Micro: Fungal And Parasitic Infections Flashcards
What are the 3 kinds of Fungi ?
True Mold, True Yeast and Dimorphic
Which form of dimorphic fungi are pathogenic and diagnostic ?
YEAST (yeast in the beast)
List the 4 major dimorphic fungi
Blastomyces, Coccidiodes Histoplasma and sporothrix
“Can Have Both Shapes”
List two True yeast fungi
Cryptococcus Neoformans and Candida
List two True Mold pathogens
Aspergillus and Mucor.
Where is Coccidiodes immitis found geographically ?
South West US, San Jaoquin Valley.
Transmission of Coccidiodes immitis
Inhalation of mold (anthroconidia)
Diagnostic form of Coccidiodes is referred to as a …
Spherule.
In progressive pulmonary disease associated with Coccidiodes, pulmonary nodules can lead to what complication ?
Pneumothorax and Hemoptysis
(this is not diagnostic however, as most dimorphs can do this .
What skin condition is associated with Coccidiodes ?
Erythema Nodosum (this is diagnostic for fungal infection. No other fungi make this )
Seen in 25% of cases
What media do you grow coccidiodes on ?
Sabourad Dextrose.
What preparation destroy bacterial and animal cells but preserves fungal cells ?
KOH prep ?
What is the main treatment for uncomplicated coccidiodes
Fluconazole
What would you give a pregnant woman who is infected with coccidiodes ?
Amphotericin B (Fluconazole and all Azoles are teratogenic)
What is the treatment would you give an Immunocompromised patient ?
Amphotericin B followed by 1 yr of fluconazole.
How would you describe the yeast of Blastomyces dermatitis ?
Broad based budding yeast ! (hyphae with nondescript conidia) ..
This is seen on microscopy (3 B’s )
Where is Blastomyces found, geographically ?
Ohio and Mississippi River basins and the Great Lakes region
What is the drug of choice for Blastomyces ?
Amphotericin B
Itraconozole may be used in immune competent adults
Where is Histoplasma Capsulatum found geographically ?
Ohio, Missouri River Valleys
Blastomyces is associated with what conditions (environmental) ?
Decaying matter such as leaves and rotting wood (beaver dams)
Descibe a sever infection with blastomyces
ACUTE ONSET, lobar infiltrates, HIGH FEVER, cough.
May disseminate to : SKIN, CNS(AIDS patients)
What is the DOC for treating a blastomyces infection ?
Amphotericin B
Itroconozole can be used in immune competent adults
What cells does Histoplasma capsulatum infect ?
WBC’s.
They are INTRACELLULAR pathogens. (Yeast in the beast)
Describe the Mold phase of Histoplasma
Hyphae with Microconidia ( is inhaled)
Tuberculate macroconidia
Histoplasma is associated with what geographic location ?
Ohio, Missouri and Mississippi River Basins. (Much like Blastomyces)
What animals/conditions are associated with greater risk for Histoplasma infection ?
BIRDS (Bird keepers, nest removal and places where birds and bats live like caves.)
In the rare case of extreme infection with Histoplasma, what will be seen in the lungs on CXR ?
Patchy infiltrates (Lobar infiltrates are seen in Blastomyces infection)
What is indicative of blastomyces infection while diagnosing with microscopy ?
Intracellular invasion of WBC’s
How would you treat a severe/acute infection with Blastomyces ?
IV Amphotericin B followed by 12 wks of Itraconozole
How would you treat a chronic infection with blastomyces ?
Amphotericin B followed by 2 years of Itraconazole
Is Paracoccidiodes brasiliensis a yeast, mold or dimorphic ?
dimorphic !
Where is Parracoccidiodes located geographically ?
Central and South America
Describe the Chronic infection associated with Parracoccidiodes
Persistent Cough, Purulent sputum, Chest Pain and Fever.
Shows nodular, infiltrative, fibrotic and cavitary lesions.
The multiple budding yeast pattern of Parracoccidiodes is reffered to as …
a “Pilots Wheel”
Aspergillus is shown to have what angle in its septate hyphae ?
45 degrees
It is truly septated as well.
What kind of conditions is Aspergillus associated with ?
Air
Soil
Decaying matter (like Blastomyces, however the later is a dimorphic while aspergillus is a true mold.)
Shower heads, water tanks and plants
How is Aspergillus acquired ?
inhalation of conidia.
What are the three Categories of Asperigillosus infections ?
Allergic (3 Kinds)
Non-invasive Pulmonary Disease
Invasive Pulmonary Disease
IgE Mediated Asthma to Aspergillus (1) will result in what clinical findings ?
