Renal failure occurs when the kidneys fail to perform their regular function of filtering the wastes from blood and maintaining acid base and mineral balance in the body.

Renal failure can be acute or rapid or sudden in onset where it is termed acute renal failure or acute renal insufficiency. When renal failure occurs after long term kidney disease, it is called chronic renal failure.

Some of the causes of acute renal failure include:-

Causes that lie before the kidneys or prerenal causes

• Severe fall in blood volume that may be caused by dehydration. Dehydration results from severe vomiting, diarrhea, sun exposure, sweating etc.
• Excessive loss of fluids and electrolytes from the gastrointestinal tract due to vomiting or diarrhea
• Excessive fluid loss due to extensive burns
• Severe bleeding due to injuries or other causes
• Anaphylactic shock or severe allergic reaction caused due to certain allergens like peanuts, medications like penicillin etc.
• Septic shock
• Heart failure and cardiogenic shock
• Decrease in renal blood flow due to certain medications and contrast dyes used for imaging studies

Causes that lie within the kidneys or renal causes

• Prolonged lack of blood to the kidney tissues or ischemia
• Acute tubular necrosis
• Due to toxins like heavy metals and organic solvents and drugs that damage the kidneys like aminoglycoside antibiotics (Gentamicin, Amikacin etc.)
• Hemoglobinuria, myoglobinuria, myeloma light chains, or uric acid casts that lead to blockage of the tubules within the kidneys
• Acute glomerulonephritis
• Serious kidney infections of pyelonephritis

Causes that lie beyond the kidneys or postrenal causes

• Obstruction of both ureters stopping urine flow
• Obstruction at the outlet of bladder creating a back flow and pressure of the urine on the kidneys

Causes of chronic renal failure

Chronic renal failure results from long term damage to the kidneys due to disease. Some of the causes include:-

• Diabetic nephropathy or diabetic kidney disease
• Hypertensive nephropathy or kidney damage caused by persistent high blood pressure
• Long term glomerulonephritis
• Polycystic kidney disease