The clinical presentation is variable and is determined by the rate of progression of the underlying kidney disease. In patients with a slow decline in eGFR, fatigue, anorexia, weight-loss, and nausea are the presenting signs. Cognitive dysfunction is slow, progressive, and subtle. Psychometric testing is required to identify the involvement of the central nervous system. At the other end of the spectrum are patients with a rapid decline in eGFR. These patients can present with confusion, delirium, seizures, and coma.

physical exam reveals cognitive dysfunction in the form of abnormalities in memory, judgment, and ability to perform calculations. Hyperreflexia, asterixis, papilledema, and nystagmus are frequently present. Neuropathy and myopathy may be present.

Renal function studies – Markedly elevated blood urea nitrogen (BUN) and creatinine levels are seen in uremic encephalopathy

Serum electrolyte and glucose measurements To rule out hyponatremia, hypernatremia, hyperglycemia, and hyperosmolar syndromes as the cause of encephalopathy

Complete blood cell count –To detect leukocytosis, which may suggest an infectious cause, and to determine whether anemia is present (anemia may contribute to the severity of mental alterations)

Serum calcium, phosphate, and parathyroid hormone (PTH) levels –To assess for hypercalcemia, hypophosphatemia, and severe hyperparathyroidism, which cause metabolic encephalopathy

Serum magnesium level –This may be elevated in a patient with renal insufficiency, particularly if the patient is ingesting magnesium-containing antacids; hypermagnesemia may manifest as encephalopathy