Colonoscopy is widely recognized as one of today's most effective diagnostic tools for the early detection of certain cancers. Regular screening with this procedure has become an important part of the well-patient physical exam.

One frequently prescribed bowel preparation regimen is an oral sodium phosphate solution ("OSPS") sold by various drug stores, and marketed by CB Fleet Co., Inc. as Phospho-soda® in liquid form or in tablet form as Visicol®. Alternative bowel cleansing preparations are available and should be discussed with your health-care professional.

In 2004, Dr. Glen S. Markowitz of the Columbia University Medical School and a team of pathologists and nephrologists reported on a cohort of 5 patients with normal renal function before colonoscopy, who presented with rapid onset Acute Renal Failure with dramatically elevated serum creatinine levels (from 3 days to 2 months) post-colonoscopy. Renal biopsies performed on all 5 patients revealed a distinctive pattern of acute nephrocalcinosis with abundant deposition of calcium phosphate in distal tubules and collecting ducts.

In all 5 patient histories examined, colonoscopy was preceded by a bowel cleansing regimen involving OSPS such as Phospho-soda®. Over the next few months, the patient’s serum creatinine begins to drop, and appears to level off at 2.8 mg/dl. (the body's range of normal for creatinine is recognized to be between 0.6-1.6 mg/dl).

It is clear that the patient has suffered ARF likely due to a tubular interstitial process such as acute interstitial nephritis or acute tubular necrosis.

But, what caused this process to occur? The answer may be the bowel cleansing solution the patient used in preparation for his or her colonoscopy.

The 2004 study concluded that the incidence of ARF due to acute nephrocalcinosis after use of Phospho-soda® is likely to increase as the population ages (age 55+) and more screening colonoscopies are performed routinely.Renal Failure Due to Acute Nephrocalcinosis Following Oral Sodium Phosphate Bowel Cleansing. Human Path. 35:675-684, 2004. In 2005, Dr. Glen S. Markowitz published the results of his expanded study examining oral sodium phosphate solutions, including Phospho-soda® and Visicol® as under recognized causes of kidney and renal failure.  Acute Phosphate Nephropaty following Oral Sodium Phosphate Bowel Purgative: An Underrecognized Cause of Chronic Renal Failure.