Term
| How long after innoculation is the acute HIV syndrome with wide dissemination of virus and seeding of lymphoid organs? |
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Definition
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Term
| What is the characteristic appearance of PCP on CXR? |
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Definition
| bilateral fluffy pulmonary infiltrates, prominent in the hilum and base of the lungs |
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Term
| What does a biopsy of PCP pneumonia look like? |
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Definition
| eosinophilic frothy material; a combination of pneumocystis and plasma constituents present in many of the alveolar spaces |
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Term
| What stain is used with pneumocystis jiroveci? |
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Definition
| silver stain highlights the wall and central body of the organism |
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Term
| What are the different ways to get a sample for PCP testing? |
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Definition
| transbronchial biopsy, BAL, bronchial washing, induced sputum |
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Term
| What are the lab tests done on sputum for PCP? |
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Definition
| direct flourescent antibody (DFA) test (silver stains in some labs) NOT CULTURED!!! |
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Term
|
Definition
| close contact via bodily fluids |
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Term
| What organs are commonly invovled by disseminated CMV in immunocompromised patients? |
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Definition
| eyes (CMV retinitis), gut, kidneys, liver, pancreas, lungs, salivary glands, thyroid gland, adrenal gland, brain |
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Term
| Describe the fundoscopic exam of a patient with CMV retinitis. |
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Definition
| multiple retinal hemorrhages and regions of purulent exudate |
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Term
| What would be seen on microscopy of CMV retinitis? |
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Definition
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Term
| What methods can be used for diagnosis of CMV? |
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Definition
| PCR, serology (esp IgM), cell culture (esp rapid shell vials) |
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Term
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Definition
| in rapid shell vials; centrifuged to get CMV to enter cells more rapidly; read using immunoflourescence (flourescently labeled monoclonal antibodies) |
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Term
| What virus can cause ulcers and pseudomembrane formation that resembles C diff colitis? |
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Definition
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Term
| What causes the ulcers of a CMV infected colon to be green? |
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Definition
| fecal material adherent to the ulcerated mucosa |
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Term
| What causes ulceration of the colon in CMV infections? |
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Definition
| infection of the vascular endothelium leading to thrombosis and necrosis of the colonic epithelium; also some direct cytotoxic effect of the epithelium by the CMV |
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Term
| How do you diagnose CMV infection of the colon? |
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Definition
| biopsy= pseudomembrane overlying a necrotic mucosa with viral inclusion characteristic of CMV in macrophages |
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Term
| T/F CMV infect only cells of the immune system. |
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Definition
| false; it infects many different cell types |
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Term
| Why are CMV inclusions so unique? |
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Definition
| CMV is able to produce intranuclear and intracytoplasmic inclusions |
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Term
| What's the difference between CMV and C diff pseudomembranous colitis? |
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Definition
| C diff associated pseudomembranes result from toxin-mediated destruction of the epithelium as well as ischemic necrosis secondary to thrombosis of underlying small vessels |
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Term
| How do you test for C diff? |
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Definition
| C diff antigen test for toxins A and B using EIA (ELISA) |
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Term
| Describe the toxins of C difficile. |
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Definition
| toxin A is an enterotoxin; b is a cytotoxin |
