Microbiology - Pulmonary fungal infections I (Dimorphs)/II (Opportunitic Infections) - Greenblatt Flashcards
How is histoplasma treated?
Treat serious lung w/ itraconazole, meningitis w/ fluconazole, disseminated w/ Amphotericin B
What are the important diagnostic factors in the diagnosis of histoplasma?
look for pancytopenia and ulcerations on tongue. Also for diagnosis: history (birds, bats, endemic area, immunocompromised, occupation), biopsy for yeast in macrophages, cultures for dimorphism, ELISA for antigen.
What are the manifestations of histoplasma infections?
causes pulmonary symptoms, previously-healthy usually clear or contain in granulomas, higher-dose infection produces TB mimic, CMI-deficient host disseminates in macrophages (yeast survive lysosomal fusion)
What kind of organism is histoplasma?
thermally dimorphic (mold/yeast), endemic to Ohio, Missouri, and Mississippi river valleys, soil-based, infectious microconidia can be kicked up by construction projects
What kind of organism is coccidiodes?
thermally dimorphic (mold/spherule), endemic to US Southwest, mold grows in wet weather, releases infectious arthrospores in dry, spores inhaled, change form
How is coccidiodes treated?
Treat if predisposed to complications (oral azoles), meningitis (fluconazole), pregnant or disseminated (Amphotericin B)
How is coccidiodes diagnosed?
Diagnose by exam, history, PPD, biopsy for spherules, culture for dimorphism, serology for dissemination
What are the risk factors for coccidiodes infection?
Risk factors: age, race, pregnancy, immunocompromise, occupational high exposure
What are the symptoms of severe coccidiodes?
severe: major pneumonia or dissemination (either bare or in macrophages)
How do most coccidiodes infections clear?
60% Mild: asymptomatic or flulike clearance by innate or containment by CMI,
moderate: valley fever/ desert rheumatism: pulmonary+EN,
What kind of organism is blastomyces?
thermally dimorphic (mold/yeast), endemic to Eastern US.
How do most cases of blastomyces resolve?
Innate immunity clears most cases, destroys conidia easily, yeasts are harder to kill (BAD1),
graulomatous response contains most, immunosuppression predisposes to hematogenous spread.
Moderate acute: pneumonia w/ purulent sputum,
Moderate chronic: mimics TB, Severe acute: ARDS.
May include EN or ulcerating skin lesions.
How is blastomyces diagnosed?
Diagnose by sputum microscopy for yeast, culture for hyphae w/ pear-shaped conidia, biopsy for yeast w/ supperating (not caseating) granulomas.
How is blastomyces infection treated?
Treat w/ itraconazole, fluconazole if meningitis, Amphotericin B if severe.
What kind of organism is paracoccidiodes?
thermally dimorphic (mold/multibud yeast), endemic to rural Latin America
Paracoccidiodes is dangerous to what populations?
severe in children/immunocompromised, moderate in adults, usually men in agriculture or construction.
What are the symptoms of paracoccidiodes infection?
Adult form has very long latency, skin&mucous lesions
How is paracoccidiodes diagnosed?
Diagnose by pus or tissue KOH mount for yeast with multiple buds, culture
How is infection with paracoccidiodes treated?
Treat w/ itraconazole, Amphotericin B if severe, combine with healthier lifestyle (semi-opportunistic).
What specific predispositions make opportunistic fungal pathogens dangerous to patients?
Opportunistic fungal pathogens may cause local symptoms in previously-healthy patients but are seldom dangerous without specific predispositions: prolonged neutropenia, uncontrolled HIV or diabetes, profound T-cell suppression.
How is cryptococcus infection treated?
Treat with combinations of azoles and Amphotericin B
How does infection with cryptococcus resolve?
Cryptococcosis is widespread environmental, enabled by reduced CMI, suppresses host inflammatory response. Infection originates in lung but usually either clears or progresses to meningitis.
How do patients present when they are infected with cryptococcus?
Patient presents late in disease with meningitis and skin nodules or pulmonary symptoms.
How is cryptococcus infection diagnosed?
Diagnose by biopsy, CSF, crag
How does aspergillosis present?
Aspergillosis presents as ABPA, aspergilloma, CNPA, or Invasive.
ABPA is a hypersensitivity rxn to infection complicating asthma or CF, diagnose on exam, treat w/ itraconazole, sinus surgery, Xolair
Aspergilloma (colonizing aspergillosis) is a fungus ball complicating cavitary lung disease, diagnose by air crescent on scan, treat w/ itraconazole and/or surgery
CNPA mimics TB; try to diagnose by air crescent on scan, needle-aspirate lung fluid for microscopy
What is ABPA?
Presentation type of aspergillosis
ABPA is a hypersensitivity rxn to infection complicating asthma or CF, diagnose on exam, treat w/ itraconazole, sinus surgery, Xolair
What is aspergilloma?
Presentation type of aspergillosis
Aspergilloma (colonizing aspergillosis) is a fungus ball complicating cavitary lung disease, diagnose by air crescent on scan, treat w/ itraconazole and/or surgery
What is CNPA?
Presentation type of aspergillosis
CNPA mimics TB; try to diagnose by air crescent on scan, needle-aspirate lung fluid for microscopy
How is CNPA treated?
Treat CNPA and invasive with voriconazole+AmphotericinB, but prognosis is poor.
How does fusarium infection present clinically?
May cause mycotoxicosis (from contaminated grain), local infection (burns, prosthetic implants, contaminated contact lens solution), or deadly disseminated infection (prolonged neutropenia, HSCT recipients).
Enters from sinus or wound site, circulates in blood, symptoms in skin, eye, lung
What organisms cause mucormycosis?
Mucormycosis caused by Mucor or Rhizopus is a very rare deadly invasive vasculitis by environmental mold, causes infarction, invades brain from sinuses.
What conditions predispose patients to mucormycosis?
Predisposition by uncontrolled diabetes, iron overload, immunosuppression.
How is mucormycosis diagnosed?
Diagnose by biopsy for histo, treat with amphotericin B and aggressive surgical removal of diseased tissue, prognosis poor.
How is fusarium diagnosed?
Diagnose by blood culture, histology
How is fusarium infection treated?
Treat aggressively with surgery, amphotericin B, voriconazole, prognosis poor
Where is fusarium found?
Fusarium is a ubiquitous environmental mold, infection is rare overall but frequently fatal in predisposed population
