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2010-05-11 18:19:21

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  1. what are the main differences between the upper and lower respiratory tract? (sterility, morbidity, mortality, cause)
    • URTI: non sterile, high morbidity, low mortality, viral
    • LRTI: sterile, high morbidity, high mortality, bacterial
  2. what are the 2 main viral causes of rhinitis? and what type of viruses are they?
    • rhinovirus: small RNA virus
    • coronavirus: RNA virus
  3. what is the pathogenesis of rhinitis?
    infection/inflammation of nasal mucosa
  4. what are the symptoms of rhinitis?
    itchy eyes, blocked nose, sore throat, cough,
  5. what is the main presentation of pharyngitis?
    sore throat
  6. what is the most common cause of pharyngitis? give e.g.
    virus: influenza, parainfluenza, EBV, HSV, Coxsackie A
  7. what is the most important bacterial cause of pharyngitis?
    group A streptococcus=strep progenies
  8. what are the other bacterial causes of pharyngitis?
    • haemophilus influenzae
    • Group C and G Streptococci
    • rarely Corynebacterium diphtheriae
  9. how would you differentiate a bacterial sore throat from a viral?
    • spiking temperature
    • pus
    • higher severity: barely swallow
    • necrosis (white patches)
  10. if you suspect bacterial pharyngitis what investigation needs to be done and why is it good and what is the immediate treatment and what needs to be avoided?
    • bacterial THROAT SWAB as S.pyogenes grows overnight as beta-haemolytic clones on blood agar
    • Rx: start penicillin for 10 days
    • avoid: amoxicillin as if it is EBV - you can get a rash due to cross reaction between abx and virus
  11. why do you treat GAS so aggressively?
    • to prevent the immunological sequelae:
    • acute glomerulonephritis
    • rheumatic fever
    • these happen due to immune mimicry: Ab against GAS cross react and bind to glomerular BM or cardiac membrane
  12. why do some people with bacterial pharyngitis go red? what happens around eye?
    • GAS makes an erythrogenic toxin which makes you go red = scarlet fever
    • circumoral pallor: around eyes still white!
  13. what is the test for glandular fever?
    monospot or EBV antibody detection
  14. what does acute otitis media and sinusitis usually follow?
    viral UTRI
  15. why is AOM more in children under 5?
    short eustachian tube
  16. name 3 of the most common causes of AOM and acute sinusitis?
    • Strep pneumo
    • Haem influenzaue
    • Moraxella catarrhalis
    • i.e. from URT normal flora track via ET
    • GAS
  17. what are the Rx options for AOM?
    • watch and wait
    • antimicrobials: amoxicillin
  18. what are 3 Rx options of acute sinusitis:
    • douching
    • anti microbials
    • surgical drainage
  19. how does acute epiglottitis present?
    stridor, drooling, sore throat, high fever
  20. why is acute epiglottitis an emergency?
    swelling may threaten airway
  21. what USED to be the most common cause of acute epiglottitis and why is it no longer?
    Haemophilus influenza b (now Hib vaccine)
  22. what is now the most common cause of acute epiglottitis?
    group A strep = strep progenies
  23. what is the Ix and Rx of acute epiglottitis?
    • Ix: do NOT examine mouth as may precipitate acute resp obstruction
    • treat: high dose iv cefotaxime
  24. what is whooping cough?
    • bacterial illness: bordetella pertussis
    • laryngotracheitis
  25. what are the 3 clinical stages of pertussis?
    • prodrome
    • catarrhal
    • paroxysmal whooping stage
  26. how do you diagnose pertussis?
    pernasal swab onto spcecial charcoal media or PCR
  27. what is the treatment of pertussis and for how long?
    • erythromycin for 3 weeks
    • penicillin resistant
  28. what do we do to prevent pertussis?
    acellular vaccination at 2, 3, 5 months and pre-school booster at 3-5years
  29. what is croup? and how does it present?
