Journal of neurology, neurosurgery, and psychiatry
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J. Neurol. Neurosurg. Psychiatr. · Jul 1990
L-3,4-dihydroxyphenylalanine (levodopa) lowers central nervous system S-adenosylmethionine concentrations in humans.
To determine whether levodopa reduces the levels of S-adenosylmethionine in the human central nervous system, cerebrospinal fluid (CSF) concentrations of S-adenosylmethionine, methionine, 3-methoxytyrosine, levodopa and 5-methyltetrahydrofolate were measured in six children with dopamine deficiency before and after treatment. In four, the lack of dopamine was secondary to a reduction in concentration of levodopa and these were treated with levodopa together with a peripheral dopa-decarboxylase inhibitor. In the other two, levodopa in the central nervous system naturally accumulated due to a congenital deficiency of aromatic-L-amino acid decarboxylase and these were treated with pyridoxine (which in this condition lowers central levodopa concentrations). ⋯ No change was observed in CSF methionine concentration and in all patients CSF 5-methyltetrahydrofolate concentration was normal. With one exclusion there was a linear relationship between CSF S-adenosylmethionine and 3-methoxytyrosine concentrations. This is the first demonstration of such effects in humans and the implications upon levodopa therapy are discussed.
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Five patients with chronic arachnoiditis and syringomyelia were studied. Three patients had early life meningitis and developed symptoms of syringomyelia eight, 21, and 23 years after the acute infection. One patient had a spinal dural thoracic AVM and developed a thoracic syrinx 11 years after spinal subarachnoid haemorrhage and five years after surgery on the AVM. ⋯ Small cystic regions of myelomalacia coalesce to form cavities. In other patients, central cord ischaemia mimics syringomyelia but no cavitation is present. Scar formation with spinal block leads to altered dynamics of cerebrospinal fluid (CSF) flow and contributes to the formation of spinal cord cystic cavities.