common opportunistic infections with HIV/immunosuppression Flashcards
9 common OIs with immunosuppression
esophageal candidiasis PCP MAC CMV KS AIDs dementia TB cryptococcosis
IRIS
immune reconstitution inflammatory syndrome • Reversal of HIV-related immune system decline with ART —-increases functional CD4 cells which causes a brisk immune response against pathogens (HIV, CMV, TB) • Restoring CD4 immunity sometimes causes hypersensitivity reaction to any existing antigen in the body! • Patients may develop OIs while immune system is recovering if antigen is present o Most commonly seen in patients with low CD4 within first few weeks of starting ART • Paradoxical response!! o Need to continue ART even though hard to distinguish from clinical failure; may be self-limited but also may need to be treated with antibiotic and steroids
PCP
pneumocystis jirovecii pneumonia pneumocystis jirovecii has tropism for the lungs o Nonspecific symptoms like fever, nonproductive cough, substernal chest tightness, SOB; ongoing and subtle for months o Fever and tachypnea o CXR – ground glass appearance; diffuse interstitial infiltrates; aerosolized pentamidine-upper lobe infiltrates o Labs – anemia, nonspecific increase in LDH
risk for PCP is
long term steroids and immunosuppression
what is an accurate indicator of susceptibility to PCP?
CD4 count
how to diagnose PCP
o Cysts or trophozoites in tissue or body fluid o Induced sputum via neb saline o BAL – bronchoalveolar lavage; very sensitive! (100%) o PCR – detect in oral washes; possible asymptomatic colonization
best treatment for PCP?
either bactram or TMP/SMX
other treatments (2nd line) for PCP?
-TMP/Dapsone –but dont use with GI issues -pentamidine - more toxic overall than TMP/SMX -atovaquone - but less effective than TMP/SMX
what to include in PCP treatment?
prednisone steroids if pO2 is less than 70 or Aa gradient >35
PCP prophylaxis
aerosolized pentamidine TMP/SMX or dapsone
salmonella sources
reptiles raw eggs/hollandaise/caesar dressing
bird poop can cause
cryptococcus histoplasmosis mac
toxoplasmosis -org? -susceptibility? -presentation?
Due to Toxoplasma gondii; Common cause of CNS space occupying lesion in AIDs patient o 3 forms: proliferative (tachyzoites), tissue cyst, and oocyst o Reactivation disease latent tissue cysts – acquired ingestion of raw meat (lamb) or cat feces • Susceptible when CD4 multiple ring enhancing lesion in basal ganglion o Serology –> IgG toxoplasma antibody = toxo
toxoplasmosis
toxoplasma gondii
what stain is best to directly visualize t gondii?
peroxidase-antiperoxidase stain
treatment for toxoplasmosis
- Pyrimethamine/sulfadiazine – 1st line; combo is synergistic
- Sequential blocks of folic acid metabolism that is required for T gondii proliferation
- Cysts remain viable and account for relapses
- Add leucovorin to rescue other cells
- Use steroids if cerebral edema is present
toxoplasmosis prophylaxis?
tmp/smx
tmp/smx stands for
Trimethoprim/sulfamethoxazole (TMP/SMX)
cryptococcal meningitis
- Caused by fungus C. neoformas; inhalation –> disseminates to CNS and other organs
- In patients with CD4<100
- Symptoms = days to weeks; headache, altered MS, meningismus, seizures, CN palsies; fever
- **all HIV patients with fever should have a serum cryptococcal antigen; less likely disease if on an azole
diagnosis of cryptococcal meningitis
- CRAG (cryptococcal antigen test) – latex agglutination test of cryptococcal polysaccharide antigen of capsule; very sensitive and rapid; uses blood, csf, or other body fluid
- Blood culture – can grow c neoformans; if found extraneurally –> poor px
- Csf exam = crypto antigen
- CT scan – normal
- MRI with GAD = basilar meningitis with meningeal enhancement
treatment for cryptococcus meningitis
-
AmphoB with 5FC (flucytosine) for first 2 weeks
- After no more headache or fever –> switch to fluconazole (better tolerated and less toxicity)
- Fluconazole can be first choice if MS is normal, CSF count >20, CSF crypto antigen <1:1024
-
AmphoB with 5FC (flucytosine) for first 2 weeks
CMV chorioretinitis
- CD4 cell count is main risk factor
- Begins unilaterally –> progresses to bilateral involvement secondary to viremia
- Symptoms: decreased visual acuity, floaters, visual field loss
- Exam = yellow/white granular areas with perivascular exudate and hemorrhages (cottage cheese and ketchup); begins in periphery of fundus and if untreated progresses to macula and optic disc
CMV chorioretinitis diagnosis
- Visual – dilated fundus exam
- CMV antibody indicates past exposure
- CMV blood culture – viremia common
- Routine dilated opth exams if CD4<50
IRU
-
(immune recovery uveitis) – reconstitution syndrome
- Vitreous inflammation, macular edema, and inactive or regressed CMV; only occurs in patient with immune recovery
- Persistent antigenic load in the eye
treatment of cmv chorioretinitis
- Gangiciclovir, foscarnet, or valganciclovir
- CMV systemic treatment =cidofovir (broad spectrum; long intracellular half life)
- CMV primary prophylaxis is not standard of care
MAC
(mycobacterium avium complex)
- Intracellular org; found in fresh water, sea water, soil, animals, dairy products
- Enter via GI or respiratory
- After ingestion –> spreads locally in lymphatics and then disseminates hematogenously
- Mycobacteria taken up by mononuclear phagocytic cells and reticuloendothelial cells: spleen, liver, bone marrow
- Pulmonary/COPD; cervical adenitis in kids
- Patients with CD4<100; marker of immune system failure
- Presentations
- Fever, night sweats, diarrhea, weight loss, anemia
- Reticuloendothelial disease = intraabdominal lymphadenopathy, hepatosplenomegaly
diagnosis of mac
- Isolator tube (AFB blood culture) – lytic agent/anticoagulant; promotes lysis of WBC to increase yield of culture since MAC is intracellular
- Blood or stool culture – dissemination
treatment of MAC
- Use MULti-TX – atleast 2 drugs for life or until ART immune recovery
- 1st = clarithromycin or azithromycin
- 2nd = ethambutol
- And one of more of: raifabutin, rifampin, ciprofloxacin, amikacin
- Prophylaxis = macrolides (clarithromycin or azithromycin)
