Fanconi Syndrome: A Rare Initial Presentation of Acute Lymphoblastic Leukemia

A-14-year old boy, presented with a short history of excessive thirst and increased urine output. Clinical examination showed pallor, generalized lymphadenopathy and hepatosplenomegaly. For evaluation of his polyuric state he underwent routine laboratory investigations, including renal function test, acid-base studies, urine analysis. Blood tests suggested hypokalemia, hypouricemia, hypocalcemia and hyperchloremia with normal liver and kidney function tests. The arterial blood gas analysis was suggestive of normal anion gap metabolic acidosis. Urine analysis was suggestive of hyperuricosuria, hypercalciuria and glycosuria with a positive urine anion gap. His hemogram showed pancytopenia with differential count showing 88% blasts. Bone marrow examination and flowcytometry confirmed the diagnosis of B cell acute lymphoblastic leukemia. Hence this case was atypical and very interesting in the sense that the Fanconi syndrome is very rare to be an initial presenting feature of acute lymphoblastic leukemia. The patient was started on oral as well intravenous supplementation with potassium, bicarbonate, calcium and phosphorus. Simultaneously, as per the modified BFM -90 protocol (four drug based regimen-Prednisolone, vincristine, daunorubicin, cyclophosphamide along with l-asparaginase), he was started on induction protocol. By the end of 3rd week of induction therapy, his urine output started normalizing and finally settled at the end of induction therapy. At present he is in the maintenance phase of chemotherapy.