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2010-03-20 16:46:19
Micro2 Path2

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  1. Based on the symptoms name the respiratory infection.
    A. Nasal obstruction, nasal discharge =>
    B. Hoarseness =>
    C. Sore throat, red throat (with or w/out exudate) =>
    D. Cough, chest pain, rales =>
    E. Hoarseness, barking cough, stridor (infants) =>
    F. Nonproductive cough, substernal pain =>
    G. Cough, dyspnea, wheezing =>
    • A. common cold
    • B. laryngitis
    • C. pharyngitis
    • D. pneumonia
    • E. croup
    • F. tracheobronchitis
    • G. bronchiolitis
  2. Which of the following is not an upper respiratory infection (URI)?
    cold, bronchitis, otitis, pinche cabronitis, sinusitis, pharyngitis, epiglottitis
    pinche cabronitis
  3. Is the common cold a viral or bacterial infection?
    viral (lasts 7-10 days)
  4. What microbial agent fits the following description and what illness is the result?
    Single-stranded, + sense, RNA, non-enveloped, replicates in nose, distributed worldwide, peaks seasonally, over 100 defined stereotypes, optimum temp for replication is 33 degrees C,
    Rhinoviruses (of the Picornaviridae family) => common cold (most common cause)
  5. Put the following series of events in the pathogenesis of the common cold in correct chronological order.
    1) Virus binds to host immune cell receptor ICAM-1 => gains entry into cell => replicates
    2) Virus introduced into nasal passage escapes host defense
    3) Activation of kinins results in inflammatory events => symptoms
    4) Mucociliary action transports virus from anterior nares to nasopharynx
    2, 4, 1, 3
  6. Which two events are mismatched with their symptoms?
    A. dilation of vessels : nasal obstruction
    B. transudation of plasma : sore throat
    C. stimulation of seromucous glands : mucous in nose
    D. stimulation of pain fibers : rhinorrhea
    • B. transudation of plasma : rhinorrhea
    • D. stimulation of pain fibers : sore throat
  7. What is the most common complication of Rhinovirus infections?
    Exacerbations of chronic bronchitis--40% (followed by acute bacterial otitis media, asthma exacerbations in children >2, and acute bacterial sinusitis)
  8. What is the diagnosis and treatment of Rhinovirus?
    diagnosis: made on basis of clinical syndrome (nasal swab is possible but rarely performed)

    treatment: mostly symptomatic, intranasal interferon (vaccine not available)
  9. Your Pt has a lower respiratory infections caused by a common cold virus that has: a lipid bilayer envelope; round, pleomorphic medium-sized virions; and is the largest known RNA genome-single-stranded. What is this virus?
    Coronavirus (either the 229 E or OC 43 strain)
  10. What is the deal w/ SARS?
    It was a new infection from an unrecognized strain of the coronavirus, first seen in china in 11/02, that led to several outbreaks in other cities. (8000 cases leading to 800 deaths)
  11. Major causes of pharyngitis?
    mostly viral and Grp A strep
  12. Streptococci hemolytic patterns on sheep blood agar: distinguish between
    Gamma hemolysis.
    • Alpha hemolysis - partial; greening of the agar
    • Beta hemolysis - complete; clearing of the agar
    • Gamma hemolysis - no hemolysis
  13. Name the pathogen:
    most common bacterial cause of pharyngitis
    most common in 5-15 yr. age group
    characterized by fever, sore throat, red swollen pharynx, yellow-white exudate and cervical lymphadenopathy
    Treated w/ penicillins to avoid complications
    Streptococcus pyogenes
  14. A pt comes in and thinks they have Grp A strep pharyngitis. What characteristics should be present if the Pt is correct?
    • Sudden onset
    • fever
    • headache
    • N/V/D
    • pharyngeal inflammation
    • discrete exudate
    • tender cervical nodes
    • NOT cough, congestion or conjunctivitis
  15. Penicillin is given to Pts w/ Grp A strep to avoid what complications?
    Abscesses, otitis media, sinusitis, acute rheumatic fever, acute glomerulonephritis
  16. Name the pathogen:
    asymptomatic in infnants and children
    teenage/young adults get IM
    those w/ poor hygiene or crowding are protected by early infections
    transmitted by salivary exchange (blood spread has been reported)
    • EBV (epstein-barr virus)
    • IM = infectious mononucleosis
  17. Name the pathogen:
    incubation period: 5-7 weeks
    replicates in epithelial cells or oropharynx
    spreads to B lymphocytes (in lymph nodes, spleen, or liver)
  18. Name the illness.
    Presents with: fever, malaise, fatigue, sore throat, pharyngitis, cervical adenitis, atypical nodes, splenomegally, hepatomegally, elevated LFTs (liver function tests)
    Complications: severe dz (fever, fatigue, and malaise), airway obstruction, aseptic meningitis encephalitis.
