CH 21 - Respiratory Infections Flashcards

Question

Pneumococcal pneumonia: Symptoms

Answer 1

Cough Fever Chest pain - Aggravated with cough/breathing - Breathing becomes shallow/rapid - Poor oxygenation (dusky skin, supplemental needed) Sputum production Runny nose & upper respiratory congestion - Precedes above symptoms Symptoms abate in individuals who survive 7-10 days without treatment

Answer 2

30% carry encapsulated strain in throat (biofilm form) Bacteria rarely reach lung due to mucociliary escalator - Risk increases when escalator destroyed (ex: after flu) Underlying disease & age increase risk of disease

Answer 3

Bacteria inhaled into alveoli - Inflammatory response in lung - Capsule interferes with phagocytosis Pneumococci that enter bloodstream lead to 3 often fatal complications: 1. Septicemia (infection of bloodstream) 2. Endocarditis (infection of heart valves) 3. Meningitis (infection of membranes covering brain & spinal cord) Recovery usually complete - Most bacterial strains do NOT destroy lung tissue

Answer 4

Polysaccharide vaccine - Immunity to 23 strains (of pneumonia only) - Does NOT work in children under 2yrs Conjugate vaccine - Against 13 types (in 2010; 7 types in 2000) - Available for children - Recently approved for adults - Prevents colonization

Answer 5

Antibiotics: penicillin & erythromycin - Successful if given early - More strains becoming antibiotic-resistant

Answer 6

Pneumolysin - PFT of Streptococcus pneumonia - High concentrations causes lysis (tissue damage) - Lower concentrations causes ion dysregulation (pyroptosis or necroptosis)

Answer 7

Several species of Klebsiella Klebsiella pneumoniae = primary cause - G- bacillus (LPS) - Encapsulated (avoids phagocytosis, recognitions, & complement) - ESKAPE pathogen

Answer 8

Most symptoms indistinguishable from pneumococcal pneumonia - Cough - Fever - Chest pain Other symptoms: - Repeated chills - Red/gelatinous sputum (bloody/"currant-jelly") 50-80% mortality in untreated pts - Tend to die sooner than other pneumonia

Answer 9

Normal flora of intestine (GI) in small population Colonization of mouth/throat more common in debilitated individuals - Very young/old - Alcoholics - Institutional settings

Answer 10

1. Colonizes mouth & throat 2. Carried to lung with inspired air/mucus 3. Survival in lung aided by capsule - Interferes with phagocytosis 4. Causes tissue death - Necrosis & formation of lung abscesses = necrotizing pneumonia 5. Infection in bloodstream leads to abscesses in other tissues - DIC

Answer 11

NO specific prevention measures - Disinfect environment (medical equipment) Use antimicrobials ONLY when necessary - Help control resistance

Answer 12

Mycoplasma pneumoniae - Small (found in some cell lines) - Deformed bacteria lacking cell wall - Slow growing - Aerobic - Distinctive "fried egg" appearance

Answer 13

Onset typically gradual 1st symptoms: - Fever - Headache - Muscle pain - Fatigue Later symptoms: - Dry cough (resembling "atypical pneumonia" Usually no hospitalization required - "Walking pneumonia"

Answer 14

Spread by aerosolized droplets from respiratory secretions - Survive long periods in secretions (aids in transmission) - Small infecting dose ~1/5 of bacterial pneumonias Peak incidence in young people

Answer 15

1. Attaches to receptors on epithelium - Interferes with ciliated cell action - Ciliated cells slough off 2. Inflammation initiates thickening of bronchial & alveolar walls - Difficulty breathing Produces toxin (thought to be possible cause of asthma)

Answer 16

NO practical prevention - Avoid crowding in schools & military facilities (particularly dorms/barracks) Cell wall synthesis inhibitors = INEFFECTUAL - Ex: penicillin Antibiotics of choice: tetracycline & erythromycin - Must be given early - Bacteriostatic (inhibit growth, don't kill)

Answer 17

Bordetella pertussis - G- bacillus - ONLY infects humans (particularly young children)

Answer 18

Mild upper respiratory infection Followed by paroxysmal coughing - Series of hacking coughs - Accompanied by copious mucus production - End with inspiratory "whoop" (air rushes past narrow glottis)

