URTI
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Questions and Answers

Which of the following structures is NOT considered part of the upper respiratory tract?

  • Pharynx
  • Nasal passages
  • Sinuses
  • Trachea (correct)

    • What is the main causative organism of upper respiratory tract infections?

  • Staphylococcus aureus
  • Viruses (correct)
  • Streptococcus pneumoniae
  • Mycoplasma pneumoniae

    • Which of the following is a natural host defense mechanism of the upper respiratory tract?

  • Cough reflex (correct)
  • Blood circulation
  • Acidic stomach secretions
  • Bile salts

    • What effect does stress have on respiratory tract infections?

    <p>It disrupts commensal balance leading to pneumonia.</p> Signup and view all the answers

    Which type of secretions are important for respiratory tract defense mechanisms?

    <p>Lysozyme</p> Signup and view all the answers

    Which of the following conditions is characterized by a barking cough and inspiratory stridor?

    <p>Croup</p> Signup and view all the answers

    In what way does mucociliary clearance function as a defense mechanism?

    <p>It traps and removes inhaled pathogens.</p> Signup and view all the answers

    Which of the following is a potential consequence of compromised immune system function in the respiratory tract?

    <p>Opportunistic infections</p> Signup and view all the answers

    Which type of influenza primarily requires neuraminidase inhibitors for treatment?

    <p>Influenza A</p> Signup and view all the answers

    What is a major complication of a Streptococcus pyogenes infection?

    <p>Glomerulonephritis</p> Signup and view all the answers

    Which virus is primarily transmitted via droplet inhalation and contact?

    <p>Mumps virus</p> Signup and view all the answers

    Which medication is contraindicated in children due to potential side effects from M2 ion channel inhibition?

    <p>Amantadine</p> Signup and view all the answers

    What condition can result from repeated infections with Streptococcus pyogenes?

    <p>Rheumatic heart disease</p> Signup and view all the answers

    Which type of influenza was responsible for the 1918 pandemic?

    <p>H1N1</p> Signup and view all the answers

    What symptom is primarily associated with mumps infection?

    <p>Swelling of the parotid glands</p> Signup and view all the answers

    Which of the following organisms is a common bacterial cause of sinusitis?

    <p>Moraxella catarrhalis</p> Signup and view all the answers

    Where does the mumps virus prefer to colonize in the body?

    <p>Parotid salivary glands</p> Signup and view all the answers

    Which antibiotic is commonly used for treating bacterial infections suspected in tonsillitis?

    <p>Clarithromycin</p> Signup and view all the answers

    What is the main cause of epiglottitis?

    <p>Streptococcus pneumoniae</p> Signup and view all the answers

    What symptom is commonly associated with pertussis (whooping cough)?

    <p>Uncontrollable coughing fits</p> Signup and view all the answers

    Which condition requires prompt treatment with antibiotics to prevent complications?

    <p>Bacterial pharyngitis</p> Signup and view all the answers

    What is a common complication of untreated strep throat?

    <p>Rheumatic fever</p> Signup and view all the answers

    How can otitis media commonly occur?

    <p>Through direct throat to ear infection</p> Signup and view all the answers

    What is the primary pathogenic mechanism of respiratory viruses like influenza?

    <p>Inhibition of local mucosal defenses</p> Signup and view all the answers

    Which virus is most commonly associated with the common cold?

    <p>Rhinovirus</p> Signup and view all the answers

    What is a significant risk factor for middle ear infections in children?

    <p>Small size of Eustachian tubes</p> Signup and view all the answers

    Which virulence factor helps Streptococcus pneumoniae evade macrophage phagocytosis?

    <p>Capsule</p> Signup and view all the answers

    What characterizes symptoms of sinusitis?

    <p>Facial pain or pressure</p> Signup and view all the answers

    What distinguishes bronchitis from other upper respiratory infections?

    <p>Presence of sputum production</p> Signup and view all the answers

    Which infection typically requires surgical intervention due to severe cases?

    <p>Adenoiditis</p> Signup and view all the answers

    What type of organism are professional invaders in the respiratory tract?

    <p>Microbes that invade healthy respiratory tracts</p> Signup and view all the answers

    What is the initial symptom a person experiences with influenza?

    <p>High fever</p> Signup and view all the answers

    Study Notes

    Upper Respiratory Tract Infections (URTIs)

    • URTIs affect the nose, nasal passages, sinuses, ears, throat (pharynx and larynx)
    • LRTIs affect the airways and lungs (trachea, bronchi, bronchioles, alveoli)
    • Viral infections are the primary cause of URTIs
    • Bacterial infections can also cause URTIs
    • Common bacterial causes include Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, Streptococcus pyogenes, Mycoplasma pneumoniae, RSV, Adenovirus, Influenza viruses

    Anatomy and Natural Host Defenses

    • The respiratory tract has natural defenses like saliva (pH, antibodies), sinuses (immunological defense), tonsils (lymphatic system), nose hairs (filtration), sneezing, cough reflex, cilia, mucosal layer (mucociliary escalator), and respiratory tract epithelium (antimicrobial peptides).
    • Filtration of air occurs within the nasal passages, trapping large particles.
    • Mucosal adherence and bacterial interference help maintain a healthy balance, preventing overgrowth.
    • Stress can disrupt this balance, leading to infections like gram-negative pneumonias.

