Download Common Cold

Common Cold
Common Cold
• It is a self-limiting viral infection of the upper
respiratory tract
• Accounts for ½ of all ilnesses in adults and ¾
of all illnesses in infants
• causes more time off work/school than any
other illness
• Common cold cannot be prevented or cured
• Antibiotics: ineffective
Common Cold
• “coryza”, “acute infectious rhinitis”, “catarrh”.
• The main and common causative agents: 5
viruses
- rhinoviruses  50% of cases
- coronaviruses, respiratory syncytial virus
(RSV), influenza virus (types A,B,C); echovirus;
coxackie virus, adenovirus, parainfluenza virus
How does it transmit?
Modes of Transmission
• Inhalation of the virus in sneezed
aerosols or droplets
• Ingestion of saliva by eating or
drinking implements
• Hand-to-hand contact with infected
person followed by rubbing the eye or
nose
Predisposing Factors
• The factors that increase the susceptibility to
viral URT infections are:
1. Smoking,
2. Sedentary lifestyle
3. Chronic psychological stress (e.g. ≥ 1 month)
4. Increased population density
5. Allergic disorders of the URT
6. Less diverse social networks
Pathophysiology
1. Rhinoviruses bind to intercellular adhesion
molecule on epithelial cells in the nose and
nasopharynx
2. The virus replicates and infection spreads
3. Infected cells release chemokine “distress signal”
and cytokines that activate inflammatory
mediators & neurogenic reflexes results in 
Pathophysiology
• a series of biochemical & immunological
events that result in the release of
inflammatory mediators
vascular
permeability
glandular
secretion
Sneeze &
cough reflexes
Nasal Secretion
Parasympathetic
stimulus
Stimulation of
pain nerve
fibers
Signs & Symptoms
Symptoms appear in sequence 1-3 days after
infection:
• The 1st symptom to appear: sore throat
• 2nd : nasal symptoms (stuffiness (congestion),
rhinorrhea, postnasal drip)
• Watering eyes, sneezing
• Then, cough (infrequent) by day 4-5
Less common: headache, chills, pyrexia (<37.8),
sinus pain & myalgia
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Complications
• Virus-induced inflammatory changes in the
nose may spread to other nearby structures
(e.g. Sinuses, Eustachian tube)
• This may lead to sinusitis, Eustachian tube
obstruction, otitis media & secondary
bacterial infection
• Complications in LRT: bronchitis, bacterial
pneumonia, exacerbation of asthma &
COPD
Management of common
cold
• The effective means of prevention: frequent
hand cleansing with soap or soap substitutes
• Cold symptoms are usually self-limiting and
resolve within 1-2 weeks whether treated or not
• General therapeutic measures: rest & maintain
fluid intake
• Treatment with drugs usually is symptomatic
and should be symptom specific.
Homework
• Nonpharmacological therapies (p. 179)
• Increase fluid intake.
• Humidifiers and Vaporizers.
• Intranasal saline sprays/drops/washes.
• Breathe Right nasal strips.
• Lozenges and demulcents.
• Warm salt gargles.
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Self-care for common cold
Symptomatic OTC drugs
for common cold
Symptom
Treatment
Nasal congestion &
discharge
Cough
Decongestants
Sore throat
Laryngitis
Feverishness and
headache
Hydration, demulcents, antitussive,
expectorants/steam vapors
Demulcents, saline gargles, local
anesthetics, systemic analgesics
Cool mist/steam vapors
Systemic analgesics
ACCP Practice Guidelines 2006
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Decongestants
• Mainstay treatment of common cold
• Vasoconstrictive drugs that decrease nasal
congestion
• Examples, systemic: phenylephrine,
pseudoephedrine, ephedrine
topical: naphazoline, tetrahydrozoline
Antihistamines
• Combination of first generation agents with
decongestants showed some benefit in
common cold symptoms relief
• But benefit may not outweigh the risk
Analgesics & Antipyretics
• Common cold is rarely associated with
temperature > 37.8°C
• Patient complains of feeling feverish
• Aspirin & paracetamol are effective
• Aspirin: Never in children < 16 years old ???
