6. New or more severe headaches (especially if you're over age 50)

Seek prompt medical attention if you experience:

• A sudden and severe headache, often called a thunderclap headache, because it comes on suddenly like a clap of thunder.
• A headache accompanied by a fever, stiff neck, rash, mental confusion, seizures, vision changes, weakness, numbness, speaking difficulties, scalp tenderness or pain with chewing.
• A headache that begins or worsens after a head injury.

These headache symptoms may be caused by stroke, blood vessel inflammation (arteritis), meningitis, brain tumor, aneurysm or bleeding on the brain after head trauma.

7. Short-term loss of vision, speaking or movement control

If you have these signs and symptoms, minutes count. These are signs and symptoms of a possible stroke or transient ischemic attack (TIA). Seek immediate emergency medical care if you have any of the following:

• Sudden weakness or numbness of the face, arm or leg on one side of your body
• Sudden dimness, blurring or loss of vision
• Loss of speech, or trouble talking or understanding speech
• A thunderclap headache
• Sudden dizziness, unsteadiness or a fall

8. Flashes of light

The sudden sensation of flashing lights may signal the beginning of retinal detachment. Immediate medical care may be needed to save vision in the affected eye.

9. Feeling full after eating very little

Feeling full sooner than normal after eating and having persistent nausea and vomiting that last more than a week are warning signs that should be checked by your doctor. There are many possible causes, including pancreatic cancer, stomach cancer and ovarian cancer.

10. Hot, red or swollen joint

These warning signs may occur with a joint infection, which requires emergency care to save the joint and keep bacteria from spreading elsewhere. Other causes may include gout or certain types of arthritis such as rheumatoid arthritis.