Hematology and Oncology
Polycythemia refers to an increase in red blood cell mass due to increased production by the bone marrow. Polycythemia can be due to many causes and is categorized into different types, each with a different treatment plan. An increased amount of red cells make the blood thick and viscous, which moves sluggishly in the blood vessels and may also form clots. Symptoms appear late in the disease and include headaches, nose bleeds, fatigue, dizziness, etc.
The increased production of red cells may be due to the stem cell disorder of the bone marrow or increased demand for the production by other factors. Based on this, it is categorized into two types;
1. Primary polycythemia: It is also known as polycythemia rubra vera, or polycythemia vera is a disorder of the stem cells or cell lines precursors in the bone marrow leading to increased production of all cell lines(RBCS, WBCS, Platelets), particularly red blood cells. It is a neoplastic myeloproliferative disease.
2. Secondary polycythemia: In this disorder, only red blood cells are increased, which is not due to bone marrow neoplasm. Instead, increased RBC production is induced by chronic hypoxemia (decreased oxygen in the blood) caused by other conditions. These conditions include; chronic obstructive pulmonary disease (COPD), obstructive sleep apnea, residing at high altitudes, and heavy cigarette smoking. Some tumors produce erythropoietin which is a growth factor inducing the production of red blood cells. These cancers include renal cell carcinoma, hepatocellular carcinoma, and adrenal adenoma.
Blood cells are produced in the bone marrow by precursor cells (stem cells) triggered and supported by some growth factors. Innate abnormalities in these factors or the process can lead to the neoplastic production of blood cells, causing polycythemia vera in which all the cell lines (Red blood cells, white blood cells, and platelets) are increased. Erythropoietin is one of the factors required to produce red blood cells. Some diseases lead to decreased oxygen levels in the blood, which releases erythropoietin from the kidneys to stimulate the production of red blood cells so that oxygen can be delivered throughout the body. These conditions may also cause polycythemia but only in red blood cells. Diseases affecting the lungs and kidneys are included in this category.
Sometimes the fluid part of the blood is decreased through dehydration, burns, or stress resulting in a relative increase in the number of blood cells called relative polycythemia.
The following factors can increase your chances of polycythemia;
· Age above 60 years
· Male gender
· Presence of Genetic mutations similar to other blood cancers (JAK2 gene)
· Living at high altitudes
· Chronic Smoking
· Lung diseases
· Presence of Tumors releasing erythropoietin
In the USA, Polycythemia vera (PV) is a rare disorder affecting around 0.6-1.6 people/million population. It is found in men more than in women. The most common age group affected is 50-70 years. The frequency of Secondary polycythemia depends on the prevalence of underlying conditions.
Signs and symptoms appear late in the disease and include the following;
· Easy bleeding, especially through the nose
· Generalized body aches and weakness
· Tingling or numbing sensations
· Feeling itchy, particularly after a warm bath
· Abdominal fullness after food.
If you feel like having any of the above symptoms, talk to your healthcare provider, who may obtain a detailed history and perform a physical examination, and advise the following investigations;
Blood tests: For a complete blood count test, you will be asked to submit a blood sample n the lab, where it will be checked for an increased number of blood cells, hematocrit levels, and hemoglobin.
Bone marrow biopsy: This test will be ordered if the doctor suspects PVC. It involves aspirating a little amount of bone marrow via needle and sent to the lab for detailed examinations regarding the cells etc.
Genetic tests: These tests can indicate the presence of mutations resulting in the disorder (like JAK2 mutation.)
Some of the disorders to be excluded from the diagnosis of Primary polycythemia are;
· Essential thrombocytosis (ET)
· Chronic myelogenous leukemia (CML)
· Chronic Myelogenous Leukemia (CML)
· Primary Myelofibrosis
Some of the disorders to be excluded from the diagnosis of Secondary Polycythemia are;
· Chronic Obstructive Pulmonary Disease (COPD)
· Cor Pulmonale
· Obstructive Sleep Apnea (OSA)
· Renal Arteriovenous Malformation
· Renal Artery Stenosis
· Renal Cell Carcinoma
· Adrenal Carcinoma
Treatment depends on the type of polycythemia. Secondary polycythemia caused by other conditions needs treatment and controlling of the underlying disease. However, primary polycythemia or PV has no cure. The goals of treatment are to control the symptoms and prevent the production of blood cells.
Different modalities of treatment include;
Phlebotomy: It is a procedure in which some amount of blood is withdrawn from your vein via injections to reduce the number of red blood cells. It just looks like the process of donating blood. The frequency and amount of blood withdrawn will depend on the individual case.
Myelosuppressive drugs: They help stop the production of blood cells in the bone marrow. Hydroxyurea is one of them.
JAK2 inhibitors: They stop the JAK2 enzyme involved in the overproduction of the cells. For example; ruxolitinib
Supportive therapies: Symptomatic treatment is given for other complaints, e.g., for itching, antihistamines are prescribed. To lessen the viscosity of blood, some blood thinners like aspirin are given.
The outlook of the disease depends on the type and the treatment modalities used. The secondary polycythemia is usually relieved by controlling the underlying disorder.
With proper treatment, patients with PV can have a near-normal life span. Without treatment, people may develop complications like enlarged spleen, blood clots, angina attacks, stroke, etc.
Since PV has no cure, adopting some lifestyle changes can help you cope with the illness.
Exercise: Perform some form of exercise daily to improve blood circulation, improve muscular activity, and combat weakness and tiredness.
Avoid smoking tobacco: Tobacco has harmful effects on the blood vessels, increasing the chances of stroke and heart attack.
Maintain good oxygen environments: Avoid living or going to places with low oxygen supply like high altitudes, climbing, skiing, etc.
Take care of your skin: Avoid hot showers, as they may provoke itching. Avoid scratching and keep the skin well hydrated and moist. Take care of foot or hand sores as they are difficult to heal with poor circulation.
Care regarding extreme temperatures: Too hot or too cold temperatures can further reduce your blood flow. Keep yourself warm in cold weather and vice versa.
Underlying conditions: Take good care of any disorder you have, or that may be responsible for secondary polycythemia. Keep your medicines and follow-up visits in check.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on May 06, 2023.