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Term
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Definition
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Term
| Name some pathogens that commonly cause diarrhea in AIDS. |
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Definition
| cryptosporidium, mycobacterium avium-intracellulare, cytomegalovirus, giardia, isospora belli |
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Term
| What is the gross appearance of small bowel with a MAC infection? |
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Definition
| nodular pattern the entire length of the small bowel |
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Term
| What is the microscopic appearance of small intestine infected with MAC? |
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Definition
| mycobacteria inside the histiocytes |
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Term
| How do you test for intestinal MAC infection? |
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Definition
| DO NOT CULTURE THE STOOL; biopsy and culture the biopsy specimen. This is because MAC is in the histiocytes in the laminopropia not in the stool |
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Term
| How does MAC enteritis differ pathologically from cryptosporidiosis? |
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Definition
| cryptosporidium is not invasive; the organisms attach to the superficial portions of the intestinal epithlium; MAC organims are found inside the histiocytes within the lamina propia and submucosa |
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Term
| What is the best way to diagnose cryptosporidium? |
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Definition
| giardia/cryptosporidium combined EIA performed on stool specimen |
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Term
| What percent of patients with AIDS have clinical evidence of neurologic dysfunction? |
|
Definition
| 30-50% of patients with AIDS develop some neurologic impairment during the course of their illness |
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|
Term
| When addressing the issue of altered mental status in AIDS patients, there are two basic categories of diseases you could be dealing with: |
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Definition
1) primary HIV-associated syndromes
2) opportunistic diseases |
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Term
| What is HIV encephalopathy? |
|
Definition
| areas of demyelination due to HIV neuroinvasion via infected monocytes, HIV virotoxins, and cellular activation/defense (cytokines) |
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|
Term
| When during the course of HIV do patients get HIV encephalopathy? |
|
Definition
| can occur early-during seroconversion |
|
|
Term
| What is AIDS-related dimentia? |
|
Definition
| progressive decline in cognitive function with symptoms of memory loss and withdrawal and later global dementia |
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Term
| When in the course of AIDS does AIDS-related dementia occur? |
|
Definition
| advanced AIDS when CD4 is less than 200 mm3 |
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|
Term
| An HIV positive patient with deep (subcortical) gray matter and white matter demyelination= |
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Definition
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|
Term
| What is the appearance of AIDS-related dementia under the microscope? |
|
Definition
| infiltrates of lymphocytes and macrophages, markedly elevated numbers of activated astrocytes, and hallmark=multinucleated giant cells |
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Term
| What does CT scan of a brain with AIDS related dementia show? |
|
Definition
| widened sulci and expansion of cerebral ventricles: cerebral atrophy |
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Term
| What are viral opportunistic CNS diseases? |
|
Definition
| CMV and progressive multifocal leukoencephalopathy |
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|
Term
| What are some bacterial opportunistic CNS diseases? |
|
Definition
| tuberculosis and pyogenic bacterial infections |
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|
Term
| What are some fungal opportunistic CNS diseases? |
|
Definition
| cryptococcus, histoplasmosis, coccidiomyocosis |
|
|
Term
| What are some parasitic opportunistic CNS processes? |
|
Definition
|
|
Term
| What are some opportunistic neoplasms in the CNS? |
|
Definition
| CNS lymphomas both primary and metastatic (kaposi sarcoma is almost unheard of in the CNS) |
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|
Term
| Demylination in HIV can be caused by... |
|
Definition
|
|
Term
| What is the incidence of PML in AIDS? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| What is the pathophys of PML? |
|
Definition
| JC virus infects oligodendroglia directly, causing necrosis; demylination occurs in the infected areas |
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|
Term
| What is the histological appearance of PML? |
|
Definition
