Fungi

The Fungi section provides High Yield Information needed for USMLE, COMLEX, Medical School, Residency, and as a practicing Physician.

Aspergillus Fumigatus

US Department of Health and Human Services., Public domain, via Wikimedia Commons

• About:
  • catalase +
  • transmission = inhaled condiophores (fruiting bodies)
  • ALLERGIC BRONCHOPULMONARY – (type I hypersensitivity, high IgE levels) aka “Farmer’s lung”
  • aflatoxins it produces are carcinogenic–> HEPATOCELLULAR CARCINOMA
  • forms aspergillomas (fungus balls) in lungs
  • pts w/ neutropenia at risk for angioinvasive form (renal failure, endocarditis, ring-enhancing brain lesions, nasal sinus necrosis)
• Dx:
  • GALACTOMANN’S TEST.
  • 45 degree ACUTE ANGLE BRANCHING
• Treatment:
  • voriconazole for mild
  • amphotericin B for angioinvasive
  • surgical debridement for aspergillomas

Blastomycosis Dermatitidis

Joel Mills, CC BY-SA 3.0, via Wikimedia Commons

• About:
  • GREAT LAKES AND SOUTHERN US
  • dimorphic
  • inhaled spores
  • PULMONARY- XR shows patchy alveolar infiltrate
  • also cutaneous form
  • systemic infections in immunocompromised (osteomyelitis, damages skin and bones)
• Dx:
  • urine antigen test, BROAD BASED BUDDING for replication, same size as RBCs
• Treatment:
  • litraconazole for immunocompetent
  • amphotericin B for systemic infections

Candida Albicans

DataBase Center for Life Science (DBCLS), CC BY 4.0, via Wikimedia Commons

• About:
  • PSEUDOHYPHAE at 25 C and GERM TUBES at 37
  • catalase +
  • only endogenous fungus (GI & GU tracts)
• Diseases: 
  • DIAPER RASH
  • THRUSH (can be scraped off, prepped w/ KOH)
  • ESOPHAGITIS and white pseudomembranes
  • VULUOVAGINITIS when pH > 4 (but it does NOT change the pH)
  • CUTANEOUS- intertriginous areas
  • SYSTEMIC- high mortality
  • CHRONIC DISSEMINATED – hepatosplenic
  • ENDOPTHALMITIS- “cotton ball” on eye exam
  • AIDS-defining illness (pts w/ CD4 <200 at risk)
  • other risk factors: diabetes, ABX use, birth control pills
• Dx:
  • (1-3)beta-D-glucan test
• Treatment:
  • azoles for minor
  • amphotericin B for major
  • nystatin for oral or esophageal
  • capsofungin for resistant

Coccidioides Immitis

See page for author, Public domain, via Wikimedia Commons

• About:
  • SAN JOAQUIN VALLEY FEVER
  • seen in CA, AZ, NM
  • inhaled SPORES
  • common after earthquakes
  • forms SPHERULES PACKED WITH ENDOSPORES in lungs, not yeast
  • arthralgia, pneumonia, fever, erythema nodosum (on shins) in immunocompetent pts only
  • disseminates to skin, lungs, bones, meninges
• Dx:
  • KOH prep, IgM against cocci indicates recent infection
• Treatment:
  • azoles for local lung infections
  • amphotericin B for severe

Cryptococcus Neoformans

CDC/Dr. Leanor Haley, Public domain, via Wikimedia Commons

• About:
  • heavily ENCAPSULATED
  • antiphagocytic repeating capsular antigen
  • transmitted via PIGEON droppings
  • inhaled into lungs then disseminates
  • UREASE +
  • risk factors: HIV, high dose steroids, malignancies
  • resp sx aminly, can spread to CSF
  • AIDS-defining illness (CD4< 200)
  • #1 cause of FUNGAL MENINGITIS
• Dx:
  • SOAP BUBBLE LESIONS (bronchopulmonary)
  • stain with MUCOCARMINE OR INDIA INK
  • latex agglutination test
• Treatment:
  • joint therapy of ampho B and flucytosine, maintenance w/ fluconazole

