Nephrology

Nephrology is the internal medicine subspecialty focused on kidney health — the diagnosis, treatment, and management of conditions affecting the kidneys and their regulation of fluid, electrolyte, and acid-base balance. Nephrologists manage the full spectrum from early chronic kidney disease (CKD) to end-stage renal disease (ESRD) requiring renal replacement therapy. Chronic kidney disease affects approximately 37 million Americans (15% of the adult population), with diabetes and hypertension being the leading causes. Nephrologists coordinate multifactorial risk factor modification — tight blood pressure control (target <130/80 mmHg), renin-angiotensin-aldosterone system (RAAS) blockade with ACE inhibitors or ARBs, SGLT-2 inhibitors (which have shown significant nephroprotective effects in addition to glycemic control), and dietary protein and potassium restriction to slow CKD progression. Glomerular diseases — including IgA nephropathy, membranous nephropathy, focal segmental glomerulosclerosis (FSGS), lupus nephritis, and rapidly progressive glomerulonephritis (RPGN) — require kidney biopsy for definitive diagnosis and immunosuppressive therapy tailored to histological findings. Complement-targeted therapies and novel biologics have recently transformed treatment of some glomerulonephropathies. Acute kidney injury (AKI) complicates 10–15% of all hospital admissions and up to 50% of ICU admissions. Nephrologists consult on AKI etiology (prerenal, intrinsic renal, postrenal), management, and initiation of renal replacement therapy when indicated. Dialysis modalities — hemodialysis (three times weekly at outpatient centers or daily home hemodialysis) and peritoneal dialysis (performed by patients at home) — sustain approximately 500,000 ESRD patients in the U.S. Kidney transplantation offers superior outcomes — nephrologists manage immunosuppression protocols and monitor for rejection and chronic allograft nephropathy.