Two Cases of Methemoglobinemia Induced by the Exposure to Nitrobenzene and Aniline

OBJECTIVE: To report two cases of methemoglobinemia induced by inhaled nitrobenzene and dermally absorbed aniline. METHODS: We have evaluated a 37-year-old male worker exposed to nitrobenzene by inhalation while conducting maintenance job of mononitrobenzene pump and a 25-year-old male worker exposed dermally to aniline while unloading. RESULTS: The first case is a 37-year-old male exposed to nitrobenzene. His blood methemoglobin concentration level was initially 19.8%, and chest X-ray was normal. After oxygen therapy, the blood methemoglobin concentration level decreased to 2.1%, and the symptoms were alleviated. The second case is a 25-year-old male exposed dermally to aniline. His chest X-ray was normal, but blood methemoglobin concentration level reached maximally 46.8%. He was treated with methylene blue due to relatively high blood methemoglobin level. Gradually after the treatment, his methemoglobin concentration level was normalized to 0.8% and simultaneously symptoms were resolved. CONCLUSIONS: After the thorough exposure investigations and medical evaluations, we have concluded that these cases were methemoglobinemia induced by occupational exposure to nitrobenzene and aniline. We suggest that businesses which handle methemoglobinemia-causing substances control the engineering process strictly, implement periodic screening, and establish emergency patient management system.

Analysis of Causative Factors and Effects to Cognitive Functions of Cerebral White Matter Changes

BACKGROUND: The aim of this study was to identify causative factors for cerebral white matter changes on MRI and relationship between cerebral white matter changes and cognitive function. METHODS: The patients who were admitted to the Department of Neurology ward or visited to outpatient clinic at the Chungnam National University Hospital from September 1999 to July 2000 were selected. All patients underwent brain MRI with 1.5 T for determination of degree and distribution of cerebral white matter changes. The patients were evaluated their cognitive function with the Mini Mental State Examination (MMSE) and the Modified Mini-Mental State Examination (3MS), which has more extensive and detailed tool for fluency and memory domains of cognition compared with the MMSE. Statistical analyses were performed to identify whether there was difference in causative factors and cognitive status between patients with white matter change and patients without white matter changes. RESULTS: White matter changes were significantly more common in patients with hypertension and women. On correlation analyses, hypertension and aging were significantly related with cerebral white matter changes. General cognitive status in patients with white matter changes were worse than those of patients without white matter changes and of control group. Frontal lobe functions like fluency, attention, and visuo-constructive function were especially affected by white matter changes on the 3MS. CONCLUSIONS: Hypertension, female sex and aging may contribute to the development of cerebral white matter changes. Cerebral white matter changes may be responsible for the general cognitive decline. (J Korean Neurol Assoc 19(5):471~477, 2001)