| oligodendroglial nuclei: chromatin appears glassy, dark, and smudged |
|
|
Term
|
Definition
| multiple focal white matter lesions |
|
|
Term
|
Definition
| PCR or CSF for JC virus (get radiologic evidence first!) |
|
|
Term
| What type of immunocompromised patient usually gets toxoplasmosis? |
|
Definition
| bone marrow transplant population |
|
|
Term
| What is the pathophys of toxoplasmosis infection in immunocompromised patients? |
|
Definition
| typically reactivation of a prior infection |
|
|
Term
| Describe the appearance of toxoplasma encephalitis under the microscope. |
|
Definition
| areas of necrosis infiltrated by reactive, rod-shaped, microglial cells; called microglial nodules |
|
|
Term
| How do you test for toxoplasma encephalitis? |
|
Definition
| test CSF for toxo using PCR (only appropriate if there are focal brain lesions on CT or MRI) |
|
|
Term
| What are sites most commonly involved by toxoplasma? |
|
Definition
| lung (pneumonitis), lymph nodes (lymphadenitis), choroid and retina (chorioretinitis) like CMV, and brain (encephalitis) |
|
|
Term
| Where does HSV go latent? |
|
Definition
| HSV-1 usually in the trigeminal ganglia; HSV-2 usually in the sacral ganglia |
|
|
Term
| HSV encephalitis typically is due to HSV latent in the _____. |
|
Definition
|
|
Term
| What area of the brain is affected by HSV encephalitis? |
|
Definition
| usually inferior and medial temporal lobes, sometimes frontal |
|
|
Term
| How does HSV injure neurons? |
|
Definition
| directly infects cells in the cerebral cortex causing necrosis and a glial reaction leading to lytic, hemorrhagic injury |
|
|
Term
| How do you diagnose HSV encephalitis? |
|
Definition
| PCR of the cerebrospinal fluid |
|
|
Term
| What is the appearance of HSV meningoencephalitis on microscopy? |
|
Definition
| inflammation in the meninges and the brain parenchyma; also hemorrhage surrounding the perivascular lymphocytic infiltrates; produces a glial nodule (similar to toxoplasma) |
|
|
Term
| Describe the CSF in HSV encephalitis? |
|
Definition
| typically mononuclear pleocytosis (50 to several hundred WBCs), RBC count usually elevated, protein levels increased (an exception from the general viral rule) |
|
|
Term
| How is HSV encephalitis diagnosed? |
|
Definition
| CSF cuture is INSENSITIVE and slwo so PCR of CSF to detect HSV DNA is the gold standard (brain biopsy was the old way) |
|
|
Term
| What type of imaging should you get for HSV encephalopathy? |
|
Definition
| brain MRI is more sensitive than CT; abnormalities are found in approximately 90% of HSV encephalitis. Localized temporal, sometimes frontal, abnormalities are classic |
|
|
Term
| What does EEG show for a patient with HSV encephalitis? |
|
Definition
| focal abnormalities of the temporal lobes |
|
|
Term
| If you have an AIDS patient with altered mental status but no focal lesions by CT scan or MRI you can rule out... |
|
Definition
| toxoplasmosis, CNS lymphoma, and abscess |
|
|
Term
| If you have a patient with AIDS presenting with altered mental status but they don't have focal white matter lesions on MRI you can rule out... |
|
Definition
|
|
Term
| _____________ is an important treatable cause of altered mental status in immunocompromised patients and should be ruled out by a negative CSF ______ test. |
|
Definition
| cryptococcosis; CSF cryptococcal antigen test |
|
|
Term
| What quick stain should you use if you suspect a zygomyces? |
|
Definition
|
|
Term
| Name the medially important zygomycetes. |
|
Definition
| mucor, rhizopus, absidia, Cunninghamella |
|
|
Term
| What is the classical linical presentaiton of a periorbital zygomycete infection? |
|
Definition
|
|
Term
| How do you distinguish mucormycosis from aspergillus? |
|
Definition
| mucormycosis ahs long, aseptate, ribbon like hyphae; aspergillus has septae and 45 degree angle branching along with condiaphores |
|
|
Term
| What happens to sporangiospores that are inhaled? |
|
Definition
| they are cleared by phagocytosis-> macrophages kill intracellular spores by oxidative mechanisms; neutrophils damage fungal hyphae by extracellular means; in immunocompromised hosts, spores may survive phagocytosis and germinate |
|
|
Term
| What are the complications caused by fungal spores germinating in immunocompromised hosts? |
|
Definition
| hyphae invade the oral and sinus mucosa, invading blood vessels and causing thrombosis and tissue necrosis |
|
|
Term
| What diseases/medical situations cause predisposition to invasive disease by mucormycosis? |
|
Definition
| diabetes, steroid treatment, hematopoietic stem-cell transplants |
|
|
Term
| Why does diabetes, steroid therapy, etc. predispose patients to invasive fungal disease? |
|
Definition
| neutropenia and impaired phagocyte function |
|
|
Term
| What are the physical exam findings of invasive zygomycosis? |
|
Definition
| inflammation or tissue necrosis (black eschar) late in infection |
|
|
Term
| Definitive diagnosis of rhino-orbito-cerebral zygomycosis is based upon.. |
|
Definition
| culture and/or histopathology |
|
|
Term
| How is invasive mucormycosis treated? |
|
Definition
| intravenous amphotericin B and extensive surgical debridement |
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