    • laryngotracheobronchitis
    • fever, barking inspiratory noises, cough, hoarseness
  30. what is the most common causes of croup?
    viral: infleunza and parainfluenza
  31. what are the symptoms of influenza?
    • sudden onset, fever, malaise, headache, myalgia, non productive cough, sore throat
    • last 4-7days
  32. what type of virus is influenza? (2 marks)
    • orthomyxovirus
    • RNA virus with segmented genome
  33. what does the envelope of influenza contain?
    • haemagglutinin (HA)
    • neuraminidase (NA) proteins
  34. what are the different types of influenza?
    • A: epidemics and pandemics
    • B: milder disease, pandemics
    • C: not pathogenic in man
  35. what is the difference between epidemic and pandemic?
    • epidemic: out of control in one nation
    • pandemic: out of control in more than 3 countries in the world
  36. what time of the year does influenza outbreak?
  37. what is the incubation period of influenza?
    1-4 days
  38. how does influenza spread as epidemics and pandemics?
    • antigenic change in HA and NA
    • shift: major change
    • drift: minor change
  39. what are the complications of influenza?
    • primary influenza pneumonia (rare, often fatal - pregnant women)
    • secondary bacterial pneumonia - causes death. infected with Staph aureus, pneumo, h.influ
  40. how do you make a lab diagnosis of influenza?
    • nasopharyngeal secretions or nose/throat swabs and do:
    • viral culture, PCR, antigen detection by immunofluorescence
  41. why is serology useless in most diagnosis?
    retrospective so limited value. when get results, illness over!
  42. how is influenza prevented? 3 ways from simple to complex
    • 1. hand washing, disinfecting surfaces and use of masks to stop you touching your mouth
    • 2. oseltamivir (NA inhib): use for post exposure prophylaxis
    • 3. inactivated (killed) vaccine with current strains of influenza A and B
  43. who is influenza vaccine given to?
    • over 65 yo
    • healthcare workers
    • chronic illness: renal failure, heart probs, respiratory disease, liver disease, immunosuppressed
  44. what is the treatment of influenza? and how does it work?
    • oseltamivir or zanamivir both neuraminidase inhibitors give as soon as symptoms start
    • they limit viral shedding
  45. what type of virus is parainfluenza?
    • paramyxovirus
    • RNA
    • 4 serotypes, 4 lower pathogenicity
  46. what is the Rx of parainf?
    Rx not usually indicated
  47. which are the normal flora of the URT that cause LRTI?
    • strep pneumoniae
    • haemophilus influenzae
    • moraxells catarrhalis
    • staph aureus
  48. why do normal flora of the URT cause LRTI?
    reduced host defences
  49. how are some bact/viruses transmitted?
    droplet spread
  50. how is coxiella burnetti spread?
    transmitted via contact with animals/animal products
  51. how is legionella pneumophila spread?
    aerosolised contaminated water supplies
  52. name 9 host defences:
    • nasopharyngeal infiltration
    • mucosal adherence
    • lysozyme, protease, lactoferrin present in respiratory secretions
    • mucociliary escalator
    • cough and gag reflex
    • immunoglobulins: IgA in nasal mucosa
    • complement
    • T and B lymphocytes
    • alveolar macrophages
  53. name 5 groups of patients that have reduced host defence and explain why door each one:
    • ventilated patients: bypassed nasopharyngeal filtration, bypassed gag and cough reflex, reduced mucociliary clearance
    • smokers: mucosal adherence is not as effective, mucociliary function impaired
    • cystic fibrosis
    • asplenic
    • COPD
  54. what are Strep pneumo and h.infl's virulence factors?
    • produce IgA protease: disable mucosal IgA
    • polysaccharide capsules: resistant to phagocytosis
  55. what is Bordatella pertussis' virulence factor?
    makes endotoxins - widespread local damage
  56. what is the main pathogen for bronchiolotis?
    RSV: respiratory syncytial virus
  57. who is most affected by bronchiolotis?
    infants esp. in first 6 months of life
  58. what type of virus is RSV and how many serotypes?
