Fungal Infections
Slackers Facts by Mike Ori
Disclaimer
The information represents my understanding only so errors and omissions are
probably rampant. It has not been vetted or reviewed by faculty. The source is our
class notes.
The document can mostly be used forward and backward. I tried to mark
questionable stuff with (?).
If you want it to look pretty, steal some crayons and go to town.
Finally…
If you’re a gunner, buck up and do your own work.
What is a tinea
A superficial fungal infection defined by its
anatomical location
List common tinea locations and names
Name
Location
Capitis
Head
Barbae
Beard/face
Faciei
Face
Corpus
Body (ringworm)
Cruris
Inguinal (Jock itch, usually not
scrotum/penis)
Pedis
Foot (Athletes foot)
Manuum
Hands – expect pedis to be present too
Unguium
Nails/nail bed (onychomycosis)
Etiologic agent: Itchy scrotum
Candida
Vaginal candidiasis predisposing factors
Diabetes
Antibiotic use
Pregnancy
HIV
What is a woods lamp and why is it used
It is a UV lamp that causes some fungal
infections to fluoresce and hence serves as a
diagnostic tool.
What is the slide mount prep for fungal
infections
KOH prep
Etiologic agent: Angular chelitis
Candida
Etiologic agent: Erythematous depapillation in
midline of lingua
Candida
Etiologic agent: pseudomembranous plaques in
mouth
Candida
Candida treatment
Topicals - Nystatin rinse (swish and swallow),
OTC azoles
Systemics – Triazoles or amphotericin B
Onychomycosis sx
Opaque, yellow, thickened, chalky nails with
debris accumulation
Onychomycosis tx
Usually long term systemic anti-fungals like
fluconazole, itraconazole, terbinafine.
Aspergilla source
Environment - soil
Aspergillosis categories
• Non-invasive
• Allergic reaction
• Aspergilloma
• Invasive
• Chronic necrotizing
aspergillosis
• Invasive pulmonary
aspergillosis
Aspergilloma tx
Surgical removal if aspergilloma is problematic.
Medical tx cannot adequately penetrate the
ball.
Chronic necrotizing aspergilloma features
Invades lung parenchyma but does not invade
vasculature
Chronic necrotizing aspergilloma epidemiology
Lung disease accompanied by “some” immune
suppression
Invasive pulmonary aspergillosis
characterization
Destruction of the lung parenchyma with
invasion into the vasculature (angio invasive)
Invasive pulmonary aspergillosis epidemiology
Prolonged neutropenia as in cancer tx
Fusariosis characterization
Commensal organism on many grains that
causes keratitis in contact lens users. Infection
occurs by direct inoculation and may spread
systemically in immunocompromised hosts.
Fusariosis risk factors
Prolonged neutropenia or immune suppression
due to allograft transplants
Bioterror potential of Fusariosis
Mycotoxins have been weaponized
Scedosporis characterization
Dimorphic fungus with clinical disease similar to
Fusariosis.
Scedosporiosis risk factors
Prolonged neutropenia, immune suppression
due to allograft transplants, diabetes.
Zygomycosis chracterization.
AKA: Mucormycosis
Nasal sinus infection extending into the brain or
orbit as a result of Mucorales species.
Zygomycosis epidemiology
Immune compromised hosts with acidemia as
occurs in diabetes. Also occurs in poor
nutrition, burns, and neutropenia.
Zygomycosis tx
Aggressive surgical debridement
Identify Etiology: A patient complains of dry
cough, dyspnea, and fevers. CXR shows
diffuse bilateral interstitial infiltrate. ABG
shows hypoxemia and hypocarbia. HX
includes treatment for rheumatoid arthritis.
Pneumocystis jirovecii
Is it likely the PT above is HIV +?
While PJP is most commonly associated with
HIV, it can occur in situations of depressed
cellular immunity independent of HIV status.
What is the tx for PJP?
TMP-SMX both for TX and prophylaxis.
What is the likely illness of an HIV + with a CD4 <
100 individual that cleans chicken coops?
