Dietary Management for Chronic Kidney Failure
Chronic renal failure is also known as “ureamia”, as the level of urea in blood is very high. When 90% of functioning renal tissue is destroyed ureamia occurs. It may be the acute glomerulonephritis, pyelonephritis and nephrotic syndrome. This articles tell you about the dietary management of chronic kidney failure.
The diet of chronic kidney failure should be palatable, must have varieties, adjusted according to altered biochemistry and physiology (hyperphosphatemia and hypertension) adequate enough for growth in children.
Adequate kilocalories are mandatory. Carbohydrate and fat must supply sufficient non-protein kilocalories to spare protein for tissue protein synthesis and to supply energy. Patients are encouraged to consume all the carbohydrate and fats they can, since the end products of their metabolism, carbon dioxide and water, do not impose a burden on the progressive renal failure.
If energy intake is inadequate, endogenous protein tissue catabolism takes place to supply energy and will further aggravate the existing ureamia. Requirements of calories is similar to the normal requirements.
Protein intake can be reduced to 0.5 g/kg of body weight per day. Failing kidneys need to be given rest. There is then a parallel fall in urea production and fall in blood urea and anorexia and vomiting are relieved. This may result from a reduction in the diffusion of urea from the plasma into the intestinal lumen, Where it is hydrolysed by bacteria to ammonium carbonate. The ammonium ion is a well known gastrointestinal irritant and could thus mediate the potentially toxic effects of increased blood urea.
The ammonia released in the gut is reabsorbed and taken to the liver by the portal circulation where it is either recycled to urea or used for synthesis of non-essential amino acids. This provides an important metabolic pathway which is exploited in patients on very low protein diets in the treatment of severe chronic renal failure. To prevent endogenous losses protein intake should be 0.25 g/kg body weight or 15-20 g daily in older children and adolescents.
Very low protein diets should be advised during severe degree of chronic renal failure.
With these dietetic measures, a patient in whom the GFR has fallen to 2 to 4 ml/min can sustain. Otherwise dialysis would be necessary. In chronic renal failure, the protein intake can be adjusted according to the creatinine clearance. If the patient has a creatinine clearance of 40 ml/min or high no protein restriction should be required.
In general, a patient with creatinine clearance below 8 ml/min requires dialysis and will probably require transplantation.
Fluid And Electrolytes:
In patients with less than 5% of the original functioning kidney tissue, other steps have to be taken in addition to protein restriction to preserve fluid and ionic balance. Oedematic diuresis is secondary to plasma hyperosmolality. thirst controls fluid intake. Increase in fluid intake often increases the excretion of urea. If fluid retention occurs the patient should be given diuretic and sodium should be restricted especially if weight increases in the presence of hyponatraemia. If all the above measures fail, dialysis is considered. The usual fluid permitted is, volume of daily urine plus 500 ml.
Excretion of sodium is more or less constant in chronic renal failure. Ideal intake: 1 to 2 mMol/kg body weight for infants 40-60 mMol/day for older children.
Strict restriction is necessary only if hypertension and oedema are present. 0.2 mMol/kg of body weight/day + diuretics are given until crisis is over.
This has to be restricted to 1 mMol/kg of body weight/day. If not possible, calcium, potassium exchange resin is given. Hypokalemia can occur at any time in chronic renal failure. If it occurs, small dose of potassium should be given and serum levels are motivated.
Hypokalemia occurs only in severe glomerular filtration failure. Treatment is same as in acute renal failure.
A combination of high potassium, low calcium and high magnesium have an adverse effect on heart. Double boiling and draining excess water reduces potassium content.
Also know about: Diet for Chronic Kidney Failure patient.