Intro to Micro Respiratory Infectious Disease - Zimmer Flashcards Preview

CRRAB II Week 5 - WLB > Intro to Micro Respiratory Infectious Disease - Zimmer > Flashcards

Flashcards in Intro to Micro Respiratory Infectious Disease - Zimmer Deck (65):
1

What are the major mechanisms of defense of the upper respiratory tract (URT)?

(Hint: 5 mechanisms)

1. Mucociliary lining of the nasal cavity (with help of "baffle plates")

2. Change of direction of the airway from the sinuses to the pharynx (location of adenoids)

3. The ciliary elevator

4. Normal flora competition (Staphylococci)

5. Alveolar macrophages eliminate microorganisms in the lungs

2

What are the major mechanisms viruses employ to avoid these defenses?

1. Cytopathic effect – viral infection disrupts normal cell physiology which can lead to cell death and disease.

2. Host immune response – response of the host to the virus causes illness.

3. Tumorigenesis – viral infection promotes uncontrolled proliferation of infected cells.

3

What are the major mechanisms bacteria employ to avoid these defenses?

1. Toxin production – bacteria release toxin that causes illness.

2. Host immune response – response of host to bacteria that causes illness.

3. Bacterial proliferation and invasion – growth and spread of bacteria that causes damage that is significant in illness.

4

What is the medical term for the common cold?

Rhinitis

5

What is the most common pathogen causing the common cold?

Rhinovirus

6

What is the second most common pathogen that causes the common cold?

Adenovirus

7

Why is the common cold so prevalent and we get so many bouts of it every year?

There are at least 100-200 immunologically distinct forms rhinoviruses, 50 immunologically distinct adenoviruses, and several types of coronaviruses that can cause the common cold (other minor viral causes as well).

8

How do Rhinoviruses infect the cells lining the nasal passages and the pharynx following attachment?

 Utilize the intercellular adhesion molecule (ICAM) ICAM-1 of the cells.

9

When do symptoms peak in Rhinitis?

2-5 days post-infection

10

Ciliated epithelial cells regenerate how many days after being destroyed by localized inflammation and lytic infection of Rhinovirus?

day 14 post infection

11

What kind of infection can happen simultaneously or directly following Rhinitis?

Secondary bacterial infection by normal flora.

  • Results in:
    • change from clear nasal secretions to → purulent (cloudy/yellow) nasal secretions
    • Sinus blockage can result in → sinusitis or otitis media
    • infection gaining access to the lower respiratory tract causing → bronchitis

12

What time of year are Rhinitis infections most common?

Usually seen in the winter, with the exception of adenovirus infections (year round).

13

What is the viral classification of rhinovirus?

-DNA

-Nucleocapsid shape

-Class

-Family

  • RNA virus
  • Icosahedral Nucleocapsid
  • Nonenveloped
  • SS (+) Nonsegmented Genome (Class IV)
  • Picornaviridae

14

What is the viral classification of adenovirus?

-DNA

-Nucleocapsid shape

-Class

-Family

  • DNA virus
  • Icosahedral Nucleocapsid
  • Nonenveloped
  • DS linear DNA (Group I)
  • Adenoviridae

15

What is the viral classification of coronavirus?

-DNA

-Nucleocapsid shape

-Class

-Family

  • RNA virus
  • Helical Nucleocapsid
  • Enveloped
  • SS (+) Nonsegmented Genome (Class IV)
  • Coronaviridae

16

What is the viral classification of Paramyxovirus?

-DNA

-Nucleocapsid shape

-Class

-Family

  • RNA virus
  • Helical Nucleocapsid
  • Enveloped
  • SS (-) Nonsegmented Genome (Class V)
  • Paramyxoviridae

17

What is the viral classification of Influenza virus A, B, C?

-DNA

-Nucleocapsid shape

-Class

-Family

  • RNA virus
  • Helical Nucleocapsid
  • Enveloped
  • SS (-) Nonsegmented Genome (Class V)
  • Orthomyxoviridae

18

What is the viral classification of Coxsackievirus A + B?

-DNA

-Nucleocapsid shape

-Class

-Family

  • RNA virus
  • Icosahedral Nucleocapsid
  • Nonenveloped
  • SS (+) Nonsegmented Genome (Class IV)
  • Picornaviridae
  • Enterovirus

19

What are the most common causes of pneumonia in young children?

  •      RSV
  •      Parainfluenza virus (Paramyxovirus)

20

What are the most common causes of aseptic meningitis?

  • Coxsackievirus
  • Echovirus
  • Mumps virus

21

What are the most common causes of palm and sole rash?

  •      Syphilis
  •      RMSF
  •      Coxsackievirus

22

What are the most common causes of conjunctivitis?

