Acquired Fanconi syndrome secondary to light chain deposition disease associated with monoclonal gammopathy of renal significance: A case report

A 57-Year-Old Female Presenting With Cardiopulmonary Arrest Secondary to Severe Hypokalemia From a Fanconi-Like Syndrome: A Case Report

Fanconi syndrome is a multi-factorial disorder that involves diffuse malfunction of the proximal convoluted tubule in the kidney. Renal wasting of potassium, glucose, bicarbonate, amino acids, and phosphorus characterize the condition. We report a case of a 57-year-old female who presented to our emergency department with cardiopulmonary arrest. After successful resuscitation, she had extensive workup to uncover the cause of her cardiac arrest. She had extensive negative workup but was found to have severely low potassium, prompting further evaluation. She was noted to have elevated urine potassium, with a trans-tubular potassium gradient of 9. She was also found to have severe glycosuria, hypophosphatemia, proteinuria, and an elevated urine anion gap, suggesting proximal convoluted tubular dysfunction. The hypokalemia noted on admission was thought to have been the causative factor for the cardiopulmonary arrest and was thought to be due to proximal tubule dysfunction, with the major suspected diagnosis being a Fanconi-like syndrome. This report highlights the diagnosis and treatment of hypokalemia, the broad differential involved with hypokalemia, and the syndromes involved with renal potassium wasting. This report also seeks to raise awareness of the association of renal potassium wasting with cardiopulmonary arrest.

Lambda light chain-induced monoclonal gammopathy of renal significance, manifesting with Fanconi Syndrome and osteomalacia

BACKGROUND

Monoclonal gammopathy of renal significance (MGRS) encompasses a heterogeneous group of kidney diseases in which a monoclonal immunoglobulin secreted by a clone of B cells or plasma cells causes kidney damage without meeting the hematological criteria for malignancy. Among the various forms of involvement, MGRS can manifest as a proximal tubule disorder, such as Fanconi syndrome (FS), characterized by urinary loss of phosphate, glucose, amino acids, uric acid and bicarbonate. Few cases of MGRS have been described in the literature, manifesting as FS and monoclonal production of lambda light chains, almost all of which are secondary to the production of kappa light chains.

CASE PRESENTATION

Here we report a clinical case of a 45-year-old Brazilian male, African descent, with proximal weakness of the lower limbs, whose initial assessment showed a urine summary with the presence of proteinuria and glycosuria without hyperglycemia, associated with mild worsening of renal function, hypouricemia, hypocalcemia and phosphaturia. Evolution was characterized by a MGRS manifesting as FS and osteomalacia.

CONCLUSION

The diagnosis of MGRS is not always easy, it requires knowledge of the clinical characteristics, diagnostic criteria and prognosis of each case. Therefore, all possible efforts should be made for multidisciplinary diagnosis.

Ifosfamide as a Cause of Fanconi Syndrome

Ifosfamide-induced Fanconi syndrome is a rare complication that occurs in patients in treatment with ifosfamide. It is usually characterized by type II proximal renal tubular dysfunction, as evidenced by glycosuria, proteinuria, electrolyte loss, and metabolic acidosis. We outline two case reports of patients who received ifosfamide as chemotherapy for Ewing’s sarcoma and extranodal B-cell lymphoma.