    Infectious mononucleosis
  19. Whats the best way to test for mono in children over 5?
    Rapid slide (spot) tests: 85-90% specific, response my be delayed so repeat test may be needed 1-2 wks later. (mono serology tests is one of the most overused, confusing and least understood tests performed, but may be necessary in young children)
  20. Does HSV-1 or HSV-2 cause cole sores?
  21. Name the most likely pathogen.
    Nonspecific fever, rash, conjunctivitis, pleurodynia, aseptic meningitis, pericarditis, myocarditis, enephalitis, fatal sepsis in newborns.
    Enterovirus (coxsackie A and B)
  22. With what clinical manifestations would you suspect enterovirus?
    • Asymptomatic infection most likely
    • nonspecific febrile illness
    • pharynigits and URIs (more common than Grp A strep)
    • Pneumonia
    • Pleurodynia: Coxsackie B; fever severe knifelike chest pain
    • Hand foot and mouth dz
  23. What causes Herpanigina and what are the symptoms/physical presentation?
    • Caused by Coxsackie A
    • Fever, sore throat, dysphagia, vesicles in pharynx, palate, uvula, that can last for weeks.
  24. How would you assess a Pt for sepsis?
    • Take history
    • Physical (temp, HR, RR)
    • Draw blood for CBC w/ WBC differential
    • Get CRP only if WBC and other changes are equivocal
    • Consider cultures
    • If Pt has difficulty breathing get electrolytes & arterial blood gas.
  25. Describe physiologically how a fever (>38C) develops.
    Cytokines & TLR/microb products => hypothal. endothelial activation => glial cAMP => altered temp set point
  26. Describe physiologically what causes tachycardia (>90 b/min).
    • 1) Cytokines, NO, others => vasodilation, permeability => fluid & proteins leak into tissues, increased vascular volume, high met. rate, low peripheral resistance, altered blood flow, low myocardial contractility, low blood return to heart, low BP => sympathetic activation => tachycardia.
    • 2) fluid loss (sweating, n/v/d) => volume depletion => tachycardia
  27. What causes Tachyapnea (>24 r/min)?
    High vascular permeability => fluid in lungs, lung injury => poor gas exchange, high met. rate & poorly distributed blood flow => tissue anoxia => lactic acidosis => tachyapnea
  28. What causes Leukocytosis (>12 k/nL) or Leukocytopenia (<4k) or Bands (>10%)?
    cytokines => high production of neutrophils & high recruitment to periphery => high neutrophil & band count (platelets can be high too, unless DIC has begun), high delivery to inflammation site, clumping => low neutrophil count
  29. What is sepsis?
    SIRS plus evidence of infection (SIRS = 2 or more of fever, tachycardia, tachyapnea, luekocytosis, leukocytopenia, or bands)
  30. What is severe sepsis?
    • Sepsis (SIRS + evidence of infection) + 1 or more of:
    • Hypoxemia, Acute renal failure, thrombocytopenia, lactic acidosis
  31. Hypoxemia
    • lung fluid & injury => poor gas exchange
    • V/Q mismatch
  32. Acute renal failure (<0.5 ml/kg/hr with good hydration)
    hypoxemia, hypotension & uneven blood flow => inadequate tubular oxygenation => injury or death of proximal tubular cells = ATN (acute tubular necrosis)
  33. Thrombocytopenia ( <80k, 50% drop in 3 days)
    • inflammation => intravascular coagulation with fibrin => platelet activation => more coagulation & inflammation, vascular blockage, thrombocytopenia.
    • (also hemodilution)
  34. Lactic acidosis (pH < 7.3 or lactate > 1.5nl (3.3 mmol/L))
    poor blood flow, hypoxemia => tissue hypoxia => anaerobic metabolism => lactate
  35. Septic shock = ?
    Sepsis + systolic BP<90 or >40 mmHG decrease
  36. What organs are affected in severe sepsis?
    • Lungs (ARDS)
    • brain,
    • heart,
    • kidney,
    • liver ( mild increase in AST & ALT),
    • GI,
    • Hematologic
    • Immunologic (diminished function)
  37. What is required to diagnose a Pt w/ MODS (multiorgan dysfunction syndrome)?
    • Intervention in at least 2 organs:
    • ARDS, dialysis, gastric ulcers req. transfusion, DIC, Coma, Juandice (bili >8 mg/dL), shock not responsive to pressors.
