Management of Chronic Renal Failure

February 09, 2013

Definition- Chronic renal failure or CKD (chronic kidney disease) is defined as renal dysfunction which is irreversible unlike acute renal failure. Causes of CKD include DM, analgesic abuse, chronic glomerulonephritis, hypertension, polycystic kidney, medullary cystic kidneys etc.

CKD is a continuum ranging from stage 1 which is the earliest stage to stage 5 which is also referred to as end stage renal failure (ESRF).Diagnosis of CKD is based on history like history of DM, analgesic abuse, obstruction like renal stones supported by renal imaging like renal ultrasound and blood test of urea, creatinine and estimation of GFR.When seeing a patient for first time, it is important to always assume it is acute renal failure until proven otherwise. This requires repeat test like blood test. It is advisable that patient be referred to a nephrologist for initial workout to confirm the diagnosis and rule out any reversible factors which may be contributing to the kidney failure. Once this is done, patient may be followed up by his regular doctor. When he approaches advanced renal failure, he should be referred back to the nephrologist for counselling and prepare for renal replacement therapy. It is to be noted that not all CKD patients will reach ESRF.A proportion of them dies before reaching the terminal state and the major cause of mortality in CKD patients are cardiovascular events. Patients should preferably be followed up by a particular doctor who keeps track of his regular blood results like creatinine and urea. Over a period of time, based on the test results, a rough prediction of when ESRF occurs can be made.Meanwhile, treatment is conservative including lifestyle, dietary modification and medications.

A low protein diet of 0.8-1 gram/kg/day is advised. Low protein diet slows progression of renal failure by reducing intraglomerular pressure. Malnutrition with low albumin level on the other hand must be avoided, as hypoalbuminaemia is a predictor of increased mortality.

Nephrotoxic drugs like NSAID and traditional medicine must be avoided. I have encountered patients who insisted on seeing sinsehs who assure them that they can be cured and dialysis is not necessary. It is difficult if not impossible to convince them otherwise. Nevertheless, it is our responsibility to explain to them so they can at least make an informed choice. When patient is oliguric, salt and water need to be restricted.

Activation of vitamin D occurs at the liver and kidneys. Impaired activation of vitamin D causes renal osteodystrophy.Phosphate retention is another factor. To reduce the phosphate level, phosphate binders are used. Commonly used are CaCO3 which binds phosphate and is also a source of calcium. Newer agents like lantanum carbonate are much more expensive. When a patient reaches stage 3 of CKD, addition of vitamin D analogues will suppress SHPT (secondary hyperparathyroidism).

Hypertension must be treated aggressively as hypertension accelerates renal damage. The aim is to bring down the BP with whatever drugs.ACEI/ARB are shown to have effects beyond BP lowering in proteinuric renal disease. One has to be aware of its hyperkalaemic effect and effect in lowering GFR.

CKD is recognised to predispose to coronary heart disease and all risk factors must be addressed. The usual principle applies. Stop smoking, exercise, and loose weight. Treatment of dyslipidaemia in CKD is now advocated following the result of SHARP (study of heart and renal protection) which shows that treatment with simvastatin and ezetimide in CKD patients reduces mortality from cardiovascular disease and strokes. Reduced dosage of statins may be considered.

In DM, tight glycaemic control slows renal dysfunction. My preference is to use insulin, though oral hypoglycaemics like second generation sulphonylurea are claimed to be safe in renal impairment, albeit in reduced dosage. It is important to ensure that tight glycaemic control should not be at the expense of frequent hypoglycaemia which is deleterious. In certain groups like in advanced age with multiple co morbid conditions like CHD stroke and is not expected to live long, a certain degree of allowance is necessary as tight control is of not much benefit.

Erythropoietin produced by kidneys stimulate RBC production and lack of this hormone contributes to anaemia of CKD.A high proportion of patients with CKD are also deficient in iron, and iron supplements or haematics are routinely given unless contraindicated like in thalassaemia or carrier state. Correction of anaemia has been shown to improve quality of life, exercise tolerance and cardio respiratory function. Use of erythropoietin may be started in the predialysis stage. Various preparations are available. Some are given 2x or 3x per week. Some are given once a month.

When the patient is approaching ESRF, he should be referred to a nephrologist for counselling on the various options. Family members are to be involved. The options available are haemodialysis, peritoneal dialysis i.e. continuous ambulatory peritoneal dialysis (CAPD) and renal transplant. Patients at advanced age with multiple complications like retinopathy, neuropathy, CHD and cerebrovascular disease generally have poor outcome inspite of dialysis. In this group it is justified to advise against dialysis but to opt for conservative management i.e. to optimise medical treatment and allow nature to take it’scourse.For those who opt for dialysis even for CAPD,it is imperative that long before the expected onset of ESRF,at least 6 months, they should be referred for the construction of an arteriovenous fistula(AVF).This is usually done by a urologist or a vascular surgeon. An AVF takes time to mature, at least a month or longer. Diabetic patients with vasculopathy take much longer to mature and even need repeat construction. The advantage of having an AVF on standby is that anytime haemodialysis is required, there is no worry of vascular access. Patients who have not reached ESRF may occasionally be admitted for acute on chronic renal failure precipitated by events like sepsis, dehydration, ingestion of nephrotoxic drugs. A period of temporary dialysis is required. An AVF will save the patient and the doctor the hassle of having to insert an internal jugular catheter for temporary vascular access

Dr. Ng Butt Chin
Consultant Physician