You wake up one morning with a scratchy tickle at the back of your throat. It’s nothing, you think, but by the evening you’re worried. What are you coming down with now? In all likelihood, it’s just a cold. The sore throat will persist for a few days, along with a runny nose and stuffy head. You may develop a cough. About a week after the scratchy throat began you begin to forget about the cold and by ten days it is a memory. Your body has met a small bit of protein-coated RNA called a virus, and defeated it.
The difference between a cold symptoms and flu symptoms
The next month another bit of protein-coated RNA called an orthomyxovirus finds its way into your nose. This time the story is very different. At noon, you are feeling well. By 4PM you have been felled. Getting up from your desk feels like climbing Mount Everest. You cannot get warm – even under a pile of blankets. Then come the muscle aches, as if you’d run a marathon. This time there is no hope of sticking to a routine – you have the flu. The worst of the symptoms fade after a week, but fatigue and lack of energy may persist for several more. Rest, time and patience eventually lead you back to health. Next year, you think, you will get that flu shot.
The viruses that cause the problems
The viruses that caused these two illnesses are superficially similar. They are little protein bags full of bits of RNA– technically not living things, but able to commandeer the machinery of living cells to reproduce themselves. Carried in droplets spewed into the air by coughs and sneezes of infected people, they are directly inhaled or carried into the nose and mouth on fingers from surfaces where those droplets landed. Specialized proteins on viral surfaces attach them to the cells in the upper airways. These proteins (H, or hemagglutinin and N, or neuraminidase) and their numbered subtypes (1, 2, or3) give flu viruses their unimaginative names. Swine flu virus becomes H1N1.
For reasons not yet understood, the body’s response to the attack of cold viruses is not as severe as it is to flu viruses. Once inside cells, flu viruses elicit a flood of proteins called interferons, which are the source of fever, muscle aches and profound fatigue. The viruses rapidly go about the business of making more of themselves, sending them out to infect more cells and generating a new wave of symptoms. In the meantime, white blood cells begin to produce antibodies that target viral surface proteins and prevent them from locking onto more cells. Eventually the tide of the battle turns and no more cells are infected. The rest of the illness -the recovery phase – involves cleanup of the remnants of the fight.
Why flu shots don’t always work
Flu shots use mixes of several different flu virus types to stimulate the body to make antibodies to those viral surface proteins in advance of “catching” the flu. If and when the virus invades, the antibodies are in place, ready to block the initial attachment to cells in the upper airways. Because the flu viruses that travel the world vary over time, each year’s flu vaccine is a composite of some of the currently circulating strains and may or may not be a good match to the virus that ultimately shows up.
Immunization is recommended for children (older than 6 months), the elderly, people in the health and teaching professions, those living in nursing homes and dormitories, and for all age groups who are at risk for flu complications, namely those with other respiratory problems, cardiac disease, diabetes and immune system impairments (including those induced by treatment of other diseases like cancer). Most adults in good health have the immune wherewithal to recover from flu and colds without complications or medical intervention.
Complications of the flu
The complications of the flu and of colds are similar. Both infections affect the upper airways, causing swelling and inflammation of the linings of the nose, throat and sinuses and blocking narrow passageways within. Earaches and pain in the forehead or the face develop but often resolve with simple measures like propping head up while sleeping, and taking an anti-inflammatory medication like aspirin or Advil. Unremitting pain, with or without fever, may indicate secondary bacterial infection of the ears or sinuses – the only reason for the prescription of an antibiotic during a cold.
Pneumonia is the most serious flu complication. Pneumonia means that the lungs’ spongy structures where carbon dioxide is exchanged for oxygen are swollen and filled with inflammatory debris. Reappearance of fever and fatigue after the flu has begun to improve may be the first sign of pneumonia. Other symptoms are chills, chest pain, shortness of breath, and dry or productive cough. Sometimes the pneumonia is caused by bacteria, but more often by the original virus or another. Pneumonia caused by bacteria, at least outside hospitals, is much less common. Prompt medical attention is in order because oxygen levels may be low. Medical attention should also be sought for other delayed symptoms like change in mental status, particularly in babies and the elderly. Occasionally diarrhea and vomiting are part of the flu and may produce dehydration.
Why hydration is important
Dehydration is also a result of fever, the metabolic equivalent of exercising in a warm environment. Dehydration stresses already inflamed airways. The easiest way to keep track of hydration status is to look at your urine – the darker the color, the drier you are. Aim for almost clear urine by drinking plenty of water.
Fever, while distressing, is part of the body’s defense against cold and flu viruses, which thrive in the relatively cooler temperatures of the upper airways. Some of the fever related discomfort can be relieved with a bath. Aspirin is not to be used in children with the flu because of a rare complication called Reyes syndrome, a liver failure. Tylenol is safe for them.
What about anti-viral drugs for the flu
Antiviral drugs (Tamiflu, Relenza. Symmetrel, and Flumadine) drugs are only effective if begun in the first 24-36 hours after symptoms begin. They lessen the duration of symptoms by about a day. Widespread use will produce increasing numbers of drug resistant strains of viruses.
New flu viruses appear regularly and prompt anxious comparisons to devastating epidemics of the past. Worrying about them doesn’t help. Taking care of what you can do for yourself and your contacts (see below) is your best option.
Useful actions to prevent colds and flu
- Maintain good health habits throughout the year: adequate sleep and exercise, nutritious diet, no smoking, modest alcohol use.
- Cover your nose and mouth with a disposable tissue when you cough or sneeze, with the crook of your elbow in the absence of a tissue.
- Wash your hands with soap and water or an alcohol based cleanser after coughing or sneezing, before eating, and after being out in public.
- Keep your hands away from your eyes, nose and mouth.
- During flu outbreaks avoid crowded, closed environments when possible and wash hands when you come home.
- Remember that your flu is infectious for up to 7 days and try to avoid infecting others.
- Get a flu shot if you are in a high risk group.