    • RNA virus
    • 1 serotype
  59. how is RSV spread?
    droplet spread or contact with fomites
  60. why do you have to end diagnose RSV?
    source isolation
  61. how is RSV diagnosed?
    • throat swab, nasopharyngeal aspirate into viral CULTURE
    • viral antigen detected using IMMUNOFLUORESCENCE
  62. how is RSV bronchiolitis managed?
    • admit if severe LRTI
    • supportive Rx: oxygen thearpy
    • Ribavarin by AEROSOL inhalation or severe
    • source isolation
    • hand washing: prevent nosocomial transmission
  63. what is used to prevent RSV in high risk infants?
    • monoclonal RSV Ab vaccine: palivizumab
    • in prewinter season to high risk babies. but £
  64. what is the definition of pneumonia
    inflammation of lung parenchyma caused by infection usually
  65. what is the definition of community acquired pneumonia
    presenting in community or within 48 hours of attending hospital
  66. what are the 4 typical causes of bacterial CAP?
    • strep pneumonia
    • haemophilus influenzae
    • moraxella catarrhalis
    • staph aureus
    • all give lobar pneumonia (typical)
  67. what are 4 causes of atypical bacterial CAP?
    • Mycoplasma pneumoniae
    • Legionella pneumophila
    • Chlamydia
    • Coxiella burnetti: Q fever - rare - contact with animal product - vets
  68. what is the leading cause of CAP in under 2yo?
  69. name 3 viral causes of CAP and who does it affect?
    • influenza
    • parainfluenza
    • human metapneumovirus
    • elderly and immunocompromised most at risk
  70. what are the symptoms and signs of TYPICAL pneumonia?
    • fever
    • productive cough
    • breathlessness
    • purulent sputum
    • haemoptysis
    • pleuritic chest pain
    • shallow rapid breathing
    • reduced chest movements
    • dull to percussion
    • bronchial breathing with COARSE crepitations
  71. what type of bacteria is strep pneumo?
    gram positive diplococcus
  72. how does strep pneumo grow on blood agar?
    ALPHA haemolysis
  73. what is strep pneumo the LEADING CAUSE OF?
    • CAP
    • AOM
    • acute sinusitis
    • acute exacerbations of COPD
  74. how is strep pneumo diagnosed?
    • CULTURE: blood or sputum
    • antigen detection on URINE dipstick
  75. what is the empirical treatment of typical CAP? give mild, mod sev
    • mild-mod: amoxicillin
    • severe: benzyl-penicillin plus clarithromycin OR cefurozime and clarithomycin
  76. what is the presentation of ATYPICAL pneumonia?
    • fever
    • confusion
    • non productive cough
    • myalgia
    • headache
  77. what are the CXR signs of atypical pneumonia?
    patchy consolidation
  78. what are the CXR signs of typical pneumonia?
    lobar consolidation
  79. who does legionella pneumophila commonly affect?
    middle aged males
  80. what time of year does legionella come about?
    • summer months - related to travel - hotels with dodgy AC or water supply
    • need exposure to CONTAMINATED WATER - showers, AC, sprays
  81. how is legionella diagnosed?
    • antigen in urine
    • culture of respiratory secretions
  82. what is the treatment of legionella pneumophila?
    • macrolide: clarythromycin
    • and rifampicin if severe (orange urine)
  83. do patients with legionella pneumonia need to be source isolated?
    no because it doesn't transmit from person to person
  84. what type of year does mycoplasma pneumonia present?
    sporadic or epidemic - 4 yearly cycles
  85. who does mycoplasma pneumoniae affect?
    children and young adults
  86. how is mycoplasma pneumonia diagnosed?
    • serology
    • PCR on resp secretions
  87. what is the treatment of mycoplasma pneumonia?
    macrolide: clarythromycin
  88. what is the definition of hospital acquired pneumonia?
    acute pneumonia commencing 48 hours or more after admission to hospital
  89. what are the risk factors for HAP?