Answer 19

Spreads via infected respiratory droplets - Most infectious during runny nose period - Number of organisms decrease with onset of cough Primarily occurs in infants & young children - Milder forms seen in older children/adults

Answer 20

1. Enters respiratory tract via inspired air - Attaches to ciliated cells via filamentous hemagglutinin (Fha) 2. Mucus secretion increases - Ciliary action decreases while ciliated cells sloughed off - Cough relex = only way to clear secretions 3. Produces numerous toxic products - Pertussis toxin - Adenylate cyclase toxin - Tracheal toxin

Answer 21

A-B toxin B portion attaches to cell surface A portion enters cell & inactivates cAMP regulation (overproduction) - Increased mucus formation - Inhibits many leukocyte functions (chemotaxis, phagocytosis, respiratory burst) - Impairs NK cell killing - Contributes to bacterial binding to ciliated epithelial cells

Answer 22

Increased production of cAMP Increased mucus formation Decreased phagocytic & NK cell killing

Answer 23

Causes release of NO from goblet cells - Death of ciliated epithelial cells Release of IL-1 - Fever causing cytokine

Answer 24

Vaccination of infants - Preventions disease in 70% of individuals - Injections given at 6 weeks & 4, 6, 18 months DPT = combined with diphtheria & tetanus toxoids

Answer 25

Erythromycin - Reduces symptoms if given early Antibiotic eliminates bacteria from respiratory secretions - Little bearing on course of disease due to toxin productive Supportive therapy - O2 therapy - Suction of mucus (especially infants)

Answer 26

Mycobacterium tuberculosis - G+ rod - Obligate anaerobe - Mycolic acid in cell wall (acid fast staining) Slow growing - Generation time = 12 hrs or more Resists most methods of control #1 respiratory bacterial infection in world (affects 1/3 of population)

Answer 27

Chronic illness - Slight fever with night sweats - Progressive weight loss - Chronic productive cough - Sputum often blood-streaked

Answer 28

1. Inhalation of airborne organisms - Taken up by pulmonary macrophages in lungs 2. Resists destruction within phagocyte - Prevents fusion of phagosome with lysosome - Allows multiplication in protected vacuole 3. Activated macrophages can kill bacteria 4. Intense immune reaction occurs ~ 2 weeks post infection - Macrophages fuse & form multinucleated giant cells - Granuloma (tubercle) forms when macrophages & lymphocytes surround large cell to wall off infected tissue 5. Lysis of activated macrophages release contents into infected tissue - Death of tissue & formation of "cheesy" material 6. Granulomas can contain live organisms & lead to reactivation TB

Answer 29

Tuberculin test (Mantoux) - Type IV hypersensitivity response - Small amounts of TB Ag injected under skin - Does NOT detect very recent infection (< 4 weeks) + test = red/firm - Exposed to TB - Doesn't indicate active disease

Answer 30

Vaccination used in many parts of world - NOT given in US (eliminates TB test as diagnostic tool) Bacillus of Calmette & Guérin (BCG) - Derived from Mycobacterium bovis - Gives partial immunity against TB

Answer 31

Antibiotic treatment for active TB - 2 or more meds given together (to reduce resistance) Rifampin & isoniazid (INH) - Target actively growing organisms & metabolically inactive intracellular organisms Prolonged therapy - At least 6 months (tubercle) - 2 years for active infection

Answer 32

Legionella pneumophila - G- bacillus

Answer 33

Early: - Headache - Muscle ache - Rapid rise in temp - Confusion - Shaking chills Later: - Dry cough - Sputum production - Pleurisy Alimentary tract symptoms (1/4 of cases): - Diarrhea - Abdominal pain - Vomiting

Answer 34

Widespread in natural warm waters (within amoebae) Relatively resistant to chlorine Survives well in water system of buildings - Lives in A/C Person-to-person transmission does NOT occur

Answer 35

1. Breathe aerosolized contaminated water - Healthy people = resistant 2. Lodge in/near alveoli - Stimulate phagocytosis 3. Bacteria release macrophage invasion potentiator (MIP) - Aids in entry of macrophage 4. Necrosis of alveolar cells & inflammatory response - Small abscesses, pneumonia, pleurisy - Fatal arrest in 15% of hospitalized cases

