Skin and Systemic Mycoses Flashcards
Which of the following is NOT a general feature of phaeohyphomycosis?
A. Most common form is a cyst
B. Tissue morphology shows sclerotic bodies
C. Post-traumatic mycotic infection of subQ tissue caused by dematiaceous fungi
D. Rarely causes disseminated infection
E. Diagnosis is based on histopathology and culture of skin scraping or biopsy at the involved site
B.
Tissue morphology is mycelial, with pigmented septate hyphal fragments (below), thus distinguishing it from chromoblastomycosis, which has sclerotic bodies.
strain of Candida that is most common at every site of infection
C. albicans
organism that causes scutula formation (yellow crusts composed of hyphae, neutrophils and epidermal cells) that can coalesce to cover much of the scalp
trichophyton schoenleinii
A 72 year old British male presents to your clinic with fever, chest pain, cough, chills and night sweats. Chest raidograph shows diffuse infiltrates, some of which are nodular (see below). Broncoscopic biopsy grew mold at 5 days. The patient says that he just returned a week ago from the World Championship of Model Airplane Flying in California. What is the diagnosis?
Coccidioidomycosis
*note that the microscopy shows spherules filled with endospores
44 yo male presents to ETC with fevers, wt loss, cough, and painful orolabial lesion. Temp was 38.5C, and he had tender lesions involving the oral mucosa and lip. Chest x ray showed nodular infiltrates. He recently entered US from a rural village in Guatemala to seek work. What is the diagnosis
paracoccidioidomycosis
this organism was formerly classified as a protozoan and is a major cause of opportunistic infections in people with AIDS, long term corticosteroid use, congeintal immunodeficiencies and transplant patients
Pneumocystis jiroveci
Over 95% of human Aspergillosis disease is caused by 3 species, the most common of which is what?
A. fumigatus
organism that:
- requires a lipid-rich environment to live
- is transmitted human to human
- is a superficial chronic infection of the stratum corneum, and easily treated
- causes tinea versicolor infection, characterized by hypo or hyperpigmented maculae on the trunk and limbs
Malassezia (globosa furfur)
*has a “spaghettti and meatballs” look under microscopy
A 44-year-old man from Davenport, IA decided to clear out his chimney flue with a bowling ball, which crashes into the fireplace in a cloud of dust, dirt, straw, and feathers. 10 days later, his son and a housepainter, both of whom were in the living room when the bowling ball was dropped, were both admitted to a local hospital with fevers, cough, and diffuse pulmonary infiltrates on chest radiography. What is the diagnosis?
histoplasmosis
*natural reservoir is soil; bat and avian habitats
name the disease caused by this organism:
blastomycosis
*broad based budding blasto!
this organism causes an infection characterized by brownish malculae on palms and soles and may resemble melanoma (tinea nigra); most common in tropical and subtropical areas
hortae werneckii
*under microscopy, this organism shows darkly pigmented, branched septate hyphae, usually also with budding cells
pigeon poop disease that is the #1 cause of fungal meningitis, and can be detected by antigen testing for its polysaccharide capsule in CSF/blood, microscopy, and/or culture
cryptococcus (c. neoformans most common species)
name of dermatophyte infection when it occurs below the eyes
tinea corporis
*often treated topically
this specific strain of organism:
- is found in Central-South America in rural areas with close soil contact
- Causes mucocutaneous orolabial and nasal lesions
- Mostly affects males 30-50
- Shows characteristic “pilot’s wheel” under microscopy (see below)
paracoccidioides brasiliensis
organism that grows as budding yeast that can form pseudohyphae and rarely my form true septate hyphae:
candida
this organism is the most common cause of athlete’s foot, fungal infection of nail, jock itch, and ringworm worldwide
trichophyton rubrum
thermally dimorphic fungus that causes sporotrichosis, characterized by skin lesions following minor trauma
sporothrix schenckii
Which of the following statments about Candida is FALSE?
A. It is the leading cause of opportunistic fungal infection
B. Causes local disease of the skin, nails and mucosa as well as invasive bloodstream infection
C. Causes infection at sterile sites
D. Causes hepatosplenic candidiasis, a type of invasive infection unique to patients with cirrhosis of the liver
E. Many species of Candidiasis cause disease but only 5 species account for >95% of human infections.
D.
Hepatosplenic candidiasis is unique to cancer patients with prolonged neutropenia, often with minimal inflammatory signs/symptoms.
amazonian blastomycosis that is associated with dolphin exposure in S. America
lobomycosis (locazia loboi)
Which of these is NOT a feature shared between Histoplasmosis and Blastomycosis?
