Fungi Flashcards
Histoplasma Capsulatum (Histoplasmosis): where is it located, how is it transmitted, and what does it look like?
- midwestern/central U.S. (Mississippi/Ohio Rivers)
- from bird/bat poop (recently in cave/chicken coop)
- inhaled spores, phagocytosed yeast (macrophages with intracellular oval bodies on KOH prep)
Dimorphic! (mold in the cold/yeast in the heat)
Histoplasm Capsulatum (Histoplasmosis): what four things does it cause clinically? (PECH)
- MIMICS TUBERCULOSIS (pneumonia/granuloma formation in lungs, erythema nodosum of shins. calcified lung deposits)
disseminated histoplasmosis (immunocompromised) can cause hepatosplenomegaly
Blastomyces Dermatitidis: where is it located, how is it transmitted, and what does it look like?
- Southern/Eastern US (Great Lakes/Ohio River Valley)
- inhaled as mold spore (aerosol/dimorphic)
- broad based budding; same size as RBC
Blastomyces Dermatitidis: what does it cause clinically?
- patchy alveolar infiltrate on Lung X-Rays
- pulmonary granuloma formation (lesions and cavities)
- disseminated (immunocompromised) –> skin (lesions), genitourinary problems, bone (osteomyelitis)
Coccidioides Immitis (San Joaquin Fever): where is it located, how is it transmitted, and what does it look like?
- California and Southwest US
- inhaled mold spores (earthquakes inc. spread)
- Dimorphic; forms spherules filled with endospores inside the lung (larger than RBCs)
Coccidioides Immitis (San Joaquin Fever): what does it cause clinically?
- self-limited community acquired pneumonia (cough/fever/arthraligia)
- unilateral infiltrate on chest X-Ray that is unremarkable in half of affected patients; associated with erythema nodosum on shins
- disseminated (immunocompromised) can cause skin and bone lesions as well as cause MENINGITIS
Paracoccidioides Brasilinesis: where is it located, how is it transmitted, and what does it look like?
- Brazil and South America
- transmitted as respiratory droplets
- Dimorphic; yeast looks like a “Captains Wheel”; larger than RBCs
Paracoccidioides Brasilinesis: what does it cause clinically?
- leads to pulmonary granuloma formation
- disseminated causes cervical lymphadenopathy
- chronically presents as mucocutaneous lesions of the mouth
Malassezia furfur (Pityriasis versicolor): what does it look like and where is it mainly found?
- lipid-dependent fungus
- “spaghetti and meatballs” appearance on KOH prep
- stays only in the stratum corneum (most superficial layer) –> trunk and upper extremities
Malassezia furfur (Pityriasis versicolor): what does it cause clinically and who is it commonly associated with?
- hypo/hyperpigmentation on trunk and upper extremities (produces melanocyte damaging acids via lipid degradation)
- associated with NICU neonates receiving Total Parenteral Nutrition via Catheters (inc. lipid transfusions)
Dermatophytes (Tinea –> RINGWORM): where is it found and how is it acquired?
- acquired from infected pets and is commonly associated with swimmers/wrestlers (athletes)
- hypae can be visualized on KOH skin scrap prep
- most infections are pruritic (cause itching)
What does Tinea Capitis, Tinea Corporis, Tinea Cruris, and Tinea Pedis cause?
T. Capitis –> head and scalp infection
T. Corporis –> body infection
T. Cruris –> groin (“Jock’s Itch”)
T. Pedis –> foot (“Athlete’s Foot”)
Sporothrix Schenckii (Rose Gardener’s Disease): how is it acquired, what does it look like, and what does it cause clinically?
- found in soil and plant matter, and is commonly transmitted by cuts from Rosebush thorns
- dimorphic; yeast looks like elongated cigar-shapes w/granulomas
- causes local ulcer @ site of infection, and can infect lymphatics causing ascending lymphatic infection (subcutaneous)
Candida Albicans: what does it look like and what is a positive test for it?
- dimorphic BUT –> yeast in cold and mold in heat
- CATALASE (+)
- usually normal GI tract flora
Candida Albicans: what does it cause clinically? (4) - (DR/OT/VI/IE)
- diaper rash in infants
- disseminated disease in immunocompromised
- oral thrush, HIV-associated esophagitis (CD4 < 200)
- AIDS-defining illness
- vulva/vagina infection
- vulvar pruritis, thick white vaginal discharge
- pH remains NORMAL
- inc. risk in diabetics, birth control, antibiotics
- infective endocarditis of tricuspid valve
- IV drugs, prosthetic valves, indwelling lines
Aspergillus fumigatus: how is it transmitted, what does it look like, and what is a positive test for it?
- condiophores w/fruiting bodies (spores are inhaled)
- septate hyphae that form 45 degree branching angles
- CATALASE (+)
A. flavus toxins associated with hepatocellular carcinoma and are found in nuts, wheat, peanuts
Aspergillus fumigatus: infections (ABPA, balls, angioinvasion - RER))
- Allergic Bronchopulmonary Aspergillosis
- Type I hypersensitivity
- wheezing, fever, inc. IgE production (CF/asthma)
- Fungus Balls
- form in people that have preexisting lung cavities
- fever, hemoptysis, cough
- GRAVITY-dependent positioning (X-Rays)
- Angiovasive Aspergillosis (invade BV and dissems)
- immunocompromised pts (neutropenia)
- renal failure, endocarditis, ring enhancing lesions
- also paranasal sinus inf. w/necrosis around nose
Cryptococcus neoformans: what does it look like, how is it acquired, and what is a positive test for it?
- yeast cells heavily encapsulated (repeating polysaccharide capsular Ags) –> antiphagocytic
- enters body via inhalation (soil and pigeon poop)
- UREASE (+)
Cryptococcus neoformans: what does it cause clinically and what do the India Ink and Latex Agglutination Tests show?
- pulmonary often asymptomatic (cough, fever)
- mainly seen in immunocompromised
- # 1 cause of fungal meningitis (fever/neck stiffness)
- “Soap Bubble” lesions in gray matter of brain
India Ink: white “halo” capsules on black background
- CSF testing
LA Test: detects polysacc. Ag (serum and CSF)
Mucormycetes (Mucor and Rhizopus): how is it acquired, what does it look like, and what is the most common predisposing factor for it?
- spore inhalation, proliferate in BVs and enter brain through CRIBIFORM plate
- molds form neoseptate rods with 90 degree wide angle branches
- Rhizopus STRONGLY associated with Diabetic Ketoacidosis (also bread molds and diabetes)
Mucormycetes (Mucor and Rhizopus): what does it cause clinically?
frontal lobe abscess that causes necrosis of the surrounding tissue
- necrosis of nasal cavity (black eschar on the palate or turbinates)
Pneumocystis jirovecii and HIV
- P. jirovecii pneumonia is the MOST PREVALENT opportunistic infection in HIV patients (AIDS-defining illness)
- infects immunocompromised patients almost exclusively (CD4+ < 200)
Pneumocystis jirovecii: what does it cause clinically, and what does it look like on X-Rays and biopsy?
- opportunistic fungal pneumonia
- chest X-Ray: “ground-glass” infiltrates; silver stain of lung biopsy/bronchoalveolar lavage shows DISC-SHAPED YEAST (crushed ping pong ball appearance)
