Polycythemia ~ Pureheal96

Polycythemia:

Polycythemia is increase in red blood cell (RBC) count. Increased hemoglobin level or hematocrit level; according to the age and gender.

It’s an acquired, Philadelphia-chromosome negative myeloproliferative disorder. Male: Female ratio is 2:1.

Etiology:

Causes depends on the type of polycythemia:

Spurious/Stress

True

Due to volume depletion rather than increase in RBC

In case of diarrhea/ severe vomiting

It depends on the erythropoietin (EPO) level;

· Primary: (Low EPO level); it occurs due to polycythemia vera, congenital & primary familial

· Secondary: (High EPO level); is occurs due to high altitude, COPD, Pickwickian syndrome. Cyanotic heart disease, Renal disorder, Increased carboxy hemoglobin and EPO secretin tumors.

Pathology:

In case of high EPO level: Cellular hypoxia can occur.

In case of low EPO level: Acquired mutation of tyrosine kinase JAK2. Loss of auto- inhibitory pseudo-kinase constitutive activation, which results into hypersensitivity to EPO and EPO- independent erythroid colony formation.

Signs and symptoms:

· Fatigue/headache/dizziness

· Amaurosis Fugax (temporary vision impairment due to lack of blood supply)

· Transient ischemic attacks

· Pruritus after warm water shower especially on back

· Epistaxis

· Gastrointestinal bleeding

· Easy bruising

· Peptic ulcers

On examination:

· Abnormal facial ruddiness

· Cyanosis, clubbing

· Murmurs on auscultation

· Nicotine stained nails and teeth

· Barrel shaped chest

· Splenomegaly

Work-up:

· Hemogram: Hematocrit level <49% in males and <48% in females. Leucocyte level: 10,000 to 20,000/ microliter

· Serum EPO level (normal range: 2.6 to 18.5 mU/mL)

· Serum ferritin level: Decreased; Serum Vitamin B12 level: Increased; Folate level: Decreased

· Renal function test: May indicate secondary polycythemia; Uric acid often raised as a result of increased cell proliferation.

· Hepatic study: Liver cirrhosis and inflammatory liver disease is associated with secondary polycythemia

· Ultrasound sonography

Differential diagnosis:

· Myelofibrosis

· Chronic myeloid leukemia

Treatment and Management:

· Phlebotomy: In hematocrit stable patient approximately 500 ml blood per week is removed. Here, target hematocrit level in under 45%

· Hydroxyurea: It’s the second line therapy. Standard dosage is 500 to 1500 mg/day

· Ruxolitinib: Introduced when there is hydroxyurea intolerance. The risks are, anemia and thrombocytopenia. Standard dosage: 10mg twice a day

· Low dose aspirin (40 mg to 100 mg/day): Due to phlebotomy there is increase chance of thrombosis.

· Hypouricemic agents: Allopurinol and febuxostat

· Antihistamines and selective serotonin reuptake inhibitor for pruritus

Complication:

· Bleeding: Recurrent epistaxis or gastro-intestinal bleed; which results into iron deficiency anemia

· Thrombosis: Due to hyper viscosity. Arterial thrombosis leads to digital infarcts, cerebral ischemic infarct. Venous thrombosis causes Budd-Chiari syndrome.

References:

1. https://www.ncbi.nlm.nih.gov/books/NBK526081/

2. https://www.webmd.com/cancer/polycythemia-vera#1

Polycythemia

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