Opportunistic Fungal Infections Flashcards Preview

Micro/Immuno > Opportunistic Fungal Infections > Flashcards

Flashcards in Opportunistic Fungal Infections Deck (11):

Opportunistic fungal pathogens may cause

local symptoms in previously-healthy patients, but are seldom dangerous without specific predispositions: think prolonged NEUTROPENIA, uncontrolled HIV or diabetes, profound T-cell suppression (PUN). Effective treatment deals with current infection and underlying problem


Cryptococcus is

1. widespread environmental (pigeon droppings), enabled by reduced CMI (not enough helper T's or Abs to capsule), and suppresses host inflamm response (wide polysaccharide capsule); VERY LITTLE INFLAMM RESPONSE, also has melanin in cell wall that's antiphagocytic and phospholipase B to invade tissue
2. presents late in disease with meningitis and skin nodules or pulmonary symptoms (immunocomp host keeps it in lungs)
3. diagnose by biopsy, CSF (stain with India ink), crag (cryptococcal antigen in blood and CSF)
4. treat with combo of azoles and amphotericin B (with flucytosine for meningitis or cryptococcoma)

NOT THERMALLY DIMOPRHIC; no human-to-human, only INHALED!!


Aspergillosis presents as

ABPA, aspergilloma, CNPA, or invasive (look for septate hyphae with V-shaped branches); airborne


ABPA (allergic bronchopulmonary aspergillosis) is a

hypersens rxn to infection complicating asthma or CF (cough up brownish bronchial plugs with hyphae);
diagnose on exam (Xray or CT could show clusters of mucus-clogged bronchi), treat with itraconazole (and oral corticosteroids), sinus surgery, Xolair (SIC X)


Aspergilloma or _____ IS a

colonizing aspergillosis; fungus ball complicating cavitary lung disease, and diagnose by air cresent on scan (X-ray or CT), treat with itraconazole and/or surgery

The crescent moon does not look like a ball!!


CNPA (chronic necrotizing pulmonary aspergillosis)

mimics TB (and can cause pneumonia with hemoptysis and granulomas); underlying disease of alcoholism, collagen-vascular disease, COPD or chronic granulomatous disease with long-term corticosteroid therapy; try to diagnose by air crescent on scan, needle-aspirate lung fluid for microscopy

PA trying to MIMIC an actual doctor like TB


Invasive aspergillosis presents as

respiratory distress with history of profound immunosuppression with things like corticosteroids(infarction, hemorrhage, necrosis, often fatal);
diagnose by halo sign on CT scan, needle or tissue biopsy for histo

In Halo, a different species is INVADING, and they are not cute (acute angle of branching hyphae); I can't breath anymore


Treat CNPA and invasive with

voriconazole and Amphotericin B, but POOR PROGNOSIS


Mucormycosis, caused by ____ or ____, is a

Mucor, Rhizopus; very rare deadly invasive vasculitis by environmental mold, causes infarction, and invades brain from sinuses (can prolif in lungs, gut, skin, disseminated);
2. predisposition by uncontrolled diabetes, iron overload, immunosuppression
3. diagnose by biopsy (nonseptate hyphae branching at right angles) and culture (spores in sporangium) for histo (RHINOCEREBRAL PRESENTATION)
4. treat with amphotericin B and aggressive surgical removal of diseased tissue, POOR PROGNOSIS;


Dead On Impact (predisposing factors)
At the RIGHT angles we can trap the SPORES!! (diagnosis)
Matt Ryan has ABS (treatment)


Fusarium is a

1. ubiquitous environmental mold, with infection rare overall but frequently fatal in predisposed population (banana-shaped macroconidia)
2. could cause mycotoxicosis (contaminated grain; get alimentary toxic aleukia), local infection (burns, prosthetic implants, contaminated contact lens solution), or deadly disseminated infection (prolonged neutropenia, HSCT recipients, long term use of steroids)
3. enters from sinus or wound site, circulates in blood, with symptoms in skin, eye, lung
4. diagnose by blood culture, histo (yeast form with acute-branching hyphae)
5. Treat aggressively with surgery, amphotericin B, voriconazole, (prevention is keeping high-risk patients in HEPA-filtered rooms at positive pressure); POOR PROGNOSIS

You won't make such a FUSs if you have a banana!! Prospects look DIM if you are infected with fusarium (what it could cause);


Aspergillosis: diagnosis

colonies with radiating chains of conidia; look for septate hyphae branching at acute angles in invasive case; in ABPA, look for IgE specific to aspergillus and eosinophilia