Lecture 21: Infections in Immunocompromised Flashcards
For infections, why is there usually a delayed diagnosis in immunocompromised patients?
An impairment in the inflammatory response results in diminished symptoms and atypical presentation
Name the 3 examples of humoral defense mechanisms.
Immunoglobulins
B lymphocytes
Complement system
Infections associated with barrier injury: what are the organisms commonly seen with damaged skin?
Coagulase negative Staphylcocci
S. aureus
Central line related infex (Gram negative organisms; Candida sp.)
What organisms are commonly seen in oral mucositis?
Streptococcus sp.; anaerobes
H influenze, N meningitidis
What common organism are seen in GI mucosal barrier injury?
Gram negative rods, anerobes,
micro-aerophilic streptococci, enterococci
What organisms are typically seen in patients with antibody defects?
Encapsulated Organisms: Strep pneumoniae, N meningitidis, H influenzae
Enterovirus
Giardia
What organisms are typically seen in patients with complement defects?
Encapsulated organisms
What infectious organisms are associated with defects macrophages?
Fungi: Cryptococcus, Histo, Pneumocystis
Protozoa: Toxoplasma
Bacteria: Legionella
Parasites: Strongyloides
What infectious organisms are associated with defects in cytotoxic T-cells?
Viruses: CMV, HCV, EBV, HSV, VZV
Define Neutropenic Fever
Fever: single temp >38.3 C or sustained temp >38 C for 1 hour or more.
Neutropenia: ANC less than 500
What are the common gram positive organisms seen in neutropenic patients?
- Coag. Negative Staph (7-51%)
- Staph aureus
- Enterococcus species, like VRE
- Strep pneumoniae
- Strep pyogenes
(Mortality @ 5%)
What are the common gram negative organisms seen in neutropenic patients?
- Enterobacteriaceae (8-50%)
- Psudomonas aerginosa (28%)
- Actinobacter
- Stenotrophomonas maltophilia
(Mortality @ 18%)
What is the most important risk factor for infections in cancer patients?
Neurtropenia is the most important risk factor
Other RFs - Mucositis (infection w/oral flora or gut flora)
which predisposes to bloodstream infections
What organisms are associated with Ecthyma Gangreonosum?
Psudomonas aerginosa
Staph aureus
Fungi: candida, Aspirgillus, zygomycosis
When are anaerobes more likely an infectious cause in neutropenic patients?
Post abdominal sugery/ileus, GI abscesses
+ C. Diff associated with antibiotic use
On a chest CT scan, you see what looks like ground class infiltration, so called a “Halo sign”; what is this a major concern for?
Fungal pneumonia
What are the most common fungal infections in cancer patients?
Candida sp. (Central lines, mucositis, causes bacteremia)
Aspergillus sp. (seen in blood malignancies + neutropenia, respiratory infxs)
Pneumocystis jirovecii (pneumonia infxs)
aaaaand Cyptococcus, zygomycosis, Fusarium
Describe patients w/ neutropenia that are high risk patients.
> 7 days + profound neutropenia ( less than 100)
In high risk patients w/ neutropenic fever, what are the 3 steps of treatment?
- ) Prompt anti-gram neg antibiotics by IV (antipseudomonal, cefepime, piperacillin, carbapenem)
- ) Consider vanco - indwelling line, hypotension, pneumonia, skin infxs
- ) Add anti-fungals if persistant fever (4-7 days) post therapy
In low risk patients w/ neutropenic fever, what is the main treatment?
Oral antibiotics (cipro + amoxicillin/clavulante)
Between 4 weeks and 6 months post organ transplant, what kinds of infections are patients at high risk for?
Opportunistic, relapsed, residual infections (cause it’s the period of most intensive immunosupporession)
In the first 4 weeks post organ transplant, what infections are patients most at risk for?
Nosocomial infections (Hospital Associated Infxs)
