I’ve got the flu!

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January 21, 2014

Many of our common illnesses are viral. What’s the difference between the common cold and “the flu”? First, “the flu” is not one disease. You can get “flu-like” illnesses anytime, but the REAL flu is influenza virus, the very same one you get a “flu shot” for every fall. The influenza vaccine components are determined after the CDC tracks influenza throughout the world and monitors disease activity months ahead of our flu season. Even if the strains of influenza that occur do not match the vaccine perfectly, there is some cross-reactivity and benefit. Flu-like illnesses can be caused by any of a host of viruses, as can the common cold.

Influenza virus causes a respiratory illness, usually seen in outbreaks or epidemics, and is associated with fever, headaches, muscle aches, fatigue, and weakness, often accompanied by a dry cough and sore throat. Usually it resolves on its own without treatment in a few days to a week or so. Many people, especially the elderly, have continued symptoms of debilitation for weeks afterwards, but this should resolve.

You can become infected with influenza via “respiratory droplets” – from sneezing, coughing, and talking – if you’re within receiving distance of other people’s respiratory particles. That’s the main reason we get viruses more in the winter – we’re indoors more and we’re closer together. The infectious period is from ½ day after exposure to about 4-5 days later, but this can vary. In more severe cases, influenza can be complicated by pneumonia, especially in people over 50, and in those with chronic illness such as diabetes, kidney, lung, or heart disease, cancer, and those living in nursing or group homes. One of the reasons we ask everyone to have the vaccine is to develop ‘herd immunity’ – i.e. if there is less flu illness in the general population, it is less likely that it will spread to these more vulnerable people.

Despite what some people say, you cannot get the flu from the flu shot! It is a dead vaccine, and we cannot create live virus from dead virus. Flu mist, on the other hand, is a live virus vaccine solution delivered by nasal spray. It has been approved for adults only up the age of 49. It is less effective than the injection, and can’t be given to people who are immunosuppressed, chronically ill, or people who are in contact with those with reduced immunity.

Influenza can be treated by an anti-viral drug called Tamiflu, or oseltamivir. It is effective against both of the common strains, influenza A and influenza B. Treatment is more likely to be effective if started within 48 hrs of the onset of fever, and may cause a reduction in the duration of the illness. The other treatments for influenza target the annoying symptoms. These include Tylenol or ibuprofen for fever and aches, maintenance of hydration and over-the-counter mucolytics to loosen and clear out the phlegm (Robitussin, Mucinex, and others), with or without cough suppressants (like dextromethorphan). Antibiotics should only be used in the event of complications such as pneumonia, sinusitis, etc. If you think you have influenza, come in and get tested, to see if Tamiflu is appropriate for you.

Upper respiratory infections (URIs), what we usually refer to as a “cold”, can be caused by many different viruses, including rhinovirus, coronavirus, adenovirus, etc.. The common cold is the most frequent acute illness in the USA, and is manifested by sneezing, nasal congestion, runny nose, sore throat, cough, low grade fever, headache and malaise. Usually it is not possible (and not worth it) to determine which virus is the causative agent. Colds can be spread through hand contact with an infected person (wash your hands often!), or particles in the air from an infected person’s sneeze or cough (so don’t get too close!) You don’t get a cold from being outside in the cold (unless someone coughs on you). This may be the only thing Grandma said that isn’t true. And wearing a scarf won’t prevent it either! Neither will zinc, echinacea or vitamins C and E, though they do help keep drug manufacturers in business. What may help symptoms in adults is intranasal ipratroprium (Atrovent) solution, nasal cromolyn (Intal), antihistamines (though they dry you out), dextromethorphan products, guaifenesin (Robitussin, Mucinex), and decongestants (Sudafed, Afrin). Never use a nasal decongestant like Afrin for more than three days, as your nose actually can become accustomed to it, and you could have rebound worsening when you stop it. Antibiotics cause more harm than benefit because they may have adverse effects such as diarrhea and don’t treat viruses.

You can get ear symptoms from a cold, as the tissues of the nose and sinuses swell, preventing adequate drainage. This can lead to the feeling of pressure or fullness in the ear, and is often caused by Eustachion tube dysfunction (that’s the tube from the ear to the sinus/nasal cavity) from the swelling.

Moving down from the sinuses, acute bronchitis, or inflammation of the airways, is common; again, the vast majority of cases are due to viruses. Acute bronchitis is one of the most common reasons people take antibiotics inappropriately. Symptoms include cough for greater than 5 days, usually with production of purulent (green, thick) sputum and other symptoms of URIs. The cough can last for up to three weeks. Sometimes cough persists because of spasm in the airways (bronchospasm), and we need to treat the spasm and not use antibiotics. If your cough is lingering and overall you’re not steadily improving, you should contact your doctor. Progression to pneumonia is suggested when there is fever, a rapid pulse, or rapid breathing, in association with an abnormal examination of the lungs. This would be diagnosed by an abnormal exam and confirmed by chest x-ray.

So, the common cold and other URIs are usually viral, self-limited and benign, but when in doubt, and especially if you have an underlying medical illness, consult with your doctor.

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