Francescaromana Festuccia

Hyponatremia and the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)

The syndrome of inappropriate ADH secretion (SIADH), also recently referred to as the “syndrome of inappropriate antidiuresis”, is an often underdiagnosed cause of hypotonic hyponatremia, resulting for instance from ectopic release of ADH in lung cancer or as a side-effect of various drugs. In SIADH, hyponatremia results from a pure disorder of water handling by the kidney, whereas external Na+ balance is usually well regulated. Despite increased total body water, only minor changes of urine output and modest edema are usually seen. Renal function and acid-base balance are often preserved, while neurological impairment may range from subclinical to life-threatening. Hypouricemia is a distinguishing feature. The major causes and clinical variants of SIADH are reviewed, with particular emphasis on iatrogenic complications and hospital-acquired hyponatremia. Effective treatment of SIADH with water restriction, aquaretics, or hypertonic saline + loop diuretics, as opposed to worsening of hyponatremia during parenteral isotonic fluid administration, underscores the importance of an early accurate diagnosis and careful follow-up of these patients.

Hemodialysis in patients requiring 131I treatment for thyroid carcinoma.

Purpose Thyroid malignancies can be treated by surgery followed by ablation of the remnant tissue with 131I. As iodide removal from the body occurs by renal extraction, in patients suffering from end-stage renal disease it is necessary to properly evaluate both timing and method of the extracorporeal treatment. Methods We present two patients on regular hemodialysis, admitted in isolation to the Nuclear Medicine Department and treated with 131I for thyroid carcinoma diagnosed during the check-up for transplantation. Both patients underwent two hemodialysis sessions with a portable machine for CRRT (continuous renal replacement therapy), 24 and 48 hours after the administration of 50 mCi of 131I. The nursing staff were monitored with a dosimeter. Radioactivity of the patients, dialysate and urines were measured during hemodialysis. Results The greater reduction was obtained with the first dialysis, but in both patients a further, though shorter, hemodialysis at 48 hours was necessary for reaching a patients radioactivity compatible with discharge. Radioactivity measured in the dialysate demonstrated the almost total removal of radioiodine by dialysis alone. In both patients, follow-up exams revealed a complete ablation of thyroid tissue, without signs of local recurrence. The dose of radioactivity of the dialysis staff was below allowable limits. Conclusions We conclude that a successful reduction of radioactivity, without dispersing its therapeutic efficacy, can be obtained with daily hemodialysis with a CRRT machine in patients in isolation treated with 131I. A therapeutic model is proposed.

Serum Free Light Chains Removal by HFR Hemodiafiltration in Patients with Multiple Myeloma and Acute Kidney Injury: a Case Series

Background/Aims: Multiple myeloma (MM) represents 10% of all haematologic malignancies. Renal involvement occurs in 50% of MM patients; of them, 12-20% have acute kidney injury (AKI), with 10% needing dialysis at presentation. While hemodialysis (HD) has no effect upon circulating and tissue levels of monoclonal proteins, novel apheretic techniques aim at removing the paraproteins responsible for glomerular/tubular deposition disease. High cut-off HD (HCO-HD) combined with chemotherapy affords a sustained reduction of serum free light chains (FLC) levels. One alternative technology is haemodiafiltration with ultrafiltrate regeneration by adsorption on resin (HFR–SUPRA), employing a “super high-flux” membrane (polyphenylene S-HF, with a nominal cut-off of 42 kD). Aim of our pilot study was to analyze the effectiveness of HFR-SUPRA in reducing the burden of FLC, while minimizing albumin loss and hastening recovery of renal function in 6 subjects with MM complicated by AKI. Methods: Six HD-dependent patients with MM were treated with 5 consecutive sessions of HFR-SUPRA on a Bellco® monitor, while simultaneously initiating chemotherapy. Levels of albumin and FLC were assessed, calculating the rates of reduction. Renal outcome, HD withdrawal and clinical follow-up or death were recorded. Results: All patients showed a significant reduction of FLC, whereas serum albumin concentration remained unchanged. In three, HD was withdrawn, switching to a chemotherapy alone regimen. The other patients remained HD-dependent and died shortly thereafter for cardiovascular complications. Conclusion: Our study suggests that HFR-SUPRA provides a rapid and effective reduction in serum FLC in patients with MM and AKI, while minimizing the loss of albumin. When started early in combination with chemotherapy, blood purification by HFR-SUPRA was followed by the recovery of renal function in half of the patients treated.