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Blood Clots (cont.)

Blood clots in arteries

Blood clots may form acutely in an artery that has been gradually narrowed by plaque in vessels affected by arteriosclerosis. Plaque is a collection of cholesterol, calcium, fibrin and cell waste products that can form, grow and gradually narrow an artery. If the plaque ruptures, it may initiate the clotting cascade, and a newly formed clot can completely block an artery. The risk factors for arterial clot are those commonly associated with heart attack, peripheral vascular disease, and stroke.

These include:

Blood clots in other areas

When bleeding occurs outside an artery or vein the blood tends to pool and clot. Passing blood clots in the urine, the vagina, or in the stool is very frightening and should not be ignored. There may be a significant problem, or the bleeding may be easily explained. For example, bleeding is commonly seen with bladder infections or hemorrhoids.

Bleeding or blood clots in the urine should not be ignored and presumed to be "just a bladder infection." The bleeding may arise from a bladder tumor or irritation of the bladder lining from other reasons (for example, cancer radiation therapy), or it may originate in the kidneys because of kidney stones or cancer. Sometimes, if there is enough bleeding, clots will form in the bladder and may pass in the urine. This is commonly seen in older male patients with enlarged prostate glands that may cause difficulty with urination.

Blood in the stool or rectal bleeding is never normal and should always be investigated. While hemorrhoids or anal fissures may be the source, bleeding may also be due to a variety of other illnesses including tumors, or cancer, inflammatory bowel disease, infections, and diverticular bowel disease. Again, if there is enough bleeding present, blood clots may form and be passed as part of a bowel movement. Passing blood clots from the vagina happens almost routinely in menstruation. If blood from the uterus pools in the vaginal area, blood clots of varying sizes may form. However, vaginal bleeding during pregnancy is never normal and medical advice should always be accessed if this occurs, either by telephone or in person.

Medically Reviewed by a Doctor on 8/30/2017

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