8/10/2009

Mercury Poisoning Looks Like Autism How?

Brodkin, E., Copes, R., Mattman, A., Kennedy, J., Kling, R., & Yassi, A. (2007, January 2). Lead and mercury exposures: interpretation and action.. CMAJ: Canadian Medical Association Journal Supplement, 176(1), 59-63. Retrieved August 10, 2009, doi:10.1503/cmaj.060790

So autism looks like this how?

"Signs and symptoms of mercury toxicity vary with the form of mercury and route of exposure but include gingivitis, stomatitis and excessive salivation. Sensory peripheral neuropathy is
common, and central nervous system effects include personality changes, irritability, fatigue, tremor (usually intention tremor), ataxia, difficulties with memory and concentration, sleep disturbances and a metallic taste. Renal effects include both tubular and glomerular damage. In the fetus, organic mercury disrupts the cytoarchitecture of the developing brain and has been associated with neuropsychological changes after birth" (Brodkin et al., 61).

Oh, I bet folks who think it's mercury poisoning will point to the last, except they aren't arguing it was fetal poisoning. They are arguing it's the 12.5 to 25 micrograms of thimerosal in certain vaccines that did, forget about the 11.5 or so micrograms of mercury in a can of tuna. My bad. Then, they'll point out absorption and excretion is completely different.

What about chelation?

"The first step in treating all cases of heavy metal toxicity is to reduce or remove the source of exposure. In most cases this is all that is required.3,16 Chelation therapy has historically been used to reduce the body burden of heavy metals in patients with se-vere symptoms and highly elevated circulating levels of heavy metals.26 It is a process in which heavy metals are removed
from the body with the use of a chelating agent, a charged molecule that binds metals in a stable complex known as a chelate. The chelate is subsequently excreted in the urine" (Brodkin et al., 61-62).

"Chelation therapy should be carried out only in a hospital setting by experienced physicians" (Brodkin et al., 62).

What about chelating and then doing a urine test?

"This procedure is more commonly known as the chelation challenge test or
provocation chelation. It entails measuring urine levels of heavy metals before and after a single loading dose of a known chelating agent. It has been used to determine whether chelation therapy is indicated but is also used by some alternative health care providers to diagnose heavy
metal poisoning. There is no good evidence supporting the use of the chelation challenge test for either purpose, and findings from some studies have suggested that it can lead to misleading diagnostic advice" (Brodkin et al., 62).

Okay, so most parents of kids with autism who think it is heavy metal toxicity don't IV chelate. Gotcha.

So what about oral chelating agents DMPS and DMPA?

Here's a study showing them ineffective in removing elemental mercury after a person intentionally injected himself with elemental mercury in a suicide attempt.

Eyer, F., Felgenhauer, N., Pfab, R., Drasch, G., & Zilker, T. (2006, July). Neither DMPS nor DMSA is Effective in Quantitative Elimination of Elemental Mercury After Intentional IV Injection.. Clinical Toxicology (15563650), 44(4), 395-397. Retrieved August 10, 2009, doi:10.1080/15563650600671795

"Although treatment with DMPS or DMSA was associated with marginally increased renal excretion of Hg in our patient, clinically relevant elimination did not occur and evidence of
benefit is doubtful" (Eyer et al., 397).

So, I'll have to do some more digging, but for now it appears that the oral chelating agents DMPS and DMSA are ineffective, at least when mercury is injected.

Update:

In case you think oral chelators are no big deal:

"Chelation agents like DMPS or DMSA are increasingly used and are available over the counter in some countries. These drugs are used in patients with complaints that are attributed to mercury-containing dental amalgams and in children with autism. Conclusion. The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation. The reported association suggests that SJS may be a potential complication of DMPS therapy, and this should be considered in the risk-benefit analysis of chelation."

References
AA, V., S, P., GP, G., & JN, B. (2008, June). Stevens-Johnson syndrome in a child with chronic mercury exposure and 2,3-dimercaptopropane-1-sulfonate (DMPS) therapy. Clinical Toxicology (Philadelphia, Pa.), 46(5), 479-481. Retrieved August 10, 2009, from MEDLINE database.