    Common URTI Types and Their Characteristics:

    • Croup: Primarily in children, caused by parainfluenza virus. Symptoms include barking cough, hoarseness, inspiratory stridor, and respiratory distress. Sometimes requires medical intervention (corticosteroids or nebulized epinephrine).
    • Epiglottitis: Bacterial infection of epiglottis, often caused by Haemophilus influenzae type B (Hib) or Streptococcus pneumoniae. Symptoms include rapid onset of severe sore throat, high fever, difficulty swallowing, and drooling. Rapid progression to airway obstruction and respiratory failure is possible.
    • Pertussis (Whooping Cough): Caused by Bordetella pertussis. Symptoms progress from a common cold to severe, uncontrollable coughing fits (paroxysmal cough) accompanied by a "whooping" sound. Potentially life-threatening, especially in infants and young children.
    • Adenoiditis: Infection/inflammation of the adenoids, often viral or bacterial. Symptoms include nasal congestion, mouth breathing, snoring, and recurrent ear infections. Severe cases may require surgical intervention.
    • Pharyngitis (Sore Throat): Viral (e.g., common cold, flu), or bacterial (e.g., strep throat). Symptoms include throat pain, difficulty swallowing, and swollen tonsils with or without white patches. Bacterial pharyngitis (strep throat) needs antibiotics to prevent complications.
    • Otitis Media (OM): Middle ear infection, often following a cold. The Eustachian tube, connecting the middle ear to the throat, facilitates spread during colds. Fluid buildup puts pressure on eardrum, causing ear pain and sometimes reduced hearing. More common in children due to smaller Eustachian tubes and reduced immunity. Typically viral, but sometimes bacterial. Often self-limiting.
    • Common Cold (Viral Rhinitis): Caused by rhinoviruses, coronaviruses, or adenoviruses. Mild symptoms include nasal congestion, runny nose, sore throat, cough, and sneezing.
    • Influenza (Flu): Caused by influenza viruses (types A, B, and rarely C). Shows sudden onset of high fever, chills, headache, muscle aches, fatigue, dry cough, and sore throat. Can lead to severe complications (pneumonia) in high risk individuals.
    • Sinusitis (Sinus Infection): Often follows a viral URTI or allergies. Symptoms include facial pain or pressure, nasal congestion, headache, and post-nasal drip. Can be bacterial.
    • Strep Throat (Streptococcal Pharyngitis): Caused by Group A Streptococcus (Streptococcus pyogenes). Symptoms include severe sore throat, difficulty swallowing, fever, and swollen tonsils with white patches. Left untreated, can lead to complications like rheumatic fever or post-streptococcal glomerulonephritis.
    • Bronchitis: Typically a lower RTI, also affects trachea (part upper RTI). Inflammation of bronchial tubes, frequently viral. Symptoms include persistent cough, sometimes with sputum production, chest discomfort, and low-grade fever. Treatment with antibiotics may be necessary for bacterial bronchitis.

    Pathogenesis

    • Most URTIs are caused by viruses
    • Microbes spread to cause localized infection or spread throughout the body
    • The immune response (adaptive) may be needed to resolve an infection

    Virulence Factors

    • Crucial for bacteria to cause infection - bacteria must colonize, multiply, and evade the immune system.
    • Examples include pili (adhesins), capsules, M proteins, and toxin production.

    Influenza (detailed)

    • Influenza viruses (types A, B, and C)
    • Transmission by droplet inhalation and contact
    • Antigenic variation causes changes in the virus's form over time (antigenic drift or shift)
    • Major historical influenza outbreaks include Spanish Flu, Asian Flu, Hong Kong Flu, Russian Flu, H5N1, and 2008 flu or swine flu.

    Treatment & Prevention (Influenza)

    • Vaccination is the foremost preventive measure
    • Treatment should begin within 48 hours of symptom onset.
    • Neuraminidase inhibitors (oseltamivir, zanamivir) limit infection severity.
    • Amantadine blocks virus uncoating in the host cell.

    URTI Bacterial Causes & Treatment

    • Streptococcus pyogenes: Most common cause of pharyngitis; treat with penicillin.
    • Streptococcus pneumoniae: Causes sinusitis, pneumonia, otitis media; treat with penicillin (check resistance guidelines).
    • Haemophilus influenzae: Common in children, causing sinusitis and otitis media; Hib vaccine significantly reduced severe infections.
    • Staphylococcus aureus: Often associated with skin infections but can cause sinusitis/otitis media in susceptible individuals; treat with flucloxacillin
    • Moraxella catarrhalis: May cause sinusitis and otitis (in adults/children with underlying respiratory conditions, like cystic fibrosis).
    • Bordetella pertussis: Causes whooping cough—severe coughing fits; vaccination highly effective in reducing this disease.

    Complications of Streptococcus pyogenes

    • Otitis media, sinusitis, mastoiditis
    • Scarlet fever
    • Rheumatic fever (myocarditis/pericarditis)
    • Rheumatic heart disease
    • Acute glomerulonephritis

    Additional Information

    • Mumps is a viral infection causing swelling in the parotid salivary glands. It can cause complications in males, and is generally self-limiting.
    • Investigations for URTIs are usually not necessary except for suspected strep throat (throat swab).

    Treatment Options (Bacterial URTI)

    • For bacterial infections like tonsillitis, sinusitis, and otitis media, phenoxymethylpenicillin is a common treatment. Alternatives include clarithromycin or doxycycline (caution with children). Amoxicillin is an often used alternative.

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