Polycythemia, Spurious
Characterized by increased hematocrit and normal or decreased red blood cell (RBC) total mass, spurious polycythemia results from decreasing plasma volume and subsequent hemoconcentration. This disease is also known as relative polycythemia, stress erythrocytosis, stress polycythemia, benign polycythemia, Gaisböck’s syndrome, and pseudopolycythemia.
Causes
Possible causes of spurious polycythemia include the following.
Dehydration. Conditions that promote severe fluid loss decrease plasma levels and lead to hemoconcentration. Such conditions include persistent vomiting or diarrhea, burns, adrenocortical insufficiency, aggressive diuretic therapy, decreased fluid intake, diabetic ketoacidosis, and renal disease.
Hemoconcentration due to stress. Nervous stress leads to hemoconcentration by some unknown mechanism, possibly by temporarily decreasing circulating plasma volume or by vascular redistribution of erythrocytes.
High-normal RBC mass and low-normal plasma volume. In many patients, an increased hematocrit merely reflects a normally high RBC mass and low plasma volume.
Other factors that may be associated with spurious polycythemia include hypertension, thromboembolic disease, pregnancy, elevated serum cholesterol and uric acid levels, and familial tendency.
Complications
Spurious polycythemia can be complicated by hypercholesterolemia, hyperlipidemia, and hyperuricemia. Thromboembolic complications may result if the condition goes untreated.
Assessment
The patient with spurious polycythemia usually has no specific signs or symptoms but may have vague complaints, such as headache, dizziness, and fatigue. Less commonly, the patient may report diaphoresis, dyspnea, and claudication. The patient’s history may reveal existing cardiac or pulmonary disease.
Inspection typically reveals a patient with a ruddy appearance and a short neck. Palpation usually discloses associated hepatosplenomegaly. Auscultation may detect slight hypertension and hypoventilation when the patient is recumbent.