Cryptococcus neoformans meningitis
Cryptococcal DX tests
India ink stains showing encapsulated yeast.
Serology
Cryptococcus TX
Amphotericin B followed by fluconazole
A 30 year old female presents to your clinic with
complaining of a yeast infection that “won’t
go away”. She has tried OTC treatment. She
has not been sexually active for the last 4
years. She is has never used IV drugs. What
tests would you recommend?
HIV test. Recurrent or intractable yeast
infections can be a sign of HIV. Remember
HIV can take years to develop. (Not sure if you
would culture the infection)
What are the signs of thrush.
Angular chelitis
Midline lingual erythema
Psuedomembranes
Dysphagia
Odynophagia
A patient in the ICU suffered a traumatic
laceration to their bowel. They are receiving
TPN and antibiotics. They are currently
tachycardic, hypotensive, and febrile. Three
blood cultures drawn 4 hours apart are
negative for bacteremia. What is the likely
agent.
Candida fungemia
Lab tests identify Candida krusei. What possible
agent would you administer to resolve the
fungemia.
Triazoles
amphotericin B
echinocandins
You administer triazoles but the patient does
not improve. Why?
Candida krusei is increasingly resistant to
triazoles through a Ca++ dependent efflux
pump.
What are the major endemic mycoses?
Histoplasmosis
Blastomycosis
Coccidioidomycosis
Paracoccidioidomycosis
Sporotrichosis
Penicillosis
Describe the endemic mycoses morphology
They are dimorphic and exist as yeast forms at
body temperature.
Histoplasmosis epidemiology
Worldwide distribution with concentrations in
the Mississippi and Ohio river valleys. In
particular areas with high nitrogen content
such as bat caves.
I am the bat!!
Histoplasmosis histology
Macrophages with intracellular yeast that may
be confused for ingested RBC’s
Histoplasmosis DX
Histology
Serology
Histoplasmosis treatment caveats
Primary pneumonia usually does not require tx.
Disseminated disease usually responds to
intraconazole or amphotericin B if severe
Blastomycosis epidemiology
South and north central US in outdoorsy people
with exposure to wooded areas. Hunters and
nudists (?).
Blastomycosis histology
Broad based budding yeast
Blastomycosis serology caveats
Serology is not useful as cross reactions to other
common pathogens occurs.
Coccidioidomycosis epidemiology
Endemic in the soils of the San Joquin valley and
parts of the southwestern US and northern
Mexico.
Coccidioidomycosis histology
Endospore containing spherule forms
Coccidioidomycosis sx
Pneumonia
Eosinophilia
Hilar and mediastinal lymphadenopathy
Night sweats
Fatigue
Weight loss
Meningitis
Coccidioidomycosis meningitis prognosis and TX
Universally fatal if not treated. TX with lifelong
Fluconazole or itraconazole
Describe role of anti-fungals in cocci
Most primary cocci pneumonia resolves without
TX so TX is reserved for prolonged disease
with high IgG titer and significant weight loss.
Describe the utility of delayed type sensitivity
testing in cocci diagnosis
Not particularly useful as most people are
seropositive. IgG titers are used to follow
course of disseminated disease.
Compare the culture growth rate of Cocci, hist,
blasto.
Cocci – fast (days)
Hist – slow (weeks)
Blasto – slow (weeks)
Paracoccidioidomycosis epidemiology
Endemic to Brazil
Paracoccidioidomycosis sx
Ulcerating skin, nasal, and oral lesions in middle
aged and older males.
Associated with EtOH and tobacco use
Paracoccidiodomycosis histology
Steering wheel yeast forms
Sporotrichosis epidemiology
Occupational or recreational exposure to fungus
living trees, shrubs, and soil. Commonly
associated with punctures from rose thorns.
Sporotrichosis sx
Lymphocutaneous disease with pustules, ulcers,
and lymphangitic spread moving away from
site of injury.
Clsssic sporotrichosis tx
Potassium Iodide