Monica Adhikari
Consultant Dietician, Great Ormond Street Hospital, London.

Chronic renal failure (CRF) is a disease in which the kidneys gradually stop working over a period of few years.

In a healthy body, the kidneys filter waste and other impurities from the blood. In people with CRF, toxins that the kidneys normally eliminate in urine slowly build up in the body. The most commonly measured of these toxins are urea-a nitrogen waste product and creatinine. The amount of toxins in the blood roughly indicates how well the kidneys are working. In CRF the nephrons (functional unit of kidneys) are gradually and progressively destroyed and the remaining nephrons hypertrophy (increase in size) to maintain normal functioning of the kidney..With the destruction of 80% of nephrons, the functions are affected seriously and the patient goes into uremia (presence of large amounts of end products of protein metabolism such as urea, creatinine, uric acid in blood) characterized by nausea, vomiting, headache, diminished vision and at times convulsions.

Signs and symptoms: The symptoms associated with CRF are progressive weakness, shortness of breath, lethargy, fatigue, weight loss, anorexia (loss of appetite), mouth ulceration, metallic taste, frequent hiccups, increased aches and pains in joints due to osteodystrophy(bone disease), increased or decreased urine output depending on the stage of CRF.

Causes and risks: A primary kidney disease may cause CRF. It may also be due to other diseases that affect kidneys such as diabetes, high blood pressure, glomerulonephritis (the swelling of the glomerulus which is the part of the kidneys consisting of blood vessels and nerve fibres), polycystic kidneys (a condition in which the kidneys become enlarged and grow cysts), uropathy (any condition that blocks the flow of urine) or cancer of the bone marrow.

Since many diseases lead to CRF, the diagnoses of diseases causing CRF can vary. There are a few common abnormalities associated with the condition. For instance: Urinalysis may show protein, red blood cells or different types of casts (structures made when minerals collect on the walls of the kidney). A blood sample may show elevated creatinine and urea nitrogen which are both toxins. Levels of erythropoietin- a hormone produced by the kidneys may be low. Levels of serum potassium, phosphorus, Parathyroid hormone, magnesium may be high with/without low levels of calcium. Malnourishment can occur. Treatment involves dialysis at regular intervals with ultimately renal transplant.