Presentation
Syncope and fall due to weakness with underlying newly diagnosed end stage renal failure
Patient Data
Symmetrical confluent hypo densities involving both lentiform nuclei (globus pallidi and putamen). Midbrain and thalamus are spared. The normal anatomical boundaries between deep subcortical grey matters appear obliterated.
Lentiform fork sign present, slightly lower attenuation involves the white matter(bilateral internal and external capsules) appear to engulf the lentiform nuclei bilaterally.
Annotate images showed the bilateral hypointensities in both lentiform nuclei surrounded by lower attenuation of white matter.
Lentiform form sign in CT scan.
Case Discussion
The CT features are quite characteristics for uremic encephalopathy in the correct clinical setting. This patient has newly diagnosed end stage renal failure on dialysis. Upon presentation to emergency department, patient has markedly elevated urea and creatinine as well as severe metabolic acidosis.
Lentiform fork sign is exclusively described for MRI rather than CT scan. It represents bilateral symmetrical hyperintensities in basal ganglia surrounded by hyperintense rim white matter on T2WI and FLAIR sequences. It is postulated to result from metabolic acidosis of any cause.
Otherwise, the vital signs (blood pressure, heart rate and pulse oximetry) were normal. No documented hypotensive episodes as well as no electrocardiogram evidence of myocardiac infarction/ischemia. Therefore, the possibility of anoxic/hypoxic ischemic encephalopathy is lower.