Acute Renal Failure

Acute Renal Failure (ARF) is a rapid loss of renal function due to damage to the kidneys, resulting in retention of nitrogeneous (urea and creatinine) and non-nitrogenous waste products that are normally excreted by the kidney. Depending on severity and duration it is also accompanied by metabolic acidosis (acidification of blood) and hyperkalaemia (elevated potassium levels), changes in body fluid balance, and effects on many other organ systems. It can be characterized by oliguria or anuria (decrease or cessation of urine production), although non-oliguric ARF may occur.

ARF is infact a sudden loss of the ability of the kidneys to excrete waste, concentrate urine and conserve electrolytes. It is a serious condition characterized by a sudden shutdown of kidney function due to decreased renal flow, acute glomerular or tubular damage. It results in decline in Glomerular Filtration rate (GFR), associated with azotemia (accumulation of nitrogenous waste products in the blood) and fall in urine output.

The causes of ARF are circulatory shock, large blood loss and reduced renal blood flow as in traumatic injury, shock, severe burns, surgery, septicemia, dehydration and fluid loss; mismatched blood transfusuions, nephrotoxins like carbon tetrachloride, certain poisonous mushrooms, infections, snake bite, bee sting, immunological reactions to drugs like certain antibiotics and renal diseases like acute glomerulonephritis.

The onset of ARF is sudden with the course of the disorder having two phases, Oliguria or initial acute phase and diuretic phase.

The common nutritional problems include poor appetite, inability to take food/ fluids orally due to intubation and hypercatabolism (increased metabolism) due to underlying illnesses such as infection, postoperative healing.

Diet therapy in this condition focuses on re-establishment of fluid electrolyte balance, maintenance of acceptable levels of bloodurea and creatinine while supporting tissue healing and making up catabolic losses and preventing infection.

The dietary guidelines in ARF are as follows:

Nutrients	Note
Calories	Provide sufficient amount for weight maintenance or 30-40 Kcal/Kg. Increase to 40-45 Kcal/kg in hypercatabolic subjects. Encourage non-protein calories from fats and simple carbohydrates.
Proteins	If not on dialysis, 0.6 g/kg/day. If on dialysis, 1-1.2 g/kg from dietary or parenteral sources.
Sodium	In oliguric phase, restrict to 500-1000mg. On dieresis, the amount may be increased.
Potassium	If hyperkalemia is present restrict to 1000-2000 mg. On improvement increase to 60-70 mEq.
Fluids	Limit fluids to an amount equal to urine volume plus 500 ml.

Also read about other Diseases of the Kidney in the Diet Corner column.

Post by Faiz Lahori