• chronic glomerulonephritis,
• hypertensive nephrosclerosis,
• diabetic nephropathy
• Urinary calculi.

In the early stage, lost of renal function will not cause much symptoms. When the creatinine clearance falls to around 40 ml/minute, patient may start to notice general malaise or anorexia. Treatment is by conservative means.

When the creatinine falls to around 5-10 ml/minute, symptoms of end-stage renal failure or uraemia will occur. Treatment at this stage is by dialysis or renal transplantation which is collectively known as renal replacement therapy.

The number of new patients requiring renal replacement therapy in Hong Kong is around 102/million population per year. Haemodialysis and renal transplantation treatment was started in Hong Kong at around 1969. Continuous ambulatory peritoneal dialysis (CAPD) was introduced to Hong Kong in 1980, and this has become the major mode of treatment.

1. Search for treatable factors

• When a patient presents to the doctor with renal failure, every effort should be made to search for some correctable factors such as urinary tract obstruction or rapidly progressive glomerulonephritis.

2. Good medical Control

• Correction of hypertension is the single most important medical intervention which can delay the progression of renal failure. An ACE inhibitor may offer additional benefit, the main problem is it may cause coughing in many Chinese patients.
• Dietary protein restriction will reduce the uraemic symptoms. It may also reduce the rate of renal deterioration.

Using the above treatment, the development of end stage renal failure will be delayed. If the patient does develop end stage renal failure, he would experience weakness, general malaise or fluid retention. In Hong Kong, many patients seek medical treatment late and they may go to the emergency room presenting as acute pulmonary oedema.

Renal replacement is needed if the patient develops uraemic symptoms despite conservative treatment. The options include haemodialysis, CAPD or renal transplantation.

A patient is usually advised to have renal dialysis if the serum creatinine is about 1000 umol/l. If one plot the reciprocal of the serum creatinine against time, the line is roughly linear and this can allow the physician to have a rough estimation of the time when dialysis is needed and he can make preparations for the dialysis in advance. To increase the predictive value, there are preESRD calculators in the Internet (http://www.nephron.com/preESRDcalc.html) which can take into account of additional factors like the mean arterial blood pressure, blood urea nitrogen and allow better prediction of the rate of renal deterioration.

It is dangerous to make the decision on when to recommend dialysis just by serum creatinine or blood urea alone. Since serum creatinine is a product of muscle metabolism, the serum level is directly proportional to the muscle mass. Hence if a chronic renal failure patient developed muscle wasting because of chronic malnutrition, his serum creatinine may fall despite a deterioration in renal function. Similarly, an ureamic patient may have very low protein intake because of anorexia, and the blood urea may fall as a result of the protein intake alone. A more reliable parameter is the creatinine clearance which is an estimation of the glomerular filtration rate, renal replacement therapy is advised if the creatinine clearance falls below 10 ml/minute.

Since creatinine is also secreted in the renal tubules in addition to glomerular filtration, creatinine clearance may over-estimate the glomerular filtration rate. Recently, it is advocated that the tubular secretion can be blocked by giving the patient a single dose of cimetadine by mouth, this simple method enhances the accuracy of creatinine clearance in the estimation of glomerular filtration rate.

Haemodialysis, CAPD or renal transplantation is not mutually exclusive. Usually a patient can be put either on haemodialysis or CAPD. The choice includes the availability of the service, the preference of the patient and the medical indication. Renal transplantation is the best option for surgically fit patients. If the graft fails, the patients can be put back to dialysis.