General description

Uremic encephalopathy is a metabolic encephalopathy resulting from metabolic abnormalities associated with renal failure, leading to the accumulation of uremic toxins in the central nervous system. This accumulation causes an imbalance between excitatory and inhibitory neurotransmitters and hormonal disturbances. Patients typically exhibit symptoms such as decreased concentration and memory, impaired consciousness, myoclonus, asterixis, and delirium.

In the acute phase, lethargy and confusion are common, which can progress to seizures and coma in the chronic phase. Several neurochemical alterations have been reported during both acute and chronic phases, including changes in water transport leading to cerebral edema, disruptions of the blood-brain barrier, and alterations in cerebral metabolism.

Radiographic features

MRI shows the characteristic lentiform fork sign, with bilateral swelling and T2WI/FLAIR hyperintensity of the lentiform nuclei, accompanied by bilateral hyperintensity along the external and internal capsules. The lentiform fork sign can also be observed in conditions associated with metabolic acidosis, such as Methanol intoxication, Ethylene glycol intoxication, lactic acidosis caused by Metformin intoxication, acidopathies including L-2-hydroxyglutaric aciduria and Pyruvate dehydrogenase complex deficiency, and HELLP syndrome.

MRI also reveals T2WI and FLAIR hyperintensity in the hippocampus, thalamus, and midbrain.