Like lead, arsenic interferes with sulfhydryl groups on proteins. It can also replace the phosphorus in phosphate, making it more reactive. Arsenic binds to dihydrolipoic acid, which is a cofactor for pyruvate dehydrogenase. When this enzyme is inhibited by arsenic, pyruvate cannot be converted to acetyl coenzyme A, the first step in gluconeogenesis. Thus, arsenic exposure results in impairment of glucose metabolism. Arsenic has also been shown to adversely affect insulin secretion, alter gene expression, and affect insulin-stimulated glucose uptake in skeletal muscle cells.
Acute arsenic poisoning can present with headache, nausea, vomiting, diarrhea, abdominal pain, hypotension, fever, hemolysis, seizures, and mental status changes. Diarrhea and paresthesias of the hands and feet can also occur. Chronic poisoning, referred to as arseniasis, can present with the same symptoms but to lesser degrees, making a diagnosis of chronic exposure difficult since symptoms are nonspecific.
