Term
| This fungus is the most common opportunistic infection of AIDS patients |
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Definition
| Pneumocystis jirovecii (carinii) |
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Term
| True or false: Pneumocystis invades type I alveolar epithelial cells |
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Definition
| False, it is an extracellular pathogen, it adheres to the epithelium of alveoli but does not invade, causing interstitial pneumonia |
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Term
| Because they are extracellular pathogens, Pneumocystis infection is controlled by this arm of cell-mediated immunity |
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Definition
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Term
| Trimethoprim-sulfamethoxazole prophylaxis is necessary to prevent HIV+ patients from contracting this illness if their CD4 count dips below 250 |
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Definition
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Term
| True or false: degree of morbidity in PCP is determined less by organism load and more by the degree of inflammation brought about by the immune response |
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Definition
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Term
| True or false: it is rare to have a normal lung examination if PCP is present |
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Definition
| False, lung examination is typically normal though pts present with tachypnea, cough, fever and tachycardia, X-Rays show an interstitial pattern |
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Term
| True or false: Since P. jirovecii cannot be cultured, it must be obtained through sputum or bronchoalveolar lavage, the visualized on light microscopy |
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Definition
| True, cysts must be stained with methanimine silver, while trophozoites can be stained with wright-giemsa or papanicolau stains |
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Term
| True or false: In addition to TMP-SMX, patients with more severe lung disease (pO2<70 mmHg) should receive a corticosteroid like prednisone |
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Definition
| True, to decrease inflammation and improved lung function |
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Term
| True or false: like bacteria, some fungi can survive in anaerobic environments |
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Definition
| False, always need oxygen to survive |
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Term
| What important difference between fungi cell membranes and human cell membranes enables drugs to affect the fungi without destroying human cells? |
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Definition
| Instead of cholesterol, fungi have ergosterol in their cell membrane, amphotericin-b and nystatin bind to ergosterol and punch holes in the cell wall, while miconazole and the like interfere with ergosterol synthesis |
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Term
| Contrast the immune response to systemic infection with cryptococcus neoformans or mucor |
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Definition
| The immune response to C. neoformans is typically a granulomatous one, mediated by macrophages and CD4+ T cells, while mucor and others elicits a pyogenic response, mainly by neutrophils |
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Term
| Why is the KOH test a useful tool to distinguishing fungal infection? |
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Definition
| It disrupts the fungal structure allowing hyphae to be visualized |
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Term
| What are the two most common causes of iatrogenic Candida infections in humans? |
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Definition
| In-dwelling catheter use and abx |
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Term
| What is unique about C. albican's reproductive strategy? |
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Definition
| It can reproduce sexually through mitosis, parasexually, where diploid chromosomes formed during mitotic diffusion fuse with diploid chromosome from another fungus and crossing over occurs |
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Term
| True or false: C. albicans is catalase positive |
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Definition
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Term
| Name the 4 drugs used in TB therapy |
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Definition
| Isoniazid (INH), rifampin, ethambutol and pyrazinamide, necessary to avoid resistance |
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Term
| Describe the initial phase of tx for active TB |
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Definition
| 2 months of daily doses of all 4 drugs, if pyrazinamide cannot be taken then the tx duration is extended |
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Term
| Describe the continuation phase of TB tx |
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Definition
| 4-6 months of RIF and INH only, extended to 9 if PZA was not taken in the initial phase of if the patient has a cavitary lesion on chest x-ray |
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Term
| What is the most important side effect with TB therapy, especially with INH? |
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Definition
| Hepatotoxicity, patients with hx of liver dysfxn should be monitored closely, compliance is also an issue |
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Term
| What can be administered with INH therapy to prevent neurologic side effects? |
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Definition
|
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Term
| This MOA makes INH specific for mycobacteria |
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Definition
| Mycolic acid synthesis, a component of the TB cell wall |
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Term
| This antibiotic inhibits DNA-dependent RNA polymerase |
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Definition
|
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Term
| This TB drug can provoke gouty attacks |
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Definition
| Pyrazinamide, also causes hepatic injury |
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Term
| This type of infection most commonly results in lung abscesses, accompanied by a putrid smell on the breath and lack of any pathogen in sputum cultures |
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Definition
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Term
| What is the usual antecedent of primary abscess formation in the lungs? |
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Definition
| Aspiration pneumonia, usually gingival anaerobes |
