause PML?

Answer 26

AIDS patients also humanised monoclonal Abs natalizumab - MS treatment

Question 27

What two conditions can BK virus cause in the immunosuppressed?

Answer 27

Haemorrhagic cystitis Nephropathy

Question 28

How to treat BK virus post transplant

Answer 28

cystitis - intravesical cidofovir (direct into bladder – avoid nephrotoxicity) nephropathy - IVIG (cidofovir is nephrotoxic)

Question 29

How to treat influenza and SARS Cov 2 in immunocompromised?

Answer 29

influenza - oseltamivir (oral) 5 days -\> zanamivir (inhalation/IV) SARS Co2 - sotrovimab or casirivimab/imdevimab

Question 30

For which hepatitis viruses are there vaccines?

Answer 30

Hep A and B

Question 31

What are the markers of disease in Hep B?

Answer 31

Question 32

What are the markers of immunity in Hep B?

Answer 32

Question 33

Describe the status of HBV sAg, cAb and sAb in current/past/vaccination infection

Answer 33

Question 34

What drugs can be given for Hep B prevention?

Answer 34

nucleoside (lamivudine) nucleotide (tenofovir, entecavir) prophylaxis

Question 35

What is HHV4?

Answer 35

EBV

Question 36

What is HHV8?

Answer 36

Kaposi's sarcoma associated herpesvirus

Question 37

Why is adenovirus particularly problematic in post-bone marrow transplant children?

Answer 37

You get disseminated disease

Question 38

What is the treatment for disseminated adenovirus?

Answer 38

Cidofavir

Question 39

What disease does parvovirus cause in a chronically immunosuppressed patient?

Answer 39

Anaemia

Question 40

What is the most common clinical syndrome caused by CMV infection?

Answer 40

Retinitis

Question 41

Answer 41

HSV most likely