Term
| what bacteria are seen in community acquired acute pneumonia? |
|
Definition
| strep pneumoniae, h. influenzae, moraxella catarrhalis, s aureus, legionella pneumophila, klebsiella pneumoniae, pseudomonas |
|
|
Term
| what is the most common pathogen causing community acquired acute pneumonia? |
|
Definition
|
|
Term
| who is at an increased risk for strep pneumoniae pneumonia? |
|
Definition
| sickle cell, post-splenectomy |
|
|
Term
| what would we see on a sputum smear in someone with strep pneumoniae pneumonia? |
|
Definition
| gram positive diplococci inside neutrophils |
|
|
Term
| who gets the pneumococcal vaccine? |
|
Definition
| (against capsular polysac) for >60yo or high risk patients |
|
|
Term
| how would h flu look on a sputum smear? |
|
Definition
| gram negative rod or coccobacillus |
|
|
Term
| what is the pathogen that is the most common bacterial cause of acute exacerbation/pneumonia in COPD? second most common? |
|
Definition
|
|
Term
| this bug is a common cause of acute LRT infections in children and pneumonia in the adult |
|
Definition
|
|
Term
| why are nonencapsulated infections increasing? |
|
Definition
| bc there are vaccines against type b h flu, which used to be the most common cause of severe disease |
|
|
Term
| aside from pneumonia, what other infections does h flu cause? |
|
Definition
| otitis media, sinusitis, bronchopneumonia |
|
|
Term
| why does h flu have a high mortality rate in children? |
|
Definition
| bc it makes thick mucus plugs that cause problems in clearing bacteria and that can plug the airways with exudate |
|
|
Term
| whawt are some virulence factors that helps h flu survive in the host? (4) |
|
Definition
| adheres to respiratory epithelium thru pili (then works its way down into lungs), secretes a factor that disorganizes ciliary beating and a protease that degrades IgA, has capsule that prevents opsonization (increases survival in blood stream) |
|
|
Term
| what does moraxella catarrhalis look like on sputum gram stain? |
|
Definition
|
|
Term
| whos mainly affected by moraxella? |
|
Definition
|
|
Term
| what organisms commonly cause otitis media in children? |
|
Definition
|
|
Term
| what does s aureus look like on sputum stain? |
|
Definition
| gram + coccus in clusters |
|
|
Term
| what is the organism commonly responsible for secondary bacterial pneumonia in children after viral illnesses (ie measles)? |
|
Definition
|
|
Term
| what is the organism commonly responsible for secondary bacterial pneumonia in healthy adults after the flu? |
|
Definition
|
|
Term
| what are 2 pathologic entities commonly associated with s. aureus respiratory infections? |
|
Definition
| lung abscesses and empyema |
|
|
Term
| what subpopulations of people are at risk for s aureus pneumonia? |
|
Definition
| IVDAs (assoc with endocarditis) and hospitalized/immunosuppressed patients (nosocomial) |
|
|
Term
| what does klebsiella pneumoniae look like on sputum stain? |
|
Definition
|
|
Term
| what kind of patients are at risk for klebsiella pneumonia? |
|
Definition
| debilitated patients, especially chronic alcoholics |
|
|
Term
| what is a characteristic pathogenic mechanism of klebsiella? |
|
Definition
| has a thick capsule or polysaccharides --> produces very thick mucus --> sputum production difficult --> harder to clear organisms |
|
|
Term
| what does pseudomonas look like on sputum stain? |
|
Definition
|
|
Term
| which patients are at risk for pseudomonas pneumonia? |
|
Definition
| debilitated patients, cystic fibrosis patients, neutropenic patients, nosocomial |
|
|
Term
| which organisms causing community acquired pneumonia like to get into the blood and cause vasculitis? |
|
Definition
| klebsiella and pseudomonas |
|
|
Term
| which patients are at risk for legionella pneumonia? |
|
Definition
| patients with predisposing medical conditions (elderly or transplant patients) |
|
|
Term
| what is the fatality rate of legionella pneumonia in immunosuppressed patients? |
|
Definition
|
|
Term
| how do we diagnose legionella pneumonia? |
|
Definition
| (do regular stain...if see mix of neutrophils and macrophages do silver stain to ID organism); detect legionella antigen in urine, fluorescent antibody test in sputum or culture |
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|
Term
| what are the 2 morphologies of bacterial pneumonias? |
|
Definition
