The symptoms of encephalopathy (headache, drowsiness, mental confusion, delirium, and convulsive seizures) may also occur as part of acute or chronic intoxication. In the latter case, they are accompanied by weakness and muscular aching, hemolysis, chills and fever, mucosal irritation (in patients exposed to arsine gas), diffuse scaly desquamation, and transverse white lines, 1 to 2 mm in width, above the lunula of each fingernail (Mees lines). Acute poisoning by the oral route is associated with severe gastrointestinal symptoms, shock and death in a large proportion of patients. The CSF is normal. Examination of the brain in such cases discloses myriads of punctate hemorrhages in the white matter. Microscopically, the lesions consist of capillary necrosis and of pericapillary zones of degeneration, which, in turn, are ringed by red cells (brain purpura). These neuropathologic changes are not specific for arsenical poisoning, but have been observed in such diverse conditions as pneumonia, gram-negative bacillary septicemia from urinary tract infections, sulfonamide and phosgene poisoning, dysentery, disseminated intravascular coagulation, and others.
The diagnosis of arsenical poisoning depends on the demonstration of increased levels of arsenic in the hair and urine. Several of the aspects of testing have been reviewed by Moyer. Arsenic is deposited in the hair within 2 weeks of exposure and may remain fixed there for long periods. Concentrations of more than 0.1 mg arsenic per 100 mg hair are indicative of poisoning. Arsenic also remains within bones for long periods and is slowly excreted in the urine and feces. Excretion of more than 0.1 mg arsenic per liter of urine is considered abnormal; levels greater than 1 mg/L may occur soon after acute exposure. We would caution, however, that individuals who consume fish on a regular basis, as occurs in coastal regions, may have slightly or moderately elevated levels of arsenic and that various conditions such as neuropathy and amyotrophic lateral sclerosis (ALS) may be mistakenly attributed to this innocuous finding. The levels return to normal within a few months of abstaining from fish.
The CSF protein level may be raised (50 to 100 mg/dL).
Treatment Acute poisoning is treated by gastric lavage, vasopressor agents, dimercaprol (BAL), maintenance of renal perfusion, and exchange transfusions if massive hemoglobinuria occurs. Once polyneuropathy has occurred, it is little affected by treatment with BAL, but other manifestations of chronic arsenical poisoning respond favorably. There has been a gradual recovery from the polyneuropathy under our care.