Fungi Flashcards
What are the mycoses that are systemic infections?
Histoplasmosis
Blastomycosis
Coccidioidomycosis
Paracoccidioidomycosis
What fungi is common among farmers in the Ohio River Valley and causes granulomas in the lungs?
Histoplasmosis
- respiratory route from fucking caves, bat/bird droppings, and farmers
If an immunocompetent patient is infected with Histoplasmosis, what might be found on microscopy and x-ray?
- Chronic Cough, granuloma w/ fibrosis in the lung
- Yeast form
- Multiple ovul bodies within Macrophages, lungs/liver
What are symptoms a patient might expect from histoplasmosis?
- Resp Symptoms
- Hepatosplenomegaly
- Erythema Nodosum – from immune response
How do you differentiate a granuloma of histoplasmosis from TB?
Both have granulomas in the lungs and have similar respiratory symptoms
- TB would have night sweats
- Histo - hilar calcification, antigen in urine/serus
- *Need to biopsy**
If you are looking at a respiratory biopsy with KOH and notice broad budding yeast, what is the likely infection?
Blastomycosis
- blasto buds broadly
- yeast in heat, mold in cold
What are the typical manifestations of blastomyocosis?
Typically asymptomatic in competent hosts with a hazy infiltrate in the lungs
Immunocompromised = systemic spreading to bones (osteomyelitis) and skin
Where is Coccidioidomycosis usually located and why?
Southwest US
- spreads in the air from dust of soil
- earthquakes, dust storms, construction
What is the most concerning manifestiation of Coccidioidomycosis in immunocompromised individuals?
Can spread to the Meninges causing meningitis
How does coccidioidomycosis look under microscopy?
- Spherule filled with Endospores
What fungi would you be suspicious of if you saw a “Captain’s Wheel” formation on KOH stain?
Paracoccidiodomycosis
How do the symptoms of Coccidio compared to Paracoccidio?
Coccidio – pneumonia, meningitis, bone spread
Paracoccidio – granulomatous lungs, cervical LAD, Musosal ulcers in the mouth and upper resp
What has Spaghetti and Meatball appearance on KOH stain?
Malassezia furfur / Pityriasis Versicolor
Hot / Humid near the equator with scattered hyper and hypopigmentation on the torso?
Malassezia furfur / Pityriasis Versicolor
- only affects the top layer of skin without any itching or irritation, changes pigmentation
- Selenium Sulfate
Who are at risk for systemic Malassezia furfur?
Infants who are getting TPN and Lipid infusions, because M. Furfur love lipids and thrive in blood.
How can you diagnosis a tinea infection?
- KOH with hyphae present
- Woods Lamp will illuminate
What are common oral drugs to treat tinea infections, especially onychomycosis (of the nail)?
Terbinafine
- if needed Griseofuvum
What fungi can commonly infect gardeners and has a “cigar-like yeast” form in the infected wounds?
Sporothrix Schenckii – “Rose Gardeners Disease”
– getting cuts by thorn bush or other plants
What is a unique characteristic of Sporothrix Schenckii?
Ascending Lymphadenitis from the inoculation site
- Red raised bumps
If you find a person who has oral candida and candida esophagitis, what could that indicate?
They are immunocompromised and with the esophagitis must have CD4 count below 100. AIDS defining illness.
How can you compare bacterial vaginosis vs vaginal candida?
Vaginal candida does not change the pH
Bacterial Vaginosis / Trichomoniasis increases the pH to become more basic
What might you find if a patient has had several bouts of Aspergillus Fumigatus who is not immunocompromised?
Chronic Granulomatous Disease
- Defective NADPH Oxidase (Resp Burst)
- Increased infections by CATALASE POSITIVE
What is unique about Aspergillus microscopic characteristics?
Not Dimorphic, branched 45 Degree Hyphae
- “Acute Angle Branching”
- Catalase Positive
- Conconidia stalks
Why does Aspergillus Fumigatus cause a person to have increased risk of heptatocellular carcinoma?
Produces Aflatoxin – associated with liver cancer
What are common clinical manifestations of Aspergillus in competent vs compromised patients?
Only affects Immunocompromised patients.