| lobular bronchopneumonia (patchy consolidation. can lead to confluent bronchopneumonia which is essentially lobar consolidation); lobar pneumonia (consolidation of whole lobe) |
|
|
Term
| what are the four stages of lobar pneumonia? |
|
Definition
| 1. congestion (vascular engorgement, leaky capillaries, intra-alveolar fluid and bacteria) 2. red hepatization (massive exudate of red cells, neutrophils and fibrin in alveolar spaces, becomes like a liver) 3. gray hepatization (red cells lyse, neutrophils and fibrin persist) 4. resolution or fibrosis (resolution: alveolar macs ingest fibrinopurulent material in alveoli. fibrosis: alveolar spaces obliterated, alveolar walls excessively thickened with fibrous tissue --> fibrous space clogged up with granulation type tissue --> air space unusable --> collagen retracts, coalesces, collagen and elastin accumulate) |
|
|
Term
| what is fibrinous pleuritis? |
|
Definition
| if inflammation in lobar pneumonia reaches pleural surface it may organize into fibrous tissue called adhesions |
|
|
Term
| what does bronchopneumonia look like grossly? |
|
Definition
| dry, granular, gray, red or yellow firm areas, poorly delineated at margins, can occur at multiple lobes, more common in lower lobes |
|
|
Term
| what does bronchopneumonia look like microscopically? |
|
Definition
| patchy areas, neutrophils in alveoli, bronchioles and bronchi |
|
|
Term
| how is community acquired atypical pneumonia different from typical? |
|
Definition
| patchy inflammatory changes confined to alveolar septae and interstitium, lack of alveolar fibrinopurulent exudate, little sputum, no physical findings of consolidation, moderate elevation in wbc |
|
|
Term
| what are the 4 main causes of community acquired pneumonia? |
|
Definition
| mycoplasma, viruses (influenza A and B, rsv, adenovirus, rhinovirus, rubella, varicella), chlamydia, coxiella |
|
|
Term
| what things predipose patients to community acquired atypical pneumonia? |
|
Definition
| malnutrition, alcoholism, debilitating illness |
|
|
Term
| describe the pathogenesis of community acquired primary atypical pneumonia |
|
Definition
| attachment of organisms to upper respiratory tract epithelium --> necrosis/inflammation --> extends down trachea, bronchi, alveoli --> interstitial inflammation and outpouring of fluid into alveolar spaces --> denudation of resp epithelium --> inhibit mucociliary clearance and predispose to bacterial infec |
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|
Term
| what does atypical pneumonia look like grossly? |
|
Definition
| patchy involvement, red, blue, congested, subcrepitant |
|
|
Term
| what does atypical pneumonia look like microscopically? |
|
Definition
| interstitial inflammation (within alveolar walls), composed of mononuclear cells (lys, histiocytes, plasma cells) and neutrophils |
|
|
Term
| what does the exudate look like in atypical pneumonia? |
|
Definition
| mostly proteinaceous material, acellular, pink hyaline membranes similar to ARDS |
|
|
Term
| how does resolution happen in atypical pneumonia? |
|
Definition
| pink hyaline membranes made up of fibrin, dead type I and II pneumocytes and macrophages line the alveoli and interfere with gas xc --> eventually alveolar macrophages eat up hyaline --> type II pneumocyte grows back and type Ii and transform into type I --> resolution! |
|
|
Term
| compare clinical course of classic pneumonia with atypical pneumonia |
|
Definition
| classic: abrupt onset of high fever, chills, cough with purulent sputum and sometimes hemoptysis; atypical: like a bad chest cold, +/- cough, no sputum, fever, headache, muscle aches |
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|
Term
| in june 2009, the WHO rasied worldwide pandemic alert for H1N1 to what level? waht does this mean? |
|
Definition
| level 6, rapid widespread infection |
|
|
Term
| who is at risk for significant morbidity and mortality with the H1N1 virus? |
|
Definition
| pediatric and pregnant patients |
|
|
Term
| how do people get the H5N1 influenza virus (avian flu)? |
|
Definition
| direct contact with infected poultry, oral ingestion or contact with contaminated surfaces or water. no spread by aerosols, few cases of human to human spread not beyond 1 person |
|
|
Term
| what is the mortality rate of avian flu and why is it so severe? what causes most of the deaths? |
|
Definition
| 60%, severe bc of its increased tissue tropism. can be cleaved by ubiquitous proteases thorughout the body to enter the cell. ARDS causes most of the deaths |
