Infections in an immunocompromised host.

Question 1

What infections are associated with central line infections? - 2

Answer 1

gram negative org’s

and candida

Question 2

What infections are associated with oral mucositis? - 4

Answer 2

• streptococcus sp.
• anaerobes
• H. influenzae
• N. meningitidis

Question 3

Defects in antibodies make a patient susceptible to which type of infections? Name the three organisms in this category

Answer 3

• encapsulated organisms!!
• Streptococcus Pneumoniae
• N. Meningitidis
• H. influenzae

also, antibody defects predispose to enterovirus and giardia

Question 4

Defects in macrophages predispose to which type of infections?

Answer 4

intracellular organisms!!

• fungi
• protozoa
• legionella
• parasites (strongyloides)

Question 5

Defects in cytotoxic T cells predispose to which types of infections?

Answer 5

viruses.

Question 6

Which tests do you order in someone with neutropenic fever? - 7

Answer 6

• CBC/diff
• creatinine
• hepatic enzymes
• total bilirubin
• 2 sets of blood cultures
• culture specimens from other sites of infection
• chest radiograph or chest CT

Question 7

What are the criteria for neutropenic fever?

Answer 7

Fever
-single temp>38C or a sustained temp >38C for 1 hr

Neutropenia
-absolute neutrophil count

Question 8

what is the most common source of infection in neutropenic fever? - 2

Answer 8

• patient’s endogenous flora (break in skin / mucositis)

- nosocomial infection

Question 9

T/F: Neutropenic fever is usually due to gram positive organisms

Answer 9

False. It is 50/50 gram pos/ gram neg. However gram negative is more fatal!!

Question 10

Most common gram positive organisms causing neutropenic fever.

Answer 10

• coag negative staph (7-51%)

- staph aureus

Question 11

Most common gram negative organisms causing neutropenic fever.

Answer 11

• enterobacteriaceae

- pseudomonas aeruginosa

Question 12

What are the 2 most important risk factors for infection in cancer patients?

Answer 12

• Neutropenia (especially >7 days)

- Mucositis

Question 13

Patient has neutropenia and oral mucositis. What organisms would you expect to cause an infection? -3

Answer 13

• streptococcus sp (viridans strep)
• oral anaerobes
• candida sp.

Question 14

Patient has neutropenia and mucositis in his gut. What organisms would you expect to cause an infection? -3

Answer 14

• enterobacteriacea sp.
• psudomonas aeruginosa
• enterococcus
• candida

Question 15

Patient is neutropenic and has a central venous catheter. What org’s would you expect?

Answer 15

• coag negative staph
• gram negative rods
• candida

might see polymicrobial infection

Question 16

what is ecthyma gangrenosum and what causes it?

Answer 16

it is a frequent skin infection in immunocompromised hosts, usually results from bacteremia. Start as painless red areas and can develop into gangrenous ulcers.

**pseudomonas aeruginosa is a major cause.

-staph aureus and fungi also cause.

Question 17

What are the most common fungal infections in cancer patients?

Answer 17

• candida sp.
• aspergillus sp.
• pneumocystis jirovecii

Question 18

Who should you admit (and give IV antibiotics) with neutropenic fever?

Answer 18

"High risk pt's" Definition: 
profound neutropenia (

Question 19

Which antibiotics should you treat “high risk” neutropenic fever pt’s with?

Answer 19

-give them antibiotics which cover pseudomonas!!! And cover gram negatives as well.

Question 20

When should you treat with antifungals in a neutropenic fever pt?

Answer 20

if there is persistent fever after 4-7 days of antibiotics

Question 21

when do most opportunistic infections occur in organ transplant recipients?

Answer 21

4weeks to 6 months after the transplant.

Question 22

Case: woman 10 weeks out from a renal transplant. she is fatigued, has fevers, abdominal pain, loose stools, and an oral sore. What is a likely diagnosis?

Answer 22

CMV. It can cause infection in the immunocompromised.

characteristics:
- subacute
- GI symptoms
- oral ulcer
- pancytopenia
- elevated transaminases.

Question 23

Case: 55yo man, renal transplant 5 years ago, takes immunosuppressives for it.
-2 weeks of flu like illness with malaise, weakness, URI symptoms, and low grade fever. He began coughing more and was out of breath after walking. PE: crackles on R. Lung. CXR shows right lower lobe pneumonia. Broncheolar lavage shows gram positive diplococci.
Likely organism?

Answer 23

strep pneumo.

probably not an opportunistic infection, due to the timeline - 5 years after the transplant
this is just the same type of pneumonia an immunocompetent person would get.

Question 24

Case: 55yo male with rheumatoid arthritis, high dose steroids and methotrexate, and started anti-TNFa treatment 10 weeks ago.

• progressive SOB
• cough (no sputum)
• fever 39C

What are the top 2 differential diagnoses?

Answer 24

Anti-TNFa therapy ddx:

• mycobacterial infections (increased risk for TB 2-10 fold, atypical mycobacterium quite common in the US)
• fungal infections (aspergillus, jirovecii, histoplasmosis)

Question 25

Which arm of the immune system does steroids impact?

Answer 25

Trick question - all of them!!

Question 26

infliximab is which type of drug?TNF-a inhibitor

Answer 26

TNF-a inhibitor