Polycythemia is an abnormally increased concentration of red blood cells or hemoglobin in the blood. There are several types including primary, secondary, relative, and stress polycythemia. Symptoms result from increased blood volume and viscosity and include fatigue, headache, and shortness of breath. Diagnosis involves blood tests showing elevated red blood cell count, hemoglobin, and hematocrit levels. Treatment may include phlebotomy to reduce blood volume, medications to decrease blood cell production, and lifestyle changes like exercise and avoiding tobacco. Nursing care focuses on monitoring for blood clots, administering treatments, providing skin care and pain management.