|
|
Term
| what are the sx of the SARS pneumonia? |
|
Definition
| 2-10 day incubation period --> dry cough, malaise, myalgias, fever and chills (one third gets better, two thirds progress to severe respiratory distress disease with 10% mortality mostly from ARDS) |
|
|
Term
| what virus causes SARS pneumonia and how is it spread? |
|
Definition
| coronavirus. virus infects palm civits (eaten in china). virus spreads person to person by infected respiratory secretions, less commonly stool. |
|
|
Term
| what viral class does human metapneumovirus belong to and what does it cause? |
|
Definition
| paramyxovirus. causes URT, LRT, severe bronchiolitis or pneumonia |
|
|
Term
| who does human metapneumovirus affect? |
|
Definition
| young children, elderly, immunocompromised |
|
|
Term
| what are the most common organisms causing nosocomial pneumonias? |
|
Definition
| (gram neg rods) pseudomonas, enterobacteriaceae, (gram+ cocci) s aureus, s epidermidis |
|
|
Term
| who is at risk for aspiration pneumonia? |
|
Definition
| alcoholics, debilitated patients with abnormal gag or swallowing reflexes, normal patients who aspirate bc theyre unconscious, during repeated vomiting |
|
|
Term
| what is the pathology/complication of aspiration pneumonia? |
|
Definition
| necrotizing pneumonia bc of irritation of gastric acid and mixed bacteria. frequent cause of death, lung abscesses d/t acidic material is a common complication |
|
|
Term
| what does the morphology of lung abscesses look like? |
|
Definition
| suppurative destruction of the lung parenchyma in the center of the abscess. fibrosis develops around the edge, purulent material may drain into a bronchus, possibly saprophytic infections superimposed (aspergillus) |
|
|
Term
| what is the clinical course of necrotizing pneumonias and lung abscesses? |
|
Definition
| cough, fever, copious amounts of foul-smelling possibly bloody sputum. CLUBBING, assoc with lung carcinoma in 10-15% of cases, resolves with antibiotic therapy |
|
|
Term
| possible complications of necrotizing pneumonia and lung abscesses? |
|
Definition
| empyema, hemorrhage, septic emboli causing meningitis or brian abscesses, secondary amyloidosis if chronic (AA amyloid) |
|
|
Term
| what are the 4 types of chronic pneumonias? |
|
Definition
| TB, histoplasmosis, blastomycosis, coccidioidomycosis |
|
|
Term
| how do we stain for mycobacteria? |
|
Definition
| acid fast stain, weakly + gram stain, or silver stain |
|
|
Term
| what causes a false + PPD? |
|
Definition
| infection by atypical mycobac |
|
|
Term
| what are 3 substances important in keeping TB latent? |
|
Definition
| interferon gamma (produce by mature TH1 cells) stimulate formation of phagolysosomes (dstruction of TB), also stimulates NO (makes free radicals that kill TB), and stimulates macrophages to produce TNF (recruits monocytes that differentiate into epithelioid histiocytes, making granulomas) |
|
|
Term
| describe progressive primary Tb |
|
Definition
| (when primary infection does not become latent) acute bacterial pneumonia with lower and middle lobe involvment. hilar adenopathy and pleural effusions common. may be massive lymphohematologic dissemination causing TB meningitis and miliary TB. rarely cavitation |
|
|
Term
| where does secondary tuberculosis affect the lung? |
|
Definition
| apex of upper lobes d/t high oxygen tension there |
|
|
Term
| what are the features of secondary TB? |
|
Definition
| apex of upper lobes, rapid tissue destruction (caseation and cavitation), cavitation disseminates mycobac along airway leading to infectious sputum, purulent sputum, 50% hemoptysis can be life threatening, pleuritic pain secondary to infection of pleural surface, asymptomatic at first then malaise anorexia weightloss fever night sweat |
|
|
Term
| gross morphology of primary tb? |
|
Definition
| ghon focus (area of caseous necrosis where organism first implants in lung, usually mid chest) ranke complex aka ghon complex (tb bacilli drain to local LN which also undergo caseous necrosis. ghon focus + hilar LN draining it = complex); lymphatic and hematologic dissemination, but usually does not develop into lesions bc of cell mediated immunity |
|
|
Term
| microscopic morphology of primary tb? |
|
Definition
| gramulomatous inflammation: caseating and noncaseating with multinucleated giant cells, fibroblastic rim of epithelioid histocytes with chronic inflammation in and around it |