  1. H. influenza
  2. Adenoviruses
  3. S. pneumoniae

23

What is the most common predisoposing factor for Sinusitis? Other factors?

  • Most common:
    • viral infection (URI)
  • Others:
    • allergies
    • structural problems in the skull

24

What is acute rhinosinusitis?

inflammation or infection of the mucosa of the nasal passages and at least one of the paranasal sinuses that typically lasts no longer than 4 weeks

25

What are the two most common pathogens causing community acquired acute bacterial rhinosinusitis infections? Others?

  • Most common:
    • Streptococcus pneumoniae
    • Haemophilus influenzae
  • Others:
    • Streptococcus pyogenes
    • Staphylococcus aureus

26

Although rare, fungal sinusitis infections are usually identified when?

after antibacterial drugs fail to clear the sinus infection

27

What is the most common pathogen causing of fungal sinusitis?

Aspergillus fumigatus

28

How do you differentiate between viral and bacterial rhinosinusitis?

  • bacterial rhinosinusitis is likely when:
    • adult has moderate symptoms of rhinosinusitis that persists beyond 7 days
    • severe symptoms of any duration that include facial swelling or tooth pain
    • children with moderate symptoms of rhinosinusitis that last longer than 10-14 days
    • severe symptoms of any duration that include a fever of >39C or >102F with facial swelling or pain.

29

Is viral or bacterial rhinosinusitis most common?

  • Viruses cause most cases. 
    • Symptoms resolve within 5 to 7 days
    • most people recover without medical treatment.

30

What time of year are Rhinosinusitis infections most common?

More likely in the winter months, coincides with the common cold.

31

What percent of adult vs. child viral rhinosinusitis infections progress to acute bacterial infections ?

2% of adult and 10% of children’s viral rhinosinusitis infections progress to acute bacterial infections

32

What is the treatment for Rhinosinusitis?

  • viral rhinosinusitis:
    • Symptomatic treatment is recommended  
  • bacterial rhinosinusitis:
    • Antibiotic treatment is recommended:
      • broad spectrum antibiotics → Amoxicillin (Augmentin), Azithromycin

33

What is one symptomatic treatment that has been proven to shorten the length and severity of infection?

Oral hydration + nasal saline washes and steam

34

What is the bacterial classification of S. pneumoniae?

-Gm +/-

-Shape

-Catalase

-Hemolysis

-Other unique traits

  • Bacteria
  • Gram (+)
  • diploocci
  • Catalase (-)
  • Alpha-Hemolytic
  • Bile-Esculin Negative
  • Optochin Susceptible

35

What is the bacterial classification of H. influenzae?

-Gm +/-

-Shape

-Other unique traits

  • Bacteria
  • Gram (-)
  • Coccobacilli, Pleomorphic
  • X & V Factors Required

36

What are the most common causes of pneumonia in adults & elderly?

  • Adults (40-65 yrs)
    •      S. pneumoniae
    •      H. influenzae
    •      Legionella
  • Elderly (>65 yrs)
    •      S. pneumoniae
    •      Gram (-) rods
    •      H. influenzae

37

What are the most common causes of meningitis in 60+ yrs?

  •      S. pneumoniae
  •      Gram (-) rods
  •      Listeria

38

What are the most common causes of meningitis in children aged 6 months to 6 years?

  •      S. pneumoniae
  •      N. meningitidis
  •      H. influenzae type B

         

(rate decreasing with the use of the Hib vaccine)

39

90% of sore throats in adults and 60-75% of sore throats in children are caused by what?

VIRUSES

40

What is the most common bacterial pathogen causing of acute pharyngitis?

Streptococcus pyogenes

41

What symptoms associated with pharyngitis strongly suggest a viral cause?

  • Conjunctivitis
  • Cough
  • Hoarseness
  • Inflammation of the mucus membrane
  • Diarrhea

42

How do patients with Streptococcus pyogenes pharyngitis commonly present?

  • Fever
  • Severe pain upon swallowing (sudden onset)
  • Red tonsils with or without exudate
  • Headache
  • Nausea and vomiting and abdominal pain may be present
  • Enlarged, tender cervical lymph nodes are also often present. 

43

What is required in suspected S. pyogenes pharyngitis infections? Why?

rapid Strep test is required

S. pyogenes infections must be treated with antibiotics to block the development of glomerulonephritis and rheumatic fever. 

***Treatment should start within 9 days of the first signs of infection.

44

Pharyngitis due to Group A (GAS) S. pyogenes is usually a disorder of children what age?

5-15 yoa

45

What time of year is Pharyngitis most common?

In temperate climates it is most common during the winter and spring.

46

How is the infection established in viral pharyngitis?

