Respiratory Tract and Upper Respiratory Infections

Upper and Lower Respiratory Tracts

• The upper respiratory tract contains the nasal cavity, nostril, and oral cavity
• The larynx, pharynx, and trachea are also part of the upper respiratory tract
• The lower respiratory tract includes the left and right primary bronchus, and the left and right Lungs
• The diaphragm is a part of the lower respiratory tract

Upper Respiratory Infections (URIs)

• The common cold is a URI that affects the nasopharyngeal tract
• Acute rhinitis is a URI that causes inflammation of the nasal mucous membranes
• Sinusitis is a URI that causes inflammation of the sinus mucous membranes
• Acute pharyngitis is a URI that causes inflammation of the throat

URIs: Common Cold

• The common cold is caused by Rhinovirus
• This URI is most contagious 1–4 days before the onset of symptoms
• The common cold is also highly contagious during the first 3 days
• The common cold spreads via touching contaminated surfaces, then touching nose or mouth
• Viral droplets from sneezing also transmit the common cold
• Nasal congestion, nasal discharge, cough, and increased mucosal secretions are symptoms of the common cold
• Medications are generally not curative for common cold

Comparing Cold, Flu, and COVID-19 Symptoms

• Cold Symptom onset is gradual, fever is rare, aches are slight, and chills are uncommon
• Fatigues/weakness is sometimes present, sneezing is common, and chest discomfort/cough is mild to moderate
• Stuffy nose and sore throat are common, and headaches are rare for colds
• For the Flu, symptom onset is abrupt, fever is usual, aches are usual, and chills are fairly common
• Fatigue/weakness is usual, sneezing is sometimes present, and chest discomfort/cough is common
• Stuffy nose and sore throat are sometimes present, and headaches are common for the Flu
• For COVID-19, fever, fatigue, cough, and headaches are usually present
• Sore throat, runny nose, shortness of breath, and body aches are also commonly present for COVID-19
• Diarrhea and/or vomiting symptoms are less common for COVID-19
• Loss of taste/smell, red/swollen eyes, and skin rashes are common for COVID-19

Anticholinergics

• They have the same effect as parasympatholytics
• Anticholinergics block acetylcholine
• They target the central and peripheral nervous system
• Block parasympathetic nerve impulses by blocking acetylcholine binding to receptors

Anticholinergic Side Effects

• Anticholinergics lead to adverse reactions like dilated pupils
• Vasodilation/flushing might occur if someone takes an anticholingeric
• Hyperthermia might result in someone takes an anticholinergic
• Dry skin and hallucinations/agitation are symptoms of taking anticholinergics
• Ileus and cardiac events are possible with anticholinergic use

Medications for URIs

• Antihistamines
• Sympathomimetics (systemic and nasal)
• Intranasal glucocorticoids
• Expectorants
• Antitussives

Histamine Repsonse

• An allergic reaction can cause capillary widening, increased permeability, and an attraction of leukocytes
• The immune systems response is a variety extravasation of leukocytes
• Allergic reactions can result in watery eyes, runny nose, stuffy nose, and itchy throat
• Allergic reactions may cause symptoms like heat, redness, swelling, tenderness, and pain

Antihistamines

• H1 blockers antagonize and compete with histamine for receptor sites
• These drugs prevent a histamine response
• Antihistamines facilitate vasoconstriction of smooth muscles lining the nasal cavity
• They decrease nasal itching and tickling that cause sneezing
• These drugs are rapidly absorbed but are not potent enough to combat anaphylaxis

First-Generation Antihistamines

• Prototype: diphenhydramine
• Competes with histamine for receptor sites and prevents a histamine response
• Useful for acute and allergic rhinitis and are pre-meds prior to blood transfusions; also help with insomnia, urticaria, motion sickness
• Side effects include anticholinergic effects, wheezing, and blood dyscrasias
• Avoid anticholinergic use with narrow-angle glaucoma, asthma, urinary retention, HTN, and impaired kidney or liver
• Avoid use with severe liver disease or with other CNS depressants

