"Lentiform fork sign" in uremic striatopallidal syndrome: a rare cause of parkinsonism

"Sinal da forquilha lentiforme" na síndrome estriadopalidal urêmica: uma causa rara de parkinsonismo

An 88-year-old diabetic man, with end-stage chronic kidney disease, on dialysis, presented with nausea and diarrhea for 2 days. After this period, the patient's family sought emergency care due to a significant and acute reduction in movement, dysphonia, and dysphagia. His physical examination was consistent with akinetic-rigid parkinsonian syndrome. A brain magnetic resonance imaging scan was performed, and the lentiform fork sign was identified (Figure 1), which, associated with metabolic acidosis, corroborated the diagnosis of uremic striatopallidal syndrome.

Figure 1
Head computed tomography (CT) scan showing symmetrical hypodensity in the lentiform nuclei bilaterally (A). Brain magnetic resonance imaging (MRI) scan in fluid-attenuated inversion recovery (FLAIR) (B) and T2-weighted (C) sequences demonstrateing hyperintensity in the lentiform nuclei bilaterally. The white arrows show T2 and FLAIR hyperintensity in the white matter surrounding the lentiform, representing edema in the internal and external capsules. This finding forms the basis of the fork of the "lentiform fork sign". Facilitated diffusion can be seen on the diffusion-weighted imaging (DWI) (D) and apparent diffusion coefficient (ADC) (E) sequences. Illustrative representation of a fork (F).

Uremic striatopallidal syndrome is a rare cerebral complication of metabolic acidosis. It may present in the form of chorea or, more commonly, acute parkinsonism.¹

Acknowledgments

Pedro José Tomaselli is supported by a strategic award from the medical research council (MRC) to establish an International Center for Genomic Medicine in Neuromuscular Diseases (ICGNMD) MR/S005021/1.

References

• ¹
  Bhowmick SS, Lang AE. Movement Disorders and Renal Diseases. Mov Disord Clin Pract (Hoboken) 2020;7(07):763–779. Doi: 10.1002/mdc3.13005 PMID: 33043074; PMCID: PMC7534014
  » https://doi.org/10.1002/mdc3.13005

Edited by

Editor-in-Chief: Hélio A. G. Teive.

Associate Editor: Leandro Lucato

Publication Dates

• Publication in this collection
  12 Aug 2024
• Date of issue
  2024

History

• Received
  28 Feb 2024
• Reviewed
  29 Mar 2024
• Accepted
  06 Apr 2024