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840 > Invasive Fungal Infections > Flashcards

Invasive Fungal Infections Flashcards

1
Q

General Fungal Classifications

A
  • Yeasts: unicellular, reproduce by budding (candida, cryptococcus)
  • Molds: multicellular, filamentous colonies (aspergillus, blastolycosis, histoplasmosis)
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2
Q

Rapid Diagnostic Tests of IFIs

A
  1. B-D-glucan
  2. Mannan antigen/Anti-mannan antibody
  3. Nucleic acid PCR
  4. Galactomannan
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3
Q

B-D-glucan

A
  • Species: Candida, Aspergillosis, PJP
  • Low sensitivity and specificity
  • Limitations: Doesn’t detect cryptococcus or zygomycetes, controversy surrounding optimal cutoff value
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4
Q

Mannan/Anti-manna Tests

A
  • Species: Candida species
  • Highest sensitivity/specificity when used in combination
  • Both tests have better specificity than sensitivity
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5
Q

Nucleic Acid PCR

A
  • Species: Candida species
  • High sensitivity and specificity
  • Limitations: Using too early may decrease sensitivity
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6
Q

Galactomannan

A
  • Species: Aspergillus and some other molds
  • Relatively high sensitivity and specificity
  • Limitations: not as sensitive in non-neutropenic patients
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7
Q

Invasive Candidiasis Epidemiology

A
  • Most common IFI
  • Usually healthcare associated infections: broad antibiotic use, corticosteroids, dialysis
  • 40-50% mortality rate
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8
Q

Candida Auris

A
  • Emerging pathogen
  • Behaves more like nosocomial bacteria than traditional fungi
  • Drug-resistant and spreads in healthcare facilities
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9
Q

Diagnosis IC Difficulties

A
  • Nonspecific clinical signs/symptoms
  • Colonization vs infection
  • Physical exam: candida endophthalmitis, skin lesions, muscle soreness
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10
Q

IC Risk Factors

A
  • Central venous catheters
  • Candida colonization
  • Increasing severity of illness
  • Broad spectrum antibiotic use
  • Abdominal trauma/surgery
  • Dialysis
  • Parental nutrition
  • Corticosteroids
  • Certain surgical patients: recurrent GI perforation, anastomotic leaks, acute necrotizing pancreatitis
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11
Q

Diagnosis Candidiasis

A
  • Blood cultures = gold standard
  • 2-3 day turn-around time
  • 40-75% false negative rate
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12
Q

Candidemia Treatment Guidelines

A
  • Fluconazole: acceptable in select patients (non-critically ill, no prior triazole therapy)
  • Lipid AmB: recommended for suspected azole/echinocandin-resistant candida infections
  • Voriconazole: effective but not advantageous over fluconazole
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13
Q

Susceptibility Testing

A
  • Azole Susceptibility: recommended for all blood stream isolates
  • Echinocandin Susceptibility: consider for patients previously receiving an echinocandin or with prior C.glabrata or parapsilosis infections
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14
Q

Managing Candidemia

A
  • Remove central venous catheters if possible
  • Dilated opthalmological examination
  • Repeat blood cultures daily to establish clearance
  • Duration of therapy minimally 2 week if no metastatic complications
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15
Q

Aspergillosis Epidemiology

A
  • Ubiquitous mold existing all over world
  • Exposed via inhalation
  • Most common invasive mold infection
  • A. fumigatus is most common species
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16
Q

Aspergillosis Disease Spectrum

A
  • Immunocompetent Hosts: allergic reaction, ABPA
  • Immune impairment: chronic necrotizing pulmonary aspergillosis (fungal ball, fibrocavitary aspergillosis)
  • Immune compromised: acute, invasive aspergillosis, lower respiratory tract infection and hematogenous dissemination into other tissues
17
Q

IA Risk Factors

A
  • Prolonged neutropenia (degree and duration)
  • Recipients of hematopoietic stem-cell transplants or solid organ transplants (highest after lung transplants)
  • HIV Stage 3 (AIDS)
  • Chronic granulomatous disease
18
Q

Radiographic Findings

A
  • Halo sign: solid nodule filling with hemorrhage and edema fluid, earlier sign
  • Air-crescent sign: air between infarcted lung and surrounding lung parenchyma, late sign
19
Q