1st Generation Antihistamines Considerations

• Older adults are at a higher risk of side effects and anticholinergic toxidrome
• Side effects include lower blood pressure, confusion, and cognitive decline
• Also causes a fall risk and decreases in drug clearances
• Consider a second-generation antihistamine option for older patients
• Beers Criteria say to avoid diphenhydramine because it can cause anticholinergic effects

Second-Generation Antihistamines

• Prototype: cetirizine (Zyrtec), azelastine (intranasal)
• Mechanism of action: similar to 1st generation antihistamines
• For allergic rhinitis and chronic idiopathic urticaria
• Fewer anticholinergic symptoms and are non-sedating

Sympathomimetic Decongestants

• Pseudoephedrine is a systemic sympathomimetic decongestant
• Alpha₁ adrenergic agonists cause vasoconstriction of blood vessels and relieve nasal congestion
• Adverse reactions include jitteriness, restlessness, increased BP, hyperglycemia, agitation, insomnia, tachycardia, and palpitations
• Sympathomimetics relieve nasal congestion longer than nasal decongestants
• Contraindications include HTN, cardiac disease, and hyperthyroidism

Nasal Decongestants

• Prototype: oxymetazoline
• Stimulates alpha-adrenergic receptors to vasoconstrict capillaries
• Use stimulates alpha-adrenergic receptors producing vasoconstriction
• This shrinking nasal mucous membranes which results in reducing fluid secretion (rhinorrhea)
• Useful for acute rhinitis
• Side effects include rebound nasal congestion
• Act quicker than systemic decongestants
• Can result in tolerance and rebound congestion if used frequently

Intranasal Glucocorticoids

• Fluticasone is a prototype glucocorticoid medication
• This classification of drugs work as an anti-inflammatory
• Useful for congestion, runny nose, sneezing, itching, and/or swelling of the nasal passageway
• Adverse effects include dry mucus membranes, sore throat, epistaxis
• Use in combination with an H₁ antihistamine
• Spray away from nasal septum to prevent dryness of the nasal mucosa

Expectorants

• Use guaifenesin to treat colds and other URIs that trigger mucus production
• Guaifenesin reduces the viscosity of tenacious bronchial secretions
• This medication facilitates the removal of secretions in bronchitis
• Can result in dizziness, drowsiness, headache, GI distress, rash
• Increase fluid intake while taking this medication to at least 8 glasses water/day to loosen mucus
• Causes toxicity if taken with MAOIs, narcotics, barbiturates, antidepressants, alcohol

Antitussives

• Prototypes: codeine (opioid), dextromethorphan (non-opioid)
• Act on the cough-control center in the medulla to suppress the cough reflex
• Relief of non-productive cough
• Side effects related to CNS depression, dizziness, and lightheadedness
• Monitor when changing positions and administer this medication with food to avoid GI distress
• Take only when needed; encourage a diet high in fluids & fiber

Antivirals for Influenza

• Prototype: oseltamivir
• MOA: inhibits neuraminidase, affecting release of viral particles
• Used for acute, uncomplicated influenza A and B
• Adverse reactions: N/V, headache, pain, Steven-Johnson syndrome, toxic epidermal necrolysis, and erythema multiforme
• Do not administer until 48 hours following cessation of TAMIFLU
• This drug will be ineffective if administered after 18 hours of the onset

Nirmatrelvir/Ritonavir (Paxlovid)

• Inhibits COVID-19 protease (Mpro) which prevents viral replication
• Used for the treatment of adults and peds patients (12 years and older weighing at least 40 kg) with mild-to-moderate COVID-19
• For those at high risk for progression to severe COVID-19
• Side-effects: dysgeusia, diarrhea, hypertension, myalgia, anaphylaxis, rashes
• Do not take if taking lovastatin, phenytoin, sildenafil, colchicine, amiodarone, rifampin, St. John's wort

Nirmatrelvir/Ritonavir (Paxlovid) Contras

• Monitor liver functions when administering this drug
• Contradicted with concomitant use with phenytoin
• Contraindicated w/ severe hepatic impairment
• Use with caution when administering CYP3A inducers and/or plasma concentration medications due to possible resistance

Nursing Care for URIs

• Promote rest, increase fluids and nutrition
• Use a clean humidifier or cool mist vaporizer, avoid smoking, second hand smoke, and pollutants
• Take acetaminophen, ibuprofen, or naproxen to help with pain and/or fever
• Use saline nasal spray