  38. Causes of Sepsis & what to look for
    • pneumonia, empyema, peritonitis, pyelonephritis (dysuria, costovertebral angle tenderness), meningitis (headache, stiff neck, meningismus), brain abscess, endocarditis
    • Clues from skin: rash, erythema, line site erythema, tenderness, crepitus, petechiae.
  39. What are some of the treatments for Sepsis and septic shock? (other than the obvious of treating organs as they fail, adequate O2, BP, etc)
    • Find & treat infection (may need to drain abscess.
    • Activated protein C (avoids DIC), glucocorticosteroids.
    • Avoid very high fever
    • (DO NOT USE: inhibitors of TNF, IL-1, PAF, bradykinin, ibuprofin, IL-10, high dose glucocorticosteroids, or high dose oxygen delivery)
  40. Effusions in Sepsis are usually exudates made by infections or inflammation, what does one find in an exudate?
    • Albumin in fluid similar to blood
    • High total protein, high LDH (lactic dehydrogenase)
    • abundant neutrophils
  41. Tachyapnea, low pH, high blood lactate and a high anion gap indicate what?
    Metabolic acidosis
  42. What is a normal anion gap, and how do you calculate Anion gap?
    • 8-16 (too high of an anion gap => acidosis)
    • Na - (HCO3 + Cl)
  43. ARDS, acute pancreatitis, aspiration pneumonitis, trauma (major surgery w/out infection), anaphylaxis, adrenal insufficiency, and acute liver failure mimic what serious diagnosis?
    Septic shock
  44. Adenovirus biology
    • non-enveloped
    • pentons
    • linear, ds DNA genome
    • Resistant to many physical and chemical agents
  45. Adenovirus epidemiology
    • 50% asymptomatic
    • 6 mo. to 5 yrs => most infected
    • resp. dz -- winter/spring
    • Pharyngocunjunctival fever -- summer
    • Gastroenteritis -- no pattern
    • Transmission: direct contact, fecal-oral and water/equipment
    • Risk factors: crowded, low socioeconomic
  46. What pathogen fits the following description.
    10 day incubation
    persistent lymphocytic infections
    epithelial cell necrosis
    can circumvent host's immune system by binding to MHC class I molecules reducing expression on cell surface.
  47. Describe the pathway of an adenovirus infection.
    • penton binds to resp. or GI epithelial cells =>
    • internalized by receptor mediated endocytosis=>
    • disruption of endosome=>
    • escape into cytoplasm=>
    • DNA replication in host cell nucleus=>
    • viral assembly and release of virions (10^5)
  48. What are the clinical syndromes of adenovirus?
    • URIs
    • Tonsillitis
    • Pneumonia
    • pharyngoconjunctival fever
  49. What is the pathogen and illness associated w/
    unilateral conjunctivitis lasting 1-2 wks
    pre-auricular lymphadenopathy
    sore throat
    epidemics occur following swimming pool exposure
    Adenovirus => pharyngoconjunctival fever
  50. What is the difference between keratoconjunctivitis and pharyngoconjunctival fever?
    Kera- mostly in adults, photophobia, spread of hands my medical personnel, contaminated opthalmic solutions, common use bathrooms.
  51. What pathogen can cause hemorrhagic Cystitis? and what are they symptoms?
    • Adenovirus
    • Symptoms: Gross hematuria, urgency, frequency, fever (male predilection, seen following bone marrow and renal transplantations)
  52. Who is adenovirus usually detected?
    Its not, but there are antigen detection tests as well as serotype tests.
