4. Unexplained changes in bowel habits

What's considered normal for bowel movements varies widely. Consult your doctor if you notice unusual or unexplained changes in what's normal for you, such as:

  • Bloody, black or tarry-colored stools
  • Persistent diarrhea or constipation
  • Unexplained urges to have a bowel movement

Changes in bowel habits could signal a bacterial infection — such as campylobacter or salmonella — or a viral or parasitic infection. Other possible causes include irritable bowel disease and colon cancer.

5. Confusion or personality changes

Seek medical attention if you have sudden:

  • Poor thinking skills
  • Difficulty focusing, sustaining or shifting attention
  • Behavior changes

These changes could be caused by many problems, including infection, poor nutrition, mental health conditions or medications.

6. Feeling full after eating very little

If you consistently feel full sooner than normal or after eating less than usual, get checked by your doctor. This feeling, known as early satiety, also might be accompanied by nausea, vomiting, bloating or weight loss. If so, be sure to tell your doctor about these signs and symptoms as well.

Possible causes of early satiety include gastroesophageal reflux disease, commonly known as GERD, and peptic ulcers. In some cases, a more serious problem — such as pancreatic cancer — could be a factor.

7. Flashes of light

Bright spots or flashes of light sometimes indicate a migraine. In other cases, sudden flashes of light could signal retinal detachment. Immediate medical care can help prevent permanent vision loss.

May. 20, 2014 See more In-depth