(Hint: initiation ⇒ damage)

  • Initiates with viruses gaining access to the mucosal cells lining the nasopharynx.
  • Replication initiates in these cells. 
  • Damage to host cells is common at these sites of replication.

47

How is the infection established in bacterial pharyngitis?

 

  • Initiated when S. pyogenes attaches to the mucosal epithelial cells using:
    • M protein
    • lipoteichoic acid
    • fibronectin-binding protein (protein F)
  • Capsule is composed of hyaluronic acid (HA) and prevents phagocytosis by macrophages. 
  • Invasion virulence factors include protease and hyaluronidase.

48

What is the bacterial classification of S. pyogenes?

-Gm +/-

-Shape

-Catalase

-Hemolysis

-Other unique traits

  • Bacteria
  • Gram (+)
  • Cocci
  • Catalase (-)
  • Beta-Hemolytic
  • Bacitracin Sensitive

49

What is the bacterial classification of C. diptheriae?

-Gm +/-

-Shape

-Other unique traits

  • Bacteria
  • Gram (+)
  • Bacilli
  • Non-spore Forming
  • Non-motile

50

How should S. pyogenes infections be treated?

1st penicillin

or

2nd erythromycin for those allergic to penicillin

51

How can S.pyogenes cause Scarlet Fever?

  • By secreting certain streptococcal pyogenic exotoxins:
    • ssa, speA and speC
      • These toxins are superantigens.

 

(Get “strawberry tongue” & pimple-like dry rash.)

52

How does Corynebacterium diphtheriae cause pharyngitis infection?

  • Secrete Diphtheria toxin → A-B exotoxin
    • come from genes from a lysogenized phage
    • If the toxin reaches → blood stream it can result in:
      • myocarditis (heart failure)
      • neuritis (temporary paralysis of the limbs, soft palate, and diaphragm

53

What is the medical term for viral croup?

laryngotracheobronchitis

54

What is the symptom progression of viral croup infection?

  • Croup typically begins with: 
    • mild upper respiratory tract infection
    • general cold-like symptoms
    • fever of 38-39C (100.4-102.2F)
    • restlessness
    • shortness of breath
    • nasal congestion
    • sore throat
    • cough that lasts 2 to 3 days
  • This is followed by a harsh, “bark-like” cough (noise coming from Larynx)
  • Respiratory stridor (noisy breathing) 

55

Children with severe croup have what kind of concerning symptoms or other warning signs of severe respiratory disease ?

  • Primarily inspiratory stridor at rest with nasal flaring
  • Suprasternal and intercostal retractions
  • Lethargy or agitation may be a result of hypoxemia
  • Tachypnea
  • Tachycardia out of proportion to the presence of fever, lethargy, pallor, and hypotonia (decreased muscle tone).
  • Cyanosis is a late and ominous sign. 

56

When do croup symptoms usually peak? Resolve?

Croup symptoms usually peak over 3–5 days and resolve within 4–7 days. 

57

What age are patients most susceptible to viral croup?

Young children are most susceptible to viral croup, which typically occurs in children 6 months to 6 years of age. 

(Boys are more likely to develop croup than are girls.)

58

What time of year does viral croup most commonly occur?

late fall and early winter

59

What kind of infections can cause viral croup anytime during the year?

Parainfluenza

60

What time of year does Influenza virus and respiratory syncytial virus infections tend to occur?

more frequently during the winter and early spring

61

What are the most common causes of pneumonia in young children?     

  • RSV
  • Parainfluenza virus

62

What is the viral classification of Respiratory Syncytial Virus?

-DNA

-Nucleocapsid shape

-Class

-Family

  • Virus
  • Helical Nucleocapsid
  • Enveloped
  • SS (-) Nonsegmented
  • Paramyxoviridae
  • Pneumovirus

63

What pathogen(s) cause Epiglottitis?

  • beta-hemolytic streptococci - group A (most frequent), B, C
  • Haemophilus influenzae type b (Hib)
  • but possibly others.

64

How do you treat Epiglottitis?

  • If respiratory distress is present, priority one is to secure airway
  • Broad-spectrum second- or 3rd-generation cephalosporins in combination with penicillinase-resistant penicillin is typical empiric therapy 

65

What characteristics are to Epligottitis when comparing it to Croup?

  • Age: infants, older children, or adults
    • Croup: 6 mths - 6 years
  • Onset: sudden
    • Croup: gradual onset
  • Location: Supraglottic
    • Croup: subglottic
  • Temp: High fever
    • Croup: low grade fever
  • Severe Dysphasia
    • Croup: mild or absent
  • Dyspnea
    • Croup: also present
  • Drooling
    • Croup: absent
  • No cough
    • Croup: characteristic cough
  • Position: Sitting forward with mouth open
  • Radiograph: Positive thumb sign
    • Croup: Positive steeple sign