  53. Besides adenovirus, what other organisms can cause conjunctivitis?
    • Viruses: herpes simplex, varicella zoster
    • Bacteria: strep pneumoniae, H influenzae, H aegyptius, Grp A strep, Staph aureus, Chlamydia trachomatis, Neisseria gonerrhoeae
    • Fungi: aspergillus, fusarium
    • Parasites: acanthamoeba
  54. Eye infection by staph aureus
    Blepharitis (eye lids)
  55. Eye infection: S. aureus, strep pneumoniae
    Dacrocystitis (tear ducts)
  56. Eye infection: S aureus, Pseudomonas, candida
  57. Eye infection: syphilis, HSV, VZV
    Iridocyclitis (uveal tract)
  58. Eye infections: TB, CMV, HSC, VZV, histoplasma, candida, toxoplasma
  59. What is the most common organism associated with Otitis Externa?
    pseudomonas (typically from water)
  60. What are the common causes of otitis media and what are some common features?
    • 50% viral
    • Bacteria: S. pneumo, H. flu, moraxella
    • Follows uri's
    • Ear pain/pulling
    • 60% no fever
    • Antibiotics little value
  61. Name the pathogen.
    Gram negative diplococci
    lives in resp. tract
    causes otitis, bronchitis, pneumonia, sinusitis, SBE, meningitis
  62. What syndrome?
    more common in adults
    follows uri's
    mostly viral
    facial pain, HA, upper teeth pain, opacity by transillumination
    antibiotics don't help much
  63. What syndrome?
    Dyshpagia, drooloing stridor
    acute airway obstruction (medical emergency)
    lateral neck x-ray
    protect airway
    almost always caused by Haemophilus influenzae
  64. Epiglottitis
  65. Name the pathogen:
    was THE major ped pathogen before immunization (meningitis)
    Still a common cause of URI's
    pleomorphic gram negative coccobacilli
    type b is most important (encapsulated)
    mousy odor
    fastidious (due to need of growth factors X and V)
    antigen detection possible
    Haemophilus influenzae
  66. What major diseases can be caused by H influenzae?
    • Septic arthritis
    • bacterial conjunctivitis
    • bacterial epiglottitis
    • buccal cellulitis
    • sinusitis
    • otitis
    • (pneumonia, bronchitis, sepsis)
  67. Hib vaccine targets what?
    H influenzae type b (extremely important vaccine)
  68. Name the pathogen/illness
    Bordatella _______
    Gram neg. coccobacilli
    Strictly aerobic
    Slow growing; req. special media
    Does not survive the environment; direct person-person spread
    Adults are reservoirs, but kids have worse dz
    Vaccine effective (immunization rates vary)
    Highly contageous (90%)
    300,000 deaths/yr
  69. Describe how pertussis causes illness.
    • Adheres to resp. ciliated epithelium and releases toxins
    • Cytotoxin destroys cilia and cells
    • Toxins enters circulation and may cause systemic effects
  70. Clinical pertussis
    • 7-10 day incubation
    • Catarrhal stage: cold for 1-2 wks
    • Paroxysmal stage: sudden cough, inspiratory whoop, vomiting, apnea (1-6 wks)
    • Convalescent phase: prolonged cough for wks to months
  71. How do you diagnose pertussis?
    • Clinically diagnosis is most effective.
    • Direct detection: fluorescent antibody tests
    • Culture
    • DNA amplification tests being developed.
  72. Prevention of pertussis
    • Whole cell vaccine (older, not as good)
    • Acellular vaccine (Dtap-kids or Tdap-adults) -- much better than old vaccine, much less severe side effects
  73. Parainfluenza virus
    • 2/3 of infants get PIV3 (not very serious)
    • causes Croup
  74. What are the symptoms of Croup caused by parainfluenza virus?
    • fever
    • hoarseness
    • barking cough
    • stridor
    • major cause PIV1 (then 2 and 3)
  75. Treatment and diagnosis of parainfluenza virus
    not much tx, diagnosis not usually necessary but culture is possible (antigen detection is less sensitive)
  76. Mumps Virus
    • winter/spring
    • school-aged children--not very serious
    • lifelong immunity follows natural infections
    • seems to be coming back
  77. Mumps virus pathogenesis
    • Viral replication in resp. epithelial cells=> spread to regional lymph nodes=> plasma viremia=> dissemination to glandular and neural tissue
    • Highly contagious
    • Airborne resp droplets
    • 18 day incubation
  78. Mumps clinical syndromes
    • fever, malaise, headache, ear pain
    • salivary gland swelling (bilateral parotid swelling)
    • extrasalivary gland manifestations
    • (complications: gonads, pacreas, myocarditis, hearing loss)
  79. Mumps virus diagnosis and treatment
    • Parotitis -- halmark
    • confirm w/ lab tests (culture is definitive test)
    • Prevention: vaccine and boosters
    • Treatment: symptomatic only