Renal disease: causes, types, diagnosis and treatment

Causes and common mechanisms

Many different processes can damage the kidneys. Common systemic causes and mechanisms include:

• Metabolic disease such as diabetes mellitus, which causes diabetic nephropathy through long-term high blood glucose and vascular injury (see diabetes-related kidney damage).
• Chronic high blood pressure (hypertension), which damages renal blood vessels and accelerates loss of function (hypertension and kidneys).
• Nephrotoxic medications and substances. Long-term use of certain pain medicines and other drugs can reduce kidney function; common examples include some nonsteroidal anti-inflammatory drugs and specific antibiotics (drug-induced kidney injury).
• Immune-related injury and transplant-related toxicity: immunosuppressant drugs used after organ transplantation may adversely affect kidney function (transplantation and renal effects, immunosuppression concerns).
• Infections and viral causes, including HIV and chronic viral hepatitis, which may produce glomerular disease (viral-associated kidney disease, HIV-related nephropathy).
• Environmental and toxic exposures such as aristolochic acid, associated with a distinct form of nephropathy in contaminated foodstuffs or herbal preparations (aristolochic acid nephropathy).

Types and distinctions

Clinicians commonly distinguish acute kidney injury (AKI) — a rapid decline in function over hours to days — from CKD, a progressive loss over months to years. Other important clinical categories include:

• Glomerular diseases (nephritic or nephrotic syndromes) characterized by proteinuria and blood in the urine.
• Interstitial and tubular disorders driven by toxins, drugs or infections.
• Congenital and structural diseases such as polycystic kidney disease or urinary tract obstruction.

Symptoms, diagnosis and tests

Early kidney disease may be silent; signs become evident as function declines. Patients can develop swelling (edema), fatigue, changes in urine output or appearance, and symptoms from electrolyte imbalance. Clinicians rely on simple tests to detect and stage disease: blood creatinine and estimated glomerular filtration rate (eGFR), urine protein or albumin measurements, urinalysis, imaging (ultrasound/CT) and, when needed, kidney biopsy. For introductory resources and clinical guidance consult diagnostic approaches.

Treatment, management and prevention

Treatment focuses on addressing the underlying cause, slowing progression, and managing complications. Common approaches include blood pressure control (often with ACE inhibitors or ARBs), optimal glucose control in diabetes, avoiding or adjusting nephrotoxic medications, treating infections, and dietary measures. Advanced or end-stage kidney disease is managed with dialysis or kidney transplantation; post-transplant care requires lifelong immunosuppression and surveillance (transplant care, immunosuppressant effects).

History, importance and notable facts

Recognition of kidney disease spans centuries, with advances in understanding glomerular structure, the role of blood pressure and metabolic disease emerging in the 19th–20th centuries. Today CKD is an important public health issue because of its links to cardiovascular disease and its rising prevalence with aging populations and increasing rates of diabetes and hypertension. Awareness, early detection and risk-factor management are key public-health strategies; authoritative clinical information and patient resources are available at many professional and public health sites (hypertension resources, general resources). Additional clinical summaries and topic-specific reviews can be found through specialty or guideline portals (medication safety, toxic exposures, infectious causes).