Behind the Scenes Videos
Antifungal Agents: A Clinical Summary
Key Points:
- Azoles:
- Older agents: yeast-only activity
- Newer agents: active against yeast, mold, some dimorphic
- Amphotericin:
- Broad yeast and mold coverage; use limited by adverse effects
- Echinocandins:
- Strong yeast activity; limited mold coverage
- Neutrophil activity is the best defense against fungi
- Neutrophil activity and function are equally important.
Amphotericin In Clinical Practice
Key Points:
- Binds ergosterol, destabilizing fungal cell membranes
- First-line for cryptococcal meningitis, mucormycosis, severe dimorphic infections.
- Reserved for infections resistant to azoles and echinocandins.
- Major toxicities: nephrotoxicity, hypokalemia, hypomagnesemia, and infusion-related reactions.
- Liposomal formulations reduce toxicity.
Thrush: Physical Exam Findings
Key Points:
- Suspect thrush when scraping of the tongue:
- Removes a creamy white substance
- Leaves an erythematous base
- Risk factors include:
- Antibiotic exposure
- Steroid use
- Immunosuppression
Candidemia: Making The Diagnosis
Key Points:
- High risk patients: severely immunosuppressed (i.e. chemotherapy), recent surgery/ instrumentation, and ICU stay.
- Blood cultures are~50% sensitive; repeat cultures often needed to confidently exclude the diagnosis.
- Beta-D-Glucan (BDG) is a component of most fungi’s cell walls; positive test is nonspecific.
- Sensitivity improves with repeat cultures and + BDG
Aspergillosis: Who’s At Risk And How We Find It
Key Points:
- Galactomannan is a component of Aspergillus cell wall.
- Other fungi such as Histoplasma and Fusarium may less frequently result in a positive galactommanan assay.
- Only test patients with risk factors.
- Primary risk factors for invasive Aspergillosis:
- Anatomical dysfunction (ex. bronchiectasis)
- Neutropenia / neutrophil dysfunction
- Status post solid organ transplant