Understanding the Common Cold

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Questions and Answers

What is the common cause of the common cold?

Rhinoviruses or influenza viruses

Which of the following are common cold symptoms? (Select all that apply)

Sore throat (correct)

Fever

Runny nose (correct)

Cough (correct)

Sneezing (correct)

What is the main focus of treatment for the common cold?

Alleviating symptoms (correct)

Preventing transmission

Long-term effects

Eliminating the virus

Antihistamines are effective in eliminating the cause of the common cold.

False Signup and view all the answers

What type of receptors do antihistamines block?

H1 receptors Signup and view all the answers

What are some common examples of H2 blockers? (Select all that apply)

Famotidine Signup and view all the answers

Drowsiness is a common adverse effect of antihistamines.

True Signup and view all the answers

What is the purpose of antitussives?

To stop or reduce coughing Signup and view all the answers

What types of antitussives are there?

Opioid Signup and view all the answers

Expectorants help the body remove mucus from the __________.

respiratory system Signup and view all the answers

What is a common adverse effect of nasal decongestants?

Insomnia Signup and view all the answers

What is the primary mechanism of action of beta-agonists in bronchodilation?

Stimulation of beta-2 adrenergic receptors Signup and view all the answers

Which of the following is NOT a common side effect of bronchodilators?

Dry mouth Signup and view all the answers

What type of anticholinergic is Ipratropium bromide classified as?

Short-acting Signup and view all the answers

Which of the following statements best describes the role of methylxanthines in respiratory therapy?

They inhibit phosphodiesterase, resulting in increased cAMP. Signup and view all the answers

What is a key indication for using long-acting anticholinergics such as Tiotropium?

Maintenance therapy in COPD and asthma Signup and view all the answers

Study Notes

The Common Cold

Caused most commonly by rhinoviruses or influenza viruses
Invades the mucous membranes of the upper respiratory tract, causing an upper respiratory infection
Symptoms include a runny nose, sore throat, cough, and sneezing

Mucus Production

The immune system releases chemicals to fight the virus leading to inflammation
This inflammatory response causes excessive mucus production, which is thick and sticky
Designed to trap the virus and prevent it from spreading

Common Cold Symptoms

Sore throat caused by mucus irritating the pharynx
Coughing due to the body trying to clear airways
Mucus can drip into the esophagus and lower respiratory tract, causing other symptoms like a cough, upset stomach
Sneezing is triggered by irritation of the nasal mucosa
Nasal congestion is caused by mucosal irritation and blood vessel dilation in the sinuses

Treatment of the Common Cold

Symptomatic relief focuses on alleviating symptoms, not eliminating the underlying cause
Antiviral therapy is not effective for the common cold
Empiric therapy often focuses on treating the most likely cause, viral or bacterial, regardless of confirmation

Antihistamines

Directly compete with histamine, a key chemical mediator in the body's inflammatory response
Two types of histamine receptors: H1 and H2
Block the action of histamine at H1 receptor sites
Prevent histamine from binding to histamine receptors, reducing the inflammatory response

Anaphylaxis

Severe, life-threatening allergic reaction
Occurs when the body releases excessive amounts of histamine
Histamine release causes smooth muscle constriction, increased secretions, vasodilation, and edema

H2 Blockers

Reduce the production of gastric acid
Effective for treating peptic ulcer disease
Examples include cimetidine (Tagamet), famotidine (Pepcid), and nizatidine (Axid)

Antihistamines: Mechanism of Action

Antihistamines compete with histamine for binding at unoccupied receptors
Antihistamine must be present in a higher concentration than histamine to effectively block its action
Antihistamines should be administered early in treatment to prevent histamine binding

Antihistamines: Other Effects

Reduce capillary permeability, decreasing redness and swelling caused by histamine release
Anticholinergic effects reduce nasal, salivary, and lacrimal gland secretions, lessening symptoms like runny nose, tearing, and itchy eyes
Some antihistamines can cause drowsiness, often called "first-generation" antihistamines

