Renal Diseases

Disease / Phenomenon

Renal diseases impair the kidneys' ability to filter blood, regulate fluid and electrolyte balance, control blood pressure, maintain acid-base equilibrium, activate vitamin D, and stimulate red blood cell production through erythropoietin. Chronic kidney disease develops silently over years, often without symptoms until substantial function is lost, which is why it is frequently detected incidentally through elevated creatinine or protein in the urine. Diabetes and hypertension are the leading causes worldwide, followed by glomerulonephritis, polycystic kidney disease, and recurrent obstruction or infection. Acute kidney injury, by contrast, develops over hours to days from ischemia, sepsis, or nephrotoxic exposure, and may resolve or leave lasting damage.

Progression follows recognizable biology. Glomerular hyperfiltration and podocyte injury permit protein leakage, and filtered protein itself provokes tubular inflammation. Renin-angiotensin-aldosterone system activation raises intraglomerular pressure and drives fibrosis through angiotensin II and TGF-beta signaling. Tubulointerstitial inflammation involves NF-kB activation, IL-6, TNF-alpha, and complement, while hypoxia, oxidative stress from NADPH oxidase activity, and mitochondrial dysfunction sustain injury. Epithelial-mesenchymal changes and myofibroblast expansion deposit collagen, replacing functional nephrons. Mineral and bone disorder, anemia, and uremic toxin accumulation follow. This page separates these processes into their pathways and measurable biomarkers.