Answer 36

Prevention focused on equipment to minimize risk of infectious aerosols Adequate disinfection

Answer 37

Antibiotics = successful Erythromycin - High doses Rifampin - Administered concurrently in some cases Bacteria produce beta-lactamase enzymes - Resistant to penicillins & cephalosporins

Answer 38

Respiratory syncytial virus (RSV) - Paramyxovirus family - ssRNA - Enveloped (lacks hemagglutinin & neuraminidase)

Answer 39

Incubation period 1-4 days - Runny nose - Cough & wheezing - Difficulty breathing - Fever (may/may not be present) - Dusky skin (poor oxygenation) 1 of causes of croup in older infants

Answer 40

1. Enters through inhalation 2. Infects respiratory epithelium - Death & sloughing off of infected cells 3. Bronchiolitis - Common feature - Bronchioles obstructed by sloughing cells (wheezing)

Answer 41

Outbreaks = common - Late fall to late spring - Peak = mid-winter Recovery produces short-lived immunity Healthy adults/children = mild disease - Rapidly spread infection ~60,000 hospitalization & ~6,000 deaths (65+ yrs)

Answer 42

Vaccine (May 23) - Recommended for 60+ yrs & pregnant mothers (week 32-36) Isolation of sick = best prevention NO effective antiviral meds

Answer 43

1. Coccidiodomycosis (Valley Fever) 2. Histoplasmosis (Spelunker's Disease) 3. Blastomycosis

Answer 44

Coccidiodes immitis Dimorphic fungus - Mold in soil (barrel-shaped arthrospores on ends of hyphae) - Spherule in tissue (containing endospores)

Answer 45

Inhalation of arthrospores (mold form) Endemic in arid regions of SW USA & Latin America

Answer 46

Often asymptomatic - Mild pneumonia/flu-like symptoms May spread from lungs to bones & CNS Overall rate of dissemination = ~1% - 10x higher in Filipinos & African Americans - Occurs most often in immunocompromised Resolution of disease results in long-term immunity against reinfection

Answer 47

Histoplasma capsulatum Dimorphic fungus - Mold in soil (contaminated with bat/bird droppings; caves) - Yeast in tissue (tuberculate macromicroconidia multiply within macrophages)

Answer 48

Inhalation of conidia Endemic in central & eastern states (especially Ohio & MS River Valleys)

Answer 49

Often asymptomatic - Mild respiratory symptoms Spreads throughout body within macrophages - Small granulomatous foci of infection heals by calcification Dissemination occurs most often in immunocompromised

Answer 50

Blastomyces dermatitidis Dimorphic fungus - Mold in soil - Yeast in tissue (broad-based bud)

Answer 51

Inhalation of conidia

Answer 52

Chronic granulomatous disease Primary pulmonary stage frequently followed by spread to other sites (ex: skin & bones) Dissemination may result in ulcerated granulomas of skin, bone, & other sites

Answer 53

1. Streptococcal pharyngitis 2. Diphtheria 3. Pinkeye, earache, & sinus infections 4. Common cold 5. Adenoviral pharyngitis 6. SARS & COVID-19

Answer 54

Streptococcus pyogenes - G+ coccus in chains - B-hemolytic - Group A (Lancefield grouping - carbohydrate in cell wall)

Answer 55

- Difficulty swallowing - Fever - Red throat with pus patches - Enlarged tender lymph nodes (localized to neck)

Answer 56

Spread readily by respiratory droplets

Answer 57

Causes wide variety of illnesses Numerous virulence factors

Answer 58

1. C5a peptidase 2. Hyaluronic acid capsule 3. M protein 4. Protein F 5. Protein G 6. SPEs 7. Streptolysins O & S 8. Tissue degrading enzymes

Answer 59

Inhibits attraction of phagocytes by destroying C5as

Answer 60

Inhibits phagocytosis Aids penetration of epithelium

Answer 61

Interferes with phagocytosis by causing breakdown of C3b opsonin

Answer 62

Responsible for attachment to host cells

Answer 63

Interferes with phagocytosis by binding Fc segment of IgG

Answer 64

Superantigens responsible for scarlet fever, toxic shock, & "flesh-eating" fascilitisT

