ID: Infections in Cancer and Transplant Patients

Question 1

List causes of immunocompromise

Answer 1

• Disease related e.g.
  
  • Acute leukaemia
  • AIDS following chronic HIV
  • Rheumatoid Arthritis
  • Diabetes especially during DKA
• Iatrogenic e.g.
  
  • Chemotherapy for cancer
  • Therapy with DMARDs
  • Steroids for COPD

Question 2

What does immunocompromise risk depend on?

Answer 2

Defect

Depth

Duration (e.g. breast cancer only brief suppression for chemo, whereas HSCT immunosuppressed for long time)

Question 3

What are the causes of neutropenia?

Answer 3

Quantitative

• Inherited
• Acquired
  
  • Drug induced
    
    • cytotoxics
    • adverse drug reaction
  • Bone marrow irradiation
  • Cancer related (invading bone marrow)
  • Aplastic anaemia

Qualitative

• Defects in
  
  • chemotaxis
  • opsination
  • intracellular killing

Question 4

Explain the phases of opportunistic infections among allogeneic HSCT recipients in relation to engraftment

Answer 4

Question 5

How is febrile neutropenia defined?

Answer 5

• Single temporature of >38.3 or sustained temperate >38 for 1 hour
• Occuring in pt with neutrophils <500 cells/uL or <1000 cells/uL with predicted nadir of <500 cells/uL

Question 6

What are the signs (sometimes) or fever in the neutropaenic patient?

Answer 6

Medical emergency! Often no signs; has no neutrophils.

On examination:

• elevated pulse
• low BP
• high temp
• mucositis (?)
• nil to hear in chest
• nil to palpate

Question 7

What are the guidelines for treatment of fever in neutropaenic patient?

Answer 7

• infections caused 70% of deaths in acute leukaemia patient
• consensus guidelines recommend ALL patient with neutropaenic fever be promptly evaluated
• treated with empiric broad-spectrum antibiotics
• ~10% mortality per hour delay in antibiotic treatment

Question 8

What are the most common infections in febrile neutropaenia?

Answer 8

• Gram-postive organisms
  
  • MSSA, MSRA
  • Staphylococcus epidermidis
  • Streptococci (especially viridans group)
  • Enterococci (VRE)
• GNB in the 1980s (particular P. aeruginosa)

Question 9

What antimicrobial management is given to febrile neutropenic patient?

Answer 9

Tazocin 6 hourly

+ Vancomycin if in shock

THEN

Targeted therapy when organism identified

Question 10

What are the common infections in solid-organ transplant in recipients?

Answer 10

Question 11

Which fungal infections are we worried about in transplant recipients?

Answer 11

Candida - prophylaxis has reduced morbidity/mortality but increased resistance

Aspergillus, Fusarium, Zygomycetes - “halo sign” surrounding a nodule = small vessel angioinvasion

Question 12

Explain fever in a post-splenectomy patient

Answer 12

• Spleen maintains normal immune function
• Severe infections in 25% patients
  
  • S pneumoniae (50-90%)
  • N meningitidis, Hib
• Greatest risk infection first 6 months
• Management = empiric antibiotics (ceftriazone plus vancomycin)
• Pevention = vaccination, prophylactic antibiotics, education