Symptoms and Signs of High Red Blood Cell Count (Polycythemia Vera)

Polycythemia (High Red Blood Cell Count) Symptoms

Symptoms of polycythemia can vary widely. In some people with polycythemia, there may be no symptoms at all.

In secondary polycythemia, most of the symptoms are related to the underlying condition responsible for polycythemia.

Symptoms of polycythemia vera can be vague and quite general. Some of the important symptoms include:

• easy bruising;
• easy bleeding;
• blood clot formation (potentially leading to heart attacks, strokes, blood clots in the lungs [pulmonary embolism]);
• bone and joint pain (hip pain or rib pain);
• headache;
• itching;
• itching after taking a shower or bath (post-bath pruritus);
• fatigue;
• dizziness; and
• abdominal pain.

Polycythemia (High Red Blood Cell Count) Causes

In primary polycythemia, inherent or acquired problems with red blood cell production lead to polycythemia. Two main conditions that belong to this category are polycythemia vera (PV or polycythemia rubra vera [PRV]) and primary familial and congenital polycythemia (PFCP).

• Polycythemia vera (PV) is related to a genetic mutation in the JAK2 gene, which is thought to increase the sensitivity of bone marrow cells to Epo, resulting in increased red blood cell production. Levels of other types of blood cells (white blood cells and platelets) are also often increased in this condition.
• Primary familial and congenital polycythemia (PFCP) is a condition related to a mutation in the EPOR gene and causes increased production of red blood cells in response to Epo.

Contrary to primary polycythemia in which overproduction of red blood cell results from increased sensitivity or responsiveness to Epo (often with lower than normal levels of Epo), in secondary polycythemia, more red cells are produced because of high levels of circulating Epo.

The main reasons for higher than normal Epo are chronic hypoxia (poor blood oxygen levels over the long-term), poor oxygen delivery due to abnormal red blood cell structure, and tumors releasing inappropriately high amounts of Epo.

Some of the common conditions that can result in elevated erythropoietin due to chronic hypoxia or poor oxygen supply include:

• chronic obstructive pulmonary disease (COPD, emphysema, chronic bronchitis),
• pulmonary hypertension,
• hypoventilation syndrome,
• congestive heart failure,
• obstructive sleep apnea,
• poor blood flow to the kidneys, and
• living in high altitudes.

2,3-BPG deficiency is a condition in which the hemoglobin molecule in the red blood cells has an abnormal structure. In this condition, hemoglobin has a higher affinity to hold on to oxygen and is less likely to release it to the tissues. This results in more red blood cells being produced in response to what the tissues in the body perceive as an inadequate oxygen level. The outcome is more circulating red blood cells.

Certain tumors have a tendency to secrete inappropriately high amounts of Epo, leading to polycythemia. The common Epo-releasing tumors are:

• liver cancer (hepatocellular carcinoma),
• kidney cancer (renal cell carcinoma),
• adrenal adenoma or adenocarcinoma, and
• uterine cancer.

There also are more benign conditions that may cause increase Epo secretion, such as kidney cysts and kidney obstruction.

Chronic carbon monoxide exposure can also lead to polycythemia. Hemoglobin naturally has a higher affinity for carbon monoxide than for oxygen. Therefore, when carbon monoxide molecules attach to hemoglobin, polycythemia (increased red cell and hemoglobin production) may occur in order to compensate for the poor oxygen delivery by the existing hemoglobin molecules. A similar scenario can also occur with carbon dioxide in long-termcigarette smoking.

Polycythemia in newborns (neonatal polycythemia) is often caused by transfer of maternal blood from the placenta or blood transfusions. Prolonged poor oxygen delivery to the fetus (intrauterine hypoxia) due to insufficiency of the placenta can also lead to neonatal polycythemia.