Chronic Obstructive Pulmonary Disease (COPD)

• Airway obstruction with increased airway resistance that obstructs airflow to lung tissues
• Chronic bronchitis
• Bronchiectasis (enlarged bronchial tubes) caused by chronic infection and inflammation
• Emphysema
• Asthma

Bronchial Muscle

• The tracheobronchial tube composed of smooth muscle
• Sympathetic Nervous System causes bronchodilation when epinephrine is released
• Parasympathetic Nervous System causes Bronchoconstriction when acetylcholine is released

Categories of Asthma & COPD Medications

• Short-Acting β₂ Agonist (SABA)
• Long-Acting β₂ Agonist (LABA)
• Anticholinergics / Long-Acting Muscarinic Antagonist (LAMA)
• Sympathomimetics
• Methylxanthines
• Leukotriene Receptor Antagonist
• Glucocorticoid
• Mucolytic
• Mast Cell Stabilizers

Alphan and Beta Adrenergic Receptors

• Vasconstriction, peripheral resistance, increased BP, increased closure of valve
• Inhibition of norepinephrine, acetylcholine, and insulin release
• Tachycadia, increased lipolysis, increased myocardial contractility, and increased renin release
• Vasodilation, decreased peripheral resistance, bonchodialtion, and increase muscle and liver glycolysis
• Increased glucagon and uterine smooth muscle relation

Short-Acting B₂ Agonists

• Albuterol is a prototype SABA
• Stimulates B₂ receptors to stimulate bronchodilation
• Useful for acute bronchospasm and asthma and/or bronchi spasm prophylaxis
• Adverse reactions: palpitations, tachycardia, headache, rhinitis, excitability, tremors, and angina
• Use with cation in patients with hypokalemia and/or taking tachy drugs

Long Acting Beta 2 Agonist

• Prototype: salmeterol
• MOA: Stimulates B2 receptors → bronchodilation
• Uses: prevention bronchospasm, asthma, stable COPD
• Adverse reactions: tachycardia, headache, tremor, nausea, palpitations
• Cautions/Contraindications: Not to be used for acute asthma exacerbation

Anticholinergics / Long-Acting Muscarinic Antagonist

• Prototype: ipratropium
• Antiicholinergics relief and reduced secrections
• Maintenance for COPD
• Dry mouth and sinusitis with an upper infection
• Monitor retention and provide water or hard candy while on medication
• Not to be used as rescue asthma drug

Sympathomimetic

• Prototype: epinephrine
• Increases cAMP in lung tissue to promote bronchodilation, restores circulation, and airway patency
• For acute bronchospasm, angioedema, and congestions for the nose
• Dizziness, angina, palpations and arrhythmia's will affect medications
• Monitor CAD angina as medication can make it worse

Methylxanthines

• Relaxes the muscles of the bronchi with little side effects
• Relaxes the muscle of the bronchi by relaxing smooth muscles
• Long term used to manage Asthma with side effects like insomnia, arrhythmias, and seizures
• Monitor and assess routinely while the meds

Leukotriene Receptor Antagonists

• Prototype: Montelukast
• Suppresses the effects of Leukotrienes by causing it to release inflammations of vasoconstriction
• Used to maintain asthma, exercise related to asthma, and reactive diseases
• Adverse include dizziness, head aches, and depression Suicidal thoughts

Glucocorticoids

• MDI: fluticasone
• Tablet: prednisone
• IV: methylprednisolone
• Prevents from being released in asthma

Mucolytics

• Prototype: N-acetylcysteine
• MOA: liquids that loosen mucus secretions
• Uses: Pulmonary toileting, antidote for acetaminophen overdose
• Adverse Reactions: Bronchospasm
• Should not be mixed with other drugs
• By nebulizer

Mast Cell Stabilizers

• Prototype: cromolyn
• Long term with asthma related conditions, or rhinitis
• Cough and bronchi spasm as side effects
• Use for weeks for therapeutic
• In effective with acute conditions

Nursing Care: Lower Respiratory Conditions

• Read the Peak to flow
• Monitor tripod 02
• Diet and exercise care
• Don’t smoke again