January 6 2011 —A person with 1 microgram of cobalt in their bloodstream has nothing to worry about.
Someone whose blood contains more than 25 micrograms has cobalt poisoning.
And a patient whose blood contains more than 100 micrograms? Probably has a DePuy ASR hip implant.
As more and more patients who received DePuy ASR Acetabular hip replacement systems ask their doctors for blood tests, the numbers of people who have extraordinarily high levels of cobalt in their bloodstreams become staggering. Several of our own clients have received the worrying news that their cobalt levels are far above normal, and at least one doctor has published a case study of two DePuy hip implant recipients who have cobalt levels that are 100 to 500 times normal.
How Much Cobalt Is Normal?
If you go to a doctor and get a blood test, the amount of metal (including cobalt) in your bloodstream will be calculated in micrograms per deciliter. A healthy person has approximately 0.019 micrograms per deciliter - about one microgram for their entire body. The metal in your bloodstream only presents in very, very small amounts; someone with normal cobalt levels could gather all the cobalt in their system together and come up with an amount smaller than a grain of sand.
Even at highly toxic levels, the actual amount of cobalt looks very, very tiny. 0.5 micrograms per deciliter of cobalt is considered toxic. That's about five grains of sand in a giant bucket of water. Seems small - but those tiny grains of metal can throw the entire chemistry of your body wildly out of order.
In Britain, there are regulations for keeping close observations on patients who have metal-on-metal bearings in any hip implants, including the ASR hip implants. At cobalt levels of 0.7 micrograms per deciliter, patients must be kept under observations. Symptoms at those levels include hip pain, dying tissue, and pseudotumors - masses under the skin. Generally doctors recommend revision if a patient with a hip implant has a cobalt concentration of 1.9 micrograms/deciliter or above.
Revision isn't suggested until cobalt concentrations are one hundred times the mean average - even though levels are considered toxic at twenty-five times the average.
One patient with severe cobalt poisoning had levels of 6.6 micrograms/deciliter. That's nearly three hundred and fifty times the mean average. The dangers of cobalt levels so high were quite apparent: in addition to hip pain, the patient showed declining cognitive function, was losing control of his senses like hearing and sight, suffered from seizures, heart failure, and multiple other problems.
The amount of cobalt that patient had in his blood was still small enough that it wouldn't have filled a teaspoon. But the damage was great enough to threaten his life.
What is Cobalt Poisoning?
Cobalt is one of the many metals that is found naturally in the body, but as with all other metals, in excess amounts it becomes toxic and leads to many harmful and potentially permanent side effects. Cobalt poisoning has caused cardiomyopathy, hypothyroidism, and neurological damage as well as impairing the senses. It can cause neuropathy, seizures, blindness, headaches, and liver damage. Cobalt has also been linked to cancer.
For DePuy hip implant recipients, it can also mean that future hip revisions have a lower chance of success. Excess amounts of cobalt in the bloodstream lead to metal sensitivity and metallosis, which can seriously damage surrounding tissue and make a second implant less likely to succeed.
Doctors Unaware of Risk
For many patients with DePuy ASR hip implants, the symptoms of cobalt poisoning either go unnoticed initially or are chalked up to other pain and problems related to the hip implant failure. For example, a patient might have deteriorating mental function, mood disorders, or vertigo - but if the patient is also in a great deal of pain because the hip implant is failing, it is very possible that he might assume the other symptoms are related to his pain and will go away if he has a revision surgery.
Meanwhile, doctors who are fully aware that DePuy ASR XL Acetabular System is failing at inordinate rates may recommend a revision surgery to solve problems of pain and inflammation. Those doctors may not know that the friction of the hip implant is releasing excess amounts of metal ions into the bloodstream and causing potential problems with far more long-reaching effects.
A patient could walk out of surgery with heavy metal poisoning - and not be aware until the symptoms become extreme enough to return to the hospital.
What Should You Do?
If you have a DePuy ASR Acetabular hip implant and are concerned about cobalt poisoning, see your doctor as soon as possible to discuss your options and express your concerns. Our medical crib sheet for DePuy ASR hip implant patients can give you some guidance on questions you may want to ask your doctor and tests you may wish to request.