Urine concentration impairment in sickle cell anemia: genuine nephrogenic diabetes insipidus or osmotic diuresis?

The objective of the present study was to investigate the mechanism of hyposthenuria in patients with sickle cell anemia. We performed an observational study of patients with homozygous SS sickle cell anemia and data available on the fasting plasma antidiuretic hormone (ADH) concentration. A total of 55 patients were analyzed. The fasting plasma ADH values ranged from 1.2 to 15.4 pg/mL, and 82% of the patients had elevated ADH values and low fasting urine osmolality (<505 mOsm/kg). Plasma ADH was negatively associated with plasma tonicity and natremia (P <0.001). None of the patients experienced polyuria and fasting free water clearance was negative in all cases - thus ruling out nephrogenic diabetes insipidus. The tertile groups did not differ with regard to fasting urine osmolality, plasma renin level, mGFR, or several hemolysis biomarkers. The negative fasting free water clearance in all cases and the strong association between 24-hour osmolal clearance and 24-hour diuresis favors the diagnosis of osmotic diuresis due to an impaired medullary gradient, rather than lesions to collecting tubule.PMID:38059298 | DOI:10.1152/ajprenal.00313.2023
Source: Am J Physiol Renal P... - Category: Urology & Nephrology Authors: Source Type: research