Difference Between Polycythemia and Erythrocytosis

The key difference between polycythemia and erythrocytosis is that polycythemia refers to the condition in which both red blood cells and haemoglobin increase above the normal level while erythrocytosis refers to the condition where the red blood cell mass increases beyond the normal level.

Polycythemia and Erythrocytosis occur when there are abnormal levels of red blood cells in the blood. There is a slight distinction between the two terms. Polycythemia is the condition in which both red blood cells and haemoglobin increase above the normal level. On the other hand, erythrocytosis is the condition where the red blood cell mass increases beyond the normal level.

CONTENTS

1. Overview and Key Difference
2. What is Polycythemia
3. What is Erythrocytosis
4. Similarities Between Polycythemia and Erythrocytosis
5. Side by Side Comparison – Polycythemia vs Erythrocytosis in Tabular Form
6. Summary

What is Polycythemia?

Polycythemia refers to the overproduction of red blood cells. Sometimes, the decrease in plasma levels also leads to polycythemia. It is mainly due to an abnormality in the bone marrow. Also, it can be due to physiological states such as being a recipient twin in pregnancy, etc. The most common treatment for polycythemia is phlebotomy.

There are two types of polycythemia. They are primary polycythemia also known as polycythemia vera and secondary polycythemia. Primary polycythemia is the overproduction of red blood cells due to abnormalities in the bone marrow. In this condition, white blood cells and thrombocytes are also overproduced.

Secondary polycythemia is caused by natural or artificial factors. Therefore, it is known as physiologic polycythemia. Conditions such as high altitude and hypoxic lung diseases may lead to secondary polycythemia. Genetics play a major role in both primary and secondary polycythemia. Symptoms of polycythemia include dizziness, nausea, headache, increased blood pressure and blurred vision.

What is Erythrocytosis?

Erythrocytosis is the condition in which the red blood cells increase abnormally in mass and number. It may be due to a mutation in the gene which controls the red blood cells size and number. Erythrocytosis can also be due to polycythemia. During erythrocytosis, the red blood cell concentration increases in volume. The immediate treatment is phlebotomy.

Moreover, erythrocytosis can also occur due to other factors such as smoking, high altitude, tumors and certain medication. The symptoms of erythrocytosis are much similar to that of polycythemia, and therefore, the effects are similar in both cases.

What are the Similarities Between Polycythemia and Erythrocytosis?

• Both lead to an increase of red blood cells in the blood.
• Genetics affects both conditions.
• Furthermore, the symptoms of both conditions include high blood pressure, dizziness, nausea and headache.
• Moreover, the treatment for both conditions are similar – phlebotomy.
• Also, high altitude and smoking also affect both polycythemia and erythrocytosis.

What is the Difference Between Polycythemia and Erythrocytosis?

Polycythemia and erythrocytosis are two conditions in the blood that arise due to the abnormal levels of red blood cells. The key difference between polycythemia and erythrocytosis is that polycythemia is the condition which arises due to the abnormal increase of red blood cells and haemoglobin while the erythrocytosis is the condition which arises due to the increased red blood cell mass. During the polycythemia, red blood cells, white blood cells and platelets may increase while during the erythrocytosis, only red blood cells increase in number. Hence, it is also a difference between polycythemia and erythrocytosis.

Summary – Polycythemia vs Erythrocytosis

Polycythemia and erythrocytosis are conditions which go hand in hand. Moreover, polycythemia is one cause of erythrocytosis where there are more red blood cells produced in both cases. The polycythemia is mainly characterized by the abnormalities in the bone marrow which produces red blood cells. Phlebotomy is the treatment procedure for both conditions. The symptoms are also similar, which include high blood pressure, headache and dizziness, etc. This is the summary of the difference between polycythemia and erythrocytosis.

Reference:

1. “Erythrocytosis: Definition, Causes, and Symptoms.” Healthline, Healthline Media. Available here  
2. Valentine, William N., et al. “Polycythemia: Erythrocytosis and Erythremia.” Annals of Internal Medicine, American College of Physicians, 1 Sept. 1968. Available here   

Image Courtesy:

1.”Polycythemia vera, blood smear”By The Armed Forces Institute of Pathology (AFIP) (Public Domain) via Commons Wikimedia  
2.”Red Blood Cell”By qimono (CC BY-SA 4.0) via Commons Wikimedia