A. They are both found in the midwest.
B. They are both thermally diorphic.
C. They both affect the reticuloendothelial system
D. They both exist as yeasts in vivo.
E. They are both mainly pulmonary syndromes but can involve dissemination.
C.
HIstoplasmosis affects the RES while blastomycosis affects the skin and bones.
the most common clinical presentation of this disease is interstitial pneumonia: insidious onset of dyspnea, tachypena, and nonproductive cough and fever in an immunocompromised patient
pneumocystosis
*ground glass infiltrates on CXR, or cavitary lesions; may spread to lymph nodes, spleen, bone marrow and liver, etc in AIDS patients
Fungi share with human cells all of the following structures EXCEPT:
A. Golgi
B. Endoplasmic reticulum
C. Nucleus
D. Phospholipid bilayer
E. Chitin
E. This is a feature of fungal cell walls that is antigenic and provides their shape and rigidity.
47 yo male admitted with fever, headache, periorbital cellulitis and diabetic ketoacidosis. Exam reveals redness around the eye and c_ranial nerve II, III, IV and VI abnormalities_. MRI reveals maxillary and ethmoid sinusitis with extension to the orbit and a biopsy is performed (see below). What is the diagnosis?
zygomycosis (Rhizopus), Rhizomucor
*histopathology shows “wide ribbon” aseptate hyphae. cultures are often negative. grows fast.
Which of the following statements regarding clinical Aspergillosis syndromes is INCORRECT?
A. Allergic bronchopulmonary aspergillosis is characterized by bronchospasm and bronchiectasis with segmental collapse and scarring
B. Aspergilloma in a pre-existing cavity results from a secondary colonization of a lung cavity
C. Semi-invasive aspergillosis is characterized by hemoptysis and fungal ball formation
D. Invasive aspergillosis is extremely serious with a high mortality rate and is characterized by tissue infarction with rapid spread and dissemination
C.
Fungal ball formation is associated with aspergilloma in a pre-existing cavity. Semi-invasive aspergillosis shows chronic thickening/fibrosis on radiography.
name of dermatophyte infection that occurs above the eye level
tinea capitis
*treated with oral therapy
disease diagnosed by urine antigen test, and microscopy shows the following:
histoplasmosis (acorns in a macrophage)
These are the top three methods for visualizing fungi in tissue and other clinical samples
- KOH/wet prep: dissolves human cells
- Calcofluor white: binds chitin in cell wall
- Gomori methenamine silver (GMS): silver stains preferred for detecting fungi in tissue specimens
most common cause of invasive mold infection in bone marrow and SCT patients
Aspergillosis
*portal of entry is the lung via inhalation of conidia
32 yo patient admitted to IV drug use and presents with increased fatigue, fever, headaches and somnolence. HIV antibody and antigen are both +. Patient began worsening with increased headache, so LP was performed and it was significant for 6 WBC. Micoscopy showed encapsulated yeast (below). Diagnosis?
Cryptococcus
*C. gattii is a newer species that causes pulmonary disease in immunocompetent patients, generally in NW US and Australia
32 yo Vietnamese male with cough, dyspnea, 18 lb wt loss and new skin rash on face for the past 2 weeks. PE reveals lymphadenopathy and palpable spleen. Chest x ray shows bilateral infiltrates and HIV test is positive. He travels to Vietnam each year for 2 months. What is the diagnosis?
penicillium marneffei
*usually only causes disease in immunocompromised
organism that causes white piedra
trichosporon spp
a chronic infection involveing cutaneous, subcutaneous and lymphatic tissues that is frequently encountered in gardeners
sporotrichosis
Which of the following statements about Penicillium marneffei is FALSE?
A. hallmark skin lesions seen on face and trunk
B. rarely causes human disease, except in immunocompromised
C. it is dimorphic and multiplies by budding
D. found in soil and bamboo rats in southeast asia
E. appears red in microscopic exam
C.
P marneffei multiplies by fission, not budding.
organism that causes black piedra
piedraia hortae
this infection is usually diagnosed in the OR by the presence of fungal balls in the lower extremities, composed of draining sinuses containing granules
eumycetoma
*also called “Madura foot”. just way too gross to post a picture. gotta draw the line somewhere.
Which of the following is paired correctly?
