Contact The Editor
This is the time of year when respiratory tract infections act up. Here's a brief guided tour of the common cold and four of its fellow misery makers. (Flu is not included because the focus is on anatomical locations in the respiratory tract, and flu's effects are widespread.)
1. COMMON COLD
What is it? Inflammation of the mucous membranes that line the nose.
Symptoms. The medical term, viral rhinitis, may not be so familiar, but the symptoms are a stuffed-up and runny nose and sneezing. About half the time, a cold causes a sore or scratchy throat, and that's often the first symptom, although by the second or third day, the nasal problems predominate. If a cough develops, it may not start until several days after the rest of the symptoms get going and may linger for several weeks after they're gone. Adults rarely have fever with colds -- the absence of fever is one way to tell it's a cold -- but children sometimes do.
Causes. Over 200 different types of viruses have been linked to colds but all produce similar symptoms. That's partly because symptoms come from a general immune response to an infection of the respiratory tract, not direct damage that might be the signature of certain viruses. Between 30 percent and 50 percent of colds are caused by rhinoviruses. Among the many other types of viruses that cause colds are those that cause influenza.
Prevention. Washing your hands regularly is the single best way to keep from getting a cold (and every other upper respiratory infection). Most often, we pick up cold-inducing viruses by touching infected people or surfaces, such as doorknobs, and then infect ourselves by touching our nose or eyes. (Cold viruses live in airborne droplets released when people cough or sneeze, so it's possible to get infected by breathing in those droplets directly, but more often our hands are involved.) Research results for high doses of vitamin C have been mixed. Echinacea has been a bust in prevention studies; ginseng a little less so but it's hardly a sure thing.
Treatment. The cure for the common cold remains elusive, so for now, treatment is about taming symptoms. Even that less ambitious grail seems out of reach at times. The cough suppressants in many over-the-counter cold medicines haven't proved to be any more effective than placebos in clinical trials. Phenylephrine isn't as effective as pseudoephedrine, the nasal decongestant it replaced in many over-the-counter medicines.
Nasal inhalers like ipratropium bromide (Atrovent) can help, but overuse of sprays like oxymetazoline (Afrin) is a problem. Echinacea and vitamin C haven't fared well in treatment clinical trials. The results for zinc have been inconsistent; if it has any effect, studies suggest it's likely to be quite modest. In the end, you might be best off following the tried-and-true advice: drink plenty of fluids, get lots of rest -- and wait it out.
2. SINUSITIS
What is it? Inflammation of the membranes lining the sinuses.
Symptoms. Uncomfortable pressure in the face that feels painful is the telltale symptom. The location varies with the sinuses involved; for example, pain in the forehead is an indication that the frontal sinuses are affected, and if it's in the upper jaw and teeth, the maxillary sinuses in the cheeks.
Like a cold, sinusitis causes nasal congestion because of excess mucus production and swollen nasal membranes. Indeed, sinusitis often feels like a cold that just won't go away. Mucus is often thick and yellow or green (it turns green because of the large quantities of white blood cells, which, despite their name, give off a green color). Some mucus may flow back into the throat -- this is the infamous postnasal drip -- and cause a bad taste, a cough, or bad breath. Some people also get feverish and fatigued as their bodies mount an immune response.
Causes. Your sinuses are like little caves in the bones around your eyes and nose. They're lined with membranes that produce thin, watery mucus that drains through tiny openings called ostia. If those ostia get blocked, fluid and mucus build up, creating a nice, cozy place for bacteria, which are naturally present, to multiply. The body responds to the increased numbers with inflammation and swelling that produces the painful pressure and other symptoms. Colds are the most common reason ostia get plugged up in the first place, so the root cause of sinusitis is often viral, even though, by definition, sinusitis is a bacterial infection of the sinuses.
But only a small fraction of colds -- about one in 100 -- lead to sinusitis. Some people have chronic sinusitis caused by structural problems that block the ostia, such as a deviated septum or nasal polyps.
Prevention. Because sinusitis is often a complication of the common cold, much of the playbook for cold prevention applies. Some doctors recommend regular nasal irrigation, which involves sweeping out the nasal cavities with salted water, but one study showed regular irrigation may lead to more, not fewer, sinus infections. If you have a cold, don't blow your nose too hard; bacteria and mucus can back up into your sinuses.
Treatment. Re-establishing good drainage of the sinuses often eases symptoms and encourages the infection itself to wind down. Drinking lots of water and inhaling steam (try taking extra-long showers) loosens mucus so the ostia open. Sleeping with your head elevated puts gravity to good use. You can also try one of the oral nasal decongestants.
Many doctors want patients to try several days of drainage therapy before prescribing an antibiotic, partly because antibiotics are more effective if the sinuses are draining, even if just a little. But if the sinusitis is severe to begin with or is not going away, antibiotic therapy is warranted -- and usually effective.
3. PHARYNGITIS
What is it? Inflammation of the structures of the pharynx, or back of the throat, which include the back of the tongue, the soft palate (the roof of the mouth), and the tonsils. Strep throat is the form of pharyngitis caused by streptococcus bacteria.
