Upper Respiratory Tract Infections Quiz

Upper Respiratory Tract Infections

• Over 200 virus strains cause upper respiratory tract infections, with rhinoviruses being the most common.
• Viruses, not cold temperatures, cause colds, however, severe exposure leading to hypothermia may increase susceptibility.
• Colds are more common in winter due to cold temperature-induced changes in the respiratory system, decreased immune response, and low humidity.

Normal Defense Mechanisms of the Respiratory System

• The nasal cavity is lined with cells that release mucus containing lysozymes to kill bacteria.
• Nose hairs trap large particles of dust, pollen, and bacteria.
• The paranasal sinuses warm and moisten inspired air.
• The tonsils act as the first line of defense, trapping viruses and bacteria entering through the mouth or nose.

Rhino Sinusitis

• Often caused by the spread of bacteria from the nose to the sinuses.
• In immunocompromised individuals, rhino sinusitis can be caused by fungi like Aspergillus.

Pharyngitis

• Infection of the pharynx (throat).
• Can be caused by viruses such as rhinovirus and coronavirus or bacteria like Group A Streptococcus ("strep throat").

Tonsillitis

• Infection of the tonsils.
• Often occurs when pharyngitis spreads to involve the tonsils.

Laryngitis

• Infection of the larynx (voice box).
• Most commonly caused by viruses, but can also be caused by bacteria like Group A streptococcus, Streptococcus pneumonia or Haemophilus influenzae.

Epiglottitis

• Infection of the epiglottis, often caused by Haemophilus influenzae.
• The vaccine for Haemophilus influenzae type b has significantly decreased the incidence of epiglottitis.

Common Cold Symptoms

• Runny or stuffy nose (rhinorrhea), sore throat, cough, headache, and fatigue.
• Rhino sinusitis can cause facial pain or pressure and changes in voice.
• Tonsillitis causes pain and swelling in the tonsils, making swallowing difficult.
• Laryngitis causes hoarseness and a dry cough.
• Epiglottitis can cause difficulty breathing and is a medical emergency.

Common Cold Diagnosis

• Mostly based on clinical diagnosis (history, symptoms, physical examination).
• Radiographic studies can help assess complications like pneumonia.
• Laboratory studies like rapid viral antigen tests and nasopharyngeal cultures can be helpful for diagnosis and epidemiology.

Pharmacological Treatment - Decongestants

• Indication: Nasal congestion.
• Dosage forms: Oral, topical (drops, spray, inhalers).
• Mechanism of action: Alpha-adrenergic stimulation leading to vasoconstriction of blood vessels in the nasal mucosa, reducing mucosal edema and improving nasal drainage and air circulation.

Decongestant Examples

• Topical: Phenylephrine (Vibrocil), Xylometazoline (Otrivin), Oxymetazoline (Afrin).
• Oral: Phenylephrine (Rhinopro), Pseudoephedrine (Sudophine).

Decongestant Adverse Effects

• CNS: Anxiety, insomnia, nervousness, tension, tremors.
• CVS: Tachycardia, increased blood pressure.
• Local: Burning of nasal mucosa (drops and spray), managed by saline irrigation.

Decongestant Use with Caution

• Patients with hypertension, prostatic enlargement, diabetes mellitus, or active hyperthyroidism.

Decongestant Contraindications

• Patients taking monoamine oxidase inhibitors (MAOIs), uncontrolled hypertension, ischemic heart disease, or nonselective beta-blockers.
• Alternatively, saline nasal drops, levomethamphetamine (Vicks Vapor Inhaler), or local decongestants can be used.

Pharmacological Treatment - Antihistamines

• Mechanism of action: H1-receptor blockers, but primarily used for their anticholinergic effects.
• Indication: Rhinorrhea, sneezing, nonproductive cough.
• First-generation antihistamines (chlorpheniramine, diphenhydramine) are suitable for symptom management.
• Second-generation antihistamines (loratadine, fexofenadine, cetirizine) have limited anticholinergic activity.

Antihistamine Side Effects

• Anticholinergic: Dry mouth, difficulty urinating, constipation, blurred vision, irritability, dizziness.
• CNS: Sedation, dizziness, tinnitus, incoordination, fatigue, euphoria, nervousness, tremors.
• GIT: Loss of appetite, nausea, vomiting, epigastric distress (reduced by taking the drug with meals).

Antihistamine Contraindications

• Patients taking MAOIs, those with narrow-angle glaucoma or prostatic hypertrophy.
• Avoid combining with alcohol or other CNS depressants.

Pharmacological Treatment - Analgesics

• Indication: Sore throat, myalgia, headache.
• Acetaminophen, ibuprofen, naproxen.
• Acetaminophen is generally preferred, especially for patients with aspirin allergy or active ulcers.

Complementary Therapy

• Zinc: May reduce the risk of catching a cold if taken for more than 5 days in a season. May help reduce the severity and duration of cold symptoms if taken within 24-48 hours of feeling sick.
• Vitamin C: Does not prevent colds, but regular use may result in slightly shorter and milder colds.

Important Counseling Points

• Topical decongestants should be used for only 3-5 days to prevent rebound congestion: Receptor desensitization and damage to the nasal mucosa can occur.
• Selective alpha1 agonists (phenylephrine) are less likely to induce mucosal damage.
• To manage rhinitis medicamentosa, slowly withdraw topical decongestants and use saline nasal drops, Vicks Vapor Inhaler, or oral decongestants if tolerated.
• With antihistamines, avoid driving or operating heavy machinery until the patient is aware of how they will react, especially if administered at night.

Common Cold in Pediatrics

• The FDA does not recommend OTC medications for cough and cold symptoms in children under 2 years due to the risk of serious and potentially life-threatening side effects.
• Home remedies like rest and hydration can help ease symptoms.

Key Facts

• Rhinoviruses are the most common cause of upper respiratory tract infections.
• Hypothermia can increase the risk of developing a cold.
• Colds are more common in winter due to environmental factors.
• The tonsils are the body’s first line of defense against viruses and bacteria entering through the mouth and nose.
• Epiglottitis is a potential medical emergency.
• Acetaminophen is generally preferred for treating the common cold symptoms.
• Topical decongestants should be used cautiously and for a limited time to avoid rebound congestion.
• OTC medications for cough and cold symptoms are not recommended for children under 2 years old.