The "disease of the crazy hatman" and the effects of human exposure to mercury: A case report / A "doença do homem do chapéu maluco" e os efeitos da exposição humana ao mercúrio: Um relato de caso

INTRODUCTION: Mercury, in addition to being a heavy metal, is considered a neurotoxin, that is, a substance capable of negatively affecting the neurological functions of the human body. Nowadays, ““Mad Hatter's Disease”” is the name used to characterize these neurological disorders caused by mercury. PURPOSE: to report a clinical case of the manifestation of “Mad Hatter's Disease”, as well as to discuss about the effects of human exposure to mercury. METHODOLOGY: this is a clinical case report, in which the patient is essential. CASE REPORT: A 45-year-old male patient, gold miner, from a riverside community in the Amazon, was referred to the hospital with complaints of headache, extremities tremor, diarrhea, tiredness, discouragement, irritability, depression, unusual shyness and hallucinations. On physical examination, the patient was anxious, irritable, symmetrical small-amplitude tremors in the extremities, hyperreflexia ++/4+ in the upper limbs, +/4+ in the lower limbs, normal muscle strength, mild ataxia of the right hand, stained skin and mucous membranes, and acyanotic, with erythematous-scaly lesions, confluent on the trunk, palms and soles of the feet. Screening for mercury poisoning was performed, where it was found, both in blood and urine, the presence of mercury 20 times above the biological tolerance limit. A battery of specific neuropsychological tests was carried out in neurotoxicological assessments and these demonstrated impairment of the cognitive domains (deficit of memory, attention, concentration, reasoning and abstraction) and alterations in motor functions, showing reduced coordination and motor speed. The diagnosis of hydrargyrism or occupational chronic metallic mercuralism (MMCO) was given. DISCUSSION: Chronic occupational exposure to inorganic mercury can cause subclinical abnormalities, as well as long-term psychomotor and neuromuscular behavioral impairment. Neuropsychiatric abnormalities (inattention, memory, interpretation, and motor performance) appear to be dose-related. FINAL CONSIDERATIONS: chronic exposure to metallic mercury vapor characteristically compromises the nervous system, initially with nonspecific symptoms and, later, with characteristic motor disorders - small amplitude tremor, paresis, dysreflexia and difficulty in motor coordination, which gives rise to the "Disease of the Mad Hatter”, and inhaling large amounts of mercury vapor can be lethal.