University:
Michigan State University
Course:
MED 619 | Advanced Internal Medicine-Ambulatory
Academic year:

2020
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462

Pages:

58
Author:

todaviaaquik4l

Common Cold 10/26/21 Objectives Understand common cold and its pathophysiology Recognize common clinical presentation of colds Identify appropriate treatment approaches of colds Discuss product selection guidelines 10/26/21 Introduction Cold, common cold: ¡ is a viral infection of the upper respiratory tract One billion cases of colds occur annually ¡ This illness is one of the top five diagnosed in the US. Children usually have 6-10 colds /year Adults <60 years typically have 2-4 colds / year Adults >60 years usually have 1 cold / year 10/26/21 Introduction Colds may occur at any time Colds are the leading cause of work and school absenteeism. Colds are usually self-limiting ¡ Symptoms are bothersome, patients frequently self-medicate $7 billion spent annually on nonprescription cold and cough products 10/26/21 Pathophysiology Limited to the upper respiratory tract ¡ (pharynx, nasopharynx, nose, cavernous sinusoids, and paranasal sinuses) The nose, is well perfused and innervated. The nose contains sensory, cholinergic, and sympathetic nerves. ¡ When stimulated by an infectious (i.e., a cold) or allergic (i.e., allergic rhinitis) process ÷ those nerves play a role in the resulting symptoms and are also targets for some nonprescription therapies. 10/26/21 Pathophysiology Sneezing - Mechanical and thermal stimuli - Mediators such as histamine and bradykinin Congestion - Cholinergic and sympathetic nerves because they innervate glands and arteries that supply the glands. - Cholinergic stimulation dilates arterial blood flow - Sympathetic stimulation constricts arterial blood flow 10/26/21 Cause More than 200 viruses cause colds. The majority of colds in children and adults are caused by rhinoviruses. ¡ Other viruses known to cause colds include: ÷ coronaviruses, parainfluenza ÷ adenoviruses ÷ echoviruses ÷ respiratory syncytial viruses ÷ coxsackie viruses. ÷ Viral and bacterial coinfection (usually with group A beta-hemolytic streptococci) occurs but is rare. 10/26/21 10/26/21 10/26/21 VIRUSES 10/26/21 Cold Course Rhinoviruses bind to intercellular adhesion molecule receptors on respiratory epithelial cells in ¡ the nose and nasopharynx ÷ ¡ the virus replicates and infection spreads to other cells Peak viral concentrations occur 2-4 days after initial inoculation ÷ viruses are present in the nasopharynx for 16-18 days. Infected cells release: ¡ chemokine “distress signals” and cytokines ¡ activate inflammatory mediators and neurogenic reflexes 10/26/21 Activation Recruitment of additional inflammatory mediators ¡ Vasodilatation ¡ Transudation of plasma ¡ Glandular secretion ¡ Pain nerve fibers stimulation ¡ Sneeze and cough reflexes Hypersecretion of watery nasal fluid ¡ (Inflammatory mediators and parasympathetic nervous system reflex) Viral infection ends ¡ neutralizing antibody (secretory immunoglobulin A [IgA] or serum IgG) leaks into the mucosa to end viral replication 10/26/21 Transmission The most efficient mode of viral transmission is ¡ self-inoculation of the nasal mucosa ¡ conjunctiva after contact with viral laden secretions on ÷ animate (e.g., hands) or inanimate (e.g., doorknobs and telephones) objects. Aerosol transmission is also common. 10/26/21 Susceptibility Higher exposure rates ¡ (e.g., increased population density in classrooms or day care centers) Allergic disorders affecting the nose or pharynx Less diverse social networks Weakened immune system due to smoking Sedentary lifestyle Chronic (i.e., ≥1 month) psychological stress, Sleep deprivation (e.g., poor sleep quality or <7 hours of sleep per night) There is conflicting information - Cold environments, sudden chilling, or exposure to central heating (i.e., low humidity). - Walking outside barefoot, teething, or suffering from enlarged tonsils or adenoids. 