The severity of an MPD varies from patient to patient. The condition may be acute and life-threatening, or it may be very subtle, existing for years before being diagnosed , frequently during a routine physical. While each condition has its own set of symptoms they also have many in common, including:

• Weakness, fatigue, and pallor due to anemia
  
  
• Weight loss
  
  
• Splenomegaly, cells accumulate in the spleen because it makes blood cells and because it filters old or abnormal cells out of the bloodstream.  This causes the spleen to swell, which may cause abdominal discomfort.
  
  
• Bleeding and bruising, due to insufficient and/or abnormal platelets
  
  
• Night sweats
  
  
• Bone and joint pain
  
  
• Frequent infections
  

In patients with polycythemia vera, the excess number of RBCs increases the volume and thickness (viscosity) of the blood.  This can cause symptoms such as headaches, dizziness, visual distortion, itching, and paresthesia (numbness and tingling).  Sometimes the excessive RBCs may lead to complications, such as: stomach ulcers, kidney stones, venous thrombosis, stroke, and rarely to congestive heart failure. 

Myelofibrosis, which occurs most frequently in those over 60 years of age, often causes no symptoms early in the course of the disease, - about 1/3 of those who are diagnosed are asymptomatic.  Those patients who do have symptoms may experience fatigue, shortness of breath, and splenomegaly.  Fibrous tissue eventually fills the bone marrow, reducing the production of all blood cells, and anemia may become severe with this MPD. 

Most patients with essential thrombocythemia are also asymptomatic but some patients develop thrombosis (blood clots) or hemorrhage (bleeding) because of increased numbers of dysfunctional platelets.  This may cause tingling in the hands and feet, headaches, weakness, and dizziness, nosebleeds, and easy bruising.