Upper Respiratory Tract Infections Flashcards
What are the 2 main functions of the URT?
To conduct air from outside of the body to the lower respiratory tract - filters warms and humidifies the air through the nasal cavity.
Has a defence mechanism to protect the body from irritating substances.
What is the pharynx/throat?
Tube-like structure which connects the back of the nasal cavity to the larynx and oesophagus.
In order to help the air and food go into the correct passageway, pharynx contains a specialised flap-like structure called epiglottis – lowers over the larynx to prevent the inhalation of food and liquid into the oral respiratory tract.
What is the larynx?
This is the passage for air and contains vocal cords essential for human speech. Larynx is small and triangular in shape and it extends from the epiglottis down to the trachea and helps control the movement of epiglottis. Larynx also has specialised muscular folds that close off, preventing food, foreign object or secretions such as saliva from entering the lower respiratory tract.
What is the trachea/windpipe?
Tube extending from the larynx into the bronchi, carrying air from larynx right into lungs. Trachea lines with ciliated cells which push particles out and cartilage rings which reinforce the trachea and preventing collapsing during breathing.
What is rebound congestion?
Rhinitis/congestion is worsening of congestion caused by medication on withdrawal.
What is (Rhino) sinusitis?
Inflammation of the mucosal lining of the paranasal sinuses and excess mucus during sinus infection.
(Rhinitis = inflammation of nasal mucosa - continuous rhinitis = sinusitis)
What is acute sinusitis?
Sinusitis which completely resolves within 12 weeks.
What is chronic sinusitis?
Sinusitis which causes symptoms which last more than 12 weeks.
What is the definition of acute sinusitis?
An increase in symptoms after 5 days or persistence of symptoms beyond 10 days.
What are the symptoms of acute sinusitis in children?
Nasal blockage or congestion.
Discoloured nasal discharge.
Cough during the day/night/
What are the symptoms of acute sinusitis in adults?
Nasal blockage/congestion.
Nasal discharge.
Dental or facial pain/pressure.
Reduction/loss of sense of smell.
What are 3 symptoms of rhinitis if it is caused by bacteria?
Discoloured or purulent nasal discharge.
Severe localised unilateral pain.
Fever.
FeverPAIN score classification.
Fever in last 24 hours Purulence Attend rapidly under 3 days Inflamed tonsils No cough or coryzal (inflammation of mucous membranes on nose)
Centor score/TTHA classification.
Tonsillar exudate
Tender anterior cervical lymphadenopathy
History of fever
Absence of cough
What is a cough?
A reflex stimulated by irritation of mucosa of th respiratory tract.
What is the main function of a cough?
Airway clearance.
Why is the cough reflex initiated?
Due to excess mucus in airways or secretions, dust, particles or cold/hot air which irritates the trachea and sets off the cough reflex.
What are the clinical feature of acute cough?
Sudden onset. Associated cold symptoms may be present. Minimal sputum production. Worse in the evening. Associated fever.
Describe the cough reflex.
Physical or chemical stimulation of irritant receptors in the larynx, trachea or bronchial tree or inflammation in these sites results in a forceful expiratory blast which can remove inhaled material.
What are the 5 defence mechanisms of the URT?
- mucocilliary lining
- lymphatic tissue in the tonsils and adenoids
- smell and non-olfactory detection
- cough reflex
- normal flora organisms
What is the role of normal flora organisms?
- these compete with pathogens for attachment sites on the mucocilliary lining.
- can produce bactericidal substances such as toxins or acids.
What conditions must be met for a respiratory disease to be established (4)?
- Sufficient dose of infectious agent inhaled.
- Infectious particles must be airborne.
- Infectious organism must remain alive and viable while in the air.
- Organism must be deposited on susceptible tissue in the host.
List some URT infections.
Cough, otitis media, croup, common cold, sinusitis, sore throat.
What virus is the common cold caused by?
Mainly rhinovirus
Describe the steps for the pathogenesis of the common cold.
- Virus is acquired by direct contact/transmission of particles.
- Virus attaches to and infects the cells lining nasal region and pharynx.
- Virus then sheds coat, releases nucleic acids and replicates.
- Macrophages release cytokines as part of body’s innate and adaptive immune response.
- This causes inflammation in the respiratory tract - dilate blood vessels and stimulate nerve cells causing congestion and sneezing.
- The ciliated columnar epithelial cells are destroyed and slough off.
- Destruction reaches peak by day 2-5.
- Regeneration of cells occurs with new cells formed by day 14.