|
|
Term
| microscopic morphology of secondary tb? |
|
Definition
| caseating granulomas which coalesce |
|
|
Term
| describe progressive pulmonary tb |
|
Definition
| (one of the ways secondary tb can progress) usually in elderly or immunosuppressed, apical lesion enlarges with expansion of caseation. erosion into bronchus --> infectious sputum. erosion into blood vessel --> hemoptysis. destroyed lung parenchyma --> fibrotic cavities, may or may not collapse. tx inadequate or host defenses poor --> dissemination through airways (galloping consumption) or lymphohematogenous (miliary) dissemination |
|
|
Term
| what is tuberculous empyema? |
|
Definition
| when a caseous cavity opens into a pleural space, the cavity heals by obliterative fibrinous pleuritis |
|
|
Term
|
Definition
| TB lymphadenitis (kids: cervical lymph nodes with tb is frequent) also seen in HIV+ |
|
|
Term
|
Definition
| (non-pasteurized milk or swallowing infective sputum) infection esp in the ileum. organisms trapped in granulomas in the lamina propria, which eventually ulcerate |
|
|
Term
| who is at risk for MAI complex? |
|
Definition
| AIDS+ with CD4 <50. rarely seen in non-immunocompromised |
|
|
Term
| what do we expect to see in patients with MAI complex? |
|
Definition
| in aids+ see widespread infection in the mononuclear system (LN, liver, spleen, lungs, gi tract), see numerous bacilli and macs with poorly formed or no granulomas |
|
|
Term
| how does someone catch histoplasmosis? |
|
Definition
| (dimorphic fungus) inhalation of dust contaminated with bird or bad droppings (chicken coops, bulldozing, cave exploring) in southeast, mid-atlantic and central USA |
|
|
Term
| features of histoplasmosis? |
|
Definition
| great mimicker of TB. coin sized lesions on xray. self-limited or latent primary pulmonrary infection or chronic secondary lung disease located at apices with cough fever and night sweats. cavity formation less common. may present as localized lesions in extrapulm sites (adrenals or meninges) or may be widely disseminated in immunosuppressed pts |
|
|
Term
| describe pathogensis of histoplasmosis? |
|
Definition
| internalized into macs after opsonization or via HSP60 antigen on fungus which binds beta-2 integrins on the macrophage. multiply inside phagolysosome, lyse the macrophage --> T helper cells recognize fungal wall cell antigen and secrete IFNg which activates macs and kills intracellular yeast forms --> macs make TNF --> stimulates other macs to kill histoplasma and make granulomas |
|
|
Term
| morphology of histoplasmosis? |
|
Definition
| epithelioid granulomas with caseous necrosis (fibrosis --> concentric calcification --> tree bark appearance). organisms 3-5 mu yeasts, mayb e intra or extracellular (clusters of macs with yeast in them found in disseminated disease, no granulomas) |
|
|
Term
| where can one acquire blastomycosis? |
|
Definition
| (dimorphic fungus) soil in central, south eastern US, canada, mexico, middle east, africa, india |
|
|
Term
| what are the 3 forms of blastomycosis? |
|
Definition
| pulmonary, disseminated, primary cutaneous from direct innoculation |
|
|
Term
| what are the clinical features of blastomycosis? |
|
Definition
|
|
Term
| what do we see on xray for blastomycosis? |
|
Definition
| consolidation/patchy/nodular/miliary pattern in upper lobes |
|
|
Term
| what does blastomycosis look like morphologically? |
|
Definition
| suppurative granulomas. yeast 5-15mu with broad-based buds and double contoured wall. may be associated with squamous epithelial hyperplasia which may be mistaken with squamous cell carcinoma |
|
|
Term
| how/where does one acquire coccidioidomycosis? |
|
Definition
| (dimorphic) inhale spores from soil in southwestern and western US |
|
|
Term
| what is the clinical presentation of coccidioidomycosis? |
|
Definition
| most people are asymptomatic, but 10% have fever, cough, pleuritic chest pain and erythema nodosum/multiforme (san joaquin valley fever) |
|
|
Term
| what is the morphology of coccidioidomycosis? |
|
Definition
| granulomatous, pyogenic lesions or both. 20-60 mu sphereules filled with endospores |
|
|
Term
| in HIV+ patient, when CD4 >200, what is the most likely infection? <200? <50? |
|
Definition
| bacterial and mycobacterial (TB) infections; pneumocystis jiroveci; CMV and mycobac avium intracellulare |
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