03 - Respiratory System Infections Flashcards
Primary infection originated in the respiratory system:
● Meningitis
● sepsis
t/f: Lungs are very well vascularized
● Lung infections have likeliness to gain access to bloodstream
● Thus causing an invasive disease
In order to develop a respiratory tract infection:
a. Has to have shift in host factors
b. Or there is a shift in quality of normal flora
c. Or exposure of microorganism is so significant that it overwhelms host defences
Upper RT
● Collects & filters air
● Non-sterile spaces
● There is a rich microbiome → largely commensal organisms
t/f: Tonsils important for defence against infection
true
t/f: Not uncommon for the normal flora to contain microbes that are considered pathogenic; ○ As long as they remain in upper RT there is no issuesv
true
Upper RT: Defensins
antimicrobial peptides make it difficult for microorganisms to cause infection
Upper RT: Lactoferrin
bind to iron to keep its load low
Upper RT: Lactoferrin
bind to iron to keep its load low
Upper RT: Lysozyme
destroys and digests peptidoglycans
Lower RT
● Respiratory tree ● Main purpose: exchange of gas ○ Oxygen & CO2 ● Typically sterile ○ There are often no commensal organisms that are normal flora ○ There is NO microbial antagonism to contribute to resilien ● Ciliary escalator ○ Helps to move organisms out ● Secretory antibodies ○ IgA ● Phagocytes
Upper Respiratory Tract Infections; Bacterial URTIs
● Pharyngitis
○ Mostly viral
○ Streptococcal pharyngitis is the most common cause for this bacterial URTI
○ Group A streptococcus (Streptococcus pyogenes)
● Otitis media and Rhinosinusitis
○ Streptococcus pneumoniae (35%)
○ Haemophilus influenzae (20 – 30%)
Upper Respiratory Tract Infections; Viral URTIs
● Pharyngitis
● Otitis media → middle ear infection
● Rhinosinusitis
● Common cold
Upper Respiratory Tract Infections; Viral URTIs treatment
*can only provide symptomatic measures and supportive therapy
Upper respiratory infections are normally viral or bacterial?
viral
URT: Streptococcal Pharyngitis → Strep Throat
Caused by streptococcus pyogenes (Group A strep) ● Pharynx appears red ○ Presence of purulent abscesses ○ Swollen lymph nodes ○ Mostly viral can be bacterial
URT: Streptococcal Pharyngitis → Strep Throat
Caused by streptococcus pyogenes (Group A strep) ● Pharynx appears red ○ Presence of purulent abscesses ○ Swollen lymph nodes ○ Mostly viral can be bacterial
URT: Streptococcal Pharyngitis → Strep Throat Symptoms
● Pain during swallowing ● Bad breath ● Fever ● Headache ● Malaise
URT: Streptococcal Pharyngitis → Strep Throat can cause
● Laryngitis
○ If it moves to larynx
● Bronchitis
○ If it moves to bronchi = more complicated
Subtypes of streptococcus pyogenes: Scarlet fever
● Some subtypes can erythrogenic toxins
○ Cause rash over the body
○ Strawberry like tongue
Subtypes of streptococcus pyogenes: Glomerulonephritis
○ Inflammation of kidney
○ Loses ability to appropriately filter the blood
○ Can cause acute renal failure
○ Inflammation of kidney
○ Loses ability to appropriately filter the blood
○ Can cause acute renal failure
Subtypes of streptococcus pyogenes: Rheumatic fever
○ Unusual, immunological reaction to group A strep
○ Develop rheumatic fever
Suspect bacterial pharyngitis → Group A strep:
● Perform rapid strep test ○ Rapid molecular technique ○ Take swab of pharynx ○ Identify strep organism ○ Takes 15 mins to perform ○ Good level of sensitivity ● Prescribe antibiotic ○ Due to its capacity to cause scarlet or rheumatic fever ○ Do not want to leave Group A strep untreated ● Well and easy to cure with antibiotics
Strep Throat Prevention
● People are contagious 2 days after antibiotics
● Manage exposure to respiratory secretions
URT: Otitis Media
Severe ear pain due to inflammation & pressure on ear drum
URT: Otitis Media can cause
● Rupture ● Hearing impairment ● If they are viral → cannot resolve them ○ Put tubes in ears to relieve pressure ● If they are bacterial → antibiotics
URT: Otitis Media is most common in which population and why
Pediatric cases most common
● 85%
● Anatomy & immunity
○ Eustachian tubes are narrow and have angle
○ Making it difficult for them to drain right
URT infections bacterial
- strep throat
- otitis media
- rhinosinusitis
URT: Rhinosinusitis Symptoms
● Sinus pain & pressure ○ Nociceptors are actively innervated ○ Cause pain and pressure ● Headache ● Malaise ● Viral → symptom management ● Bacterial → antibiotics
Rhinosinusitis more common in adults or children?