Asthma, pulmonary infiltrates, eosinophilia, elevated serum IgE
how can you diagnose an IgE mediated hypersensitivity to Aspergillus ?
Aspegillus antigen skin test
Allergic Bronchopulmonary Aspergillosis (2) occurs when aspergillus growth is seen in the bronchial tree secretions. Describe the progression of hypersensitivities seen in this illness.
Type I: Fist to occur. Mediated by IgE –>
TypeIII: Mediated by IgG and IgM immune complexes –>
Type IV: Macrophage mediated destruction.
Allergic Bronchopulmonary Aspergillosis is seen almost exclusively in patients with which two pulmonary disorders ?
Asthma
Cystic Fibrosis.
Rarely seen in absence of either of these.
Famer’s Lung (3) , also knows as extrinsic allergic alveolitis is due to the inhalation of Thermophilic Actinomyces ( and aspergillus !). Where would find these pathogens ?
Moldy Hay or contaminated compost
What kind of hypersensitivity is Farmer’s Lung ?
Type III most likely
What is the prognosis for Farmers Lung ?
It will spontaneously resolve but WILL recur if exposure to toxin is present.
What causes Winemakers lung ?
Botrytis cinerea
What causes Coffee workers lung ?
Coffee bean dust
What causes Poultry workers lung ?
Avian antigens
What causes lab workers lung ?
rodent antigen
In Non-Invasive Pulmonary Disease, what preceding illnesses lead to the formation of a ‘fungal ball’ of aspergillus ?
Disease the lead to cavitation of the lung such as:
TB
Cystic Fibrosis
Chronic Bronchitis
The cavities left by these diseases are ripe for infections with aspergillus.
When is treatment indicated for Non-Invasive Aspergillosis ? What is the TOC for this infection ?
When there is massive hemoptysis
Surgical Removal
What TOC for Allergic Aspergillosis ?
Removal of offending substance followed by Oral steroids and oral itraconozole.
Invasive Pulmonary Disease (aspergillosis ) is seen in what subset of patients ?
Those who are IC : Neutropenic , Corticosteroid users, Transplant patients, Malignancy and AIDS
Rapidly fatal unless diagnosed ASAP (mortality rate of 70%)
What is the TOC for Invasive Aspergillosis ?
Voriconozole (not Amphotericin B, which is often used in severe infections and preggers)
How does Mucor present ?
Acute and rapidly progressing infection of the nasal, paranasal cavities and orbit of the eye.
What populations are at risk for Mucor infection ?
Diabetics (DKA),Neutropenic, leukemia, lymphoma, solid transplants and burn patients
What is seen grossly in Mucor infections ?
Black exudate around the eyes nose and mouth.
What characteristics of Mucor fungi can differentiate it from Aspergillus on microscopy ?
Non-sepatated hyphae branching at 90 degrees (aspergillus is septate and branches at 45 deg)
What is the treatment for a patient with Mucor ?
Reverse the underlying IC state
Systemic Amphotericin B
Debridement of fungal infections on the face etc.
Stachybotrys chartarum is also known as …
Black mold
No real definable illness caused by this, produces a mycotoxin
Dr. Kell likes this though
What population of patients will you see Pneumocystis Jiroveci in predominantly ?
AIDS PATIENTS !
Must prophylactically treat AIDS patients for this when CD4+ levels drop low enough (Bactrim) due to very high mortality among those affected due to respiratory failure
What doe Pneumocystis jiroveci bind to in order to induce alveolar exudate ?
Receptors on Alveolar marcrophages
When fluid from a patient with pneumocystis jiroveci is stained with Giemsa, what will you see on microscopy ?
“Dented Helmets”
What is the treatment/Prophylaxis for pneumocyxtis jeroveci ?
TMP-SMX (Bactrim)
Pargonimus westermani is also known as..
Giant Lung Fluke
How does one contract P.westermani ?
Via ingesting raw seafood like crabs, crayfish etc
What is important to ask in History when ruling in/out P. westermani infection ?
History of travel (not found in the US)
Asia, Africa, india or latin america
What is the intermediate host of P. westermani ?
Snails !
Lung fluke infection may cause Hemorrhagic Bronchopneumonia which presents as hemoptysis with ‘rust colored sputum’. How can you distinguish this from TB or S. pneumo infections ?
Look in the sputum, you will see gold brown percolated eggs !!!
Where is another likely site of dissemination for P. westermani ?
the brain
may resemble meningoencephalitis.
What is the treatment of choice for lung fluke ?
Praziquantal (DOC) or Triclabendazole.
Tropical pulmonary eosinophilia is caused by which two organisms ?
Wuchereria bancrofti
Brugia malayi
