Fever, runny nose, sore throat, headache, fatigue -- just another run of the mill cold or flu virus, right?
Perhaps, but sometimes these rather nonspecific symptoms are harbingers of something else. A number of illnesses, particularly viral infections, can begin with symptoms that are similar to a cold or the flu but, upon closer inspection or further progression, can prove far more serious than a flu bug.
Part of the reason many infections can be mistaken for a cold or a flu is because their symptoms are fairly non-specific. And they like to infect similar areas of the body.
"Flu, until it lays you out in the bed ... it really doesn't have a completely distinct set of symptoms. There's a lot of overlap," said Dr. William Schaffner, chair of the Department of Preventive Medicine at Vanderbilt Medical School in Tennessee.
Many of these symptoms are respiratory in nature -- nose, throat, and breathing-related -- because those are the places where viruses invade the host and begin to infect, prompting the immune system to try and fight them of.
But there are a few things to look out for that can alert you to something unusual.
In general, the longer an illness lasts, the more serious it may be. This criteria is different for different age groups. Children, for example, tend to have about eight colds or flu viruses each year, lasting a few weeks. Adults, on the other hand, have about three of these infections each year and they might last about one week.
The time of year is a factor. Getting a cold or flu-like symptoms in the spring or summer months might be treated with more suspicion than in the winter months, when it is more likely that illness is the result of a virus that is going around.
Finally, changes in symptoms, such as a second fever, a new rash, or developing symptoms out of the blue are a major indication that something out of the ordinary is going on.
"You know your body better than anyone," said Dr. Erica Brownfield, associate professor of medicine at Emory University School of Medicine in Atlanta. "Not that you should go for those rare zebras right up front, common things are common, but if there is something that doesn't make sense or doesn't seem right ... it could be something else."
"Pneumonia can be very difficult to differentiate between the flu and the common cold," Brownfield said.
According to Dr. Owen Hendley, professor of pediatrics at the University of Virginia School of Medicine, a typical patient story may begin with complaints of a runny nose, a cold and a fever. After several days, a second fever and perhaps coughing up more phlegm could indicate pneumonia, an illness that can lead to difficulty breathing, pain, bouts of coughing and more acute fevers.
Pneumonia is secondary to the alteration of a host's defenses. That is, once a virus has already weakened a person's immune system, pneumonia is able to infect.
In addition, it may be wise to consider what time of year it is and if people around you are sick.
In the winter, doctors may see many flu patients, all with the same symptoms, Shaffner said.
"If the ER is full of flu patients, and it's flu season, the doctor is likely to say: If it walks like a duck, quacks like a duck, and looks like a duck, it's probably influenza."
But because pneumonia can occur at any time during the year, a cold and fever combination in June could be more suspicious.
Getting a chest X-ray is the only sure way to diagnose pneumonia. But there are some clues to help determine if it is not a simple cold or the influenza virus. The secondary fever is the biggest hint that something more serious is going on, Hendley said.
Bronchitis can be difficult to diagnose, particularly in children. One of the hallmarks of the disease, following a few days of fever and a runny nose, is coughing up green or yellow phlegm.
"Kids will obligingly swallow their mucus," Hendley said, often without telling their parents what it looked like. Parents may not know that their children have a secondary infection.
But phlegm is indicative of this disease because the main air passages in the lungs, called the bronchioles, become inflamed and produce a large amount of mucus. Bronchitis can occur at any time of the year, although it tends to pop up most frequently during the winter months.
Chest soreness and congestion is also associated with bronchitis.
Pertussis is a bacterial disease characterized by spasms of violent, uncontrolled coughing. Between spasms, patients often take in sharp breaths that make a noise like a "whoop," which gives the disease it's other name: whooping cough.
"The first stage of [pertussis] for all the world is a cold," Hendley said. And if the pertussis is treated during the first stage, it likely will not progress. "The problem is, you just can't tell that. ... When they begin the paroxysmal phase, then you can tell."
But these coughing spasms, which begin about one week after the illness begins, can be quite bad, especially among children under six months because pertussis can be fatal. About 7,000 cases of pertussis are reported each year in the United States, according to the Centers for Disease Control and Prevention in Atlanta. And while young children often receive vaccines against pertussis, the CDC also reported that cases of the disease are on the rise among teenagers, with more than 20,000 cases each year.
Meningitis is an infection of the fluids in the spinal cord and around the brain. The disease can begin with headaches, high fever, stiff neck and and sensitivity to light.
Meningitis can be bacterial or viral but bacterial meningitis is more serious and can cause brain damage, hearing loss or learning disabilities. Early diagnosis and treatment is crucial to prevent permanent brain damage.
The disease is transferred through respiratory secretions, droplets sprayed when someone coughs, for example, or by kissing.
Shaffner said the relatively mild presentation of meningitis might lead many doctors to treat older patients with a pain reliever or a fever reducer and a note to return if their symptoms do not improve.
"[Meningitis] can be so sneaky that a child -- a young adult, a college student -- can be semi-comatose in the bed in five hours," Schaffner said.
"HIV virus can present with flu-like symptoms in the very beginning," Brownfield said. Fevers, blotchy skin, swollen lymph glands, fatigue and lethargy, or a dry cough can all herald an infection.
Brownfield said symptoms like these can persist for a long time -- six to twelve weeks -- before any changes occur that could offer a clue as to whether someone may have HIV. Developing a rash can be an indicator of something amiss, particularly if someone is at high risk for catching the virus, because rash is not usually co-morbid with the cold or the flu.
But the only way to know for sure if someone is infected with HIV is to be tested for it. There is no true symptomatic evidence for the infection and many people may not display symptoms of the virus for 10 or more years, according to the CDC.
"You really have to think about it in order to consider testing somebody," Brownfield said.
"Withdrawal symptoms are exactly like flu symptoms," Brownfield said, citing runny nose, fatigue, stomach aches, and fevers as symptoms.
Brownfield said these symptoms are often seen in drug users, particularly people who have developed a physical dependence on opioids such as heroin and the painkillers OxyContin and Oxycodone. Withdrawal symptoms begin within 24 hours after the last use and can last up to 10 days.
But the acute symptoms -- including pain, fever, and nausea -- will dissipate within a few days. Unfortunately, addiction is more difficult to get over than physical dependence because it is a psychological issue.
The National Pain Foundation's recommendations for avoiding serious withdrawal system are to reduce drug intake by 25 percent each day or every other day, preferably under the guidance of a doctor.
In the case of drug withdrawal, it is not difficult to know that the symptoms are signs of drug withdrawal instead of a cold or flu because of the patient's history.
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