Renal excretion of uric acid and its relation to relapse and remission in acute myeloid leukaemia

Tumor lysis syndrome: pathogenesis and management

Tumor lysis syndrome refers to the metabolic disturbances (hyperuricemia, hyperphosphatemia, hyperkalemia, and hypocalcemia) associated with lymphoproliferative malignancies which occur secondary to cell lysis. In some patients, tumor lysis results in acute renal failure. The nature and severity of the metabolic alterations are variable and may be influenced by the timing and intensity of chemotherapy, the magnitude of cell lysis, and the general condition of the patient with respect to hydration and glomerular filtration rate. Not only do hyperuricemia and hyperphosphatemia result from tumor lysis syndrome, they also contribute to oliguric acute renal failure in patients with tumor lysis. The pathogenesis of tumor lysis syndrome and current therapeutic strategies are discussed.

Renal dysfunction and hyperuricemia at presentation and relapse of acute lymphoblastic leukemia

Hyperuricemia is an unusual presenting feature of acute lymphoblastic leukemia (ALL) and is generally associated with a large leukemic cell burden. We describe three children with T-cell ALL who presented with acute renal failure and very high serum uric acid concentrations, despite a relatively small leukemic cell burden. Two of the three patients had normal complete blood counts without circulating blasts or other physical evidence of leukemia. An isolated renal relapse in one case was associated with hyperuricemia, increased renal excretion of uric acid, and renal dysfunction. An unusually high rate of purine catabolism of the lymphoblasts may cause hyperuricemia in these cases. Unexplained hyperuricemia should prompt a search for occult malignancy.

Metabolic disorders in acute myeloid leukaemia

Metabolic balance studies were carried out in 17 unselected patients with acute myeloid leukaemia. Widespread metabolic disturbances were observed. Serum Na fell below 135 mmol/1 in 14 patients (82%) and 11 patients (64%) developed hypokalaemia. An increased osmolal clearance caused by a release of electrolyte and blast cell waste (i.e. urea, urate, etc.) during chemotherapy appeared to be the principle cause of natriuresis and hyperkaluria. Seven patients had proteinuria before and eight others developed it during antileukemic therapy. Nine patients (53%) developed proximal renal tubular dysfunction with aminoaciduria, hyperphosphaturia and incomplete reabsorption of urate. No significant relation was found between this widespread glomerulo-tubular dysfunction and lysozymuria. We suggest that antileukaemic drugs release unidentified substances from blast cells which are toxic to the kidney. Metabolic alkalosis in six patients (35%) was probably related to volume depletion and hypokalaemia, while two patients developed acidaemia with the onset of renal failure. Hypocalcemia in seven patients (41%) had a multifactorial basis: hyperphosphaturia, septicaemia, malnutrition and cytotoxic drugs were among the probable causes.