Tuesday 8 January 2013

Upper Respiratory Infection (Common Cold)


5.01 Upper Respiratory Infection (Common Cold)

Presentation
Most patients with colds do not visit emergency departments, unless they are unusually ill; the cold is prolonged more than a week, or it is progressing into bronchitis or serous otitis with new symptoms. The patient may want a note from a physician excusing him from work; or a prescription for antibiotics, which "seemed to help" the last time he had a cold.
The common denominator of URIs is inflammation of the respiratory mucosa. The nasal mucosa is usually red, swollen, and wet with reactive mucous. The pharynx is inflamed directly or by drainage of mucous from the nose, and swallowing may be painful. Pharyngitis secondary to nasal drainage is typically worse upon arising in the morning, and signs and symptoms may be localized to the side that is dependent during sleep.
Occlusion of the ostia of paranasal sinuses permits buildup of mucous and pressure, leading to pain and predisposing bacterial superinfection. Occlusion of the orifices of the eustachian tubes in the posterior pharynx permits imbalance of middle ear pressure and serous otitis. The larynx can be inflamed directly or secondarily to drainage of mucus or forceful coughing, lowering the pitch and volume of the voice or causing hoarseness. The trachea can also be inflamed, producing coughing, and the bronchi can develop a bacterial superinfection or bronchospasm with wheezing. In addition to all these ills of the upper respiratory mucosa, there can be reactive lymphadenopathy of the anterior cervical chain, diffuse myalgias, and side effects of self medication.
What to do:



Perform a complete history and physical examination to document which of the above signs and symptoms are present; to rule out some other, underlying ailment; and to find any sign of bacterial superinfection of ears, sinuses, pharynx, tonsils, epiglottis, bronchi, or lungs, that might require antibiotics or other therapy.



Explain the course of the viral illness, and the inadvisability of indiscriminate antibiotics. Tailor drug treatment to the patient's specific complaint as follows:



For fever, headache, and myalgia, prescribe acetaminophen 650mg q4h, or ibuprofen 600mg q6h.



To decongest the nose, ostia of sinuses, and eustachian tubes start with topical sympathomimetics (0.5% phenylephrine nose drops q4h, but only for 3 days) and add systemic sympathomimetics (pseudephedrine 60mg q6h or phenylpropanolamine 25mg q4h).



To dry out a nose, or if the symptoms are probably caused by an allergy, try antihistamines (chlorpheniramine 4mg q6h).



To suppress coughing, prescribe dextromethorphan or codeine 10-20mg q6h.



To avoid sedation and narcotics, prescribe benzonatate (Tessalon) 100-200mg q8h which provides airway anesthesia.



With bronchitis or suspected bronchospasm, treat the cough with inhaled bronchodilators like albuterol two puffs q1-8h prn and inhaled steroids like beclomethasone four puffs q12h.



Arrange for follow up if symptoms persist or worsen, or if new problems develop.
What not to do:



Do not get bullied into inappropriate prescribing of antibiotics. Most colds are self-limiting illnesses, and many treatments may appear to work by coincidence alone. Do not prescribe inappropriate antibiotics simply because you suspect the insistent patient will obtain them elsewhere. This is not justification for poor medical practice.



Do not undertake expensive diagnostic testing on uncomplicated cases.
Discussion
Colds are produced by over a hundred different adeno and rhinoviruses, and influenza, coxsackie, and measles can also present as a URI. Especially during the winter, when colds are epidemic, it certainly helps to keep abreast of what is "going around," so that you can intelligently advise patients on incubation periods, contagiousness, expected symptoms, and duration; and also be able to pick an unusual syndrome out of the background.
 Some of the medications recommended here are available in various combinations over the counter, but when is more than symptomatic treatment indicated? Bacterial superinfections require antibiotics. Mycoplasma pneumonia can present with headache, cough, myalgias, and perhaps bullous myringitis, and may respond to erythromycin. Coughing can precede wheezing as an early sign of asthma, and response to beta agonists helps make the diagnosis. Antibiotics have not turned out to be very useful for acute bronchitis, and vitamin C as prophylaxis for colds has also not done well in controlled trials.

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