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Symptoms of Blood Disorders

By

David J. Kuter

, MD, DPhil, Harvard Medical School

Last full review/revision Jun 2021| Content last modified Jun 2021
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Blood disorders can cause various symptoms in almost any area of the body. Most commonly, symptoms are caused by decreases in the blood components.

Occasionally, symptoms may relate to increases in blood components.

  • Increased red blood cells (erythrocytosis) can cause thickening of the blood (increased blood viscosity) and thereby cause headache and a red complexion (plethora).

  • Increased immune system proteins also can cause thickening of the blood (increased blood viscosity).

  • Increased platelets (thrombocythemia) or blood clotting factors can cause inappropriate excessive blood clotting (thrombosis).

When blood disorders cause a person's blood to become thickened, the thickened (more viscous) blood may have difficulty passing through small blood vessels, decreasing blood flow to certain areas of the body, which is a serious condition called hyperviscosity syndrome. Affected people may experience symptoms such as shortness of breath, headaches, dizziness, and confusion. Hyperviscosity syndrome can occur in people who have multiple myeloma, in which it is caused by increased immune system proteins.

Blood disorders often cause symptoms that can also occur in other disorders. For example, the weakness and shortness of breath caused by anemia can be caused by other conditions that impair oxygen delivery to the body, such as heart or lung disorders. Also, easy bruising, a symptom suggestive of a blood disorder, can be caused by other conditions such as disorders of the blood vessels or the use of various drugs such as aspirin. Blood in the urine or stool can be caused by a blood disorder but is usually caused by an abnormality in the urinary or gastrointestinal tract.

Although people may have bleeding after an injury or a medical procedure (such as dental procedures) or during menstruation, the presence of some blood disorders makes such bleeding worse.

Some symptoms are more suggestive of a blood disorder. Just a few examples include the following:

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