Clinical Symptoms, Neurological Signs, and Electrophysiological Findings in Surviving Residents with Probable Arsenic Exposure in Toroku, Japan

Abstract

Chronic arsenic intoxication is known to cause multisystem impairment and is still a major threat to public health in many countries. In Toroku, a small village in Japan, arsenic mines operated from 1920 to 1962, and residents suffered serious sequelae of arsenic intoxication. We have performed annual medical examinations of these residents since 1974, allowing us to characterize participants’ long-term health following their last exposure to arsenic. The participants could not be described as having “chronic arsenic intoxication,” because their blood arsenic levels were not measured. In this study, we defined them as having “probable arsenic intoxication.” Symptoms frequently involved the sensory nervous system, skin, and upper respiratory system (89.1–97.8%). In an analysis of neurological findings, sensory neuropathy was common, and more than half of the participants complained of hearing impairment. Longitudinal assessment with neurological examinations and nerve conduction studies revealed that sensory dysfunction gradually worsened, even after exposure cessation. However, we could not conclude that arsenic caused the long-term decline of sensory function due to a lack of comparisons with age-matched healthy controls. This is the first study to characterize the longitudinal sequelae after probable arsenic exposure. Our study will be helpful to assess the prognosis of patients worldwide who still suffer from chronic arsenic intoxication.

Histopathological Changes and Antioxidant Enzymes Status in Oxidative Stress Induction Using Sodium arsenite in Rats

“…However, it has been identified which arsenicderived oxidative stress to be strongly involved in acute renal damage. 11 The liver is another target organ of arsenic toxicity. 29 In the present study, cell necrosis with degeneration, severe hemorrhage, infiltration and formation of Kupffer cells nodules at the site of cellular destruction were recognized in liver tissue.…”

“…10 Neurological mechanisms are affected mainly due to exposure to arsenic. 11 In these cases, clinical signs of encephalopathy are presented with weakness, itching, hemolysis, thrill and fever. 6 So, it is important to understand the complications of arsenic-induced toxicity in target organs by more details.…”

Arsenic Neurotoxicity in Humans

“…At least 140 million people in more than 50 countries are exposed to As-contaminated drinking water [3]. However, although a small number of acute As exposure patients have been studied in detail, relatively few studies have been performed on a detailed neuropathy of patients chronically exposed to As [4,5,6]. Although patients with chronic As exposure are numerous, their symptoms and clinical courses remain unclear.…”

Peripheral neuropathy induced by drinking water contaminated with low-dose arsenic in Myanmar

“…As mentioned above, several studies have shown that arsenic exposure induces peripheral neuropathy or neuritis [7, 9, 22–24]. A few studies have separately analyzed the function of small and large fibers, and suggested that these particular effects of arsenic are specific to small fibers [6, 9, 10]. Large-fiber function can be evaluated not only by neurological examination of vibration sensation but also by nerve conduction studies.…”

“…In regard to the peripheral nervous system, a considerable number of patients who experience chronic arsenic exposure report subjective complaints of numbness or tingling [7, 10], but nerve conduction studies reveal no abnormal findings [11]. As for the central nervous system, the central sensory conduction time of patients with chronic arsenic exposure is longer than that in age-matched normal controls [6].…”