The kidneys are responsible for filtering fluid and electrolytes out of the bloodstream, then excreting them out of the body through the urine. Renal (kidney) function can be affected by many different types of acute and chronic illnesses. Both diabetes and CHF can significantly affect kidney function in the short term and the long term. Any significant fluctuation of any chronic illness can also impact kidney function, sometimes seriously. Obstruction of urine flow out of the bladder can cause a back-up of urine in the kidneys, which can also affect kidney function.
When kidney function is severely weakened (either acutely or chronically), some people are required to undergo periodic dialysis treatments (usually lasting several hours at a time). Dialysis is when a patient is connected to a machine by a catheter that is inserted into a vein. This allows the dialysis machine to perform the filtering function that the weakened kidneys are unable to do on their own. Dialysis can be used temporarily for a short term (in the setting of an acute illness in the hospital) or can also be utilized chronically on a permanent outpatient basis.
The two simple blood laboratory tests that are usually used to measure kidney function are the BUN and the creatinine. The creatinine is the most commonly used laboratory test to evaluate kidney function. A “normal” creatinine lab value is between 0.7 – 1.4. Significant kidney failure is seen when the creatinine is greater than 3.0.
A kidney ultrasound can be performed to measure whether there is a back-up of urine in the kidneys, due to obstruction of urine flow out of the bladder (a condition known as “hydronephrosis”). A urine test (urinalysis) can also be performed to assess the urine for a select few kidney conditions.
Acute Tubular Necrosis (“ATN”) is a serious temporary kidney condition, notable for injury to the kidney that results in significant weakening of kidney function, and on rare occasions, requires temporary dialysis to stabilize kidney function until it recovers on its own. It is not well-understood what causes ATN or can precipitate ATN, as there are many various potential diverse causes.
Renal function medical expert witness specialties include nephrology, pediatric nephrology, urology, renal pathology, pathology, and dialysis nursing.