My Public Service Announcement, Courtesy Of The Louisville Courier Journal.

If you experience any of these symptoms, have it checked out. Don't wait: it might -- emphasis is on might -- be a sign of something serious (read more on C-J).

1. Unusual headache

This can signal the rupture of a life-threatening cerebral aneurysm, an abnormal bulge or "ballooning" in the wall of an artery that can lead to fatal bleeding. "Classically, they call this a thunder clap headache because it comes on all of a sudden" and is "described as the worst headache of their life," Smock said.

People who are middle-aged to older who experience severe headache accompanied by pain in their temple and a change in vision could have temporal arteritis, inflammation of the temporal artery. If it's not treated promptly, the condition can lead to blindness, Han said.

2. Sudden weakness

If you suddenly get weak, especially on one side, you could be having a stroke. Other symptoms include slurring of speech, difficulty finding words or understanding speech, paralysis, loss of balance, numbness, confusion, double-vision and sudden loss of vision. Get to an emergency room fast.

3. Passing out

This might seem like a no brainer, but some people do brush off loss of consciousness once they come to, Han said.

"The most common cause of syncope (passing out) in the elderly is a cardiac condition," Smock said.

The possibilities include stroke, seizure, heart attack, blood clot, or an arrhythmia in which the heart is beating so quickly or so irregularly that oxygen is not being delivered to the brain, Han said. "Any change of your consciousness is something to bring to your doctor's awareness."

4. Chest pain or racing heart

Chest pain can stem from many causes, including, of course, a heart attack.

Classic signs of a heart attack include "chest pain that radiates to the jaw or down the arm, and typically it's the left arm," Han said. Also, you might experience shortness of breath, lightheadedness or fainting, profuse sweating, or nausea and vomiting.

A blood clot that travels to the lungs (pulmonary embolism) typically causes sharper pain, Han said. The heart races, breathing quickens and there may be swelling in your calf days before the chest pain. It is an emergency and can lead to sudden death.

5. Unexplained weight loss or weight gain

Weight loss can be a sign of diabetes, or you could have "an overactive thyroid, which if not corrected, can cause a lot of metabolic problems, pretty much with every organ system, or it can be, in the worst case scenario, a symptom of cancer," Han said.

On the other extreme, weight gain can be associated with diabetes, an underactive thyroid gland, or even heart failure, she said.

Cancer is another possibility if, for instance, "I'm 130 pounds and I lose 13 pounds in a month that's unexplained or gain 20 pounds in a month," Kruse said.

Also, if you experience early satiety, which refers to feeling full after eating less, that could be a sign of an intestinal cancer or gynecological cancer such as ovarian cancer, especially if you have bloating, are constantly nauseous, vomiting and notice a change in weight, Han said.

6. Persistent coughing

In the Louisville area, "a lot of people have allergies," Han said, "but a persistent, unexplained cough, especially if you've been smoking, is always something to get checked out."

It's also worrisome when coughing is accompanied by shortness of breath, weight loss and bloody phlegm, she said.

Possible conditions include lung cancer, chronic obstructive pulmonary disease, asthma, heartburn and persistent infection.

7. Change in bowel habits

"Holidays, of course, you have some changes in your food or your diet, but if you're on your regular diet and you have a chronic constipation or a chronic diarrhea, narrowing of your stool, blood in your stool … that's cause for concern or to see your physician," Kruse said.

Also concerning are unusually dark or light stools, "pencil-thin stools" and presence of blood, Han said. Check with your doctor to find out if the problem is "simply hemorrhoids" or "something like colon cancer or an infection or inflammation," she said.

8. Abdominal pain

Pain in the belly, especially in the lower right portion, can be a sign of appendicitis, Smock said. The condition is serious because if an appendix ruptures, it can lead to a dangerous infection or even death.

Han said belly pain also is a concern when it lasts "several hours in a row, especially if it's associated with any kind of rectal bleeding, any fevers, any vomiting that you cannot control."

9. Fever

If you have a fever of 100.5 for more than 24-48 hours for no apparent reason, get checked out, Han said.

High fever can be a life-threatening side effect of some medications, Smock said, or it can stem from an illness, such as appendicitis or meningitis, a serious illness accompanied by stiff neck.

Always alert a doctor if you have a child just a couple of months old who develops a fever.

10. Lumps or suspicious skin changes

Because of the risk of breast cancer, any breast lump should be evaluated by a doctor sooner rather than later, Han said.

Also, Kruse said, be alert to breast pain, a nipple that looks inverted or pulled, bloody discharge from the nipple and skin changes, such as redness, scaling and dimpling.

Men should report lumps in the testicles because of the possibility of testicular cancer, Kruse said.

Because of the risk of prostate cancer, men also should get checked out if they notice increased or difficult urination or blood in their semen, she said.

Both sexes should be alert to odd moles, which may signal skin cancer. Signs include moles or lesions that are changing in size, shape or color or that have such characteristics as asymmetrical shape or irregular borders. Also, you may notice unusual scaling or a lesion with a pearl-like effect.