Podcast
Questions and Answers
What is the primary method of transmission for Coccidioidomycosis?
What is the primary method of transmission for Coccidioidomycosis?
Which patient population is considered at higher risk for developing Coccidioidomycosis?
Which patient population is considered at higher risk for developing Coccidioidomycosis?
What is the typical treatment recommended for uncomplicated cases of Coccidioidomycosis?
What is the typical treatment recommended for uncomplicated cases of Coccidioidomycosis?
Which symptoms are characteristic of Coccidioidomycosis?
Which symptoms are characteristic of Coccidioidomycosis?
Signup and view all the answers
In which regions is Coccidioidomycosis primarily endemic?
In which regions is Coccidioidomycosis primarily endemic?
Signup and view all the answers
Which of the following medications is most commonly used to treat invasive aspergillosis?
Which of the following medications is most commonly used to treat invasive aspergillosis?
Signup and view all the answers
Which of the following is NOT a risk factor for Mucormycosis?
Which of the following is NOT a risk factor for Mucormycosis?
Signup and view all the answers
What is the main difference between allergic bronchopulmonary aspergillosis (ABPA) and invasive aspergillosis?
What is the main difference between allergic bronchopulmonary aspergillosis (ABPA) and invasive aspergillosis?
Signup and view all the answers
Which of the following is a characteristic finding on chest X-ray in patients with Pneumocystis pneumonia?
Which of the following is a characteristic finding on chest X-ray in patients with Pneumocystis pneumonia?
Signup and view all the answers
Which of the following statements about Amphotericin B is TRUE?
Which of the following statements about Amphotericin B is TRUE?
Signup and view all the answers
Which of the following antifungal medications is most likely to cause visual hallucinations?
Which of the following antifungal medications is most likely to cause visual hallucinations?
Signup and view all the answers
Which of the following antifungal medications is BEST for treating dimorphic endemic fungal infections?
Which of the following antifungal medications is BEST for treating dimorphic endemic fungal infections?
Signup and view all the answers
Which of the following is a TRUE statement about azole antifungal medications?
Which of the following is a TRUE statement about azole antifungal medications?
Signup and view all the answers
Which of the following is a characteristic feature of Aspergillus infections?
Which of the following is a characteristic feature of Aspergillus infections?
Signup and view all the answers
What is the main mechanism of action of Amphotericin B?
What is the main mechanism of action of Amphotericin B?
Signup and view all the answers
Study Notes
Dimorphic Endemic Fungi
-
Coccidioidomycosis ("Valley Fever"):
- Etiology: Mold in soil, yeast in the body.
- Epidemiology: Southwest US (AZ, NV), Mexico, Central America, South America.
- Transmission: Inhalation of airborne spores, rare from solid organ transplant.
- Course: Subclinical and spontaneous resolution in 50% of patients. Lifelong immunity prevents recurrence.
- Risk factors: Exposure to endemic region, dusty outdoor activities, HIV, DM, elderly, Black/Filipino patients, pregnancy.
- Symptoms: General (fever, fatigue, headache, night sweats, weight loss, arthralgias), chest (productive cough, dyspnea, hemoptysis, pleuritic chest pain), rash (erythema nodosum, erythema multiforme). Typical presentation: Arizona man working in construction.
- Testing: IgM and IgG titers, moderate leukocytosis and eosinophilia, variable imaging.
- Treatment: Uncomplicated cases resolve spontaneously. Itraconazole 200 mg PO BID x 6 months. Progressive cases: Amphotericin B IV until titers decrease. Reportable.
-
Blastomycosis:
- Etiology: Mold in soil/water.
- Example exposure: Lumberjacking/woodcutting injuries.
- Pathophysiology: Inhalation of spores, skin trauma.
- Incubation period: 30-45 days.
- Endemic regions: Ohio River Basin, Mississippi River Basin, Great Lakes, St. Lawrence River.
