Classical bacterial pneumonias
Pneumococcus
Staphylococcus
Pneumococcus
Staphylococcus
Streptococcal (beta-hemolytic)
Klebsiella
Klebsiella
Pneumococcus
Disease of the elderly, commonly follow upper respiratory infection. Most common pneumonia. Abrupt onset of fever, shaking chills, purulent sputum. Leukocytosis, hypoxia. Lobar pneumonia on X-ray. Rx: penicillin, third generation cephalosporin. Classically, axillary lobar segment.
Disease of the elderly, commonly follow upper respiratory infection. Most common pneumonia. Abrupt onset of fever, shaking chills, purulent sputum. Leukocytosis, hypoxia. Lobar pneumonia on X-ray. Rx: penicillin, third generation cephalosporin. Classically, axillary lobar segment.
Staphylococcus
In community, see it postviral, for instance after post-influenza. Also common nosocomial. Can get cavitations, unlike pneumococcus. Variable presentation on X-ray: looks lobar is inhaled, cavities if hematogenous. Acute presentation, leukocytosis.
In community, see it postviral, for instance after post-influenza. Also common nosocomial. Can get cavitations, unlike pneumococcus. Variable presentation on X-ray: looks lobar is inhaled, cavities if hematogenous. Acute presentation, leukocytosis.
Streptococcus
Pleural effusions early in infection, can lead to empyema. Use penicillins and clindamycin if severe infection to stop toxin production early.
Pleural effusions early in infection, can lead to empyema. Use penicillins and clindamycin if severe infection to stop toxin production early.
Klebsiella
In alcoholics, diabetes, people with underlying lung disease. Red currant jelly sputum: due to necrotizing nature of Klebsiella, there is blood in sputum. Leukopenia. Bulging fissure (infection expands the affected lobe). Rx: Cephalosporins, quinolones.
Haemophilus
Usually non-typeable, common cause of bronchitis and sometimes pneumonia in patients COPD. Other organisms that can cause similar disease: Legionella pneumophila, Moraxella catarrhalis. Rx: Ampicillin, cephalosporins.
Usually non-typeable, common cause of bronchitis and sometimes pneumonia in patients COPD. Other organisms that can cause similar disease: Legionella pneumophila, Moraxella catarrhalis. Rx: Ampicillin, cephalosporins.
Atypical pneumonias: Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia pneumoniae
Mycoplasma Pneumonia
Classic walking pneumonia, second-most cause of community-acquired pneumonia after pneumococcus. Younger population (young adults especially). Spread by droplets; average incubation 3weeks versus a day or two for pneumococcus. Symptoms: low-grade fever, malaise, headache, non-productive cough, ear pain with bullous myringitis. Diagnosis: PCR, EIA, bedside "cold agglutinin" test. Rx: Tetracyclines, macrolides, quinolones. Extra-pulmonary manifestations: Can cause IgM antibodies to red cell I antigen, Stevens-Johnson syndrome, CNS disease. X-ray: interstitial pattern, also what Chlamydia looks like.
Chlamydia pneumonia (and psittaci -- zoonosis)
No peptidoglycan like mycoplasma, though it does have a cell wall; obligate intracellular organism. Resembles Mycoplasma. Tx: Tetracyclines or macrolides.
No peptidoglycan like mycoplasma, though it does have a cell wall; obligate intracellular organism. Resembles Mycoplasma. Tx: Tetracyclines or macrolides.
Legionella pneumophila
Small, fastidious, aerobic gram negative that multiplies inside macrophages (DOT and ICM virulence factors prevent phagosome-lysosome fusion). If you have impaired macrophage function as in COPD, you are more susceptible. You need TH1/IFN-gamma to activate macrophages to kill the organism. Legionella can hide inside amoeba in water, as well as enter a low metabolic state inside biofilm. Symptoms: high fever but relative bradycardia (pulse-temperature dissociation), nonproductive cough, diarrhea and abdominal pain, hyponatremia. Diagnosis: culture on charcoal yeast extract agar with cysteine; urinary antigen, serology; patchy, nodular infiltrates -- pleural or perihilar based on X-ray. Rx: quinolones or macrolides.
Small, fastidious, aerobic gram negative that multiplies inside macrophages (DOT and ICM virulence factors prevent phagosome-lysosome fusion). If you have impaired macrophage function as in COPD, you are more susceptible. You need TH1/IFN-gamma to activate macrophages to kill the organism. Legionella can hide inside amoeba in water, as well as enter a low metabolic state inside biofilm. Symptoms: high fever but relative bradycardia (pulse-temperature dissociation), nonproductive cough, diarrhea and abdominal pain, hyponatremia. Diagnosis: culture on charcoal yeast extract agar with cysteine; urinary antigen, serology; patchy, nodular infiltrates -- pleural or perihilar based on X-ray. Rx: quinolones or macrolides.
Aspiration pneumonia
Associated with anaerobes. Chronic infection, low grade fever, putrid foul smelling sputum. Cavitary lesions and abscesses in dependent lung segments.
Associated with anaerobes. Chronic infection, low grade fever, putrid foul smelling sputum. Cavitary lesions and abscesses in dependent lung segments.
Nosocomial pneumonia
Staph aureus, enteric gram-negative rods.
Staph aureus, enteric gram-negative rods.
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