Development features and clinical presentation
The disease has an insidious onset and may remain latent for a long time. Very often, the diagnosis is an incidental finding during routine laboratory blood tests.
The predominant feature in the clinical picture is plethora syndrome (hypervolemia). Its symptoms are directly related to a sharp increase in circulating blood volume (CBV) and concomitant microcirculatory impairment. Patients face a range of characteristic manifestations:
- Cerebral disorders: impaired blood supply to the brain causes persistent headaches, dizziness, unmotivated weakness, and a noticeable decrease in concentration.
- Appearance changes: objective findings include pronounced hyperemia (redness) of the skin and visible mucous membranes, as well as scleral vessel injection.
- Cardiovascular disorders: arterial hypertension develops.
- Specific symptoms: patients are often troubled by pruritus, recurrent epistaxis, and dyspeptic disorders. In 75% of patients, physical examination reveals an enlarged spleen (splenomegaly).
A specific vasomotor syndrome, erythromelalgia, is distinguished separately. It manifests as intense burning pain in the fingertips accompanied by local redness. Furthermore, due to high blood viscosity, there is an extremely high risk of thrombotic complications affecting arteries of any caliber. This can lead to myocardial infarction, stroke, pulmonary infarction, or gangrene (necrosis) of the fingers.
Laboratory and instrumental diagnostics
Confirming the diagnosis requires a comprehensive assessment of peripheral blood parameters and the state of the bone marrow.
- Peripheral blood: absolute erythrocytosis is detected (pathological increase in red blood cell count and hemoglobin levels), along with a significant elevation in hematocrit. Panmyelosis is frequently observed — a condition where erythrocytosis is accompanied by a simultaneous increase in white blood cells (leukocytosis) and platelets (thrombocytosis).
- Biochemical and rheological parameters: the blood becomes excessively viscous. Biochemical analysis frequently reveals hyperuricemia (elevated uric acid levels).
- Bone marrow examination: this is a key stage. To verify the diagnosis of polycythemia vera, trephine biopsy is performed, demonstrating total bone marrow hyperplasia (excessive proliferation of the erythroid lineage, granulocytopoiesis, and megakaryocytes).
Differential diagnosis and treatment
The physician's primary task at the diagnostic stage is to differentiate true erythremia (a neoplastic process) from secondary erythrocytosis, which is merely a symptom of other pathologies.
Secondary erythrocytosis can occur due to the following causes:
- Hypoxic states: chronic obstructive pulmonary disease, congenital cyanotic heart disease.
- Paraneoplastic processes: tumors of the kidneys, liver, adrenal glands, pituitary gland, or ovaries that secrete erythropoiesis-stimulating agents.
- Local renal ischemia: associated with cysts or renal artery stenosis.
Principles of erythremia therapy
The basis of treatment is managing the excess of formed elements and high blood viscosity:
- Hemoexfusion (phlebotomy): remains an accessible and highly effective method of choice. The procedure is performed in volumes of up to 500 mL at a time. The target parameter aimed at by physicians is reducing the hematocrit level to 45%.
- Cytostatic therapy: when necessary, patients are prescribed chemotherapy drugs to suppress excessive cell proliferation in the bone marrow.
Briefly: answers to topical questions
Which genetic mutations are the main cause of erythremia?
The cited sources identify carcinogenic agents as the cause of erythremia. Regarding genetic alterations for polycythemia vera, the JAK2 V617F mutation (also referred to as V617ZF in the text) or a mutation in exon 12 of the JAK2 gene is indicated; the presence of these mutations is included in the major WHO diagnostic criteria. Additionally, the source on pathogenesis states: mutations affect a gene whose product is involved in signal transduction from hematopoietic factor receptors. Due to the mutation, hematopoietic cells become overly sensitive to hematopoietic factors, and the proliferation rate of the myeloid lineage increases even with normal levels of stimulants.
What will the level of endogenous erythropoietin in the blood be in polycythemia vera?
Sources indicate that in erythremia, erythropoietin levels are within the normal range (not elevated). The WHO diagnostic criteria for polycythemia vera also list a reduced erythropoietin level as a minor criterion. Pathogenesis notes that due to the mutation, hematopoietic cells become hypersensitive to hematopoietic factors, and the proliferation rate of the myeloid lineage increases even at normal stimulant levels.
To memorize the typical clinical picture, use the "5 P's" rule: Patient age over 40 (Elderly), Plethora (red face), Pressure increased (hypertension), Pruritus (itching), and Palpable spleen.
Class and exam questions
Why does pruritus and facial redness occur in erythremia?
These symptoms are caused by plethora syndrome — a sharp increase in blood volume and congestion in the microvasculature, causing redness (hyperemia) and irritation of skin receptors.
What is the essence of the erythromelalgia phenomenon?
Erythromelalgia is a specific vasomotor syndrome characterized by burning pain in the fingertips accompanied by pronounced redness.
How to distinguish true erythremia from secondary erythrocytosis?
Secondary erythrocytosis is typically associated with hypoxia, renal ischemia, or tumors in other locations. Bone marrow trephine biopsy helps definitively confirm the diagnosis of erythremia.
What else to study on this topic
- Pathogenesis of microcirculatory disorders in plethora syndrome
- Mechanisms of development of paraneoplastic erythrocytosis
- Features of the course of thrombotic complications (strokes, infarctions)
- Indications for cytostatic therapy in erythremia
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