Kidney failure, also called renal failure, describes a condition in which the kidneys can no longer perform their essential tasks of filtering waste, balancing fluids and electrolytes, and regulating blood pressure. Clinically it is divided into two broad categories: chronic kidney disease that progresses over months to years, and acute kidney injury that develops over hours to days and may be reversible.
Common signs, tests, and clinical features
Symptoms range from subtle to severe and can include reduced urine output, swelling of the legs or face, persistent fatigue, nausea, confusion, and shortness of breath. Healthcare providers evaluate suspected kidney failure with blood tests (including creatinine and blood urea nitrogen), urine analysis, and imaging studies. A calculated glomerular filtration measure is commonly used to estimate kidney function and to stage chronic disease.
Causes and risk factors
- Metabolic diseases: diabetes mellitus and high blood pressure are the leading contributors to progressive kidney damage.
- Obstruction: blockages of the urinary tract from stones, tumors, or enlarged prostate can impair function.
- Infections and immune disorders: severe infections or autoimmune conditions can injure kidney tissue.
- Medications and toxins: some pain relievers, antibiotics and contrast agents can be nephrotoxic, especially when combined with dehydration.
- Reduced blood flow: shock, heart failure, or major surgery may precipitate acute injury.
Diagnosis and management
Management depends on cause and acuity. Acute kidney injury often requires identifying and removing the precipitant, correcting fluid and electrolyte imbalances, and short-term supportive care. Chronic kidney disease is managed by treating underlying conditions, controlling blood pressure and metabolic complications, and slowing progression with lifestyle and pharmacologic measures.
When kidney function falls below a threshold necessary to sustain life, renal replacement therapy is used. Options include hemodialysis (blood filtered through a machine), peritoneal dialysis (using the abdominal lining as a filter), and kidney transplantation, which provides the closest restoration of normal function when a suitable organ is available.
Historically, treatments such as dialysis and transplantation became widely available in the mid‑20th century and transformed outcomes for many patients. Prognosis depends on the underlying cause, speed of onset, coexisting illnesses and access to treatment. Preventive measures—good control of diabetes and hypertension, cautious use of potentially nephrotoxic drugs, staying hydrated during illness, and regular monitoring in at-risk people—reduce the likelihood or slow the progression of kidney failure.
For more detailed clinical guidance, specialists and patient resources can provide information about staging, local treatment options and living donation programs. Early detection and coordinated care are central to improving long-term outcomes.