Lecture 7: Infections in the Immunocompromised Host

Question 1

What are the 3 factors disposing immunocompromised pts to infection

Answer 1

3 factors disposing immunocompromised pts to infection

1. Neutropenia and Defects in Phagocytic Defenses
2. Defects in cellular immunity
3. Defects in Humoral Immunity

Question 2

1 Neutropenia and Defects in Phagocytic Defenses

• what 3 groups of patients is this common in

Answer 2

#1 Neutropenia and Defects in Phagocytic Defenses 
common in:

1. post chemo/myelosuppressive Tx
2. bone marrow transplant recipient
3. acute leukemia

Question 3

1 Neutropenia and Defects in Phagocytic Defenses

1. lower ANC = greater risk of infection (T or F)
2. what value of the ANC is a/w signif risk of infection

Answer 3

1 Neutropenia and Defects in Phagocytic Defenses

1. lower ANC = greater risk of infection –> TRUE
2. ANC < 500 a/w signif risk of infection

Question 4

in which of the 3 factors predisposing to infection does the organism typically colonize the area that becomes infected

Answer 4

1 Neutropenia and Defects in Phagocytic Defenses

Question 5

1 Neutropenia and Defects in Phagocytic Defenses

• what are the 3 common organism classes that phagocytic defenses usu protect us from

Answer 5

#1 Neutropenia and Defects in Phagocytic Defenses 
- 3 common classes of organisms 

1. Gram (-) rods - E.coli, Pseudomonas, Klebsiella
2. Gram (+) - staph and strep
3. Fungi - candida, aspergillus, mucor

note: spp organisms there for reference

Question 6

pts w/AIDs, HL, Monoclonal Ab Tx and long term CCS use typically have defects in _______

Answer 6

pts w/AIDs, HL, Monoclonal Ab Tx and long term CCS use typically have defects in cellular immunity

Question 7

2 Defects in Cellular Immunity

1. what types of pathogens are the typical cause?
2. what type of viruses typically cause this?
3. what heminth typically causes this (Vietnam vets)

Answer 7

2 Defects in Cellular Immunity

1. cause = usu opportunistic pathogens
2. herpes viruses (HSV, VZV)
3. heminth = Strongyloides (Vietnam vets)

Question 8

2 Defects in Cellular Immunity

• what 5 bacteria a/w defects in cellular immunity

Answer 8

2 Defects in Cellular Immunity

1. Listeria
2. Mycobacteria (non-TB)
3. Nocardia
4. Legionella
5. Salmonella

Question 9

2 Defects in Cellular Immunity

• what 4 fungi a/w defects in cellular immunity

Answer 9

2 Defects in Cellular Immunity

1. Cryptococcus
2. Histoplasmosis
3. Coccidiodes
4. Pneumocystis

Question 10

pts w/MM, SCD splenectomized pts, Agammaglobulinemia, and CLL w/agammaglobulinemia have defects in ______

Answer 10

3 defects in humoral immunity

Question 11

What do encapsulated, pyogenic bacteria like S. pneumo and H. flu cause defects in?

Answer 11

Encapsulated, pyogenic bacteria like S. pneumo and H. flu - defects in humoral immunity (#3)

Question 12

what 4 types of infections are common in the neutropenic host

• which has a high mortality

Answer 12

4 types of infections are common in the neutropenic host

1. Septicemia/Bacteremia - high mortality
2. Oropharyngeal infections
3. Pulmonary Infections
4. Skin/soft tissue infections

Question 13

Common infections in Neutropenic Host:

What types of infections do HSV, Candida, and bacterial infections cause?

Answer 13

Common infections in Neutropenic Host:

HSV, Candida, and bacterial infections cause oropharyngeal infections

Question 14

Common infections in Neutropenic Host: Pulm infections

• what type of infection is a/w bone marrow transplant

Answer 14

Common infections in Neutropenic Host: Pulm infections

• CMV pneumonitis = a/w bone marrow transplant

Question 15

Common infections in Neutropenic Host:

• what type of infections are a/w long term intravascular devices

Answer 15

Common infections in Neutropenic Host:

• Skin/soft tissue infections = a/w long term intravascular devices (usu cause = skin flora)

Question 16

Approach to pts w/Fever and Neutropenia

1. what is the initial therapy
2. what type of coverage MUST be included
3. if pt remains febrile even after ABXs what type of tx should be started?

Answer 16

Approach to pts w/Fever and Neutropenia

1. initial therapy = RAPID empiric ABX tx
2. MUST have gram (-) coverage (Pseudomonas)
3. febrile even after ABXs –> antifungal therapy

Question 17

what are 3 Prevention Measures for pts w/Neutropenia and Fever

Answer 17

3 Prevention Measures for pts w/Neutropenia and Fever

1. Isolation
2. ABX ppx
3. G-CSF –> improve neutrophil count