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Lithium has always been used as a first-choice therapy in bipolar disorders. However, its therapeutic index is restricted by placing patients at risk of potential nephrotoxic effects ranging from polyuria, to Insipid Nephrogenic Diabetes, to chronic kidney disease with a slow reduction of renal function over time. The Nephrologist has the role to diagnose chronic lithium nephropathy, monitoring its evolution and optimizing the management of risks associated with the treatment. In fact, the main objective, to be shared with the psychiatrist, is to encourage the maintenance of therapy even in the presence of nephropathy. Renal ultrasound, a safe, repeatable and low-cost technique, is essential to pursue this goal as it not only confirms the diagnosis of chronic lithium nephropathy hypothesized on the basis of the history and clinical picture, but is also helpful in monitoring its evolution. In this paper, we report a case of chronic lithium nephropathy in order to analyze the etiopathogenesis of renal damage, the clinical-laboratory and histological picture and, in particular, the fundamental role of ultrasound imaging., (Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.)

Diabetes mellitus (DM) is the most important non-communicable disease after hypertension. Prevalence of type 2 DM has progressively increased over the last decades. In Italy, 11.8% of the general adult population can be identified as diabetic. The major complication of DM is diabetic nephropathy (DM-CKD), which develops in approximately one-third of diabetics. Achieving optimal glycemic control is the first therapeutic goal in the management of DM-CKD. In recent years, new antidiabetic drugs have been marketed (GLP1 analogues, DPP-4 inhibitors, SGLT-2 inhibitors) to ameliorate glycemia in patients nave or treated by means of traditional agents, such as sulfonylureas, metformin, glinides, insulin. However, use of these drugs in DM-CKD should be evaluated carefully, mainly because of the higher risk of hypoglycemia that requires dosing adjustments. Metformin still represents an adequate choice if proper dose adjustments are made on the basis of renal function. Sulfonylureas with limited renal clearance, i.e., gliquidone, glipizide and gliclazide are an alternative to metformin and more effective than repaglinide on glycemic control. Other antidiabetic agents with potential nephroprotective effects, namely DPP-4 inhibitors, incretin analogues and SGLT-2 inhibitors, may allow nephroprotective effects independent of glycemic control. Insulin remains the cornerstone of therapy when oral therapy is no longer effective.

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a disorder of sodium and water balance characterized by hypotonic hyponatremia and impaired water excretion in the absence of renal insufficiency , adrenal insufficiency or any recognized stimulus for the antidiuretic hormone (ADH). An inappropriate increase in ADH release of any cause produces hyponatremia by interfering with urinary dilution, thereby preventing the excretion of ingested water. Despite being the most common cause of hyponatremia in hospitalized patients, SIADH remains a diagnosis of exclusion. SIADH should be suspected in any patient with hyponatremia, hyposmolarity, urine osmolality above 100 mosmol/hgH2O, urine sodium concentration usually above 40 mEq/L, and clinical euvolemia. a number of modalities can be used to correct hyponatremia in SIADH, with water restriction and salt administration being the most important. The rate of correction is dependent upon the degree of hyponatremia and the presence or absence of symptoms. Patients with severe neurological symptoms require prompt correction; however, excessively rapid correction should be avoided because it can lead to the late onset of neurological complications from osmotic demyelination.

Background: Although there is a higher nutrient requirement, food intake in haemodialysis patients is often inadequate. Protein nitrogen appearance (PNA) indirectly estimates the mean protein intake during the short interdialysis period, but it does not measure the daily nutrient intake, which is generally unknown. We carried out a longitudinal study aimed at estimating the daily nutrient intake and its relationship with the nutritional status of haemodialysis patients., Methods: We selected 28 haemodialysis patients with adequate nutritional status and no evidence of risk-factor for malnutrition. Patients were treated with biocompatible membranes, low-flux and high bicarbonate dialysis, Kt/V > 1.2, PNA > 1.1 g/kg/day and erythropoietin. We measured every four months daily PNA, protein and calorie intake (DPI, DCI) as well as weight gain (WG) during an entire week for one-year. The nutritional status was assessed by biochemical and BIA markers., Results: Twenty seven subjects (8 F, 19 M; age 57.1 +- 2.7 yeas; dialysis age 105 +- 13 months) completed the trial. The mean interdialytic PNA did not change in both long- and short-interdialysis periods, resulting in the "normal" range (> 1.1 g/kg/day); however, daily levels of protein and calorie intake were significantly reduced on the third day during the long interdialysis interval. Eight patients showed time-averaged values of DPI and DCI lower than 0.8 g/kg/day and 25 Kcal/kg/day, respectively, on the third day (LOW group), values that were associated with similar changes in WG. Such a highly reduced nutrient intake during the third interdialysis day was associated with a normal PNA value (1.23 +- 0.05 g/kg/day vs 1.30 +- 0.06 in CON, NS) when measured during the short interdialysis period (S), just as it is in clinical practice; in contrast, when the PNA value was measured during the long interdialysis period it was found to be significantly reduced (1.07 +- 0.08 g/kg/day vs 1.37 +- 0.06 in CON, p < 0.05 and vs S, p < 0.05). During the study, the body weight progressively decreased from 68.0 +- 5.5 to 65.8 +- 5.9 kg (p < 0.05) in the LOW group, due to the decrease in lean body mass, as suggested by the reduction in serum creatinine (9.2 +- 1.1 vs 8.1 +- 0.7 mg/dL, p < 0.05), creatinine generation (835 +- 155 vs 723 +- 106 mg/die, p < 0.05) and serum albumin (3.96 +- 0.07 vs 3.66 +- 0.06 g/dL, p < 0.05). Moreover, reactance and phase angle declined in the LOW group (from 54 +- 4 to 44 +- 3 ohms, p < 0.05 and 5.5 +- 0.3 to 4.5 +- 0.3 degrees, p < 0.05, respectively). At the end of the study the nutritional status in the LOW group was reduced as compared to the CON group., Conclusions: In stable, well-nourished haemodialysis patients, in absence of known risk factors for malnutrition, the daily nutrient intake is variable and progressively reduce during the interdialytic interval. The measurement of interdialytic PNA, as is done in clinical practice, does not enable the discovery of such abnormal eating behaviour; the low daily nutrient intake, on the contrary, can be evidenced by the daily measurement of either PNA or weight gain, and it can also be inferred by the reduced PNA during the long interdialytic period. Finally, the persistent reduction in nutrient intake below the threshold of 0.8 g/kg/day of proteins and 25 Kcal/kg/day one day a week, is capable of inducing body protein wasting and moderate impairment of the nutritional status.