Symptoms. In plain English, pharyngitis is a sore throat. If it's caused by a viral infection, the symptoms are pain with swallowing, a runny nose, hoarseness, and -- in children -- diarrhea. If it's a bacterial infection, the telltale symptoms are fever and swollen lymph nodes in the neck, usually without a runny nose or cough. Pharyngitis can also be a symptom of other bacterial infections and can occur in diseases that affect more than just the throat, such as mononucleosis and HIV infection.
Causes. By some estimates, 85 percent of cases are viral. Many of the viruses that cause colds, including rhinoviruses, also cause pharyngitis. In fact, they may cause rhinitis and pharyngitis at the same time. Many types of bacteria cause pharyngitis, but those in the Streptococcal group are the main culprits. The strep bacteria spread through droplets, much like cold viruses, although there are well-documented instances of food-borne outbreaks.
Prevention. Cue up that wash-your-hands lecture! And reread the cold-prevention handbook.
Treatment. If it's viral pharyngitis, the treatment is what doctors call "nonspecific": rest, pain relievers, salt-water gargles, throat lozenges, and chicken soup, if you like. If it's strep throat, antibiotics are effective. The trick is making sure it is strep. Symptoms are clues, but doctors will often do a rapid, in-office test of a throat swab to be sure of a strep throat diagnosis. The results should be available in minutes. If the test is positive, treatment is necessary to reduce the (admittedly low) risk of rheumatic fever, a complication of strep throat. If it's negative, a second test is sometimes done.
4. BRONCHITIS
What is it? Inflammation of the bronchial tubes that connect the windpipe (trachea) to the lungs. When people talk about having a chest cold, they're often talking about bronchitis.
Symptoms. A bad cough is the cardinal symptom. It may last for weeks or much longer if the lining of the bronchi remain irritated even after the initial infection has subsided. The cough may be a dry hack, but it may also produce phlegm (sputum), which can be clear, yellow, or green. Wheezing and chest tightness sometimes occur if inflammation has narrowed the bronchi.
Some people have chronic bronchitis due to an underlying lung disorder like chronic obstructive pulmonary disease (COPD). An infection can cause chronic bronchitis to flare up and cause more serious symptoms than usual.
Causes. Most acute cases -- those that come on fairly suddenly -- are caused by viral infections that started farther up the respiratory tract and spread down to the bronchi. The bacteria that cause whooping cough (pertussis) can cause acute bronchitis, but bacterial cases of bronchitis are infrequent exceptions to the viral rule. It's a different story if the bronchitis is a flare-up of COPD: a third to a half of those cases are caused by bacterial infections.
Prevention. Because bronchitis often starts with a cold, prevention advice is standard-issue. Adults can get a booster shot for whooping cough, and of course, there's the flu shot.
Treatment. Getting warm, moist air into the bronchi by taking hot showers or using a humidifier can ease the symptoms of acute bronchitis. In some cases, a bronchodilator, the type of inhaled medication used to treat asthma, might help. Most of the time antibiotics should not be prescribed for acute bronchitis because the cause is almost always a viral infection. But if the bronchitis is a flare-up of COPD, then antibiotics are an option.
5. PNEUMONIA
What is it? An infection and resulting inflammation deep in the lungs, affecting the small air sacs (alveoli) and nearby tissue. "Walking pneumonia" is the term sometimes used for a mild case that doesn't require hospitalization.
Symptoms. The list of symptoms is long and includes fever, chills, cough, and a feeling that you've been drained of all energy. If the pleura (the membrane that surrounds the lungs) is affected, then chest pain that worsens when you take a deep breath or cough can be a problem. About 20 percent of people also have gastrointestinal symptoms such as nausea and diarrhea. Older people may not mount much of a fever, so fatigue and mental confusion might be the most notable symptoms.
Oxygen gets into the blood through the alveoli, so bad cases of pneumonia can leave the body short of oxygen. To compensate, breathing may become hurried and labored.
Causes. Most pneumonia is caused by bacteria and Streptococcus pneumoniae bacteria are the most common culprits. About 20 percent of the pneumonia that occurs outside a health care setting is caused by viruses, including flu viruses. A small percentage are caused by fungi and other sorts of microorganisms. All of these infectious may be inhaled directly into the lungs, but more commonly, pneumonia starts when viruses or bacteria that have colonized the back of the mouth are drawn into the respiratory tract and down into the lungs. If the bacteria or viruses present are especially infectious, or the natural defense mechanisms of the lungs aren't functioning well, pneumonia is more likely.
Prevention. The pneumococcal vaccine recommended for people over 65 protects against some of the most common types of Streptococcus pneumoniae. A different pneumococcal vaccine is given to children under two. Annual flu shots (and the H1N1 vaccine) not only help prevent pneumonia caused by flu viruses, but bacterial cases that occur secondary to flu infection.
Treatment. A chest x-ray is often necessary for a definitive diagnosis. Pneumonia is presumed to be caused by a bacterial infection, so most cases are treated with oral antibiotics right off the bat. People at higher risk of complications because of heart disease and other conditions may need to be hospitalized and receive intravenous antibiotics. Usually people start to feel better after several days of antibiotic therapy, but especially in older people, pneumonia can be a life-threatening condition and must be watched closely. --- Harvard Health Letter
Comment by clicking here.