Answer 65

Enhance spread of bacteria by breaking down: - DNA - Proteins - Blood clots - Tissue hyaluronic acid

Answer 66

Most pts recover uneventfully in ~1 week Confirmed strep throat treated with 10 days of antibiotics - Penicillin or erythromycin

Answer 67

1. Scarlet fever - Erythrogenic toxin enter bloodstream & circulates throughout body - Causes redness of skin & whitish coating of tongue 2. Quinsy - Painful abscess develops around 1 of tonsils

Answer 68

Occurs week after infection (organism NOT present) Acute glomerulonephritis - Skin infections & pharyngitis - Immune complexes deposited in glomeruli (provoking inflammatory reaction) Acute rheumatic fever - Pharyngitis - Due to cross-reactions between streptococcal Ags & Ags of joint/heart tissue (M protein) - Prevented by treatment of pharyngitis within 8 days of onset

Answer 69

Corynebacterium diphtheria - Variably shaped - G+ - Non-spore forming Certain strains produce diphtheria toxin

Answer 70

Begins with mild sore throat/fever - Fatigue & malaise - Dramatic neck swelling - Whitish-gray "pseudomembrane" (forms on tonsils or in nasal cavity & can detach into larynx/trachea - airway obstruction)

Answer 71

Humans = primary reservoir Spread by air - Acquired through inhalation

Answer 72

Little invasive ability Most strains release diphtheria toxin - Production of toxin requires lysogenic conversion by bacteriophage - Toxin produced in low iron environments (repressor shuts down in high iron, repressor removed in low iron) Exotoxin released into bloodstream - Damages heart, nerves, kidneys

Answer 73

A/B toxin - Released from bacteria in inactive form - Cleaved into A & B chains B chain - Attaches to host cell membrane - Enters via endocytosis A chain - Becomes active enzyme that inhibits protein synthesis - Inactivates elongation factor 2 (EF-2)

Answer 74

1. Botulinum toxin 2. Pertussis toxin 3. Tetanus toxin 4. Cholera toxin 5. Heat-labile enterotoxin

Answer 75

Diseases primarily results from toxin absorption - NOT microbial invasion Immunization - DPT (neutralizes toxin) - Booster every 10 years (immunity wanes after childhood)

Answer 76

Early antiserum treatment - Delay may be fatal Antibiotics given to eliminate bacteria - Penicillin & erythromycin - Stops transmission of disease (NO effect on toxin absorption) 1 in 10 pts die (even with treatment)

Answer 77

Haemophilus influenza - G- bacillus Streptococcus pneumoniae - G+ diplococci (aka: pneumococcus)

Answer 78

Otitis media - Mycoplasma pneumoniae - Streptococcus pyogenes - Staphylococcus aureus Respiratory viruses (1/3 of cases)

Answer 79

- Increased tears/redness of conjunctiva - Swelling eyelids - Sensitivity to bright light - Large amounts of pus (unless viral - minimal pus & swelling)

Answer 80

- Pain & pressure (localized) - Tenderness over sinus - Headache - Severe malaise

Answer 81

- Extreme ear pain - Mild fever (may be absent) - Vomiting - Ear drum ruptures (trapped fluids released & pain ends abruptly) More common in young children

Answer 82

Few details known (bacterial conjunctivitis) Most likely from airborne respiratory droplets Resist destruction by lysozyme

Answer 83

Begins with infection of nasopharynx Spreads upwards to sinuses Pathogenesis mechanism much like otitis media

Answer 84

Often developing at time of conjunctivitis diagnosis Begins with infection of nasal chamber & nasopharynx - Moves to middle ear & damages ciliated cells Ear drum often bursts - Immediate pain relief

Answer 85

Removal of infected individuals from school/daycare Hand washing Avoid rubbing/touching eyes Avoid sharing towels

Answer 86

Eyedrops/ointments containing antibacterial meds

Answer 87

Administration of pneumococcal vaccine (reduces incidence)

Answer 88

Antibiotic therapy - Amoxicillin

Answer 89

NO proven preventative measures Treatment = supportive care - Decongestants & antihistamines DISCOURAGED (ineffective)

Answer 90

Rhinovirus (30-50%) - Over 100 serotypes - Picornavirus family - Small - ssRNA - Acid labile (killed by gastric acid) Coronavirus (~20%) - ssRNA