- Symptoms: Pulmonary (initially asymptomatic in 50%): fever, sweating, cough, nocturnal joint pain. Dissemination to bone, nervous system, lungs, liver, spleen, kidneys possible.
- Imaging: Chest X-ray, possible osteolytic lesions.
- Labs: Microscopy (broad-based budding), skin biopsy, bone marrow aspirate.
- Treatment: Itraconazole PO x 6-12 months. Severe cases: Amphotericin B. Not reportable.
Molds
-
Aspergillus:
- Pathophysiology: Produces aflatoxin, grows into surrounding tissue, can form an aspergilloma ("fungus ball"). Invasive aspergillosis commonly affects the lungs, but can spread to sinuses, CNS, eyes, etc.
- Diagnosis: Common in respiratory tree. Positive cultures alone are insufficient. Galactomannan antigen detection test needed.
- Allergic bronchopulmonary aspergillosis: Hypersensitivity to spores causing bronchiole inflammation and eosinophilia.
- Treatment: Allergic forms: Itraconazole and prednisone, or voriconazole. Invasive: Voriconazole, surgical debridement of sinusitis/focal lesions. Not reportable.
-
Mucormycosis ("Black Fungus"):
- Risk factors: DM, cancer, immunosuppression, steroids.
- Signs/symptoms: Commonly infects sinuses, eyes, and brain, often leading to tissue death due to vessel invasion.
- Diagnosis: Biopsy, culture, imaging.
- Treatment: Amphotericin B IV, surgical debridement. Poor prognosis (over 50% fatality). Not reportable.
Fungus/Protozoa
-
Pneumocystis:
- Etiology: Classified as both a protozoan and a fungal species.
- Risk factors: HIV with CD4 <200, solid organ/stem cell transplant recipients, high-dose corticosteroids (chemotherapy, rheumatology).
- Symptoms: Initial: fever, malaise, non-productive cough, progressing to sputum production, chest pain, chills, exertional dyspnea with hypoxia.
- Imaging: Chest X-ray: diffuse bilateral interstitial infiltrates, "batwinging" appearance.
- Diagnosis: Sputum sample, PCR, blood test (Beta-D-glucan). Not reportable.
Antifungal Medications
-
Amphotericin B:
- Mechanism: Binds sterols (primarily ergosterol), creating pores that leak cellular components. Targets not fungi-specific; humans have sterols too leading to side effects. Broad-spectrum; covers most yeasts, all dimorphic endemic fungi, and molds.
- Side effects: Kidney injury (>20%), low electrolytes common.
-
Azoles (e.g., Fluconazole, Itraconazole, Voriconazole, Posaconazole, Isavuconazole):
- Mechanism: Inhibiting a cytochrome P450 enzyme needed for ergosterol synthesis.
- Fluconazole: Good yeast coverage, CSF penetration, bioavailability. QTc prolongation possible.
- Itraconazole: Yeast and dimorphics, no molds. PO only. Inconsistent bioavailability, no CSF penetration. QTc prolongation possible.
- Voriconazole: Yeast, dimorphics, molds (aspergillus, not mucor). Good CSF penetration. QTc prolongation possible. Visual hallucinations (high levels) possible.
- Posaconazole: Yeast, dimorphics, molds; oral absorption issues. QTc prolongation possible.
- Isavuconazole: Similar spectrum to posaconazole, better bioavailability, QTc shortening.
- Side effects: Significant drug-drug interactions, hepatotoxicity (monitor ALT, AST), prolonged QTc (except isavuconazole), and voriconazole visual hallucinations.
- Best uses: Fluconazole (Candida albicans), Itraconazole (dimorphic endemic fungi), Voriconazole (aspergillus). Fungins: Invasive candidiasis, empiric fungal coverage (neutropenic fever). No dimorphics.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on Coccidioidomycosis, commonly known as Valley Fever. This quiz covers its etiology, epidemiology, symptoms, testing, and treatment options. Perfect for anyone interested in fungal infections and their clinical implications.
