Decremental responses to repetitive nerve stimulation (RNS) in motor neuron disease.

OBJECTIVE: To clarify the features of decremental responses following repetitive nerve stimulation in patients with motor neuron diseases (MNDs), in comparison with myasthenia gravis (MG). METHODS: The subjects consisted of 48 MND, 39 generalized MG and 19 ocular MG patients. Six muscles, both proximal and distal muscles, were tested. RESULTS: Significant decrements (>5%) in at least one muscle were observed in 83% of the MND patients, and 74% and 47% of the generalized MG and ocular MG patients, respectively. Decrements were more frequently observed in the proximal muscles both in MND and MG patients (deltoid 76% and 62%, and trapezius 71% and 51% for MND and generalized MG, respectively), suggesting lower safety factors in neuromuscular transmission in those muscles. Decrements in the nasalis were rare in MND (8%) in comparison with generalized MG (54%). CONCLUSIONS: Decremental responses were frequently observed in MND patients. There were small differences between MND and MG regarding the distribution and other features of decrements, such as the degree of the U-shape or the responses to different stimulus frequencies and to brief exercise. SIGNIFICANCE: These results imply that the underlying mechanism regulating the decrements is common to MND and MG.

[A case of multiple brain abscess effectively markedly responded to high dose panipenem/betamipron administration].

A 54-year-old, previously healthy female experienced headache, nausea and vomiting, and consulted our hospital regarding her symptoms. Her cerebrospinal fluid (CSF) showed leukocytosis with polymorphonucleosis and hypoglycemia, thus she was diagnosed with bacterial. She admitted to our hospital and combination therapy of ampicillin and cefotaxime was started. CSF and blood cultures was negative. On the third hospital day, despite a decrease in her CSF cell count, her consciousness level decreased and neck stiffness worsened. On the seventh hospital day, the CSF cell count increased again, and we changed antibiotics to panipenem/betamipron (PAPM/BP) at 4 g/day. On the tenth hospital day, the CSF cell count decreased, but by the twelfth hospital day her consciousness had deteriorated to a drowsy state. Brain CT and MRI revealed multiple brain abscesses and hydrocephalus. We increased the dose of PAPM/BP up to 8 g/day, and her neurological, CSF and brain MRI findings subsequently improved. The patient was discharged from our hospital on the sixty-ninth hospital day. As the frequency of beta-lactamase-producing bacteria is currently increasing, carbapenems should be considered as first choice of antibiotics for the initial treatment of multiple brain abscess.