Opportunistic Infections Flashcards
What are the 3 TNF-blockers in the first part of the lecutre?
Humira, Enbrel, and Remicade
What is HAART?
Highly-Active Anti-Retroviral Therapy, this is important for immunocompromised patients
What are the stages of CD4 counts and risk of infection?
- Above 500 is normal
- 200 to 500 is incrased risk for certain infections
- less than 200 increased risk of Pneuomocytis pneumonia, and chemophrophylaxis should be used to prevent it
- less than 100, should begin preventive treatment for MAC and toxoplasmosis. Increased risk of Cryptococcus Meningitis
- less than 50, increased risk for CMV and MAI
What are the important features of Cryptococcus Neoformans?
Affects immunocompromised and normal hosts
- it is an environmental yeast
- prefers alkaline bird dropping (Pigeons) as habitat
- Mucinous capsule prevents drying, resists phagocytosis
- Usually causes meningitis, but primary lung disease may occur
How do you test for C. Neoformans?
Antigen testing in the CSF, also can use india ink prep but only in the immunosuppressed
What is this image of? what are the defining characteristics?
This is Cryptococcus Neoformans- a fungi that only has a yeast form
with a soap bubble appearnce in the Virchow-Robbin space of the brain.
-capsular polysaccharide stains intense red with periodic acid
What is this image of and what type of stain?
Image of Creptocossu Neoformans stained using India Ink. Which is not very sensitive, or specific and rarely used. The preferred test is Calcifluor white staining or Croptocoocal antigen testing. Note the budding yeast body within the capsule.
How is cryptoccous neoformans transferred?
Infection is acquired by inhaling aerosolized droplest containing yeast. It is not transferred person to person. Often acquired in infancy, asymptomatic infections.
- contained within granulomas like all the diseases discussed in this lecture
- treated with anti-fungals
What is a dimorphic fungi?
Has both a yeast form and a mycelial form
- includes Histoplasa Capsulatum, Blastomyces Dermatitdue, Coccidiodes Immitus (these are granulomatous disease of the lungs that may resemble tuberculosis)
- grow as hyphae in environemental temperatures, and as yeast in the lungs at body temperature
Geographicall where is Histoplasma Capsulatum found?
Found in the Ohio and Mississipi River Valleys
Where is Histoplasma Carpsulatum often found living?
In bat or bird dropping, similar to Cyptococcus Neoformans
Where is histoplasma Capsulatum usually found within the host?
It is an intracellular pathogen found mainly in macrophages. Similar resemblance to tuberculosis
-causes mild upper respiratory tract infection, but disseminates in the immunocompromised.
The coin lesion found on this chest X-ray is characteristic of what disease?
Histoplasma Capsulatum
What is this an image of?
This is a Granuloma from Histoplasma Capsulatum
- a small budding yeast at 37 degrees C, is usually found within macrophages
- elicits granulomas, some of which may caseate, and even cavitate, a close mimic of TB
- can see normal lung on the outside and the calcification around the dark black areas encircling
What defines desseminated histoplasmosis?
This is when Histoplasma Capsulatum has spread from the lungs to other part of the body, usually only happens in immunosuppressed patients
What is this and what are the defining features?
This is histoplasma capsulatum within a patient with normal immune system. It is contained within the macrophages or giant cells.
-here the pink circles are the yeast, and the purple are the fibrosis and macrophages
What is this an image of?
This is disseminated histoplasmosis in an immunosuppressed patient, like HIV
What is this?
This is disseminated histplasmosis in an HIV patient.
Note the numerous yeast within an alveola, with not very many macrophages. The yearst are growing so fast the macrophages cannot contain them
Where is Coccidioides Immitus found?
Found in the desert southwest and California
- can infect normal hosts causing an uppe respiratory tract infection, but disseminates in the imunocompromised
- lives in the dust and soil
What does Coccidiodies Immuts may present with what indicitive characteristic?
Eryhtema Nodusum (Red nodules, due to inflammation of adipose under the skin)
What is this an image of and what is used to stain?
This is an image of Cocciodides Immitus using calciflour white stain
-has a histological appearence of spherules containing endospore. That provoke inflammatory reaction upon rupture
What is this an image of?
This is Coccidiodies immitus, with intact spherule, and the one next to is is ruptureing.
-careful on mistaking this for the granules of histoplasma encapsulatum
What is this map?
Regions where Blastomyces Dermatitidis is common
Where does Blastomyces Dermatitidis live?
Lives in soil and in association with decaying organic matter such as leaves and wood. The microscopic fungal pores can become airborne when the soil is distrubed.
A chest X-ray on a patient with Pneumocystis Jirovecii has what appearance?
Ground glass appearance
When does Pneumocystis Jirovecii often infect?
Most population is infected by age 3 to 4
- infecction is probably acquired from aerosolized mouse or rat urine
- infection is lifelong, but usually asymptomatic within a normal hsot
- HIV patients with CD4 less than 200 usually require lifelong cemo prophylaxis to prevent recrudescence
This image is what? and what are the hallmark features?
This is Pneumocystis Carinii on H and E.
-note foamy eosinophillic material within alveolar space. The organisms are no visible, except with GMS silver stain (usually necessary for dx because it can not be cultured)
What is this image?
This is Pneumocystis Jirovecii on a silver stain (BAL GMS)
-the encysted organisms have a cup or goblet shape
How is Pneumocystis JJroveccii Transmitted?
Aerosolized mouse or rat urine
