Complications of Erythrocytosis

Introduction to Erythrocytosis Complications

Erythrocytosis causes serious thrombotic and hemorrhagic complications through increased blood viscosity, with the most critical being cerebrovascular accidents, coronary events, and paradoxical bleeding diathesis—particularly when complicated by iron deficiency from inappropriate phlebotomy 1, 2

Increased blood viscosity from elevated hematocrit aggravates vascular disease in coronary, cerebrovascular, and peripheral circulation, with particularly grave consequences in elderly patients 3, 4
Laminated thrombi develop in large, partially calcified and aneurysmal pulmonary arteries in up to 30% of patients with cyanotic heart disease and erythrocytosis 1

Cerebrovascular accidents represent the most devastating complication, caused by thrombo-embolic events, rheological factors, and endothelial dysfunction 1
Iron deficiency-induced microcytosis is the strongest independent predictor for cerebrovascular events—not the severity of erythrocytosis itself 1

Both bleeding and thrombotic diathesis occur simultaneously, creating a therapeutic dilemma as patients face dual risks 1
Spontaneous bleeding is usually minor and self-limiting, while hemoptysis is the most common major bleeding event, reported in up to 100% of Eisenmenger patients 1

Hyperviscosity symptoms include headache, faintness, dizziness, fatigue, tinnitus, blurred vision, paresthesia of fingers/toes/lips, muscle pain, and weakness 1
Symptoms are classified as moderate when interfering with some activities and severe when interfering with most activities 1

Repeated inappropriate phlebotomies cause iron deficiency, which paradoxically worsens symptoms by reducing oxygen-carrying capacity and red cell deformability 2, 5
Iron-deficient red blood cells with less oxygen-carrying capacity and reduced potential for deformation lead to increased stroke incidence 2

Female gender, low oxygen saturation, older age, biventricular dysfunction, and dilated pulmonary arteries are identified risk factors for thrombotic complications 1
Pre-existing conditions like chronic obstructive pulmonary disease increase hemoconcentration risk 3, 4

Routine phlebotomies without meeting established criteria should be avoided, as they can lead to iron deficiency and increased risk of thrombotic complications 2, 5, 6
Therapeutic phlebotomy has a very limited role and should only be performed with specific criteria met and no dehydration present 2
Currently available data do not support routine anticoagulation or aspirin to prevent thrombo-embolic complications in cyanotic patients, due to increased bleeding risk 1