Hemichorea, a rare presenting feature of polycythemia vera

Rahul Bhargava¹, Jasmita Dass², Sumit Singh³, Ashok Vaid¹,  
¹ Departments of Medical Oncology and Hematology, Medanta, The Medicity, Gurgaon, Haryana, India
² Departments of Pathology and Laboratory Medicine, Medanta, The Medicity, Gurgaon, Haryana, India
³ Department of Neurosciences, Medanta, The Medicity, Gurgaon, Haryana, India

Correspondence Address:
Jasmita Dass
Departments of Pathology and Laboratory Medicine, Medanta, The Medicity, Gurgaon, Haryana
India

Full Text

Sir,

Polycthemia vera (PV) is a myeloproliferative neoplasm (MPN) characterized by elevated hemoglobin and bone marrow panmyelosis. [1] Neurological symptoms are not uncommon and include migraine, vertigo, headache, and stroke. The reported frequency of chorea in PV is 0.5-5%, [2] and the report of hemichorea both in PV and secondary polycythemia has been limited to isolated case reports. [3],[4] Differential diagnosis in elderly is broad and the etiology can be vascular, autoimmune, paraneoplastic metabolic, and drugs. [5] This report presents a case of hemichorea in a female in whom diagnostic evolution revealed PV.

A 58-year-old female presented with involuntary movements of right face, which rapidly evolved to involve the right half of her body. The movements were irregular and quasi-purposive, remitted during sleep, typically suggestive of hemichorea. No other neurological or systemic symptoms were present. She was a non-smoker and was not on any medications. Magnetic resonance imaging (MRI) brain showed symmetrical hyperintense in basal ganglia on T2-weighted and FLAIR sequence without any significant restriction on diffusion-weighted image or enhancement. Complete blood examination revealed, hemoglobin 175 g/L, total leucocyte count 13.48 × 10 9 /L, and platelet count 305 × 10 9 /L. Ultrasonography of abdomen showed mild hepatomegaly and splenomegaly. Bone marrow aspirate showed panmyelosis. Serum erythropoietin level was 4.14 mIU/mL. BCR-ABL1 mutation was negative and JAK2V617F mutation was positive by ARMS-PCR. With these laboratory findings, a provisional diagnosis of PV was considered. The patient underwent a phlebotomy with the resolution of hemichorea. The patient was started on hydroxyurea and low-dose aspirin with phlebotomies to keep hematocrit level between 42% and 45%. The patient has been under follow-up since past 1.5 years with no recurrence of hemichorea.

PV is an MPN and is characterized by elevated hemoglobin and expanded red cell mass. World Health Organization (WHO) in 2008 proposed new diagnostic criteria with stress on detection of gain of function mutation in JAK2. JAK2V617F mutation is seen in >90% patients with PV. [1] PV is associated with hyperviscosity due to elevated red cell mass, leading to alterations in cerebral blood flow. [6] Neurological signs are frequent and seen at diagnosis in 50-80% of patients. [2] Chorea is uncommon in PV and was first described in 1909. [6] Hemichorea is reported even more rarely in patients with PV. [3] Pathogenesis of chorea in PV is not established and the presumed etiology is vascular. Computed tomography (CT) and MRI in patients with PV complicated by chorea are most often normal. [3],[7] In the patient with PV and hemichorea, no specific basal ganglia lesions were seen. [3] Unilateral pattern of choreic movements in hemichorea may suggest a focal cause and necessitates work up for structural causes. [3] In a recent report of PV with chorea, brain metabolism and dopamine system were investigated using FDG PET and (99m) Tc-labeled tropane dopamine transporter [(99m) Tc-TRODAT-1] SPECT. These studies showed abnormalities that corrected on normalization of clinical symptoms following phlebotomies. This suggests that chorea in PV occurs due to transient alterations in metabolic activity of basal ganglia and cortex with disturbance in dopaminergic function. [8]

Chorea usually shows reduction in severity with phlebotomies with complete resolution in some cases. Earlier reported case of hemichorea with PV had a history of prior stroke and was initially investigated for vascular pathology. This patient was initially treated with haloperidol, and phelobotomies were instituted subsequent to diagnosis of MPN, which led to complete resolution after 10 days. [3] In our patient, since BMA was performed after review of peripheral blood counts, phlebotomy was instituted early with complete resolution of symptoms following one phlebotomy. This case highlights the fact that PV is an uncommon cause of hemichorea and should be considered in the differential diagnosis. Early institution of phlebotomies leads to complete resolution of symptoms.

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