IPA Treatment Guidelines

A
  • Primary treatment: voriconazole, initiate early in those who are strongly suspected of IPA
  • Alternatives: Liposomal AmB or isavuconazole
  • Echinocandins are NOT recommended as primary therapy
20
Q

Histoplasmosis Capsulatum

A
  • Dimorphic fungi found in Central and South America
  • Most common endemic mycosis causing human infection
  • Found from animal droppings and in caves/abandoned houses
21
Q

Disseminated Histoplasmosis

A
  • Symptomatic patients are usually immunosuppressed
  • Chills, fever, anorexia, weight loss
  • GI tract: diffuse ulcerations of the mucosa (elevated liver enzymes and serum ferritin, pancytopenia)
  • CNS involvement isn’t common
22
Q

Histoplasmosis Treatment Guidelines

A
  • Chronic/Mild/Moderate: itraconazole is preferred for non-severe
  • Alternatives: AmB or fluconazole
  • Severe/CNS: Lipid formulation of AmB followed by itraconazole
23
Q

Coccidioidomycosis

A

-“Valley Fever”

Manifestations

  • Acute pneumonia
  • Chronic progressive pneumonia
  • Pulmonary nodules and cavities
  • Extrapulmonary non-meningeal disease
  • Meningitis
24
Q

Coccidioides + Acute Pneumonia

A
  • Onset: 1-3 weeks after exposure
  • Indistinguishable from CAP
  • Coccidio Sxs: severe headache and severe pleuritic chest pain, fatigue lasting weeks to month, hilar or paratracheal adenopathy (rarer)
25
Q

Coccidiodes + Sites of Dissemination

A
  • Extra-pulmonary disease: skin, lymph nodes, bones and joints (uncommon in immunocompetent)
  • Meningitis: most severe complication, substantial morbidity (diagnose with serum and CSF cultures)
26
Q

Coccidiodomycosis Treatment Guidelines

A
  • Initiate treatment in symptomatic individuals/debilitating disease: Fluconazole >=400 mg PO daily
  • Alternative: Itraconazole or AmB (or lipid formulation)
  • Treatment of asymptomatic pulmonary nodule/cavities isn’t recommended
27
Q

Cryptococcus Epidemiology

A
  • Neoformans: immunocompromised, pulmonary and meningitis manifestations, worldwide spread
  • Gattii: immunocompetent, cryptococcomas and neurologic involvement, prolonged therapy, tropical/subtropical/temperate regions
28
Q

Cryptococcus Clinical Manifestations

A
  • Blunted immune response
  • Main Clinical Presentations: pulmonary infection, cryptococcal meningitis
  • Can infect ANY organ of body: cutaneous, eye, prostate, bone, and joint
29
Q

Cryptococcal Treatment

A
  • Mild-moderate pulmonary disease: Fluconazole
  • Severe/Cryptococcal meningitis: AmB PLUS 5-FC x 2 weeks minimum (can replace with L-AmB)
  • Maintenance: Fluconazole >= 6 mo

Combination of AmB and 5-FC reduces mortality in meningitis patients

30
Q

Murcormycoses

A
  • MANY common mucorales

- Diagnosis usually made via pathology

31
Q

Murcormycoses + Immunocompetent Risk Factors

A
  • Major trauma/contaminated lacerations
  • Surgery and use of contaminated materials
  • ICU stay with high acuity
  • Iron chelation therapy
  • Burns
32
Q

Murcormycoses + Immunocompromised Risk Factors

A
  • Diabetes
  • Uremia, metabolic acidosis
  • Hematological malignancies
  • Stem cell transplant
  • Solid organ transplant
  • Immunosuppressive drugs
33
Q

Murcormycoses Clinical Presentation

A
  • Infarction and necrosis of host tissue
  • Infection usually begins in nasal turbinates or alveoli
  • Poor prognosis, mortality rates up to 90%
34
Q

Mucormycosis Treatment

A
  • Combine surgical debridement and antifungal therapy
  • Drug of choice: L-AmB
  • Alternatives: Posaconazole, isavuconazole
  • Correction of underlying host abnormalities
  • Duration: resolution of signs of infection (usually months)

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