10/26/21 Clinical Presentation of Colds A predictable sequence of symptoms appears 1-3 days after infection: ¡ ¡ ¡ Sore throat is the first symptom to appear, Followed by nasal symptoms, which dominate 2-3 days later Cough, although an infrequent symptom (<20%), appears by day 4 or 5. Signs and symptoms of a cold may be confused with symptoms of influenza and other respiratory illnesses 10/26/21 COLD TIMELINE 10/26/21 Cold Symptoms 10/26/21 Physical Assessment Slightly red pharynx with ¡ Evidence of postnasal drainage ¡ Nasal obstruction ¡ Mildly to moderately tender sinuses on palpation First 2 days :clear, thin, and/or watery nasal secretions. ¡ As the cold progresses, the secretions become thicker and the color may change to yellow or green. ¡ When the cold begins to resolve, the secretions again become clear, thin, and/or watery. May have low-grade fever, but colds are rarely associated with a fever above 100°F (37.8°C). Rhinovirus cold symptoms persist for about 7-14 days. 10/26/21 Complications Most people do not have complications from colds. Complications may include: - Sinusitis - Middle ear infections - Bronchitis - Pneumonia - Exacerbations of asthma or chronic obstructive pulmonary disease. 10/26/21 Treatment of Colds Treatment Goals: 1) There is no known cure for colds 2) To reduce bothersome symptoms 3) Prevent transmission of cold viruses to others 10/26/21 General Treatment Approach Antibiotics are ineffective against viral infections The mainstay of treatment is non-pharmacologic therapy If a patient desires to self-treat, a stepwise approach using single entity products targeting specific symptoms is preferred over the use of combination products. 10/26/21 Exclusions for Self-treatment Fever > 101.5 F (38.6 C) Frail patients of Chest Pain advanced age Infants < 9 months age Hypersensitivity Shortness of breath Worsening of symptoms during self-treatment Concurrent cardiopulmonary disease ( asthma, COPD, CHF) AIDS or chronic immunosuppression 10/26/21 Non-pharmacologic Therapy Increased fluid intake Adequate rest A nutritious diet as tolerated Increased humidification ¡ ¡ Steamy showers Vaporizers Vaporizers: superheat water to produce steam and can accommodate medications such as Vicks ¢ Vapo Steam (camphor 6.2%). Humidifiers ÷ Humidifiers use fans or ultrasonic technology to produce a cool mist and cannot accommodate additives. ÷ ¡ Medical devices, such as Breathe Right nasal strips, are marketed for temporary relief from nasal congestion and stuffiness. 10/26/21 Non-pharmacologic Therapy Saline nasal sprays or drops ¡ moisten irritated mucosal membranes and loosen encrusted mucus Salt gargles ¡ may ease sore throats. Food products such as tea with lemon and honey, chicken soup, and hot broths are soothing. Milk products should not be withheld ¡ given the lack of evidence that milk increases cough or congestion. Aromatic oil ¡ (camphor, menthol, and eucalyptus) products such as Theraflu Vapor Patch (ages ≥ 12 years) and Vicks VapoRub (ages ≥ 2 years) ¡ ease nasal congestion 10/26/21 COLD 10/26/21 Bulb Syringe 10/26/21 Prevent Transmission Frequent hand cleansing with soap or soap substitutes ¡ (e.g., hand sanitizers). Not all hand sanitizers are effective at eradicating rhinoviruses from hands. ¡ Alcohol-based products containing isopropanol or ethanol (60% - 80% concentration) are preferred but are short-acting and require frequent reapplication ¡ Chlorhexidine, povidoneiodine, and quaternary ammonium compounds are also effective alone or in combination with alcohol-based products ¡ Use of antiviral disinfectants such as Lysol (kills >99% of rhinoviruses after 1 minute) ¡ Antiviral tissues such as Kleenex AntiViral (tissue layer containing citric acid and sodium lauryl sulphate) may also help prevent transmission to others. 10/26/21 Pharmacologic Therapy Decongestants Decongestants specifically treat sinus and nasal congestion. ¡ adrenergic agonists (sympathomimetics). Stimulation of alpha-adrenergic receptors constricts blood vessels ¡ decreasing sinusoid vessel engorgement and mucosal edema. 10/26/21 Types of Decongestants Direct Acting ¡ bind directly to adrenergic receptors - phenylephrine, oxymetazoline, and tetrahydrozoline. Indirect Acting ¡ displace norepinephrine from storage vesicles in prejunctional nerve terminals - ephedrine Mixed: have both direct and indirect activity - pseudoephedrine. 