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24 Cards in this Set
- Front
- Back
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Typical Pneumonia
Onset Symptoms Constitutional Symptoms Physical exam findings Sputum Leukocytosis CXR Response to penicillin |
Onset: acute
Symptoms: fever, cough, chest pain Constitutional Symptoms: severe Physical exam findings: rales, signs of consolidation Sputum: rusty, purulent Leukocytosis: common (bands) CXR: Air space disease Response to penicillin: prompt |
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Atypical Pneumonia
Onset Symptoms Constitutional Symptoms Physical exam findings Sputum Leukocytosis CXR Response to penicillin |
Onset: insidious
Symptoms: fever cough, headache Constitutional Symptoms: moderate Physical exam findings: rales may be minimal Sputum: clear, scant Leukocytosis: variable, mild CXR: interstitial Response to penicillin: none |
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WHAT ARE MYCOPLASMA?
Size? Gram stain? Cell wall? Membrane contains? 4 Human pathogens? (cause what?) |
The smallest bacteria (0.2-0.3 microns), not visualized with Gram stain (pass through bacterial filters)
Lack cell wall (only bacteria in which this is true) Contain cell membrane, ribosomes, and prokaryotic nucleus Membrane contains sterols (require complex growth media to grow - steroid precursors) Very diverse and widespread in nature 16 species isolated from humans Human pathogens: M. pneumoniae - pneumonia M. hominis - genital tract infection M. genitalium – genital tract infection Ureaplasma urealyticum - genital tract infection |
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GROWTH OF MYCOPLASMA
Growth speed? What does it require to grow? Size of colonies? |
Capable of growth on cell-free media.
Require source of exogenous sterols Long division time (i.e. 1-6 hrs) Can grow in broth or on agar Colonies are very small |
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EPIDEMIOLOGY OF M. PNEUMONIAE
T/F Most M. pneumoniae infections result in non-specific respiratory tract infection that is not diagnosed Most cases of pneumonia caused by M. pneumonia occur in what population group? |
True
Most M. pneumoniae infections result in non-specific respiratory tract infection that is not diagnosed Most cases of pneumonia caused by M. pneumoniae occur in school-aged children (~age 5) and young adults (up to age 30; unusual for kids 2 years of age) Accounts for up to 50% of cases of pneumonia in this age group Occurs year-round. Occasional epidemics in the fall. |
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EPIDEMIOLOGY OF M. PNEUMONIAE
Spread through? Reservoir? Prolonged colonization? |
Contagious - transmission by respiratory route
Reservoir is infected humans Prolonged colonization has not been described |
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PATHOPHYSIOLOGY OF MYCOPLASMA PNEUMONIA
Site of infection? Attachment mediated by? Histopathology? How does it cause damage? |
Site of infection: mucous membranes of respiratory tract
Attachment is via a specialized terminal organelle containing a protein attachment factor designated P1 Histopathology: Peribronchiolar cellular infiltrate composed of lymphocytes and plasma cells Damage: Binding of mycoplasma organisms is associated with ciliostasis and cytotoxicity. Elaboration of H2O2 by the mycoplasma may be important |
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CLINICAL MANIFESTATIONS OF MYCOPLASMA PNEUMONIA
Symptoms: Physical findings? Gram stain? WBC count? CXR? Resolution? |
Symptoms: cough, fever, headache
Physical findings: rales Gram stain: few neutrophils, normal respiratory flora White blood cell count: normal or slightly elevated Chest x-ray: Lobar consolidation and pleural effusions are unusual Resolves spontaneously |
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COMPLICATIONS OF MYCOPLASMA PNEUMONIA?
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Bullous myringitis (rare)
Hemolytic anemia (cold agglutinins) Skin rashes, esp, erythema multiforme Meningoencephalitis Myopericarditis Arthritis |
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LABORATORY DIAGNOSIS OF MYCOPLASMA PNEUMONIA
What is the preferred method for hospitalized patients? |
Mycoplasma-specific IgM or IgA antibodies (these come up early)
Seroconversion or 4-fold rise in antibody titer Cold agglutinins (insensitive) Culture (slow, not widely available) PCR of respiratory secretions – preferred method for hospitalized patients |
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TREATMENT OF MYCOPLASMA PNEUMONIA
MTF |
Macrolides (erythromycin, clarithromycin, azithromycin)
Tetracycline Fluoroquinolones |
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WHAT ARE CHLAMYDIAE?