Allergic Bronchopulmonary Aspergillus
Aspergillomas – after TB infections
Angioinvasive Aspergillosis – invades blood vessels
What are the characteristics of Cryptococcus Neoformins?
Encapsulated – Thick walls (UNIQUE) - polysacchride
Urease (+)
– transmitted via aerosol pigeon droppings
– looks like wide capsular halos
How can you tell if you have Cryptococcus or something else?
Stains - Mucicarmine - Methanamine Latex-Agluttination Test, detects polysacc capsule ** "Soap Bubble lesions" in the head
What are the most common clinical finding of cryptococcus neoformins?
- Meningitis (Most common fungal meningitis)
- Pneumonia/Cough/Fever
What is a unique medication used to treat Cryptococcus neoformins?
Flucytosine
+ Amphotericin B
A patient who has DM and has poorly controlled blood sugar and has several bouts of DKA per year, what might they be more prone for infection of?
Mucormycosis
- Loves Ketones, then proliferates in blood vessels
What is the most common clinical syndrome of patients infected with Mucormycosis?
- black eschar on face and nose
- necrosis of the nasal passage way and frontal sinuses
What is the unique microscopic look of Mucormycosis?
90 degree hyphae branching (Wide Angle, Nonseptate)
When might you see an infection of Pneumocystis pneumonia / jirovicii?
When an HIV patient’s CD4 count is BELOW 200
– Must be very immunocompromised to become infected with pneumocystis
What would the look of pneumocystis look like on exam?
CXR – ground glass appearance
Micro – methamine silver stain – disc shaped yeast
What is the common appearance on microscopy of candida?
Yeast Buds WITH Hyphae (Blastoconidia)
If you biopsied a specimen at 37 degrees and found “cigar-shaped” budding yeast, what clinical symptoms might you expect?
Sporothrix Schenchii
– Ascending ulcerative lymphadenitis from initial site of entrance.
What respiratory fungi would you expect different morphology on biopsy vs culture?
- Sporothrix Schenckii
- Cocciioides
- Histoplasmosis
- Blastomycoses
- Paracoccidioides
If a culture is taken of a skin lesion and it is found to have spores with endospores present, but on culture it has hyphae, what might the organism be?
Coccidiodes immitis
What is the smallest respiratory fungi that causes granulomas and has branching hyphae on culture?
Histoplasmosis
- Biopsy – Oval yeast within Macrophages
What is a common fungi that is located near the great lakes in the soil with branching hyphae upon culture from sputum sample?
Blastomyces
- BIOPSY - “Broad Budding Yeast” B - B - B
What fungi is found to have budding blastoconidia upon biopsy, that can resemble a “Ship’s Wheel” or Pilot Wheel formation?
Paracoccidiodes
- South America/Central America
- Yeast form with multiple budding from the central yeast, thus making the wheel and spokes formation
What are common NONE DIMORPHIC fungi?
- Aspergillus
- Cryptococcus
- Rhizopus/Mucor/Absidia
What is the difference in morphology between Aspergillosis and Mucormycosis?
Aspergillosis – A–> Acute Angle Branching of septate hyphae
Mucor –“Wide Angle” branching of nonseptated hyphae
**Both infect the immunosuppressed
What fungi has fungus balls and typically is found invading pre-existing cavitations in the lung (from TB)?
Aspergillus
- Fungus Ball – likes invading cavities
- Immunocompromised
What fungi that commonly causes meningitis in immunocompromised patients has a thick walled spherules?
Cryptococcus
- stains with india ink
- THICK WALLED (KEY)
What antifungal drug binds ergosterol and forms a pore on the membrane surface?
Amphotericin B – used for systemic infections
– Dose dependent renal toxicitiy
What antifungal drug inhibits 2,3-squalene 2,3 epoxide?
Terbinafine – used for skin/nail dermatophytes
What antifungal drug inhibits fungal microtubules inhibiting mitosis?
Griseofulvin
What antifungal drug blocks the production of 1,3-beta-D-glucan synthesis?
Caspofungin
– blocks fungal wall synthesis
What is the mechanism of the Azole drug class of anti-fungals?
Inhibit fungal cytochrome P450 activity
- prevents ergosterol production
What metabolite analog is used to inhibit fungal DNA/RNA synthesis?
Flucytosine