A. Yeast: unicellular and reproduce by budding
B. Mould: multicellular and reproduce by budding
C. Yeast: multicellular and reproduce by budding
D. Mould: unicellular and reproduce by forming hyphae
E. Yeast: unicellular and reproduce by forming hyphae
A
this organism causes rhinocerebral or pulmonary disease and can cause disseminated disease in immunocompromised persons (diabetics)
Rhizopus, Mucor, or Rhizomucor
57 yo male with AML undergoes stem cell transplant. His neutropenia persists and on day 23 post transplant he develops fever, cough, and then L-sided pleuritic chest pain. After broad spectrum antibiotics fail to resolve his fever, a chest CT shows halo sign. Treatment of voriconazole is begun but the patient has a seizure and head CT reveals two lesions in the brain. Diagnosis?
Aspergillosis
*remember that unlike Candida, this organism does not routinely colonize healthy persons; but, may transiently colonize immunocompromised hosts
Which of the following is not a characteristic of Fungi?
A. They are neither animals nor plants.
B. They are eukaryotic and are abundantly distributed in the air, water and soil.
C. They are distinguished clinically between yeast, mould, and dimorphic forms.
D. Their similarities to human biology limit the number of targets that can be used for anti-fungal therapy.
E. Approximately half of all species described are capable of causing human disease.
E. Only about 500 of >100,000 species are associated with human disease.
name this organism:
sporothrix schenckii
*note the rosette-like clusters of conidia at the tips of the conidiophores
histopathology of this organism shows 45 degree regular branching of its septate hyphae:
aspergillus
Which of the following is NOT a common subcutaneous mycosis?
A. Sporotrichosis
B. Eumycotic mycetoma
C. Coccidioidomycosis
D. Phaeohphomycosis
E. Chromoblastomycosis
C.
this infection:
- is caused by soil organisms that gain access to subQ tissue after trauma
- is distributed worldwide but most common in trocpial areas of barefoot populations
- causes growth of warty, cauliflower-like lesions on lower extremities
chromoblastomycosis
name given to these cutaneous mycoses that :
- utilize keratinase to hydrolyze keratin
- cause infection of the skin, nails, or hair
- can survive in shed skin cells for a long time
dermatophytes (AKA tinea, AKA ringworm)
In hematologic patients with invasive aspergillosis, this antigen test can make the diagnosis in a noninvasive way
galactomannan
*this is a polysaccharide cell wall component of Aspergillus and is FDA approved for serial monitoring of hematologic malignancy patients; however, it is not useful if the patient is on certain antibiotics (ie, piperacillin-tazobactam) or other fungal therapies
47-year-old male presents with fever, infiltrate and dyspnea. Treated with levofloxacin and steroids, but returns 3 weeks later with new skin lesion, fevers, weight loss and leg pain. Chest x ray reveals R-sided infiltrate and 2 new skin lesions are noted. Patient spent 1 month canoeing and hiking in Wisconsin. Diagnosis?
blastomycosis
organism that causes African histoplasmosis, with larger, thick-walled yeast cells , pronounced giant cell formation in infected tissue, and greater frequency of skin and bone lesions
Histoplasma capsulatum (var. duboissi)
Which of the following statements regarding black and white piedra is FALSE?
A. They are both characterized by the growth of nodules on hair
B. They can be treated with antifungal shampoos and shaving
C. White piedra is found worldwide while black piedra is limited to certain tropical regions
D. Black piedra under microscopy shows darkly pigmented, aseptate hyphae
E. White piedra grows white/yellow creamy colonies in culture
D.
Black piedra has darkly pigemented septate hyphae while white piedra has non-pigmented aseptate hyphae.
coccidiodomycosis is caused by these two organisms, and occurs most commonly in the southwestern US
C. immitis and C. posadasii
Which of the following is NOT a characteristic of Blastomycosis?
A. Causes an aymptomatic infection in over half of cases
B. Causes pulmonary infection and chronic cutaneous infection
C. May form subcutaneous nodules or ulcerations and cause disseminated infection in immunocompromised
D. Grows as yeast in both mold and culture
E. The majority of the time it is in the gut and spleen
E. Blastomycosis involves skin and bone in majority of cases but may go to gut, CNS, spleen, liver and prostate
treatment of this organism includes bactrim with a corticosteroid because of the huge release of antigen during lysis
penumocystosis
diagnosis of this condition involves KOH and direct microscopic examination, revealing Medlar bodies:
chromoblastomycosis
this organism is the predominant cause of infections in bone marrow transplant patients
aspergillus
this organism is the predominant cause of infection in solid organ transplant patients
candida