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Term
| What are some co-existing conditions increasing the risk of aspiration? |
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Definition
| EtOH abuse, sedation, anything depressing a cough reflex |
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Term
| An acute oropharyngeal infection followed by septic thrombophlebitis of the internal jugular vein is known as: |
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Definition
| Lemierre's syndrome (rare) |
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Term
| Which infectious agent represents a life-threatening course in lung infections? |
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Definition
| S. aureus can cause lung infections and abscesses, but will not cause a foul smelling sputum, high risk of septicemia and shock |
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Term
| A compact collection of epithelioid cells, lymphocytes and fibroblasts is known as a: |
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Definition
| Granuloma, plural granulomata |
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Term
| True or false: RSV is a double-stranded DNA virus with a lipid envelope |
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Definition
| False, single stranded - sense RNA virus, but it has envelope |
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Term
| RSV genome encodes () proteins of which () are non-structural |
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Definition
| 10 and 2, there are two major groups |
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Term
| True or false: RSV can survive on fomites |
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Definition
| True, but it's still unstable lasting only a few hours, soap and water and disinfectants can kill it |
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Term
| What are the two most common causes of LRI in young children? |
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Definition
| RSV and parainfluenza virus |
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Term
| True or false: Nearly 100% of children are infected by age 3 in the United States, and up to one million children will die from RSV worldwide |
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Definition
| True, costs 300 million a year |
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Term
| Describe the temporality of RSV |
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Definition
| November through April, mostly January and February |
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|
Term
| What is the incubation period of RSV? |
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Definition
|
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Term
| True or false: RSV infection of the small airways rarely causes necrosis |
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Definition
| False, Necrosis and sloughing of the epithelium occurs with RSV |
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Term
| Immune response to RSV infection is primarily mediated by (cytokine) and (lymphocyte) and the degree of response is a determinant of disease severity |
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Definition
| IFNy, and CD8 T Lymphocytes |
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Term
| These RSV proteins can block induction of anti-viral cytokines |
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Definition
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|
Term
| What observation in young children with severe RSV points to Th2 polarization in the immune response |
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Definition
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Term
| IgG antibodies against these proteins in RSV infection are protective, and this one cross-reactive against both strains |
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Definition
| F and G, F is cross-reactive |
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Term
| True or false: IgA response preceds IgM and IgG to RSV infection |
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Definition
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Term
| True or false: IgE response to RSV may contribute to atopy |
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Definition
| True, sensitized to allergens in the mucosa |
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Term
| These four drugs are used to treat respiratory viruses like influenza |
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Definition
| Amantadine, rimantidine, oseltamivir, zanamivir |
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Term
| True or false: Hemaglutinin (H) and neuraminidase (N) surface proteins determine the type of Influenza A |
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Definition
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Term
| True or false: amantadine and rimantidine cleave neuraminic acid on mucosal epithelial cells to expose sialic acid binding sites underneath the mucous layer. |
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Definition
| False, the neuraminidase inhibitors act on this component (oseltamivir and zanamivir) of the influenza virus |
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Term
| True or false: neuraminidase inhibitors block virion entry into respiratory epithelial cells |
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Definition
| False, the prevent release of virus from the cells |
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Term
| Name some viral causes of atypical pneumonia |
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Definition
| influenza virus, adenovirus, RSV, CMV, coronavirus leading to SARS |
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|
Term
| Name the three major bacterial agents causing atypical pneumonia in humans |
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Definition
| Mycoplasma pneumoniae, legionella and chlamydophila |
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Term
| T or F: unlike other bacterial pathogens, mycoplasmas lack sterols in their cell membranes |
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Definition
| False, mycoplasma is the only spp of bacteria in humans that have sterols in their membrane |
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Term
| T or F: Mycoplasma is a gram negative obligate anaerobe rod |
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Definition
| False, with no cell wall Mycoplasma doesn't stain at all, and is aerobic |
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Term
| T or F: Diagnosis of Mycoplasma requires culture evidence of the bacteria |
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Definition
| False, doubling time in binary fission is very slow so culture is slow, tx is usually initiated empirically |
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Term
| M. pneumoniae has to be cultured on this type of agar |