Antihistamines: Indications

Used to treat allergic rhinitis, a condition that causes inflammation of the nasal passages due to an allergic reaction
Help prevent and treat motion sickness by blocking histamine effects in the inner ear
Some antihistamines are used to help manage tremors and other symptoms of Parkinson's disease
Can help relieve the symptoms of allergic reactions, such as hives, itching, and swelling

Antihistamines: Contraindications

Patients should not use antihistamines if they have a known allergy to the drug
Can increase intraocular pressure, which can worsen narrow-angle glaucoma
Can increase heart rate and blood pressure, therefore dangerous for patients with heart disease or hypertension
Should be avoided by patients with kidney disease, bronchial asthma, COPD, or who are using antihistamines as sole drug therapy during acute asthmatic attacks
Can worsen symptoms of peptic ulcer disease
Some antihistamines can lower the seizure threshold, increasing the risk of seizures in people with epilepsy
Certain antihistamines can worsen urinary symptoms in men with BPH
Many antihistamines are not recommended during pregnancy, especially in the first trimester

Antihistamines: Adverse Effects

Anticholinergic effects are the most common adverse effects, including dry mouth, difficulty urinating, constipation, and changes in vision
Drowsiness is another common adverse effect

Two Types of Antihistamines

Traditional antihistamines cross the blood-brain barrier, leading to sedation and drowsiness as a side effect
Nonsedating antihistamines are less likely to cause drowsiness and are commonly used for long-term treatment of allergies

Nonsedating/Peripherally Acting Antihistamines

Developed to avoid sedation and other CNS effects
Work peripherally to block histamine receptors, reducing central nervous system side effects
Have a longer duration of action, promoting compliance and consistent symptom relief

Traditional Antihistamines

Were developed and used prior to the discovery of nonsedating antihistamines
Block histamine receptors in both the central nervous system and peripheral tissues
Also block acetylcholine receptors leading to side effects such as dry mouth and drowsiness
Examples include diphenhydramine, brompheniramine, chlorpheniramine, dimenhydrinate, meclizine, and promethazine

Decongestants: Types

Adrenergics are the most common decongestants and are sympathomimetics
Anticholinergics, parasympatholytics, are less frequently used
Corticosteroids are topical nasal steroids used for longer-term relief

Oral Decongestants

Have a longer duration of action but their effects take longer to appear
Less potent than topical nasal decongestants
Do not cause rebound congestion, unlike topical nasal decongestants
Exclusively adrenergic medications

Topical Nasal Decongestants

Topical adrenergic nasal decongestants are a common treatment for nasal congestion
Constrict blood vessels in the nasal passages, reducing swelling and congestion
Provide rapid onset of relief from nasal congestion
Intranasal steroids are the most effective topical nasal decongestants and a first-line treatment for allergic rhinitis
Intranasal ipratropium is a newer nasal spray used to treat rhinorrhea in patients with the common cold or allergic rhinitis

Nasal Decongestants: Mechanism of Action

Target blood vessels surrounding nasal sinuses
Adrenergic decongestants stimulate alpha-adrenergic receptors causing vasoconstriction, leading to the shrinkage of swollen tissues and improved drainage
Nasal steroids are anti-inflammatory drugs that inhibit immune system cells, reducing inflammation and congestion

Nasal Decongestants: Indications

Commonly used to relieve nasal congestion associated with acute rhinitis
Can be helpful for chronic rhinitis
Often used to alleviate sinus congestion and pressure related to sinusitis
Can be used to reduce nasal swelling before procedures like surgery or nasal endoscopy

Nasal Decongestants: Contraindications

Patients with a known allergy to nasal decongestants should avoid them
Can increase intraocular pressure, potentially worsening glaucoma
Should be used with caution in patients with uncontrolled cardiovascular disease
Also contraindicated in patients with diabetes, hyperthyroidism, and a history of cerebrovascular accident or transient ischemic attacks

