Mycology

Question 1

Systemic mycoses

• Define the disease assoc
• All are caused by dimorphic fungi (def?)
  
  • exception?
• Treatment for local & systemic infection?
• Systemic mycoses can mimic what?

Answer 1

• Histoplasmosis, Blastomycosis, Coccidioidomycosis, Paracoccidioidomycosis
• dimorphic= cold (20oC)= mold | warm (37oC)=yeast ‘mold in the cold, yeast in the beast’
  
  • ​coccidioidomycosis= is spherule (not yeast) in tissue
• Treatment:
  
  • local= fluconazole or itraconazole
  • systemic= amphotericin B
• systemic: mimics TB (granuloma formation) except unlike TB have NO person-person transmission.

Question 2

• Endemic location and pathologic features
  
  • Mississippi, Ohio River valleys, Causes pneumonia
• What is the disease?
• what is the call that it targets?
• Where can it be transmitted from?

Answer 2

• Histoplasmosis
• Macrophage filled with histoplasma (orgnaism is smaller than RBC)
• Bird or Bat droppings

​*Histo hides within macrophages *

Question 3

• Endemic location and pathologic features
  
  • States east of Mississipis River, and Central America
  • Causes inflmmatory lung disease, and can disseminate to skin and bone.
  • Forms granulomatous nodules
• What is the disease?
• what its its histological feature?

Answer 3

• Blastomycosis
• Broad-based budding (same size as RBC)

Question 4

• Endemic location and pathologic features
  
  • Southwestern US, California
  • Causes pneumonia and meningitis,
  • can disseminate to bone and skin
  • case rate inc after earthquakes
  • (spores in dust are thrown up in the air and become spherules in lungs)
• What is the disease?
• what its its histological feature?

Answer 4

• Coccidiodiomycosis
• Spherule (much larger than RBC) filled with endospores.
• Coccidio crowds
• ‘San Joaquin Vally fever’
• “Desert bumps” = eryhtema nodosum
• “Desert rheumatism” = arthralgias

Question 5

• Endemic location and pathologic features
  
  • Latin America
• What is the disease?
• what its its histological feature?

Answer 5

• Paracoccidoidomycosis
• Budding yeast with ‘captian wheel’ formation (much larger than RBC)

_Para_coccidio _para_sails w/the captian’s wheel all the way to Latin America.

Question 6

Define the cutaneous mycoses

Answer 6

• Tinea versicolor
• Other tineae

Question 7

Pt presents with cutaneous mycoses that has an organism that casues:

• Degradation of lipids produces acids that damage melanocytes and hypopigmented &/or hyperpigmented patches.
• Occurs in hot humid weather.
• Appearance is ‘Spaghettis and meatball’ like on histology
• What is the disease
• What is the name of the organism
• what is the treatment?

Answer 7

• Tinea versicolor
• Malassezia furfur
• Topical miconazole or Selenium sulfide (Selsun= dandruff shampoo).

Question 8

Name of cutaneous mycoses in the

• head or scalp
• body
• groin
• foot
• onychomycois on fingernalis

Answer 8

• Tinea capitis
• Tinea corporis
• Tinea cruris
• Tinea pedis
• Tinea unguinium

Question 9

• Describe the ring worm in cutaneous mycoses
• What is it caused by>
• what is seen on KOH prep.

Answer 9

• Pruritic lesions with central clearing resembling a ring
• Caused by dermatophytes (Microsporum, Trichophyton, Epidermophyton)
• See mold hyphae on KOH prep, Not dimorphic.

Question 10

systemic or superifical fungal infection

• In immunocompromised (neonates, steroids, diabetse, AIDS)
  
  • oral and esophageal thrush
• In diabetes, use of antiboitics
  
  • Vulvoginitis
• Iv drug users
  
  • endocarditis
• other
  
  • diaper rash, CMC (chronic mucocutaneous candidiasis)
• What is the organism
• **treatment for: **vaginal, oral/esophageal, systemic

Answer 10

• Candidiasis albicans
  
  • alba= white
• Treatment
  
  • _{<strong>Vaginal</strong>= topical azole}
  • _{<strong>Oral/esophageal</strong>= fluconazole or caspofungin}
  • _{<strong>systemic=</strong> fluconazole, amphotericin B, caspofungin}

Question 11

• What acute angle fungi is seen in immunocompromised and those with chronic granulomatous disease?
• What fungi is associated with asthma and CF
  
  • may cause bronchiectasis and eosinophilia
• What fungi is seen in lung cavities, especially after TB infection
• What is produces by a fungi that is assoc with hepatocellular carcinoma?

Answer 11

Aspergillus fumigatus

• Invasive aspergillosis
• Allergic bronchopulmonary aspergillus (ABPA)
• Aspergillomas
• Aflatoxins

Think A for Acute Angles in Aspergillus, Not dimorphic

Question 12

Define the mycologic organism

• Heavily encapsulated yeast, not dimorphic.
• Found in soil, pigeon droppings. Acquired through inhalation with hematogenous dissemination to meninges.
• Define the organism
• What is this organism cultured on?
• Stains with what (2)?
• Latex agglutination detects what?
• what is seen in the brain

Answer 12

• Cryptococcus neoformans
• Sabouraud agar
• India ink & mucicarmine
• Latex agg detects polysaccharide capsular antigen
• brain lessions ‘soapy bubbles’

Question 13

Presentation

• Rhinocerebral, frontal lobe abscesses, headache, facial pain, black necrotic eschar on face, may have cranial nerve involvement
• disease is mostly seen in ketoacidic diabeteis and leukemic patients
  
  • define organism
• Fungi proliferate in blood vessel walls when there is excess of what?
  
  • how does it enter the brain?
• What is the treatment?

Answer 13

• Mucor and Rhizopus spp
• ketone and glucose
  
  • thus after it leaves the blood vessel wall due to ketone and glucose being in excess
  • penetrates the cribiform plate and enters the patin.
• Treatment: Amphotericin B

Question 14

• What organism causes PCP (pneumocystis pneumoina) a diffuse interstitial pneumonia
  
  • ​yeast (orgnially classified as protozoan)
  • Inhaled, most infections are asymptomatic.
  • Diffuse bilateral CXR appearance
• What group of pt is predisposed to the disease?
• How is it diagnosed
• how does it appear on methenamine silver stain of lung tissue?
• Treatment?
• Prophylaxis? (when do you start)

Answer 14

• Pneumocystis jirovecii (carnii)
• Pt with immunosuppression are predisposed (AIDS)
• Disc shaped yeast appears on MSS
• Treatment:
  
  • TMP-SMX
  • Pentamidine
• Prophyalxis (when CD4 drops <200 cells/mm³) in HIV pt.
  
  • Dapsone
  • Atovaquone

Question 15

Pt presentation

Yeast is dimorphic cigar shaped budding yeast that lives on vegetation. When spores are traumatically introduced into the skin, typically by a thorn (rose gardener’s disease) causes local pustule or ulcer with nodules along drainig lymphatics (ascending lymphagitis). Little systemic illness.

• What is the organism?
• What is the treatment?

Answer 15

• Sporothrix schenckii
• Treatment: itraconazole or potassium iodide.