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.
Some blood disorders cause a person's blood to become thickened by increased quantities of immune-related proteins, red blood cells, white blood cells, or platelets. This 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 (see 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. On the other hand, easy bruising, a symptom suggestive of a blood disorder, can be caused by conditions other than a blood disorder, especially disorders of the blood vessels or the use of various drugs such as aspirin.
Disorders other than blood disorders can cause bleeding, but blood disorders often cause very heavy bleeding due to nosebleeds or dental procedures, menstrual bleeding or delivery of a baby, and teething in babies. Blood in the urine (see Urine, Blood in) or stool (see Gastrointestinal Bleeding) is usually not caused by a blood disorder.
Some symptoms are more suggestive of a blood disorder. Just a few examples include the following:
Last full review/revision December 2014 by David J. Kuter, MD, DPhil