Manganism
Classification and external resources
Manganese
ICD-10	T57.2
ICD-9	985.2
MeSH	D020149

Manganism or manganese poisoning is a toxic condition resulting from chronic exposure to manganese and first identified in 1837 by James Couper.^[1]

[edit] Presentation

In initial stages of manganism, neurological symptoms consist of reduced response speed, irritability, mood changes, and compulsive behaviors.^[2] Upon protracted exposure symptoms are more prominent and resemble those of idiopathic Parkinson's disease, which it is often misdiagnosed as, although there are particular differences in both the symptoms (nature of tremors, for example), response to drugs such as levodopa, and affected portion of the basal ganglia. Symptoms are also similar to Lou Gehrig's disease and multiple sclerosis.

[edit] Causes

Manganism has become an active issue in workplace safety as it has been the subject of numerous product liability lawsuits against manufacturers of arc welding supplies. In these lawsuits, welders have accused the manufacturers of failing to provide adequate warning that their products could cause welding fumes to contain dangerously high manganese concentrations that could lead welders to develop manganism. Companies employing welders are also being sued, for what colloquially is known as "welders' disease." However, it should be noted that studies fail to show any link between employment as a welder and manganism (or other neurological problems).^[3][4][5]

Another cause of the disorder is methcathinone, an amphetamine that is often prepared with poor quality control using potassium permanganate as an oxidiser, leading to high proportion of the toxic substance in the drug. The practice and its victims are reported in former USSR states.^[6]

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Another street drug sometimes contaminated with manganese is the so-called "Bazooka", prepared by free-base methods from cocaine using manganese carbonate.^{[7][citation needed]}

Reports also mention such sources as contaminated drinking water,^[8] and fuel additive methylcyclopentadienyl manganese tricarbonyl (MMT),^[9] which on combustion becomes partially converted into manganese phosphates and sulfate that go airborne with the exhaust,^[10][11][12] and manganese ethylene-bis-dithiocarbamate (MANEB), a pesticide.^[13]

[edit] Pathological mechanisms

Manganese may affect liver function, but the threshold of acute toxicity is very high. On the other hand, more than 95% of manganese is eliminated by biliary excretion. Any existing liver damage may slow this process, increasing its concentration in blood plasma.^[14] The exact neurotoxic mechanism of manganese is uncertain but there are clues pointing at the interaction of manganese with iron,^{[15][16][17][18]} zinc,^[19] aluminum,^[15][19] and copper.^[19] Based on a number of studies, disturbed iron metabolism could underlie the neurotoxic action of manganese.^[20]

It participates in Fenton reactions and could thus induce oxidative damage, a hypothesis corroborated by the evidence from studies of affected welders.^[21] A study of the exposed workers showed that they have significantly fewer children.^[22] This may indicate that long-term accumulation of manganese affects fertility. Pregnant animals repeatedly receiving high doses of manganese bore malformed offspring significantly more often compared to controls.^[23]Manganism mimics Schizophrenia. It is found in large quantities in paint and steelmaking.

[edit] Treatment

The current mainstay of manganism treatment is levodopa and chelation with EDTA. Both have limited and at best transient efficacy. Replenishing the deficit of dopamine with levodopa has been shown to initially improve extrapyramidal symptoms,^[24][25][26] but the response to treatment goes down after 2 or 3 years,^[27] with worsening condition of the same patients noted even after 10 years since last exposure to manganese.^[28] Enhanced excretion of manganese prompted by chelation therapy brings its blood levels down but the symptoms remain largely unchanged, raising questions about efficacy of this form of treatment.^[29][30]

[edit] References

[edit] External references

• Lucchini et al., "Metals and Neurodegeneration" - Research paper on heavy metals poisoning
• Antonini., "Health Effects of Welding" - Critical review including manganese discussion from National Institute of Occupational Safety and Health (NIOSH)
• Welding and Manganese Poisoning - Safety Corner column in IBEW Journal regarding manganese and welding.
• AWS Study on Welding and Exposure to Manganese - Report of an independent study commissioned by the American Welding Society
• Welding Fume Product Liability - Viewpoint of plaintiffs on welding rod litigation
• Welding Rod Litigation Information Network - Viewpoint of defense on welding rod litigation

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Manganism".