Infections in an immunocompromised host. Flashcards
What infections are associated with central line infections? - 2
gram negative org’s
and candida
What infections are associated with oral mucositis? - 4
- streptococcus sp.
- anaerobes
- H. influenzae
- N. meningitidis
Defects in antibodies make a patient susceptible to which type of infections? Name the three organisms in this category
- encapsulated organisms!!
- Streptococcus Pneumoniae
- N. Meningitidis
- H. influenzae
also, antibody defects predispose to enterovirus and giardia
Defects in macrophages predispose to which type of infections?
intracellular organisms!!
- fungi
- protozoa
- legionella
- parasites (strongyloides)
Defects in cytotoxic T cells predispose to which types of infections?
viruses.
Which tests do you order in someone with neutropenic fever? - 7
- CBC/diff
- creatinine
- hepatic enzymes
- total bilirubin
- 2 sets of blood cultures
- culture specimens from other sites of infection
- chest radiograph or chest CT
What are the criteria for neutropenic fever?
Fever
-single temp>38C or a sustained temp >38C for 1 hr
Neutropenia
-absolute neutrophil count
what is the most common source of infection in neutropenic fever? - 2
- patient’s endogenous flora (break in skin / mucositis)
- nosocomial infection
T/F: Neutropenic fever is usually due to gram positive organisms
False. It is 50/50 gram pos/ gram neg. However gram negative is more fatal!!
Most common gram positive organisms causing neutropenic fever.
- coag negative staph (7-51%)
- staph aureus
Most common gram negative organisms causing neutropenic fever.
- enterobacteriaceae
- pseudomonas aeruginosa
What are the 2 most important risk factors for infection in cancer patients?
- Neutropenia (especially >7 days)
- Mucositis
Patient has neutropenia and oral mucositis. What organisms would you expect to cause an infection? -3
- streptococcus sp (viridans strep)
- oral anaerobes
- candida sp.
Patient has neutropenia and mucositis in his gut. What organisms would you expect to cause an infection? -3
- enterobacteriacea sp.
- psudomonas aeruginosa
- enterococcus
- candida
Patient is neutropenic and has a central venous catheter. What org’s would you expect?
- coag negative staph
- gram negative rods
- candida
might see polymicrobial infection
what is ecthyma gangrenosum and what causes it?
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.
What are the most common fungal infections in cancer patients?
- candida sp.
- aspergillus sp.
- pneumocystis jirovecii
Who should you admit (and give IV antibiotics) with neutropenic fever?
"High risk pt's" Definition: profound neutropenia (
Which antibiotics should you treat “high risk” neutropenic fever pt’s with?
-give them antibiotics which cover pseudomonas!!! And cover gram negatives as well.
When should you treat with antifungals in a neutropenic fever pt?
if there is persistent fever after 4-7 days of antibiotics
when do most opportunistic infections occur in organ transplant recipients?
4weeks to 6 months after the transplant.
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?
CMV. It can cause infection in the immunocompromised.
characteristics:
- subacute
- GI symptoms
- oral ulcer
- pancytopenia
- elevated transaminases.
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?
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.
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?
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)
Which arm of the immune system does steroids impact?
Trick question - all of them!!
infliximab is which type of drug?TNF-a inhibitor
TNF-a inhibitor