adults
Upper Respiratory Tract Infections → Viral
● Most rhinosinusitis and otitis media are caused by viral infections
○ ~10% by bacteria
t/f: Most rhinosinusitis and otitis media are caused by viral infections
○ ~10% by bacteria
true
Likely to be bacterial if acute rhinosinusitis lasts…
more than 10 days
● Accompanied by:
○ High fever
○ Pus-filled nasal discharge
Upper Respiratory Tract Infections → Viral; Streptococcus pneumoniae
leading cause of bacterial middle ear and sinus infections
● Primary bacterial pathogen
● Infections move from pharynx → sinuses (via throat) or → middle ear (via auditory tubes)
● Risk of invasive pneumococcal disease
○ Pneumonia
○ Meningitis
○ Bacteremia
Upper Respiratory Tract Infections → Viral; Common Cold
● Most common human infections ● Numerous viruses responsible ○ Rhinovirus ○ Coronavirus ○ Adenovirus ● Remains infective for hours outside the body ● Highly contagious ○ Exits host cell though lysis ○ This causes symptoms
How does the common cold exit host cell?
through lysis
Upper Respiratory Tract Infections → Viral; Common Cold Transmission
● Respiratory droplets ○ Coughing on someone or object ● Fomites ● Direct contact ● Single virus is sufficient to cause infection ***Hand-washing & routine practices
Upper Respiratory Tract Infections → Viral; Common Cold Symptoms
● Prodrome of chills and rigors ○ This occurs first ● Sneezing ● Rhinorrhea ● Nasal congestion ● Dry, scratchy sore throat ● Malaise ● Cough ~1 week ● No fever (unless concomitant bacterial infection) ○ Cold does not like our body temperature ○ We are too warm
LRT infections: Pneumonia
Infection of the LRT:
● Lower lobes are Inflamed
● Fluid-filled alveoli & bronchioles
○ Feel SOB
LRT infections: Pneumonia serious cases
Empyema: Presence of pus within the pleural space
● MUST be hospitalized
Pneumonia is the what ranked cause of death
6th leading cause of death + most common cause of death due to infection
Affects of age within pneumonia
● More common in the fall and winter
○ Similar pattern to the flu
○ Flu sets good stage for pneumonia to occur
○ Flu damages lungs → opportunity for pneumonia to occur
● Length of stay increases in clients ≥70 years of age
When is pneumonia more common?
More common in the fall and winter
What sets the stage for pneumonia?
○ Similar pattern to the flu
○ Flu sets good stage for pneumonia to occur
○ Flu damages lungs → opportunity for pneumonia to occur
Age categories that all cause pneumonia related hospitalizations
Younger than 4 + those older than 65
Pathophysiology of Pneumonia
Pneumococcal pneumonia → bacterial
● 85% of community acquired cases
○ Caused by streptococcus pneumoniae
● Pathogens in pharynx aspirate into lower lobes of the lungs
○ Once it enters lower lobes = disease
● 75% of humans are colonized with S. pneumoniae
○ Belongs in upper respiratory tract
○ Cough it up = get rid of it
○ All of us microaspiration in our sleep and we cough
○ Pneumonia develops if not effectively cleared by the immune system
Pneumococcal pneumonia → bacterial Risk Factors
● Previous viral respiratory disease ● Drug abuse ● Alcoholism ○ Dramatically suppresses cough reflex ○ They microaspirate at night = cough is inhibited ○ Microorganism stays in the lower lobes ○ Causes pneumonia ● HF ● DM ● AIDS & other immune conditions
Pneumococcal pneumonia → bacterial: Three important variables
● Pathogenicity of the organism
○ What is its capacity to cause infection in lung
○ More virulent → more likely to acquire pneumonia
○ S. Pneumoniae is very virulent and pathogenic
● Degree of aspiration
○ We cough and swallow it → gut destroys microbe
○ Must effectively cough it up
● Health of the host
○ Immune and respiratory systems
Community acquired pneumonia (CAP)
Primary atypical pneumonia
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- 85% of cases are caused by streptococcus pneumoniae
Nursing home acquired pneumonia (NHAP)
● Acquire in long-term care
Hospital acquired pneumonia (HAP) → not many cases
● Hospitals are filthy with gram negative organisms
● VAP (ventilator associated pneumonia)
● HCAP (health care associated pneumonia)
○ Pneumonia in non-hospitalized patients with lots of interaction with healthcare system
○ Organism was acquired in hospital