Expectorants & Mucolytics
• Expectorants: oral agents that aid in removal of
respiratory tract secretions by either increasing
bronchial secretions or facilitating their expulsion
• FDA has classified Guiafenesin the only
monograph expectorant (all others; terpin hydrate, ammonium
chloride, iodides etc)  nonmonograph
• It is not effective in common cold
• Mucolytics: thin mucus, making it easier to expel
secretions
e.g. Ambroxol, Carbinoxamine, Erabestein, Bromhexin (not
OTC in US & UK)
Expectorants & Mucolytics
• Guiafenesin acts as expectorant by reflex gastric
stimulation, thus, it doesn’t thin the sputum or
increase production even at high doses
• GIT side effects rarely at recommended doses
• Camphor, eucalyptus oil, peppermint oil, Na
citrate, pine tar, tolu balsam, turpine oil added
to cold products for their “claimed” but
unproven expectorant properties
Antitussives
• Inhibit/suppress cough
• Indicated for suppression of dry, hacking &
non-productive cough
• Direct-acting antitussives (codeine,
dextromethorphan & diphenydramine):
1. Suppress medullary cough centers of brain
2. Sensitivity of respiratory system cough receptors
3. Interrupt transmission of cough impulses
Antitussives
• Research has shown that antitussive in common cold
are not more effective than placebo – not recommended
• Antitussives should not be used in productive cough
UNLESS it interferes with sleeping or is extremely
bothersome, because it may impair the expectoration of
secretions
• Thus, combination products of cough suppressant and
expectorants are irrational
e.g. (in Jordan, Broncholar= DXM & guianfenesin)
OTC in some
countries
Not in Jordan!
Codeine
• Is the standard antitussive, against which all other
antitussives are compared
• Dose in cough suppression (10-20 mg) is less than
analgesic dose (30-60 mg)
• Under the usual conditions of use as cough
suppressant has lower dependency potential,
however, dependence develop after prolonged use
• Most common S.E: constipation, N&V, respiratory
depression in sensitive patients or in large doses
• Allergic reaction & pruritis less common
Dextromethorphan
• Dextrorotatory isomer of morphinan molecule
• Has no analgesic properties, doesn’t depress
respiration and has low addiction potential
• May cause dependence
• In higher doses of the abuse range
intoxication with bizzare behaviour
• Most common S.E: drowsiness & GIT upset
• Never with MAOIs unless directed by a doctor
Diphenhydramine
• Antitussive & antihistamine
• Acts centrally by suppression of medullary
cough centre
• S.E: sedation & anticholinergic effects
• C/I: in narrow-angle glaucoma, benign
prostatic hypertrophy
• Additive effect: anxiolytics, sedatives,
hypnotics or alcohol
Topical Antitussives
• The only monograph topical antitussives are camphor
& menthol
• They provide local anesthetic action by aromatic vapor
when ointments rubbed on throat or chest as thick layer
(maybe covered or not)
• Both can be used as steam inhalation
• Menthol also in lozenges & compressed tablets
• Dangerous if accidentally ingested seizures
• Clinical efficacy of camphor & menthol is not
documented
Anesthetics & Antiseptics
• Lozenges, gargles, sprays containing antiseptics and
local anesthetics (benzocaine, dyclonine HCl)
promoted for treatment of sore throat
• Antiseptics (e.g. hexylresorcinol, benzalkonuim
chloride, amylmetacresol) ineffective for viral sore
throat
• Lozenges/hard candy: stimulates salivary secretion
soothing demulcent
• Warm saline gargles (1-3 tsp salt in 240-360ml warm
water) or fruit juice may be effective
Homework:
• Decongestants compatible with pregnancy
& lactation
• Use of nonprescription cold medications in
children < 2 years
Common cold
medications DO
NOT have proven
efficacies in children
Am Fam Physician
2007;75:515-20, 522.
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Controversies: vitamin C
43
Controversies: Zinc
Zinc
Common cold
medications DO
NOT have proven
efficacies in children
Am Fam Physician
2007;75:515-20, 522.
48
The last slide!
• For common cold in children, do not rush
into drugs
• Safe remedies: tea & honey, chicken soup
& hot broth.
• Supportive measures: cleaning nose with
bulb syringe, positioning the infant so that
secretions can drain from nose, maintain
adequate fluid intake
• Using saline nasal drops or steam inhalation