Lecture 3: Respiratory Infections; Learning objectives Flashcards
Explain the structure of the respiratory system and its indigenous microbiota
exp. (3) defenses
Upper Respiratory: defenses up UR limit about of microbes in LR
- musociliary
- antimicrobial sunstances
- macrophages
*microbiota may inhibit growth of pathogenic strains by competing for adhesion receptors on mucosal surface as well as nutriens- kills of bad by competition
Lower Resp: same microbiota as upper, but fewer in number
Name the Causative agent and describe the complications (8) of streptococcal phayrngitis
Streptococcus pyogenes
*gram +
- enters through respiratory droplets
- symptoms: pharyngitis, fever, HA, swollen nodes, beefy red appearance to pharyngeal tissues
*some patient’s develop scarlet fever, exhibiting rash from erythrogenic exotoxins
Complications: Suppurative (pus)- otitis media, sinusitis
non suppurative- rhuematic fever (can affect joints and heart-can cause permanent damage), scarlet fever, glomerulonephritis
C. Diptheria
signs/symptoms (5)
prevention
presentation
Caused by corynebacterium diptheriae
gram +*
-caused by respiratory droplet transmission
S: sore throat, fever, psuedomembrane, exotoxin can lead to cardiac arrythmia and coma
Prevention: DTaP vax
Differeniate between acute and chronic bacterial sinusitits
causes
symptoms
Acute: caused by various indigenous microbes of URT (streptococcus, haemophilis, moraxella, staphylococcus)!
s: pain, tenderness, swelling, runny nose, congestoin
Chronic: 8-12 weeks
s: more subtle and pain occurs less often than with acute
Differentiate between 2 types of ear infections and list usual causes
- Otitis externa- streptococcus (+), staphylococcus(+), or psuedomonas (-)
- acute otitis media- short term infection of middle ear caused by s. pnuemoniae (+), h. influenzae, moraxella, catarrhalis
chronic otitis media- long-term infection, inflammation and damage to middle ear
Influenza
structure/vriulence
transmission
virulence factors
symptoms
S/v: two spikes
- hemagglutinin (H) helps virion attach and penetrat host cells
- neurominidase (N) helps release virions from host cell after replication assembly
- M2 ion channel - small proton pump equilibrates pH across membrane antiviral drug target
t: respiratory droplets and aerosols
s: common to cold, peumonia and bronchitis may occur
Differentiate between antigenic shift and and antigenic drift and understand reasons for annual influenza vaccine
Shift: RNA segment mixingg, producing new virus (occurs every 10-15 years)
Drift: smaller changes that occur as a result of error prone viral polymerase (occurs constantly)
takes 6 months to produce flu vax
- decisions made priot to flu season based on global surveiillance of influenza strains currently circulating
- contains flu A and flu B using HA as antigetn
Common cold
causes
symptoms
prevention
transmission
c: rhinoviruses, adenoviruses
s: rhino: sneezing, sore throat, runny/stuffy nose, aches and pains *croup sometimes
adeno: paryngitis, cough, lymph nodes in neck, white gray material
P: vaccine, hand washing
t: respiratory droplets, fomites, fecal-oral
SARS
causes
symptoms
Severe Acute Respiratory Syndrome
c: person-person contact
- coronaviridae
s: headache, fever, body aches, cough, dyspnea
COVID-19
causes
symptoms
treatment
c: SARS-CoV-2
s: cough, myalgias, fever, HA, dairrhea, sore throat, taste/smell abnormalitites
MERS
causes
symptoms
treatment
Middle Eastern Respiratory Syndrome
c: a member of coronavirus
s: severe respiratory with fever, cough, shortness of breath
Whooping Cough
cause
symptoms
pathogenesis (3 stages)
prevention
c: caused by bardatella pertusis (-)
s: cough , dever, malaise
P: 1. inital/catarrhal: general malaise, low grade fever, severe cough
2. second/paroxysmal: cells and mucous accumulate in airways and cause labored breathing
pvt: vaccine introduces 1949
- Tdap >/= 7 years
- DtaP 6 weeks < 7 years old
TB
cause
detection
c: mycobacterium tuberculosis
- spread by resp. droplets
- resistant to drying, chemical disenfectans, and antibiotics
d: mantoux test- confirmatory test needed
tb blood test
or acid fast stain (Ziehl-Neelsen)
-mycobacteria apear red
Stages of TB
- Primary TB- initial macrophage response
- 1st week inhalation
- bacillus reacheas alveoli
- outcome depends on amnt of TB bacilli and strength of macrophage
- TB bacilli reproduce exponentially
- lasts until 3rd week initial infection - Latent TB- Immune control
- bacilli growth and macrophage destruction balanced
- 90% patients infected stop here
- no symptoms or signs of active disease
- bacili shielded in lung tissue and can survive for years
- primary complex- bacilli and infected macrohpage in healthy macrophage
- *not contagious - Active TB or Secondary Active TB- lung cativation
- primary complex doesn’t heal and TB bacilli become re-activated 12-24 months after 1st expo.
- bacilli reporude quickly and form cavity in lung where immune system cannot reach them
- coughing
- high contagious
- more likely if immunocompromised
- can spread through body; liver, kidney, bone (migrant TB)
False + TB tests
false positives can occur if they had a previous TB test or recent immunization