Answer 91

- Malaise - Scratchy mild sore throat - Cough/hoarseness - Nasal secretion (initially watery, later thick) - NO fever (unless 2ndary infection) Symptoms disappear in ~1 week

Answer 92

Humans = only source Close contact with infected persons/secretion necessary for transmission - High concentrations in nasal secretions during 1st 2-3 days Young children transmit easily - Lack good hygiene NO relationship btwn cold temp & development of cold virus

Answer 93

Viruses attach to specific receptors on respiratory epithelial cells - Multiply in cells - Large number of viruses released from infected cells Injured cells cause inflammation - Profuse nasal secretion, sneezing, & tissue swelling Infection halted by: 1. Inflammatory response 2. Interferon release 3. Immune response Infection can extend to ears, sinuses, & lower respiratory tract

Answer 94

NO vaccine - Too many different types of rhinovirus (impractical) - Hand washing - Keeping hands away from face - Avoiding crowds during cold season

Answer 95

Antibiotic therapy = INEFFECTUAL Certain antiviral meds show promise (must be taken at 1st onset of symptoms) Treatment with OTC meds may prolong duration (inhibit inflammation)

Answer 96

Adenovirus - Nonenveloped - dsDNA 45 types infect humans Remains infectious in environment for extended periods (transmitted easily on medical instruments) Easily inactivated with heat & disinfectants

Answer 97

- Runny nose - Fever - Sore throat (often pus on pharynx & tonsils) - Lymph nodes in neck enlarged & tender - Hemorrhagic conjunctivitis (certain strains) - Mild cough (common; worsens when disease complicates) Infection usually resolves 1-3 weeks (with/without treatment)

Answer 98

Human = only source of infection Spread by respiratory droplets - Common among school children Endemic spread promoted by high # of asymptomatic carriers

Answer 99

Virus infects epithelial cells 1. Attaches specific surface receptors 2. Multiples in nucleus 3. Escape to epithelial surface 4. Cell destruction initiates inflammation Different viruses affect different tissues - Adenovirus type 4 = sore throat & lymph node enlargement - Adenovirus type 8 = extensive eye infection

Answer 100

Same prevention as common cold NO treatment - Attenuated vaccine no longer used by military - Patients usually recover uneventfully - Bacterial 2ndary infections may occur (require antibiotics)

Answer 101

Similar coronaviruses: - SARS-CoV (2002 outbreak) - SARS-CoV-2 (Dec 2019 pandemic) Enveloped +ssRNA SARS source traced back to palm civets - Infected from original reservoir (bats) MERS (outbreak in 2012) - Camels = intermediate host

Answer 102

- Fever/chills - Cough - Shortness of breath - Fatigue, muscle & body aches - Loss of taste/smell - Sore throat - Headache - Congestion - Nausea/vom - Diarrhea

Answer 103

Enters cell through ACE2 binding - Fusion of viral envelope with host cell membrane - Mediated by spike protein

Answer 104

Direct person-to-person respiratory transmission - Close-range contact via respiratory particles - Transmitted longer distances via airborne route Infected individuals more likely to be contagious in earlier stages of illness - Larger amount of virus in upper respiratory tract

Answer 105

Treatments authorized by FDA for emergency use

Answer 106

Symptoms < 5 days: - Paxlovid - Laegevrio (molnupiravir) Symptoms < 7 days: - Bebtelovimab (mAB) - Remdesivir (Veklury)

Answer 107

COVID-19 convalescent plasma - Blood taken from people recovered from COVID-19 - Contains Abs to treat (improves immune response) Barcitinib (Olumiant) - mAb treatment Tolxilizumab (Actemra) - mAB treatment - May decrease risk of death Remdesivir (Veklury) - Antiviral - Must be given within 7 days after 1st symptoms appear

Answer 108

mRNA vaccines - Pfizer & Moderna - Uses genetically engineered mRNA to express spike protein in host cells Vector vaccines - Johnson & Johnson (AstraZeneca) - Uses viral vector to deliver material to host cells to induce spike protein production Traditional protein subunit vaccine - Developed by Novavax Before vaccines: lockdowns & face masks

CH 21 - Respiratory Infections Flashcards

(132 cards)