Dermatophytes

Microsporum. CDC/Dr. Lucille K. Georg, Public domain, via Wikimedia Commons

• About:
  • (trichophyton, epidermophyton, microsporum)
  • cause TINEA
    
  • live on the skin normally
    
  • likes KERATIN
    
  • itchy, pruritic rash
    
  • athletes at risk
• Diseases:
  • RINGWORM
    
  • jock itch, athletes foot
    
  • onchomycosis
    
• Dx:
  • woods lamp to dx microsporum, otherwaise KOH shoes hyphae
    
• Treatment:
  • terbanifine, griseofulvin

Histoplasma Capsulatum

AJC1 from UK, CC BY-SA 2.0, via Wikimedia Commons

• About:
  • BAT droppings,CAVE, chicken coop
  • MISSISSIPPI AND OHIO RIVER VALLEYS
  • respiratory transmission of spores
  • dimorphic
  • smaller than an RBC
• Presentation:
  • PNEUMONIA, forms granulomas, calcified fibrotic nodules in hilar region
  • LOOKS LIKE TB
  • erythema nodosum (painful lesions on shins)
  • hepatosplenomegaly
• Dx:
  • macrophages w/ intracellular OVOID BODIES seen on tissue sample w/ KOH prep, ELISA
• Treatment:
  • azole for mild
  • amphotericin B for severe

Malassezia Furfur

See page for author, Public domain, via Wikimedia Commons

• About:
  • PITYRAISIS (tinea) VERSICOLOR (hyper and hypo-pigmented spots)
    
  • damages stratum corneum layer of skin
    
  • malassezia fungima seen in neonates receiving TPN, causes sepsis and thrombocytopenia
    
• Dx:
  • SPAGHETTI AND MEATBALLS appearance on KOH prep
    
• Treatment:
  • topical SELENIUM SULFATE

Mucormycoses

Yale Rosen, CC BY-SA 2.0, via Wikimedia Commons

• About:
  • 2 types: mucor and rhizopus (bread mold)
  • inhaled, proliferate in blood vessels, and invade brain via cribirform plate
  • black eschar on face, nasal cavity necrosis
  • neural deficits and death
  • populations at risk: immunocompromised (neutropenia), diabetics.
  • most common predisposing factor is DKA!!
• Dx:
  • 90 deg WIDE ANGLE BRANCHING hyphae
• Treatment:
  • debride first
  • amphotericin B

Paracoccidioides Brasiliensis

Photo Credit:Content Providers(s): CDC/ Dr. Lucille K. Georg, Public domain, via Wikimedia Commons

• About:
  • SOUTH AMERICA
    
  • yeast from looks like CAPTAIN’S WHEEL
    
  • dimorphic
    
  • respiratory droplet transmission
    
  • cervical lymphadenopathy, granulomatous inflammation in lungs, organomegaly, lymphadenopathy
    
  • MUCOSAL ULCERS AND CUTANEOUS LESIONS
    
• Treatment:
  • itraconazole (mild), amphotericin B (severe)

Pneumocystis Jiroveci

Yale Rosen, CC BY-SA 2.0, via Wikimedia Commons

• About:
  • causes pneumocystis pneumonia
    
  • respiratory transmision
    
  • AIDS-defining illness (occurs mainly in CD4 <200)
    
  • DRY/unproductive cough
    
  • GROUND GLASS appearance of LUNGS
    
• Dx:
  • broncoalveolar lavage (BAL), then stain with METHAMINE SILVER STAIN and look for OVOID-shaped yeasts
    
• Treatment:
  • bactrim (abx, not antifungal)

Sporothrix Schenckii

See page for author, Public domain, via Wikimedia Commons

• About:
  • cuts from rose thorns, tree bark, etc
    
  • ROSE GARDENER’S DZ
    
  • dimorphic
    
  • forms ulcer/pustule, red NODULAR LYMPHADENITIS and inflammation
    
  • ASCENDS ALONG THE LYMPHATICS
    
• Dx:
  • branching hyphae seen at 25 deg C
    
  • CIGAR-SHAPED budding YEAST
    
• Treatment:
  • litraconazole for lymphocutaneous

Fungi Quiz

Fungi 2 Quiz