Hemiballismus as a Presenting Feature of Idiopathic Hypoparathyroidism in the Emergency Department

PRACTICAL IMPLICATIONS

Hypocalcemia is an uncommon and treatable cause of hemiballismus. Neurologists should be aware of potentially reversible metabolic diseases when approaching a patient with a new-onset movement disorder.

Case

A 66-year-old woman with a history of untreated hypocalcemia presented to the emergency department (ED) with a 3-week history of progressive right-sided hyperkinetic, quick, violent, unpredictable movements affecting proximal and distal muscles with partial voluntary control, consistent with hemiballismus. Initial blood workup was relevant for low serum calcium (6.5 mg/dL [corrected 7.5 mg/dL], reference: 8.6–10), high phosphate (5.4 mg/dL, reference: 2.5–5), low parathyroid hormone (3.9 pg/mL, reference: 12–88), and low albumin (2.8 g/dL, reference: 3.5–5.7), compatible with hypoparathyroidism. Unenhanced head CT (figure, A and B) and brain MRI (figure, C and F) showed bilateral calcifications of the basal ganglia and cerebellum, consistent with a diagnosis of bilateral striopallidodentate calcinosis (BSPDC), with no family history of endocrine or neurologic disease. Twenty-four hours after the administration of IV calcium, hemiballismus disappeared. After excluding secondary causes of hypoparathyroidism, she was discharged on oral calcium and vitamin D 1 week after admission.

Figure. Neuroimaging Findings.

Unenhanced head CT showing bilateral calcification in the (A) cerebellar dentate nuclei and (B) basal ganglia. (C and D) Axial T1-weighted and (E and F) susceptibility-weighted angiography MRI of the brain confirming striopallidodentate calcinosis.

Discussion

Movement disorders (MDs) in the ED are not uncommon as a new-onset appearance or exacerbation of a previously diagnosed syndrome.¹ Hypoparathyroidism-related BSPDC is associated with hyperkinetic MDs such as hemiballismus, chorea, and dystonia,² which can be treated symptomatically with antipsychotic drugs such as haloperidol.^1,2 However, this case illustrates a unique presentation of a metabolically induced MD that responded to electrolyte correction alone, a phenomenon also described in patients with treatment of severe hyperglycemia.¹ Neurologists should be aware of reversible causes of MDs, which can have an excellent prognosis after an underlying cause is diagnosed and treated appropriately.

Appendix. Authors

Study Funding

No targeted funding reported.

Disclosure

The authors report no disclosures relevant to the manuscript. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.