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The discussion opened by Bertazzi1 is worth integrating with practical considerations. Until 1996 every physician in Italy had licence to practice health surveillance in the workplace; differences of competence between physicians were obviously present, and this undoubtedly lead to inequalities in workers’ safety and health levels.
In 1996 we observed a case of methyl bromide (CH3Br) induced toxic encephalopathy which was not recognised for a long period.
This patient was a 44 year old man with no significant past medical history. When he was 31 years old, he began working for a firm specialising in agricultural pest control. On his fourth season at this workplace, an accidental leakage from the compressed gas cylinder splashed CH3Br on to him, causing dermal burns and vesicles on the upper and lower limbs. Immediately after the splashing, he reported heavy headedness and drowsiness. In the following 24 hours he had episodes of vomiting, muscle fatigue (mainly in the lower limbs), together with paraesthesia, unsteady gait, myoclonic jerks of the face, and finally seizure attacks. Liver function testing showed increased ALT, AST, and γ-glutamyltransferase levels. He was treated with clonazepam and carbidopa, and was permitted to continue his work. The accident was not notified to the National Institute of Insurance for Work Injury and Disease (INAIL).
In the following years, periodic medical examinations at the workplace confirmed a mild increase of liver enzymes, while markers of viral hepatitis proved to be negative. The worker continued to do his job, and to be exposed to CH3Br. Some other overexposures were reported, only one of which (chemical burn of the right foot) was reported to INAIL. He continued to have seizures (five episodes at least, two of which occurred after acute/subacute exposures to CH3Br), asthenia, and changes in liver function tests. He began to suffer from memory deficit, changes of mood, apathy, headache, leg cramps, and reduction of sexual potency.
He came to our observation nine years after the first seizure attack. He presented with myoclonus of the legs, and bilateral blepharoptosis. Action myoclonus was triggered by auditory stimuli, and increased with emotion.
The electroencephalogram showed bursts of slow anteromedial waves on the left side. The magnetic resonance image of the brain showed signal changes in the left frontotemporal region. Audiometric examination showed marked sensory-neural loss. Somatosensory evoked potentials and motor evoked potentials were normal. Electromyogram of the tibialis anterior and first interosseus showed normal amplitude and duration of the motor units with normal recruitment. A standardised neuropsychological evaluation revealed mild reduction of memory and attention. The serum concentration of bromide was moderately increased (11.7 μg/ml; normal <5 μg/ml).
Neurological effects primarily referable to the central nervous system following severe inhalation of CH3Br have frequently been reported. Myoclonus and seizures are typical of acute exposure, particularly in patients with previous low level chronic exposure.2–4
The most singular aspect of this case is the observation that the physician performing surveillance at the workplace failed to recognise the occupational encephalopathy over a very long period (nine years!). This lack of efficiency is inconceivable and points out the necessity to verify and to accredit the competence of medical doctors practising in this field.
In Italy, the adoption of European Union directives assigned medical surveillance of workers to specialists in occupational medicine, and to other physicians, already experienced in the field. The number of specialists assigned to workers’ surveillance (9000) was greater in Italy than in the United States.5 Strong corporate interests have now obtained the admission into this critical field of 40 000 physicians, with limited theoretical knowledge of occupational medicine, and without any practical training in this field. We wonder how many workers will pay in the future for such a populist decision.
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