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Definition
|
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Term
| T or F: M. pneumonia is spread by droploet nuclei and is most common in people over 30 |
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Definition
| F, most common in <30 and is spread by respiratory droplets, frequent outbreaks occur in institutionalized populations |
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|
Term
| T or F: The most common disease caused by M. pneumoniae is atypical pneumonia |
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Definition
| False, upper respiratory illness is more common |
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Term
| List some symptoms of M. pneumoniae infection |
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Definition
| Fever, chills, malaise, headache and NONproductive cough which increases in frequency and severity over two days |
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Term
| How long is the incubation period of M. pneumoniae? |
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Definition
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Term
| Give four important characteristics of fungi: |
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Definition
| Fungi are eukaryotes with chitin in their cell walls, not peptidoglycan (bacteria), two types are yeasts and molds: yeast are single cells that bud to reproduce, molds form hyphae and form a mat, medically important fungi are mostly thermally dimorphic forming different structures at different temperatures, fungi are obligate aerobes or facultative anaerobes, none are obligate anaerobes |
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Term
| What four types of fungal infections can occur? |
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Definition
| Cutaneous, subcutaneous, systemic, opportunistic |
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Term
| The four most important opportunistic fungal infections are: |
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Definition
| Candida, Asperigillosis, Cryptococcus neoformans, Mucor/Rhizopus |
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|
Term
| Cryptococcus causes (), mainly as meningitis, and is the most common life-threatening fungal disease in this group of patients. |
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Definition
| Cryptococcosis, AIDS patients |
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Term
| C. neoformans divides by (), and while it has a thin capsule outside the body once it infects the host the capsule thickens, which is useful in identifying it with this stain. |
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Definition
| narrow-based unequal budding, India ink stain |
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|
Term
| The cryptococcal capsule, known as (), is the basis for the serological tests for cryptococcal infection. |
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Definition
|
|
Term
| T or F: C. neoformans is thermally dimorphic |
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Definition
| False, one of the few that isn't |
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|
Term
| T or F: Cryptococcosis almost always occurs in immunocompromised patients. In the US 85% of cases occur in HIV+ individuals |
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Definition
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|
Term
| Human infection with C. neoformans typically is the result of inhalation of dirt and soil with this in it. |
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Definition
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Term
| The lung infection resulting from C. neoformans infection is often asymptomatic but may produce (), cavities or nodules. In patients with reduced CMI, the organism can spread to the CNS causing (), as well as other organs like (), (), () and others, abcesses in the brain appear as () lesions |
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Definition
| Pneumonia, meningitis, GI, skin, eyes, soap bubble |
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Term
| Treatment of C. neoformans is a combination of () and () for meningitis and other disseminated forms. () is used in AIDS patients for suppression of cryptococcal meningitis. |
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Definition
| Flucytosine, a nucleoside analog DNA inhibitor used for systemic mycosis, side effects include N/V, diarrhea, bone marrow suppression, and amphotericin B which binds ergosterol forming pores that disrupt cell homeostasis, used for systemic mycosis but does not cross BBB, adverse effects include F/C, hypotension, nephrotoxicity and arrhythmias, Fluconazaole and other azoles inhibit ergosterol synthesis, adverse includes hormone synthesis disruption, p450 inhibition, F/C |
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Term
| Aspergillus infection causes () and (). How does it present, who is susceptible. |
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Definition
| Lung cavity aspergilloma (fungus ball) and allergic bronchopulmonary aspergillosis. The infection is invasive and presents with pleuritic chest pain, hemoptysis and infiltrates on CXR. Aspergillus can also infect skin, eyes, ears and other organs, those who are immunocompromised or have chronic granulomatous disease are susceptible. |
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Term
| T or F: Aspergillus can exist in the body as a mold or as yeast. |
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Definition
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Term
| T or F: Aspergillus have septate hyphae that branch at acute angles. |
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Definition
|
|
Term
| Transmission of aspergillus is () |
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Definition
|
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Term
| T or F: Amphotericin has poor efficacy against aspergillosis but the fungus ball in the lungs can be excised. |
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Definition
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Term
| Mucor and Rhizopus spp. are () molds with (irregular/regular) (septate/nonseptate) hyphae that branch at obtuse angles. |
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Definition
| Saprophytic, irregular, non-septate |
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Term
| mucormycosis typically affects () and () patients. |
|
Definition
| Diabetics in ketoacidosis and leukemia. |
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Term
| Mucor/Rhizopus proliferate in the walls of () especially in the sinuses, lungs or gut and cause () and () of tissue distal to the vessel. They can cause frontal lobe abscesses as well. |
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Definition
| Blood vessels, necrosis and infarction |
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