    • time in hospital
    • time on ventilation
    • NG tube - leading to oropharyngeal (gastric) aspiration
    • PPI - inc gastric pH - as suddenly pseudomonas can survive there
    • tracheostomy
    • chronic pulmonary disease
    • severity of underlying disease
  90. what organisms cause HAP?
    • staph aureus
    • pseudomonas aeringosa
    • e.coli
    • coliforms
    • acinetobacter
    • respiratory viruses in immunocompromised
  91. what are the poor prognostic indicators of pneumonia?
    • Confusion
    • Urea > 7mmol/l
    • Resp rate > 30
    • Blood pressure: SBP<90mmHg; DBP<60mmHg
    • Age > 65yrs
    • NB this score is not good for young people as they are fit, good for older adults
  92. what is the empirical treatment for HAP?
    broad spec beta lactam: piperacillin-tazobactam (tazocin) this covers coliforms, pseudomonas, staph aureus but not MRSA
  93. what is needed in severe HAP?
    empirical + gentamicin
  94. what is needed to treat MRSA?
    glycopeptide: vancomycin
  95. what is used in penicillin allergy?
    quinolone: ciprofloxacin
  96. what is the fast way of detecting Mycobacterium (for TB)?
    auramine stain (rather than ZN stain)
  97. where is the most common primary infection of TB?
  98. name 3 rare sites of primary TB infection
    • gut
    • skin
    • lymph nodes
  99. what is primary pulmonary TB?
    first contact with bacillus
  100. what is a ghon complex a combination of?
    • initial lesion: small focus of granuloma in parenchyma/subpleural - PERIPHERY of lung
    • involvement of draining hilar LN: this is the larger response
  101. what do ghon complexes look like macroscopically?
    yellow necrotic areas in parenchyma and nodes
  102. what is secondary pulmonary TB usually due to? 2 things
    • 1. reactivation of primary TB
    • only in 5% of primary TB cases
    • 2. re-infection - e.g. health care worker
    • 3. post BCG
  103. where in the lung does primary pulm TB localise to compared to secondary, why?
    • primary: periphery
    • secondary: apices due to higher PO2 which mycobacterium love
  104. what is the pathological sign of secondary pulm TB?
    assmann focus - area of necrosis in apices of lung. more extensive parenchymal involvement of upper lobe
  105. what are the 4 sequelae of progressive pulmonary TB?
    • cavitatory fibrocaseous TB
    • bronchopneumonia
    • single organ TB
    • miliary TB
  106. what causes cavitating TB?
    • usually secondary TB
    • drainage of necrotic tissue into bronchus/bronchiole and formation of cavity
  107. what are the conseuences of cavitating TB?
    • spread of inflame within lUNGS
    • spread into upper airways - then infected sputum swallowed…
    • spread to gut
  108. what is open TB?
    once the TB has spread into the airways
  109. what causes TB bronchopneumonia?
    dissemination through airways
  110. where can Tb spread to via the blood?
    • bone - spine - Pott's disease - vertebral collapse and acute angulation of spine
    • joints - arthritis
    • kidney
    • adrenals
    • meninges
    • GU tract
  111. what is miliary TB? and what is it assoc. with?
    • WIDESPREAD via blood
    • assoc. with reduced immunity
  112. where does miliary TB usually spread to?
    • lungs
    • liver
    • spleen
    • bone marrow
    • i.e. organs with rich blood supply
  113. is miliary TB usually seen with primary or secondary TB?
  114. what are epitheloid cells?
    macrophages that have lost their phagocytic function and so are ineffective in consuming bacteria
  115. what are longhan's giant cells?
    lots of macrophages (epitheloid cells) joint together to make a multinucleate cell. nuclei arranged in a horseshoe shape
  116. name the 4 antiTB drugs and their SE
    • rifampicin: orange urine
    • isoniazid: hepatitis and peripheral neuropathy (due to depletion of vitB6 so have to give B6 supplements)
    • pyrazinamide: hepatotoxicity
    • ethambutol: visual disturbance (optic neuritis)