[Obstructive sleep apnea syndrome caused by occupational exposure to solvents]

A 52-year-old man working in a chemical laboratory was referred with the possible diagnosis of toxic encephalopathy. For 17 years he had been exposed to high concentrations of perchlorethylene and n-butanol vapours which every day had caused acute symptoms of organic solvent intoxication. Current complaints were autonomic nervous system symptoms, loss of concentration and memory, and fatigue in the second half of the day. The patient was obese but in good general condition.

Neuropsychiatric examination confirmed the reported loss of concentration and planning ability at work. The polysomnogram indicated an increased number of largely obstructive apnoea attacks.

As the patients had an obstructive type of sleep apnoea treatment consisted of positive pressure ventilation at night and weight reduction. The occupational exposure to organic solvents was the likely cause.

As the symptoms of encephalopathy and sleep apnoea syndrome overlap, the latter should be considered before an encephalopathy is diagnosed. Because a rare cause of the sleep apnoea syndrome is prolonged and marked occupational exposure to organic solvents this should be asked about in taking the history. If indeed there has been occupational exposure, it should cease at once and be reported.