Lower Respiratory Tract Infections Flashcards
What is laryngitis? Tracheitis?
- an infection of the larynx and trachea
- adults: can cause hoarseness and a burning pain
- children: have a narrow airway that is easily obstructed, making it very dangerous for them and potentially leading to hospitalization
What is the most common cause of laryngitis or tracheitis?
- parainfluenza virus, RSV, influenza or adenovirus
What bacteria usually cause the laryngitis/tracheitis infection?
- group A streptococci
- H. influenzae
What bacteria typically causes diphtheria?
- corynebacterium diphtheria
What is the prevalence of the diphtheria in the human population?
- many of us carry the bacteria diphtheria in our mouth, but we are not containing the pathogenic strain- we do not have the viral genome contained within it, which means that it is not pathogenic
- bacteria encodes for a toxin- this is what makes it pathogenic (the AB protein is what makes the protein viral)
What causes the dangerous accumulation of film in the back of the throat that makes it hard for people to breath?
- when the bacteria has an AB protein in it, it is viral- the AB protein inhibits protein synthesis and causes cell death
- the dead cells can then accumulate in the airway and can block the airway completely
- the dead mass of cells is very tightly attached to the live cells of the tissue, so it has to be surgically removed
- it is the virus that is responsible for the production of the toxin
What are some of the complications associated with diphtheria?
- myocarditis
- polyneuritis (paralysis of the soft palate that causes regurgitation of liquids)
- all of these are caused because the toxin from the diphtheria is absorbed into the lymph nodes and the blood
What is the treatment required for diphtheria?
- treatment is immediate, since this is a life threatening condition
- needs to be treated with an antitoxin (horse serum) and antibiotics
What vaccine vaccinates against diphtheria?
- combination of pertussis, tetanus, polio and H. influenza B
What bacteria is known to cause pertussis? (whooping cough)
- bordetella pertussis and parapertussis
How is pertussis spread?
- by airborne droplets - it is a disease that is confined to humans
- especially affects infants and young children
The organism attaches to and multiplies within the _________, and does not spread to deeper structures in the lungs
ciliated respiratory mucosa
What is the clinical presentation of pertussis in a child?
- early phase: viral upper respiratory tract infection
- fever is uncommon, showing paroxysms of coughing
- this is the sum of several toxins
- dry, unproductive cough
Bordatella pertussis infections are associated with the production of various _____
toxic factors
What are the 3 toxins that cause pertussis?
- pertussis toxin (A-B type- A-subunit: ADP ribosyl transferase that catalyzes transfer of ADP-ribose from NAD to host cell proteins, affects signal transduction)
- adenylate cyclase (enters neutrophils, causes increased cAMP which inhibits their chemotaxis, phagocytosis and bactericidal killing ability)
- tracheal toxin (kills tracheal cells)
What are the most common complications of pertussis?
- pneumonia as a secondary infection, which can potentially cause alveolar rupture
- CNS infections such as seizures
What are the 3 stages of a pertussis infection?
- Catarrhal (mild cold, runny nose, mild cough)
- can last several weeks - Paroxysmal (severe coughing begin)
- 15-25 paroxysmal fits/ 24 hours -> vomiting and whooping - Convalescent (slow decrease of symptoms -> 4 weeks after infection)
What does the pertussis vaccine consist of?
- acellular vaccines
- pertussis toxoid + bacterial components (filamentous haemagglutinin and fimbrae)
Describe acute bronchitis?
- inflammation of the tracheobronchial tree
- often viral in nature, but can be bacterial
What viruses are known to cause acute bronchitis?
- rhinovirus, coronavirus, influenza virus, adenovirus
What bacteria typically cause pertussis?
- bordatella pertussis, B. parapertussis, mycoplasma pneumoniae, chlamydophila pneumoniae
Is there a time of the year that bronchitis peaks?
- peaks in winter
shows cough, fever and variable amounts of sputum
Acute bronchitis usually follows an _______
upper respiratory tract infection
The spread of acute bronchitis is usually caused from damage to the _____ epithelial cells by the same viral pathogens
respiratory
What are the main complications associated with acute bronchitis ?
- secondary bacterial infections
-potentially pneumonia
S. pneumoniae or H. influenzae
_____ is the primary cause of bronchiolitis and pneumonia in infants under 2 years old
RSV
Respiratory Syncytial Virus is spread via transmission by ____
droplets
When an RSV infection occurs, the ____ narrow, causing difficulty in breathing
bronchioles
Why is an RSV infection so dangerous in young children?
- it is inhaled and there is an established infection in the nasopharynx as well as the lower respiratory tract, causing bronchiolitis or pneumonia
- his can lead to cough, fast respiratory rate and even cyanosis
- in older children however the mortality rate is better, since the infection does no go as far down into the respiratory tract