Chronic renal failure is a slowly worsening loss of the ability of the kidneys to remove wastes, concentrate urine, and conserve electrolytes.

Unlike acute renal failure, chronic renal failure slowly gets worse. It most often results from any disease that causes gradual loss of kidney function. It can range from mild dysfunction to severe kidney failure. The disease may lead to end-stage renal disease (ESRD).

Chronic renal failure usually occurs over a number of years as the internal structures of the kidney are slowly damaged. In the early stages, there may be no symptoms. In fact, progression may be so slow that symptoms do not occur until kidney function is less than one-tenth of normal.

Chronic renal failure and ESRD affect more than 2 out of 1,000 people in the United States. Diabetes and high blood pressure are the two most common causes and account for most cases. Other major causes include:

• Alport syndrome
• Analgesic nephropathy
• Glomerulonephritis of any type (one of the most common causes)
• Kidney stones and infection
• Obstructive uropathy
• Polycystic kidney disease
• Reflux nephropathy

Chronic renal failure results in an accumulation of fluid and waste products in the body, leading to a build up of nitrogen waste products in the blood (azotemia) and general ill health. Most body systems are affected by chronic renal failure.

Initial symptoms may include the following:

• Fatigue
• Frequent hiccups
• General ill feeling
• Generalized itching (pruritus)
• Headache
• Nausea, vomiting
• Unintentional weight loss

Later symptoms may include the following:

• Blood in the vomit or in stools
• Decreased alertness, including drowsiness,confusion, delirium, orcoma
• Decreased sensation in the hands, feet, or other areas
• Easy bruising or bleeding
• Increased or decreased urine output
• Muscle twitching or cramps
• Seizures
• White crystals in and on the skin (uremic frost)

Additional symptoms that may be associated with this disease:

• Abnormally dark or light skin
• Agitation
• Breath odor
• Excessive nighttime urination
• Excessive thirst
• High blood pressure
• Loss of appetite
• Nail abnormalities
• Paleness

There may be mild to severe high blood pressure. A neurologic examination may show polyneuropathy. Abnormal heart or lung sounds may be heard with a stethoscope.

A urinalysis may show protein or other abnormalities. An abnormal urinalysis may occur 6 months to 10 or more years before symptoms appear.

• Creatinine levels progressively increase.
• BUN is progressively increased.
• Creatinine clearance progressively decreases.
• Potassium test may show elevated levels.
• Arterial blood gas and blood chemistry analysis may show metabolic acidosis.

Signs of chronic renal failure, including both kidneys being smaller than normal, may be seen on:

• Abdominal CT scan
• Abdominal MRI
• Abdominal ultrasound
• X-rays of the kidneys and abdomen

This disease may also alter the results of the following tests:

• Erythropoietin
• PTH
• Renal scan
• Serum magnesium - test
• Urinary casts