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Key Clinical Message: A novel radiologic sign in patients with renal failure and uremic encephalopathy (UE) with metabolic acidosis has recently been identified as the lentiform fork sign. On magnetic resonance imaging (MRI), the "lentiform fork sign" has been described as bilateral symmetrical hyperintensities in the basal ganglia encircled by a hyperintese rim delineating the lentiform nucleus. Changes in uremic solute retention, aberrant blood–brain barrier transport, disordered vascular reactivity, altered electrolyte and acid–base balance, and altered hormone metabolism are the most likely causes of the condition. A 56‐year‐old male with end‐stage renal disease was brought to the emergency room for a progressive change in mental status and involuntary arm movements over the previous 5 days, which were accompanied by mild dyspnea. A brain MRI was performed, and it revealed hyperintensity on T2/FLAIR in the white matter surrounding the basal ganglia. the patient was treated with dialysis and improved greatly. Intensified hemodialysis and glycemic control are the cornerstones of treating diabetic uremic syndrome (DUS) with likely reversible clinical symptoms and remission of imaging abnormalities. [ABSTRACT FROM AUTHOR]

Key Clinical Message A novel radiologic sign in patients with renal failure and uremic encephalopathy (UE) with metabolic acidosis has recently been identified as the lentiform fork sign. On magnetic resonance imaging (MRI), the “lentiform fork sign” has been described as bilateral symmetrical hyperintensities in the basal ganglia encircled by a hyperintese rim delineating the lentiform nucleus. Changes in uremic solute retention, aberrant blood–brain barrier transport, disordered vascular reactivity, altered electrolyte and acid–base balance, and altered hormone metabolism are the most likely causes of the condition. A 56‐year‐old male with end‐stage renal disease was brought to the emergency room for a progressive change in mental status and involuntary arm movements over the previous 5 days, which were accompanied by mild dyspnea. A brain MRI was performed, and it revealed hyperintensity on T2/FLAIR in the white matter surrounding the basal ganglia. the patient was treated with dialysis and improved greatly. Intensified hemodialysis and glycemic control are the cornerstones of treating diabetic uremic syndrome (DUS) with likely reversible clinical symptoms and remission of imaging abnormalities.

Abstract: Background and purpose: Bilateral basal ganglia lesions are neither diagnostic nor pathognomonic of uremic encephalopathy (UE). Nonetheless, bilateral basal ganglia T2/FLAIR hyperintensities have been widely reported to be associated with UE. The aim of this study was to describe a unique neuroradiological sign seen on the MRI brain in UE, present a retrospective chart review of patients with UE over the past 10 years for evidence of similar MRI appearance, review literature for evidence of this sign, and generate a hypothesis to explain its pathophysiological basis. Methods: We describe a previously unreported and unique MRI picture, the Lentiform Fork sign, in a patient with UE. We conducted a focused retrospective chart review of patients with UE over the past 10 years, for evidence of similar MRI changes. We review literature (through PUBMED, OVID, and CENTRAL) for evidence of this sign and propose a hypothesis to explain the basis of this MRI sign. Results: We describe the Lentiform Fork sign in a patient with UE. Of our 21 retrospectively reviewed patients with UE who underwent MRI, only one had this sign. Literature review identified 22 patients with this sign who had various conditions, all associated with metabolic acidosis. Fourteen of these patients had documented evidence of severe metabolic acidosis. We propose the hypothesis that metabolic acidosis is the basis of this Lentiform Fork sign. Conclusion: Lentiform Fork sign is a unique, previously unreported MRI picture that is seen not only in patients with UE but also in other conditions that result in metabolic acidosis, helping discriminate a specific etiology from the myriad of conditions that are lumped under the rubric of “basal ganglia hyperintensity.” We propose the hypothesis that metabolic acidosis may be the key factor in the pathogenesis of this sign. [ABSTRACT FROM AUTHOR]