Kidneys [nephros in Greek] are the filters that clean the blood of all the waste introduced into it by the human physiological functions. The two fist-sized organs within the abdomen contain millions of minute filters, running up to more than 200 km in length that filter out nearly 200 litres of fluid everyday. The kidneys assiduously maintain the levels of water, sodium and other salts, produce hormones that maintain blood pressure and red blood cell numbers, and play a vital role in maintaining calcium levels in the blood. Being of such importance, kidneys have a vast reserve capacity, and these functions can remain normal even at about 10-15 per cent of efficiency. It, therefore, takes a significant reduction in the capacity of the kidneys to manifest as kidney failure.
What is Chronic Renal Failure?
A gradual and progressive decline in kidney function is termed as Chronic Kidney [Renal] Failure. Nephrons, the functioning units of the kidneys, get damaged over time and in the initial stages, the loss of nephrons is compensated by the increased functioning of the remaining nephrons. With increased loss of nephrons, the compensation fails and various manifestations of kidney failure start appearing.
The causes for chronic kidney failure are many and the risk increases with age. Diabetes mellitus is the cause for chronic kidney failure in nearly 40 per cent of patients. The damage to the kidneys starts right in the initial stages of diabetes mellitus and gradually worsens over 5-10 years, more so with uncontrolled blood sugar levels. The first indicator of renal damage in diabetes appears in the form of leakage of micro quantities of the protein called albumin in the urine [the so-called microalbuminuria] and later this protein leak increases, eventually leading to final-stage renal disease. High blood pressure [hypertension] also damages the nephrons and is an important cause for chronic kidney failure in about one-third of patients. Primary diseases of the glomeruli [a cluster of convoluted capillaries in the nephron of a kidney], certain infections, drugs, hereditary diseases, and others account for the rest of the cases of chronic kidney failure. It is noteworthy that most of the causes of chronic kidney failure are preventable.
The manifestations of chronic kidney failure are due to the accumulation of the wastes that are toxic to the body, due to changes in blood pressure, reduction in red cell count [anaemia], inability to maintain the balance of water and salts and of acids and bases, imbalance in the levels of salts like potassium, and changes in the levels of calcium and phosphorus. All these changes develop into a vicious spiral as the disease progresses, affecting the nervous system, the heart, the gut, the bones, and eventually become fatal.
Symptoms of chronic kidney failure develop slowly and are often non-specific. While in diabetes and hypertension, the problem may be identified during the routine follow-up by the treating physician, primary kidney diseases that end up as chronic kidney failure are often identified in patients with high blood pressure and anaemia. Lack of appetite, altered taste, vomiting sensation or even vomiting [sometimes in the morning], and tiredness are some common complaints. Patients may also have increased urination at night. Soreness of the tongue, generalised itching, muscle cramps and bone pains may be other symptoms. In terminal stages, patients may become drowsy or even comatose, and have deep breathing due to accumulation of acids in the blood.
Confirmation of the diagnosis of chronic kidney failure is not difficult. A blood test will reveal raised levels of blood urea and creatinine, and changes in the levels of potassium and calcium. Examination of the urine may help in identifying the cause of the kidney disease. An ultrasound evaluation of the kidneys for their size and texture may be useful in identifying the causes as well as differentiating the chronic, irreversible kidney failure from the acute, reversible failure.
Measures to be taken
As chronic kidney disease is irreversible, patients who have reached the last stage of kidney failure would need replacement of the kidney by way of transplantation from a healthy, related donor. In the initial stages however, the progression of kidney failure can be checked by proper care and medications. The underlying diseases need to be effectively controlled. Control of blood sugar and blood pressure is of utmost importance. Restriction of salt in the diet helps in controlling the blood pressure and reduces the load on the kidneys. Foods that contain high amounts of potassium like fruits and vegetables may have to be restricted if the potassium levels are very high. Intake of proteins has to be adjusted to the level of protein loss in the urine and increasing levels of blood urea and creatinine. Multivitamins, particularly vitamin D, may have to be supplemented. Ptients with anaemia need to take regular injections of the hormone erythropoietin, so as to increase the production of red cells in the bone marrow. When the urine output is reduced, drugs like furoscemide help in reducing the fluid overload.
When these measures become inadequate to maintain the renal function, regular dialysis [method of removing impurities or wastes from the blood when the kidneys are unable to do so], followed by kidney transplantation, is the only hope. However, these measures are not only expensive, but need utmost commitment from the patient and the relatives. With such facilities being available in most parts of the country, awareness regarding these options is also growing. However, financial considerations remain the biggest obstacle in obtaining these measures for many.