They are cold about 20 degrees there in mould form when they’re hot about 37 degrees there in a yeast form the only exception to this rule is with coccidioidomycosis which is a Sphero and not a yeast in tissue treatment for the systemic bite mycoses include fluconazole or kita comas all for local infection amphotericin B for systemic infections remember that systemic mycoses can mimic TB you get granuloma formation except unlike TB there’s no person-to-person transmission of the systemic mycoses once infected you can get systemic mycoses for example histoplasmosis or blastomycosis let’s talk about each of these histoplasmosis is endemic in the United States to the Mississippi and Ohio River Valley’s and causes a pneumonia.
So, what we see here are small 3 to 5 micron spores found within the cytoplasm of macrophages each of these spores is smaller than an RBC so that can give you a good idea if you’re looking at a stain compared to in red blood cell you’ll see them smaller within a macrophage so remember histo hides within macrophages and it’s normally transmitted through bird or bat droppings blastomycosis is endemic to states east of the Mississippi River as well as Central America it causes inflammatory lung disease and can disseminate to skin in the bone where it can form granulomatous nodules what you see looking under a light microscope is 5 to 15 microns spore that has budding.
So, it’s about the same size as a red blood cell but it looks like it’s budding off so you’re going to remember that blasto buds broadly coccidia mitosis is another systemic mycoses it’s endemic to southwestern United States as well as California it causes a pneumonia and also can cause meningitis it can disseminate to Bonin skin as well the case rate we’ve seen increase after earthquakes.
Which makes sense because the spherules of coccidioidomycosis are thrown up into the air what do we see when we look at the microscope we see a sphere of about 20 to 60 microns in size so much bigger filled with endospores so how do we remember this one remember coccidia crowds that spherical crowded with endospores it’s associated with San Joaquin Valley or desert valley fever para coccidioidomycosis is endemic to Latin America here on a microscope we see a 40 to 50 micron so not quite as big as the coccidia yet.
It’s a budding East with a captain’s wheel formation so think about the captain’s wheel of a boat remember para coccidia parasails with the captain’s wheel all the way to Latin America that will help you remember that so here again to review looking at the endemic areas will help you remember for the test which mold which fungus they’re talking about so if it’s southwestern United States or California King coccidia mycosis if it’s Mississippi or Ohio River Valley its histoplasmosis if it’s east of the Mississippi think blastomycosis you also need to consider this when they’re talking about Central America.
If it’s rural Latin America remember para coccidioidomycosis for that one so let’s talk about some of the cutaneous mycoses now tinea versicolor is one of them caused by malassezia furfur we have the degradation of lipids that produces acids that damage melanocytes and cause hypo pigmented patches we see it typically associated with hot humid weather treatment for tinea versicolor includes topical Meccano salt and selenium sulfide shampoos or selsun shampoos on the microscope what see is the classic spaghetti and meatball appearance on the koh prep.
Which you can see in the picture the other cutaneous mycoses include tinea pedis true risk corporis and capitis these are itchy / Illig lesions with central clearing that resemble a ring hence the name ringworm for tinea corporis they’re caused by dermatophytes like microsporum trichophyton and epidermal feyten what you see on the koh prep is mold hyphy not dimorphic pets are usually a reservoir for microsporum and can be treated with topical aids alls moving on to some of the opportunistic fungal infections will start with Candida albicans remember alba is white.
So, when you see something that’s white start thinking about Candida albicans and we’ll get to that systemic or superficial fungal infection it’s a yeast with pseudohyphae and culture at 20 degrees it’s a germ tube formation at 37 degrees which is what we used to diagnose oral and esophageal thrush in immunocompromised patients so we see this in babies we see this in people that are on steroids we see this in diabetics and we see this in AIDS patients Canada also causes vulva vaginitis and that’s due to high ph diabetes or use of antibiotics we see Canada in diaper rash.
We see Canada and endocarditis and IV drug users we can see disseminated candidiasis to any organs in immunocompromised hosts and we also see an immunodeficiency called chronic mucocutaneous candidiasis for certain lacks of t-cell subsets treatment for candida albicans is nystatin for the superficial infections amphotericin B for the serious systemic infection so looking at the picture all the way to the left we have the candidate remember candida or pseudohyphae with budding yeast at 20 degrees and then germ tubes which look kind of like sperm at 37 degrees for Aspergillus we think about the organism Aspergillus fumigatus it causes allergic bronchopulmonary aspergillosis or a BPA.
It can cause lung cavity aspergillosis or fungal balls and it can also be invasive causing invasive aspergillosis especially in immune compromise individuals and those with CJD so if you know CJD other than having those catalase positive bacteria that we talked about in another section they can also get infections with Aspergillus especially Aspergillus fumigatus so remember mold with a septate high feed that branches at acute angles less than 45 degrees so remember acute angles in Aspergillus and it’s not dimorphic what you see on the microscope is the picture second from the left we have 45-degree branching angles with septate high feet and you can see rare fruiting bodies you will not see budding yeast for Cryptococcus neoformans.
We associate this typically with cryptococcal meningitis but we can also see it in what we call cryptococcosis heavily encapsulated yeast not dimorphic so we don’t see high feed we just see the yeast found in the soil can also be found in pigeon droppings we culture it on sava rods auger and we stain it with India ink we use a test called the latent latex agglutination test which detects polysaccharide capsular antigen and we can see soap bubble lesions on the brain which are also characteristic for cryptococcal meningitis.
So, here second from the right we see a picture again that yeast heavily encapsulated no – the next species is Mew core a rhizopus they cause mucormycosis this is a mold with irregular non septic – Ching in wide angles in contrast to apps for jealous so the disease is mostly in keto acid oughta be T’s and in leukemic patients is where we see this fungus these fungi can also proliferate in the walls of blood vessels and cause infarction and necrosis of distal tissue so we can see Rhino cerebral frontal lobe abscesses as well looking at the right now in contrasting all of these fungi.
We see the new core here again irregular broad non septate branching at wide angles another common fungus seen on the boards is Pneumocystis – you’re Bessie you might know it by its former name Pneumocystis Carini i this fungus causes a use interstitial pneumonia it is a yeast was originally classified as a protozoan but later found that it had characteristics more associated with yeasts is inhaled most infections are asymptomatic and most often seen with immunosuppression like AIDS you get a diffuse bilateral chest x-ray appearance you diagnose it by lung biopsy or by lavage.
It’s identified by methane amines silver stain of the lung tissue and treatment for Pneumocystis is bactrim contaminating and dab some in HIV patients we typically start prophylaxis when the cd4 counts drop below 200 cells per milliliter another fungus that likes to show up on the board to spore threat shanky eye it causes sporotrichosis or grows Gardner’s disease the fungus itself is a dimorphic fungus that lives on vegetation when traumatically introduced to the skin typically by a thorn it causes a local pustule or ulcer with nodules along the draining lymphatic so you see a sending lymphangitis.