10/26/21 Routes of Administration Systemic decongestants ¡ pseudoephedrine and phenylephrine Intranasal decongestants include ¡ Short-acting : ÷ ¡ Ephedrine, levmetamfetamine (ldesoxyephedrine),naphazoline, phenylephrine, propylhexedrine, Long-acting : xylometazoline (8-10 hours), oxymetazoline (12 hours) Ophthalmic decongestants 10/26/21 Systemic Decongestants Rapidly metabolized by monoamine oxidase (MAO) and catechol-O-methyltransferase ÷ in the gastrointestinal (GI) mucosa, liver, and other tissues ÷ Pseudoephedrine is well absorbed after oral administration Phenylephrine has a low oral bioavailability (about 38%). Both pseudoephedrine and phenylephrine have short half-lives (pseudoephedrine, 6 hours; phenylephrine, 2.5 hours), and peak concentrations for both drugs occur at 0.5-2 hours after oral administration. 10/26/21 Indications YES Temporary relief of nasal and eustachian tube congestion Cough associated with postnasal drip. NO Nasal congestion associated with sinusitis. 10/26/21 Dosage Guidelines for Nonprescription Systemic Decongestants 10/26/21 Caution FDA has advised that cough and cold medications not be used in children <2 years of age Manufacturers have voluntarily updated cough and cold product labels to state “do not use” in children under 4 years of age. 10/26/21 Dosage Guidelines for Topical Nasal Decongestants 10/26/21 Dosage Guidelines for Topical Nasal Decongestants 10/26/21 Why Dose is important ? Acute overdose can be life threatening. Systemic decongestant overdoses cause - excessive central nervous system (CNS) stimulation, - paradoxical CNS depression, - cardiovascular collapse, - shock, and coma Treatment of decongestant overdoses is supportive. 10/26/21 Adverse effects Cardiovascular stimulation ¡ (e.g., elevated blood pressure, tachycardia, palpitation, or arrhythmias) CNS stimulation ¡ (e.g., restlessness, insomnia, anxiety, tremors, fear, or hallucinations). Children and older adults are more likely than other age groups to experience adverse effects. Accidental ingestion of nasal or ocular decongestants can cause serious adverse effects ¡ nausea, vomiting, drooling, hypotension, hyperthermia, lethargy, sedation, and coma. 10/26/21 Others Propellant or vehicle associated effects ¡ (e.g., burning, stinging, sneezing, or local dryness) Trauma from the tip of the administration device Rhinitis medicamentosa ¡ (RM; i.e., rebound congestion) - The exact cause is unknown, - Short acting products, - preservative agents (e.g., benzalkonium chloride) - long duration of therapy. 10/26/21 Rhinitis Medicamentosa (RM) Therapy of 3-5 days is the accepted duration to avoid RM. Treatment of RM consists of - slowly withdrawing the topical decongestant - - (one nostril at a time) replacing the decongestant with topical normal saline using topical corticosteroids and systemic decongestants - Two to 6 weeks of withdrawal may be necessary before mucous membranes return to normal. 10/26/21 Contraindications Patients receiving MAO inhibitors (MAOIs). Hypertension, coronary heart disease, ischemic heart disease, diabetes mellitus, hyperthyroidism, elevated intraocular pressure, and prostatic hypertrophy. ¡ ¡ ¡ Decongestants may exacerbate diseases sensitive to adrenergic stimulation Patients with hypertension should use decongestants only with medical advice. No clear evidence exists that any one agent is safer than other agents in patients with hypertension. Products specifically marketed for patients with hypertension ¡ ¡ (e.g., Coricidin HBP) Chlorpheniram-DM-Acetaminophen: do not contain decongestants. 10/26/21 Drug Interaction 10/26/21 Pharmacologic Therapy Antihistamines Monotherapy is not effective in reducing rhinorrhea and sneezing due to colds ¡ Combination of first generation (sedating) antihistamines and decongestants showed some benefit in adults ¡ Potential benefits of sedating antihistamines outweigh known risks associated with these drugs 10/26/21 Pharmacologic Therapy Local Anesthetics Local anesthetics ¡ (e.g., benzocaine or dyclonine hydrochloride) is available for the temporary relief of sore throat ¡ May be used every 24 hours ¡ Counsel patients with a history of allergic reactions to anesthetics to avoid products containing benzocaine Benzocaine has also been associated with methemoglobinemia ¡ especially in children younger than 2 years, and should be avoided in this age group. 