Lec46 Opportunistic Infections Flashcards
What are opportunistic pathogens?
- lack intrinsic virulence
- almost exclusively cause disease in individual with impaired host defense
What are principal pathogens?
- have intrinsic virulence and cause regular disease in pts immunocompetent
- occur with more frequency/severity in pts with impaired host defense
What are you at more risk for with defect in cell mediated immunity?
viral pathogens
What are you at more risk for with defect in neutrophils?
bacterial and fungal infections
How do you measure severity of neutropenia?
absolute neutrophil count
= WBC * (%neutrophils + %bands)
How do you restore immune function in neutropenic pt?
- use GCSF or other growth factor
What are four different stains used for pneumocystis and what do they stain?
GMS stain: cyst forms in bronchioalveolar lavage
Wright-Giemsa stain: stains trophic forms in foamy exudate
Calcofluor white: stains fungal cyst wall
DFA: shows cysts sand trophic forms
What are two diseases to look out for in pt with CD4 < 50?
- disseminated mycobacterium avium complex
- cytomegalovirus
When does HIV pt start to have high risk of PCP pneumonia?
at CD4 < 200
Pt with low CD4 and hypoxemia what should you think?
PCP pneumonia
What stain to find mycobacterium avium complex?
AFB stain
What are symptoms of MAC?
disseminated diseased in AIDS characterized by: bacteremia, fever/chills/sweat/weight loos/diarrhe, bone marrow suppress [anemia, low WBC]
How do you diagnose MAC?
use of special blood culture bottles and can take wks
How do you prevent MAC [mycobacterium avium complex]? Treat?
prevent: azithromycin prophylaxis
treat: 2-3 drug combo and restoration CD4
Fever/headache then seizure + ring enhancing lesions in brain with AIDS? What should you think?
cerebral toxoplasmosis
Fever/headache then seizure without enhancing lesions in brain with AIDS? What should you think?
cryptococcus neoformans [cryptococcus meningitis]
What are clinical findings of JC virus?
- no disease in immunocompetent
in AIDS: enters through resp tract and latent in kidney, reactivation –> viremia and infection of oligodendrocytes –> demyelinating disease
How is JC virus transmitted?
via respiratory tract
What is treatment for JC virus?
no treatment, poor prognosis