41-year-old male, referred for evaluation due to the finding of proteinuria. Diagnosis of PNH in the context of haemolytic anaemia. He did not require blood transfusions and had no thrombotic events. Laboratory tests showed persistent haemolytic activity, elevated LDH (1,800-3,000 U/l) and undetectable haptoglobin, haemoglobin 8.5 mg/dl, mild leukopenia and thrombocytopenia, normal ferritin 25 ng/ml.
He presented recurrent haemolytic crises with fatigue, dysphagia, abdominal pain and dark urine. Episodes usually lasted 1-3 days, every 2-3 months.
Renal function was normal, serum creatinine 0.9 mg/dl and GFR (MDRD) > 60 ml/min. Persistent haemoglobinuria with normal urine sediment, and proteinuria of 1.3 g/day with albuminuria 170 mg/day and non-selective aminoaciduria, indicating DTP. Acid-base status, phosphate and uric acid were normal. The possibility of DTP due to haemosiderin deposition was considered, so an MRI was performed with the finding of bilateral renal cortical hypointensity compatible with iron deposition. Initiation of therapy with eculizumab was considered, but was rejected due to the lack of transfusion requirement and normal GFR.

Two years later, he presented a severe haemolytic crisis with acute renal failure, which was attributed to haemoglobinuria. The patient was treated with conservative measures, with recovery of renal function in 18 days. Following this episode, treatment with eculizumab was started. Within a few weeks, LDH and haemoglobin almost normalised, maintaining low haptoglobin levels. In the following months, tubular proteinuria progressively normalised.
Fourteen months after initiation of eculizumab, a new MRI showed an improvement in signal hypointensity in the renal cortex of 34 and 51% in the left and right kidneys, respectively, indicating partial removal of iron deposits in the kidney.