Respiration? Energy metabolism? |
Obligate intracellular bacteria
Lack capacity to generate energy (cannot synthesize ATP) (must parasytize host cell that makes ATP - cannot grow on cell free media) |
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CHLAMYDIAE THAT INFECT HUMANS
Name them and their manifestations |
C. trachomatis
- A, B, Ba, C – trachoma (ocular disease - epidemic in developing world) - D-K – urethritis (most common) - L1-3 - lymphogranuloma venereum (STD) Chlamydophila psittaci - psittacosis Chlamydophila pneumoniae - respiratory tract infection, atherosclerosis (?) |
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EPIDEMIOLOGY OF C. PNEUMONIAE
common Age/Population? Reinfection? Reservoir? Transmission/contagious? |
Infection is common among school aged children. More than 50% of adults have evidence of past infection (imperfect information - results may be result of cross-reactions)
Reinfection thought to occur No known animal or environmental reservoir Not highly contagious (hard to know; at least enough to spread widely in population) |
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CLINICAL MANIFESTIONS OF CHLAMYDOPHILA PNEUMONIA
mild/severe? similar to which infection by which organism? mild cases associated with what findings? _________ may be present |
Relatively mild
Similar to Mycoplasma pneumonia Milder cases have non-specific respiratory tract infection and bronchitis Pharyngitis may be present Duration may be prolonged |
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LABORATORY DIAGNOSIS OF CHLAMYDOPHIIA PNEUMONIA
name 2 |
Species-specific serologic test such as microimmunofluorescence
Culture and PCR may detect colonization |
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TREATMENT OF CHLAMYDOPHIIA PNEUMONIA
MTF (again) |
Macrolides (erythromycin, clarithromycin, azithromycin)
Tetracycline Fluoroquinolones |
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LEGIONELLA
Resp? Gram? Spore forming? Which organism accounts for more than 90% of human legionella infections? Which serogroup causes most of these infections? What special stain shows better staining than gram- stain? What is special about L.micdadei? |
Aerobic, Gram-negative, non-spore-forming
L. pneumophila accounts for more than 90% of human Legionella infections. Most of these are caused by L. pneumophila serogroup 1. Better staining with silver stains such as Dieterle. Some strains (L. micdadei) are weakly acid-fast |
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LEGIONELLA (cont.)
Name the fastidious growth requirements: - requires? - stimulated by? - does not grow on? - medium of choice? - cell wall contains? |
Fastidious growth requirements
- Requires cysteine - Stimulated by ferric ions - Does not grow on routine sheep blood agar. - Medium of choice is buffered charcoal yeast-extract agar - Cell wall contains distinctive fatty acids |
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ECOLOGY OF LEGIONELLA
Reservoir? environment? Favors ____ temperatures? Grows within free-living? Resistant to? Found in ________? What can control growth? |
Widespread in aquatic environment
Favors warm temperatures Grows within free-living amoeba Found in building water supplies, esp. in sediment at bottom of hot water tanks Resistant to chlorine Hot water flushes and copper-silver ionization units can control growth |
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EPIDEMIOLOGY OF LEGIONNAIRES’ DISEASE
Relative contribution to cases of pneumonia? high or low? Community acquired/nosocomial? Risk factors? Outbreaks linked to what? Transmission? Person to person? |
Accounts for a small proportion of all cases of pneumonia
Can be community-acquired or nosocomial Male sex, older age, cigarette smoking, and immunosuppression are risk factors Some outbreaks have been linked to contaminated building water supplies Transmission is airborne or by aspiration No person-to-person transmission |
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CLINICAL MANIFESTATIONS OF LEGIONNAIRES’ DISEASE
similar or different to other forms of bacterial pneumonia? symptoms? evidence of multi-system disease? wbc count? gram stain of sputum? cxr? multifocal? |
Similar to other forms of bacterial pneumonia
Symptoms - high fever, malaise, non-productive cough Evidence of multi-system disease may be present: diarrhea, abdominal pain, abnormal hepatic and renal function White blood cell count - normal or slightly elevated Gram stain of sputum - normal flora Chest x-ray - air space disease. May be multifocal |
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LABORATORY DIAGNOSIS OF LEGIONNAIRES’ DISEASE
antigen detection in urine detects only? |
Culture of sputum, pleural fluid, blood
Antigen detection in urine - detects only L. pneumophila serotype 1 Acute and convalescent antibody titers |
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TREATMENT OF LEGIONNAIRES’ DISEASE
what are they? |
Azithromycin or erythromycin
Fluoroquinolones Rifampin as second agent for severe cases |