Trying to make this not look like a study dump like some folks do at some places. :-)

The 14 study argument is hogwash. There. In case I hadn't made that plain enough in my other posts. I've said it clearly. Complete and utter balderdash. I've used the IOM review in previous postings. Here's a quote from an article in Nature Neuroscience referring to it as well:

"Unfortunately, epidemiological studies do not support this link. In May 2004, a review by the Institute of Medicine (IOM)3 of over 200 studies (available online at http://www.nap.edu/catalog/10997.html) concluded “that the evidence favors rejection of a causal relationship between thimerosalcontaining vaccines and autism,” a view held by most of the international scientific community. The World Health Organization also maintains that
“there is no evidence supporting a causal association between neurobehavioural disorders and thiomersal-containing vaccines.”"

Reference: A mercurial debate over autism. (2005, September). Nature Neuroscience, Retrieved August 10, 2009, from MEDLINE database.

11 comments:

kathleen said...

Well gosh-does that mean any parent who has used oral chelators and has seen results...well does that mean that there child might have just taken some developmental steps on their own??!!!No No No you must be a pharma schill! But not the kind that sells over the counter chelators-no those are the "good" pharma schills..you know, they are friends with the purveyors of B12 pops...and home Hbot systems..:)

KWombles said...

:-)I'm still digging up studies, so there will be additional blog posts with the information I gather. Remember, no actual studies on chelation in autistic kids. So, there is only anecdotal evidence that it helps.

davidbrown said...

One of the most fundamental problems with the mercury/thimerosal argument is that, barring a massive case of local pollution, there's no way to trace actual mercury poisoning to a single source. The analogy I think is appropriate is "one particular needle in a stack of needles".

NightStorm The Aspiewolf said...

Another analogy is that a River is made of many streams.

In science, especially medicine. There is never one source, there are many.

Nostrum said...

We've got two cases of massive local mercury contamination - one in Iraq, one in Japan. And yet neither reported increases in autism. Minamata disease looks nothing like autism. So why treat the wrong cause?

KWombles said...

I'd agree, Nostrum, but when you've got folks telling you they know the cause and they've got the cure, the allure can be overwhelming. Look, just do these things, throw your money at this cure, and skip the hard work of helping your child master new skills. And if it doesn't work, it's not the cure's fault; it's because you didn't do it soon enough, you didn't give enough, you didn't try hard enough. We've seen this time and again on every imaginable disease and difficulty.

Logic, reason, scientific evidence don't mean a thing if you can sell a conspiracy to folks.

davidbrown said...

As far as the perception of autism and mercury poisoning being related, I've noticed that they cite certain alleged features of autism):
"retardation" (debunked)
"sensitivity to light" (common pharmacological effect)
"tantrums and agression" (vague and, to whatever extent it fits, explainable by stress or intentional abuse by others. See my essay "Vicious when poked with a stick".)

NightStorm The Aspiewolf said...

David how is "retardation" debunked?

davidbrown said...

In the last 10 years or so it's been widely challenged, to the point that a consensus would seem to reject it. I think the most fundamental problem is that the ca. 75% retardation figure is fully comparable to "results" of IQ testing of the illiterate and people who don't speak English (see Yerkes-Army test).

KWombles said...

David,

I suspect that your consensus is a popular consensus and one that the science has not entirely shifted on. As late as 2005, Coleman in The Neurology of Autism, is still quoting intellectual disabilities in 70% of individuals diagnosed with autism.

Whether the IQ tests are fair and accurate in assessing intelligence in individuals with disabilities is certainly up for debate, especially considering almost all psychologists agree completely that IQ tests are not in fact measures of intelligence. See some of Robert Sternberg's writings and theories on intelligence, for example, although he does not take up autism or disabilities specifically, merely how inadequate current measures of intelligence are.

What is fairly clear to researchers is that IQ tests in individuals with autism are poor indicators of functionality or capabilities. Nonetheless, the use of these tests when compared to controls and when looking specifically at differences in subtests can yield some interesting and potentially illuminating information.

davidbrown said...

From all I can see, opinion is shifting against the claimed retardation rate, though change is certainly most visible in general public, where the "rainman myth" already conveys the opposite impression... Also, in fairness and against AoA, even professionals uncritically reporting "retardation" seem to have characteristically distinguished it from what would be expected in pervasive brain damage: uneven peformance, rather than consistent lows.