Blood urea nitrogen, often called BUN, and creatinine are two waste produced in humans that are excreted by the kidney. Doctors commonly measure the BUN and creatinine to assess the health of the kidneys. In people with kidney disease, these substances can accumulate. Children with acute or chronic kidney failure may need dialysis, and using the BUN and creatinine levels can help to assess the degree of damage. Changes in these values may indicate the need to perform dialysis.
BUN and Creatinine in Renal Failure
Elevated BUN and creatinine levels are frequently seen in cases of renal failure. According to "Nelson's Pediatrics," creatinine levels normally range between 0.3 to 0.7 mg/dl. Small rises of creatinine can indicate serious kidney disease. BUN levels usually range from 5 to 18 mg/dl in the pediatric age group. By checking a child's values, doctors can determine whether kidney failure is present. In cases of acute kidney failure, doctors can use these values to determine what the cause of the kidney failure may be.
Dialysis in Acute Renal Failure
The decision to start dialysis in acute renal failure is based on symptoms or laboratory values that indicate life threatening complications. Excessive fluid accumulation in the lungs and alteration of brain function may require dialysis to remove the excess fluids. Accumulation of potassium in the blood can cause changes in the heart rhythm and requires dialysis to quickly remove the ion. Changes in pH and dangerously low calcium levels in the body also indicate a need for dialysis. BUN is rarely used to determine the need for dialysis, but levels exceeding 100 to 150 mg/dl or rapidly increasing levels warrant such treatment. Most patients with dialysis for acute renal failure need treatment for one to three weeks.
Dialysis in Chronic Renal Failure
Persistent elevated BUN and creatinine occur in cases of chronic renal failure. Dialysis is often needed in these patients once the function of the kidneys has deteriorated to a level that can no longer support life. Doctors use serum creatinine levels to calculate the degree of renal function and should check them periodically on patient visits. The loss of kidney function is classified into five stages of disease. Children who reach stage 4 kidney disease are recommended to undergo dialysis to remove toxic wastes would otherwise accumulate and cause complications.
Kinds of Dialysis
There are two major kinds of dialysis; the decision to use one or the other depends on the cause of kidney disease, the needs of the patient, and the duration of time for which dialysis is needed. Peritoneal dialysis uses a membrane within the abdomen to act as a filter to purify the blood. Peritoneal dialysis is often easier for children as treatment can be given at home. Infections are the major risk associated with this method. Hemodialysis, done using an external machine to purify the blood, may be needed for long-term treatment in some children. Children have several sessions each week and need to visit hospitals to get this treatment.
References
- "Nelson Textbook of Pediatrics"; Kliegman, et al.; 2008
- MayoClinic; Peritoneal Dialysis; December 2010
- MayoClinic; Hemodialysis; December 2010