10/26/21 Pharmacologic Therapy Local Antiseptics Some products contain local antiseptics ¡ (e.g., cetylpyridinium chloride or hexylresorcinol) ¡ menthol or camphor Local antiseptics are not effective for viral infections Menthol & Camphor may provide pain relief via stimulation of the TRPM8 or “menthol” receptor. 10/26/21 Selected Nonprescription Products for Sore Throat 10/26/21 Pharmacologic Therapy Systemic Analgesics Systemic analgesics ¡ (e.g., aspirin, acetaminophen, ibuprofen, or naproxen) ¡ are effective for aches or fever sometimes associated with colds. Aspirin containing products should not be used in children with viral illnesses ¡ ¡ q Risk of Reye’s syndrome developments in liquid infant acetaminophen products Concerns that use of aspirin and acetaminophen may increase viral shedding and prolong illness have not been proved 10/26/21 Pharmacologic Therapy Antitussives and Expectorants If present, cough associated with colds is usually nonproductive. The use of antitussives ¡ (codeine or dextromethorphan) has questionable efficacy in colds and is not recommended. Guaifenesin, an expectorant, has not been proved effective in natural colds. 10/26/21 Pharmacologic Therapy Combination Products Decongestants and antihistamines are marketed in many combinations ¡ with analgesics, expectorants, and antitussives. Products are also marketed for daytime or nighttime use. - Products for nighttime use usually contain a sedating antihistamine whereas daytime products do not Combination products are convenient, but the convenience must be weighed against the risks of taking unnecessary drugs. 10/26/21 What to Use ?! Evidence does not support the use of ¡ antihistamines, antitussives, and expectorants for treatment of symptoms related to colds. Local anesthetics and systemic analgesics have good evidence ¡ treatment of pain related to sore throat or fever related to colds. Topical decongestants are convenient dosage forms and are effective in relieving nasal congestion ¡ however, their use is limited to 3-5 days owing to concerns about RM. The major differences in topical decongestants are ¡ duration of action ¡ dosage formulation (e.g., mist versus spray versus drops) ¡ moisture content ¡ preservative content Strong evidence supports the efficacy of oral dosage forms of pseudoephedrine. 10/26/21 Special Population Pregnancy and Lactation Balance between risk and benefit. Many health care providers recommend non-drug therapy. ¡ Most colds are self-limiting with bothersome rather than lifethreatening symptoms. Pregnant or lactating women should be advised to avoid products labeled as: ¡ ¡ ¡ “extra strength,” “maximum strength,” or “long-acting,” as well as combination products. Systemic decongestants should be avoided as human data suggest risk based on theoretically decreased fetal blood flow. Pseudoephedrine has been linked to abdominal wall defects (gastroschisis) in newborns. 10/26/21 Special Population Pregnancy and Lactation There is no clear association between birth defects and the use of intranasal decongestants during pregnancy. ¡ Oxymetazoline is poorly absorbed after intranasal administration and is the preferred topical decongestant during pregnancy The American Academy of Pediatrics has found pseudoephedrine to be compatible with breastfeeding ¡ to be the preferred decongestant for lactating mothers. No human data are available for intranasal phenylephrine and oxymetazoline ¡ considered “probably compatible” in lactating mothers. Because decongestants may decrease milk production ¡ lactating mothers should monitor their milk production and drink extra fluids as needed. Dextromethorphan, guaifenesin, benzocaine, camphor (topical), and menthol (topical) have low risks of birth defects and have been found to be compatible with breastfeeding. 