fungal infections

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

DiabetesAntibiotic use

PregnancyHIV

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 chelitisMidline lingual erythema

PsuedomembranesDysphagia

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 Bechinocandins

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?

HistoplasmosisBlastomycosis

CoccidioidomycosisParacoccidioidomycosis

SporotrichosisPenicillosis

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

HistologySerology

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

PneumoniaEosinophilia

Hilar and mediastinal lymphadenopathyNight sweats

FatigueWeight lossMeningitis

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