Nasal Decongestants: Adverse Effects

Can lead to nervousness, insomnia, and palpitations due to their effects on the central nervous system
Topical nasal decongestants can cause local mucosal dryness and irritation
Excessive doses can lead to systemic effects, including tremors and palpitations, due to adrenergic stimulation of the heart, blood vessels, and central nervous system

Two Basic Types of Cough

Productive coughs (wet coughs) are associated with phlegm or mucus production
Nonproductive coughs (dry coughs) are not associated with phlegm or mucus production and are often irritated or scratchy

Antitussives

Drugs used to stop or reduce coughing
Categorized as either opioid or nonopioid
Typically used for nonproductive coughs when coughing is not productive or helpful
Can be used in cases when coughing is harmful, like with certain respiratory conditions

Antitussives: Mechanism of Action

Opioids suppress the cough reflex by acting directly on the cough center in the medulla
Nonopioid antitussives like dextromethorphan work by suppressing the cough reflex in the brainstem
Codeine and hydrocodone are commonly prescribed opioid antitussives and effective for treating nonproductive coughs
Dextromethorphan and benzonatate are common nonopioid antitussives that work by suppressing the cough reflex
Dextromethorphan works by inhibiting the cough reflex pathway in the brain without causing CNS depression or analgesic effects
Benzonatate works by numbing stretch receptors in the respiratory tract, preventing stimulation of the cough center

Antitussives: Adverse Effects

Can sometimes cause dizziness
Many antitussives can induce drowsiness
Nausea is a common side effect

Expectorants

Drugs that help the body remove mucus from the respiratory system
Work by thinning the mucus, making it easier to cough up
Aid in the removal of mucus, reducing symptoms of congestion

Expectorants: Mechanisms of Action

Some expectorants irritate the gastrointestinal tract, causing a reflex response that loosens and thins respiratory secretions
Others directly stimulate secretory glands in the respiratory tract, increasing fluid production
The ultimate goal is to create thinner mucus that is easier to cough up and expel

Expectorants: Drug Effects

Help make thick phlegm thinner and easier to cough up
Indirectly reduce the need to cough, easing discomfort
By reducing mucus buildup in the airways, breathing becomes easier

Expectorants: Indications

Helpful in treating coughs that produce mucus
Commonly used to treat coughs associated with respiratory infections
Can also be helpful for coughs caused by inflammation of the larynx or pharynx
Used for coughs associated with chronic paranasal sinusitis

Bronchodilators

Used to relax and widen the airways, making breathing easier
Two main types: Beta-agonists and Methylxanthines

Beta-agonists

Stimulate beta-2 adrenergic receptors, relaxing airway muscles
Short-acting (e.g., albuterol) are for quick relief of acute symptoms
Long-acting (e.g., salmeterol) are for maintenance therapy in chronic conditions

Methylxanthines

Inhibit phosphodiesterase, leading to increased cyclic AMP (cAMP) levels
Example: Theophylline, used for chronic asthma and COPD

Anticholinergics

Block acetylcholine receptors in the airways, leading to bronchodilation
Two types: Short-acting and Long-acting

Short-acting

Example: Ipratropium bromide, for quick relief in COPD and asthma

Long-acting

Example: Tiotropium, for maintenance treatment in COPD and asthma
Anticholinergics work by competitively antagonizing muscarinic receptors, reducing bronchoconstriction

Common Side Effects

Bronchodilators: Tachycardia, tremors, nervousness, headaches
Anticholinergics: Dry mouth, constipation, urinary retention, blurred vision

Indications

Anticholinergics are primarily used for COPD management, but may also help asthma patients needing additional bronchodilation.

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Description

This quiz covers vital information about the common cold, including its causes, symptoms, and treatment methods. Explore the role of mucus production and the immune response in combating colds. Test your knowledge of this prevalent upper respiratory infection!