10/26/21 Special Population Children Using nonprescription cold products in children is controversial ¡ lack of clinical evidence of safety and efficacy in this age group FDA does not recommend nonprescription cold medications for children younger than 2 years ¡ lack of efficacy and risk of misuse or overuse leading to adverse events and death. Manufacturers have voluntarily: - updated product labeling to include the statement “Do not use in children - added warnings to Anti-histamine containing products against their use for sedation purposes under four years of age” Health care providers should emphasize nondrug measures in children Parents should follow dosing instructions carefully and avoid combination products to avoid over-dosage. ¡ (dispensing device: dropper, cup, syringe, or spoon) Dr. Samah Al-Shatnawi 10/26/21 Patient Factors If duration of symptoms > 7- 14 days or a chronic condition is suspected ¡ patients should not self-treat Patients with chronic conditions exacerbated by, or those overly sensitive to, adrenergic stimulation should avoid decongestants Health care providers should educate patients who participate in organized sports that oral decongestants are considered “doping” products and should be used only in accordance with sport regulations Lozenges, soft chews, and nasal drug delivery forms may be preferred by patients who have difficulty swallowing or when access to water is not convenient. 10/26/21 Patient Choices Nasal delivery forms may be difficult to use for patients with severe arthritis or coordination problems Nasal sprays are simple to use, cover a large surface area, are relatively inexpensive, and have a fast onset of action. ¡ The disadvantages include: ÷ imprecise dosage, a tendency for the tip to become clogged with repeated use, and a high risk of contamination from aspiration of nasal mucus into the bottle. ¢ Metered pump sprays deliver a more precise dose. Nasal drops are preferred for small children but can be difficult to use ¡ ¡ cover a limited surface area, and pass easily into the larynx. high risk of contamination because of the tendency to touch the dropper to the nose during administration. Nasal inhalers are small and unobtrusive ¡ ¡ but they require an unobstructed airway and sufficient airflow to distribute the drug to the nasal mucosa. Nasal inhalers lose efficacy after 2-3 months even when tightly capped because of dissipation of the active ingredient 10/26/21 Complementary Therapies Numerous complementary therapies are marketed for the treatment of colds ¡ Zinc and high dose vitamin C are popular therapies 10/26/21 Zinc High local concentrations of zinc ions purportedly ¡ block the adhesion of human rhinovirus to the nasal epithelium ¡ inhibit viral replication by disrupting viral capsid formation In vitro studies have shown only a modest antiviral effect. ¡ Formulations include tablets, capsules, chews, lozenges, syrups, and oral sprays. Oral formulations may be associated with GI adverse effects (e.g., nausea, upset stomach, and bitter taste) ÷ Nasal formulations were removed from the market because of anosmia (loss of smell) ÷ Studies concluded that oral zinc (lozenges or syrup) was effective in reducing cold symptoms or duration of the cold ¡ if started within 24 hours of symptom onset and administered every 2 hours while patient is awake ¡ also prophylaxis with zinc for at least 5 months reduced the incidence of colds in healthy patients 10/26/21 Vitamin C The efficacy and safety of high dose (e.g., ≥2 g/day) vitamin C (ascorbic acid) for prophylaxis and treatment of colds have been debated, - o An analysis of 29 trials showed that, routine use of high-dose vitamin C does not appear to prevent colds, it did reduce the duration by about 8% in adults and 14% in children. o High dose vitamin C prophylaxis was effective in preventing colds in a subgroup of patients subjected to severe physical stress (e.g., marathon runners). Using vitamin C as treatment after the onset of a cold was not effective at reducing severity or duration of symptoms. Regular use of high doses may increase the risk of kidney stones in men. ÷ Doses of 4 g/day or greater are associated with diarrhea and other GI symptoms and, therefore, should not be recommended. ÷ 10/26/21

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