Manganese-induced parkinsonism in methcathinone abusers: bio-markers of exposure and follow-up.

BACKGROUND AND PURPOSE: Methcathinone abuse is a new cause of manganism. The psychostimulant is prepared from pseudoephedrine using potassium permanganate as an oxidant. We describe the clinical, biological, neuroimaging characteristics and follow-up results in a large Estonian cohort of intravenous methcathinone users. METHODS: During 2006-2012 we studied 38 methcathinone abusers with a mean age of 33 years. Subjects were rated by the Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn and Yahr (HY), and Schwab and England (SE) rating scales. Twenty-four cases were reassessed 9-70 (20 ±â€…15) months after the initial evaluation. Manganese (Mn) in plasma and hair was analysed by inductively coupled plasma-atom emission spectrometry. Magnetic resonance imaging (MRI) was performed in 11, and single-photon emission computed tomography (SPECT) with iodobenzamide (IBZM) in eight subjects. RESULTS: The average total UPDRS score was 43 ±â€…21. The most severely affected domains in UPDRS Part III were speech and postural stability, the least affected domain was resting tremor. At follow-up there was worsening of HY and SE rating scales. Subjects had a higher mean level of Mn in hair (2.9 ±â€…3.8 ppm) than controls (0.82 ±â€…1.02 ppm), P = 0.02. Plasma Mn concentrations were higher (11.5 ±â€…6.2 ppb) in active than in former users (5.6 ±â€…1.8 ppb), P = 0.006. Active methcathinone users had increased MRI T1-signal intensity in the globus pallidus, substantia nigra and periaquaductal gray matter. IBZM-SPECT showed normal symmetric tracer uptake in striatum. CONCLUSION: Methcathinone abusers develop a distinctive hypokinetic syndrome. Though the biomarkers of Mn exposure are characteristic only of recent abuse, the syndrome is not reversible.

A comparison of three doses of sufentanil in combination with bupivacaine-adrenaline in continuous epidural analgesia during labour.

BACKGROUND: Sufentanil is now frequently added to local anaesthetic in labour epidural analgesia. However, this opioid has some side effects such as pruritus, and in higher doses could harm the neonate. The purpose of this study was to compare three doses of sufentanil combined with low-dose bupivacaine, to determine the lowest appropriate dose. METHOD: In a prospective, randomized, double-blind study, 243 parturients were randomized, to receive A--0.5 microg/ml, or B--0.75 microg/ml or C--1 microg/ml sufentanil, in addition to bupivacaine 0.625 mg/ml+adrenaline 1.25 microg/ml. All were given an 8 ml bolus of the study solution, followed by continuous infusion at 6 ml/h. The analgetic effect was scored on a visual analogue scale (VAS). Onset quality was measured as VAS after 20 min, the total effect as VAS maximum during the first stage of labour. Overall maternal satisfaction was recorded within two hours post partum. Side effects were noted. RESULTS: There were no differences between groups in VAS assessments after 20 min or in maximum registered VAS. In group A, 83% had VAS 0-4 after 20 min, in group B 77% and in group C 71%. Maximum VAS during the first stage was 0-4 for 60% of group A, 68% of group B and 61% of group C. Maternal satisfaction was also the same in the three groups. In group A, 70% reported excellent effect and 22% good effect. The corresponding figures in group B were 68% and 24% respectively, and in group C 62% and 24% respectively. Group A received a mean total dose of 21 microg sufentanil, group B 30 microg and group C 44 microg. Pruritus occurred in 51% of group A, 53% of group B and 65% of group C. CONCLUSION: We found no difference in the analgesic effect between three different concentrations of sufentanil. We conclude that the lowest dose may be used. This should decrease the risk of adverse effects on mother and child.