Classification and Causes of Kidney Failure
- Kidney failure can be classified as acute kidney failure or chronic kidney failure.
- Acute kidney failure develops rapidly and may resolve, while chronic kidney failure develops slowly and can often be irreversible.
- Symptoms of kidney failure include leg swelling, feeling tired, vomiting, loss of appetite, and confusion.
- Complications of kidney failure include uremia, hyperkalemia, volume overload, heart disease, high blood pressure, and anemia.
- Causes of kidney failure include low blood pressure, urinary tract blockage, certain medications, muscle breakdown, diabetes, high blood pressure, nephrotic syndrome, and polycystic kidney disease.
- Acute kidney failure can result from prerenal, intrinsic, or postrenal causes.
- Chronic kidney failure can also present as acute-on-chronic kidney failure, which may be reversible.
- The most common causes of chronic kidney failure are diabetes mellitus and long-term, uncontrolled hypertension.
- Polycystic kidney disease is another well-known cause.
- Chronic kidney failure can also be a consequence of other diseases or conditions.
- Drug overdoses or chemical overload can cause acute kidney injury, which may progress to chronic kidney failure.
- Crush syndrome, resulting from the release of toxins after the relief of pressure on a compressed limb, can also lead to chronic kidney failure.
- The APOL1 gene is a major genetic risk locus for renal failure in individuals of African origin.
- Two western African variants in APOL1 are associated with end stage kidney disease in African Americans and Hispanic Americans.

Symptoms and Diagnostic Approach
- Symptoms of kidney failure can vary from person to person.
- Early stage kidney disease may not cause noticeable symptoms.
- Azotemia, the accumulation of waste in the blood and body, can lead to symptoms.
- Symptoms of kidney failure include high levels of urea in the blood, vomiting or diarrhea, nausea, weight loss, and acute kidney injury.
- Acute kidney injury (AKI) occurs when the blood supply to the kidneys is suddenly interrupted or when the kidneys become overloaded with toxins.
- Chronic kidney failure is measured in five stages based on the glomerular filtration rate (GFR).
- Stage 1 CKD has mildly diminished renal function with few symptoms.
- Stages 2 and 3 require increasing levels of supportive care.
- Stage 4 and 5 kidney failure usually require active treatment such as dialysis or transplant.
- GFR is considered the best overall index of kidney function.
- Glomerular filtration rate (GFR) varies according to factors such as sex, age, body size, and ethnic background.
- GFR is calculated using a serum creatinine level.
- The National Kidney Foundation offers an online GFR calculator.
- GFR is used to determine the stage of kidney failure.
- A low GFR indicates reduced kidney function.
- The renal failure index (RFI) is calculated by multiplying urine sodium by plasma creatinine and dividing by urine creatinine.
- A renal failure index (RFI) greater than 3 is helpful in confirming acute renal failure.
- The fractional sodium excretion (FENa) index is another urinary index used in diagnosing renal failure.
- Both RFI and FENa scores are used to assess kidney function.
- Abnormal RFI and FENa scores indicate renal dysfunction.

Management and Treatment of Kidney Failure
- Protein diet restriction
- Vegetarianism in chronic kidney disease patients
- Safety of high-protein, vegetable-based diets for kidney function
- Early referral to specialist nephrology services
- Current medical diagnosis and treatment options

Complications of Kidney Failure
- Cardiovascular disease
- Anemia
- Bone disease
- Fluid overload
- Electrolyte imbalances

Prevention of Kidney Failure
- Control of arterial hypertension
- Avoidance of nephrotoxic medications
- Hygiene and prevention of hantavirus infection
- Genetic testing for MYH9-associated nephropathy and ApoL1 gene mutations
- Healthy lifestyle choices to maintain kidney health