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.
What is acute phosphate nephropathy?
Acute phosphate nephropathy (also called acute nephrocalcinosis) presents as acute renal failure with minimal proteinuria and a bland urine sediment in patients recently exposed to OSP. Renal biopsy reveals acute and/or chronic renal tubular injury (depending on time to diagnosis) with calcium-phosphate crystal deposition in the distal tubules and collecting ducts and no other pattern of histological injury.
Bowel cleansing with OSP causes dehydration, decreased intravascular volume, and hyperphosphatemia (due to a large oral phosphate load). The hyperphosphatemia increases phosphate levels in the renal tubules. Decreased intravascular volume stimulates reabsorption of water from the renal tubules further increasing the phosphate concentration in renal tubular fluid. An abnormally high [Ca 2+][PO 4 2-] product in renal tubular fluid causes precipitation of calcium-phosphate crystals in the kidney and the pattern of renal injury described above.
Who may be at risk?
Patients with the following conditions and/or taking the following medications may be at increased risk for acute phosphate nephropathy:
- Decreased intravascular volume (due to congestive heart failure, cirrhosis, or nephrotic syndrome)
- Acute or chronic kidney disease
- Advanced age (OSP-associated hyperphosphatemia may be more severe in individuals ages 57 years and above 3)
- Medications that affect renal perfusion or renal function such as diuretics, ACE inhibitors, ARBs, and possibly NSAIDs. more
On May 5th, 2006, the FDA issued an "alert" regarding the occurrence of Acute Phosphate Nephropathy after the ingestion of sodium phosphates solution or tablets.
The FDA said that the individuals most at risk for this type of acute renal failure, are the elderly, persons with kidney disease or a subnormal intravascular volume, and patients using a medication that affects renal perfusion or function—a diuretic, angiotensin-converting-enzyme inhibitor, or angiotensin-receptor blocker or possibly a nonsteroidal antiinflammatory drug.
According to a 2005 FDA "science background" paper, a bowel-cleansing regimen of oral sodium phosphates has systemic effects:
• It causes dehydration;
• Decreases the volume of fluid in the blood vessels; and
• Burdens the bloodstream with an excessive amount of phosphates.
In turn, the bloodstream's burden becomes the problem of the renal tubules, which have a abnormally low amount of fluid because the body has been reabsorbing the tubules' water to correct the intravascular volume.
The FDA stated that the result is abnormally high concentrations of divalent calcium and phosphate ions in the renal tubules' fluid - high enough to precipitate calcium phosphate crystals and damage the kidney.
There are at least 21 proven cases of acute phosphate nephropathy in patients who ingested an oral sodium phosphates product that have been reported in the medical literature, FDA said. Furthermore, the FDA said that in nearly all of the cases the oral sodium phosphates product that caused the damage was Fleet’s Phospho-soda, which Fleets claims is the "leading bowel purgative."
If you or a family member have suffered Kidney Disease, Kidney Injury, Renal Failure, or End Stage Renal Disease following use of Oral Saline Laxative such as Fleet® Phospho-Soda® and other Over-the-Counter or prescription medications, contact Laszlo & Associates, LLC, immediately to discuss your legal rights - you may be entitled to monetary compensation.