Neuropathies associated with excessive exposure to lead

Abstract

Exposure to lead is a ubiquitous problem of the modern era. The majority of cases of all forms of lead intoxication, especially lead neuropathy, result from industrial exposure. In the Western world meticulous monitoring in industry has reduced the risk of overt lead neuropathy. The classic form of lead neuropathy consists of weakness that primarily involves the wrist and finger extensors but which later spreads to other muscles. There is only minimal sensory involvement. Less commonly, there is a more typical toxic neuropathy with distally accentuated sensory and motor involvement. The motor neuropathy is more likely to develop following relatively short-term exposure to high lead concentrations and evolves in a subacute fashion. Prognosis for recovery is good as long as exposure is terminated promptly. The distal sensory and motor neuropathy develops after many years of exposure, evolves more slowly, and recovery is less certain. There is a generally weak relationship between the development of lead neuropathy and blood lead levels, at least for the subacute motor neuropathy, leading to speculation that the metabolic basis for the neuropathy is interference with porphyrin metabolism. Lead intoxication in humans causes axonal degeneration, but in some other species it causes a primarily demyelinating neuropathy. It should be possible to prevent lead neuropathy by good industrial hygiene. Close monitoring should identify excessive lead exposure before it causes overt neuropathy. If evidence of excessive exposure is found or if overt neuropathy develops, exposure must be terminated immediately. The role of chelation therapy in the treatment of lead neuropathy is controversial.

Lead Poisoning and Recurrent Abdominal Pain

“…The classic form of lead neuropathy consists of weakness of the wrist and finger extensors 18) . The motor lead neuropathy usually develops after a high level of exposure and prognosis for recovery is good after prompt termination of exposure.…”

Is screening for urinary porphobilinogen useful among patients with acute polyneuropathy or encephalopathy?

“…Plasma porphyrin spectrum analysis distinguishes different types of acute porphyria and provides additional information to the diagnostics during their clinical manifestations but may be negative in remission [7]. Lead intoxication must be excluded since it resembles acute porphyria both clinically and biochemically [14]. Blood protoporphyrin elevation and low erythrocyte ALA-dehydratase activity together with increased lead concentration in the blood usually confirms the diagnosis [14].…”

Lead Poisoning Caused by Traditional Chinese Medicine: A Case Report and Literature Review

“…Decreased preganglionic acetylcholine release and intestinal Na/K-ATPase inhibition can lead to water flux abnormalities, abdominal colic, and constipation. Axonal degeneration of motor nerves can be associated with extensor weakness or "wrist/ankle drop" (Shobha et al 2009;Thomson and Parry 2006). The reaction between lead and dental plaque can result in a bluish pigmentation at the gum tooth line, which is known as a "lead line."…”