Infections in the Immunocompromised Host

Question 1

What types of pathogens typical infect immunocompromised people?

Answer 1

Endogenous flora
Hospital acquired infections
Environmental organisms
Opportunistic pathogens e.g. CoNS, aspergillus

Question 2

Primary immunodeficiency is more common than secondary immunodeficiency. T/F?

Answer 2

False - the opposite is true

Question 3

Why are we seeing increased numbers of immunocompromised patients?

Answer 3

Advances in modern medicine leads to improved survival at extremes of life, improved cancer management, developments in transplant techqnieues, developments in intensive care, management of chronic inflammatory conditions and the use of steroids.

Question 4

Isolated immunodeficiencies are rare. T/F?

Answer 4

True - a malfunction in one part of the immune system often influences another

Question 5

What are the possible causes of neutropenia?

Answer 5

Cytotoxic chemotherapy

Therapeutic irradiation

Question 6

What immune deficiency is the most important risk factor for infection?

Answer 6

Neutropaenia

Question 7

How is neutropenia defined?

Answer 7

<0.5x10^9/L

Question 8

What treatments can result in neutrophil function disruption?

Answer 8

Cytotoxic drugs
Irradiation
Steroids

Question 9

Give examples of pathogens which take advantage of poor neutrophil function?

Answer 9

S.aureus
Coagulase negative staphylococci
Strep.viridans
Enterococci
Bacteroides
Clostridia
E.coli
Pseudomonas
Klebsiella
Enterobacter

Question 10

What type of inheritance does chronic granulomatous disease follow?

Answer 10

X linked

Question 11

What is the cause of chronic granulomatous disease?

Answer 11

A defect in the gene coding for NADPH oxidase resulting in deficient production of oxygen free radical and defective intracellular killing.

Question 12

What is the result of chronic granulomatous disease?

Answer 12

Recurrent bacterial and fungal infections

Abscesses in the lung, lymph nodes and skin

Question 13

Pulmonary infection is common in chronic granulomatous disease. What organisms typically cause pulmonary infection in this case?

Answer 13

Aspergillus
S.aureus
Nocardia

Question 14

What conditions/treatments can suppress cellular immunity?

Answer 14

Di George syndrome
Malignant lymphoma
Cytotoxic chemotherapy
Extensive irradiation
Immunosuppressive drugs
Allogenic stem cell transplantation
Infections

Question 15

What conditions/treatments can cause humeral immunity?

Answer 15

Bruton agammaglobulinaemia
Decreased antibody production in lymphoproliferative disorders
Intensive chemotherapy or radiotherapy

Question 16

Humoral immunity is usually preserve in acute leukaemia. T/F?

Answer 16

True

Question 17

Disrupted splenic function can lead to increased infection with which organisms?

Answer 17

Encapsulated organisms such as strep.pneumoniae, haemophilia influenzae type b and neiserria meningitidis

Question 18

How is severe nutritional deficiency defined?

Answer 18

<75% ideal body weight or rapid weight loss combined with hypoalbuminaemia

Question 19

What are the signs and symptoms of severe nutritional deficiency?

Answer 19

Anorexia, nausea, vomiting, mucositis, metabolic derangements, compromise in integrity of host defences

Question 20

What affect does iron deficiency have on the immune system?

Answer 20

Reduce microbicidal capacity of neutrophils

Reduces T cell function

Question 21

Obstruction by a tumour can lead to infection. Which organ is particularly susceptible to this?

Answer 21

Lung

Question 22

How does stress affect immune function?

Answer 22

Reduces T cell function

Question 23

How does diabetes mellitus affect immune function?

Answer 23

Reduces opsonisation and chemotaxis

Question 24

What factors can reduce the risk of infection in solid organ transplant?

Answer 24

optimal tissue typing
donor evaluation
organ procurement
good surgical technique
tailored immunosuppressive regimens

Question 25

Give examples of common latent donor-derived infections in solid organ transplant.

Answer 25

TB
Syphillis
Viruses such as HIV, hepatitis B and CMB

Question 26

In solid organ transplant, active blood stream infection at procurement can be caused by. which organisms?

Answer 26

Staphylococci, pneumococci and salmonella

Question 27

Reactivated infections in solid organ transplant can occur. What are the common causative organisms of this?

Answer 27

M.tuberculosis
HSV
CMV
VZV

Question 28

When can neutropenic fever develop?

Answer 28

In solid tumours
Non, leukaemia haematological malignancies
Acute leukaemia

Question 29

What are the most common pathogens to infect patients with neutropenic cancer?

Answer 29

Gram negative aerobic bacteria