Clinical risk-benefit assessment of dopamine agonists

Dopamine agonists (DAs) have proven efficacy as monotherapy in early Parkinson's disease (PD) for preventing motor complications such as dyskinesia and as adjunct therapy as the disease progresses. Further, it is increasingly evident that at least some DAs may provide additional benefits, such as reduction in depressive symptoms and treatment of refractory tremor. Different side-effect profiles have been associated with levodopa and ergot or non-ergot DA treatment, such as sudden onset of sleep, reduced impulse control, hallucination, and cardiovascular fibrosis. This paper discusses the evidence for specific associations between particular treatments and side effects as well as the clinical implications for patient care. Ultimately, the choice depends on the risk-benefit assessment as it applies to the individual patient's clinical profile and the physician's preference.

Topiramate, nutrition and weight change: a prospective study

PURPOSE

To evaluate prospectively the relationship between appetite, food composition, nutritional habits and weight loss following administration of topiramate (TPM) and to identify predictors for TPM induced weight loss.

METHODS

22 patients with epilepsy who were started on TPM were prospectively followed for 6 months and contacted again after a mean follow-up time of 37.1 months.

RESULTS

Body mass index (BMI) loss occurred in 59% of patients, with a mean weight loss of 9.5 kg after 6 months while receiving TPM without further weight loss at the long term follow-up. Weight loss was associated with reduction in appetite without affecting food composition. Predictors for BMI loss after 6 months were high initial BMI and body fat. After 3 weeks of treatment with TPM, the recorded parameters did not predict BMI loss but at 3 months, weight loss, reduction of appetite and amount of food intake were predictive for the amount of BMI loss after 6 months.

Intravenous levetiracetam in the treatment of benzodiazepine refractory status epilepticus

In 2006, levetiracetam was approved as the first of the newer anticonvulsive drugs as an intravenous formulation (ivLEV) for patients with epileptic seizures who are unable to take oral medication. We report our experience with the use of ivLEV for the treatment of 18 episodes of benzodiazepine refractory focal status epilepticus (SE) in 16 patients, including four patients with secondary generalised SE. SE was controlled in all patients by the given combination of drugs; application of further antiepileptic medications after ivLEV was necessary in two episodes. No severe side effects occurred. Our data suggest that ivLEV may be an alternative for the treatment of SE in the future, even in patients that did not respond to benzodiazepines. A large prospective, randomised, controlled study is warranted to investigate the efficacy and safety of ivLEV for the treatment of SE.

Pregabalin-induced generalized myoclonic status epilepticus in patients with chronic pain

Pregabalin is often used for the treatment of chronic pain syndromes. We here describe two patients with chronic pain and pregabalin-induced myoclonic status epilepticus. Patients treated with pregabalin who experience sudden behavioral changes or mycloni should be investigated for this possible side effect, and pregabalin should be reduced or discontinued if myocloni or status epilepticus occurs.

Quantitative [123I]FP-CIT pinhole SPECT imaging predicts striatal dopamine levels, but not number of nigral neurons in different mouse models of Parkinson's disease

Single photon emission computed tomography (SPECT) using [(123)I]FP-CIT as radioligand for the dopamine transporter has become a widely used tool to monitor the integrity of the nigrostriatal dopaminergic projection in Parkinson's disease (PD). Previous studies with pinhole SPECT in small animals have demonstrated that the striatal [(123)I]FP-CIT binding indeed correlates with the striatal dopamine transporter protein level. It is unclear, however, if there is a stable relationship between the striatal [(123)I]FP-CIT binding and other functionally important parameters of the nigrostriatal system, such as the striatal dopamine levels and the number of dopaminergic neurons in the substantia nigra. To assess this question experimentally, we studied two different mouse models of PD, namely a mild 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intoxication paradigm, to model mild nigrostriatal damage and the intrastriatal 6-hydroxydopamine paradigm to model more advanced nigrostriatal damage. Our data demonstrate that the striatal [(123)I]FP-CIT binding measured by SPECT in vivo precisely predicts the striatal dopamine concentrations, but does not necessarily correlate with the nigral dopaminergic cell number. Thus, the present work underscores that FP-CIT SPECT does only allow judging the integrity of the striatal dopaminergic nerve terminals, but not the nigral dopaminergic cells in PD. This finding may have significant impact on the use of [(123)I]FP-CIT SPECT as a surrogate marker for clinical trials aimed at measuring neuroprotection.

Safety and tolerability of adjunctive tolcapone treatment in patients with early Parkinson's disease

OBJECTIVE

The safety and tolerability of adjunctive tolcapone initiated simultaneously with levodopa was evaluated with a focus on increases in liver transaminase and hepatotoxicity.

METHODS

677 levodopa-naïve patients with early stage Parkinson's disease (PD) were randomised to receive placebo or tolcapone 100 mg three times daily, added to standard doses of levodopa plus carbidopa or benserazide.

RESULTS

Increases in liver transaminase above the upper limit of normal (ULN) occurred in 69/342 (20.2%) and 92/335 (27.5%) patients in the placebo and tolcapone groups, respectively. Increases > or = 3 times the ULN occurred in 4/342 (1.2%) and 6/335 (1.8%) patients receiving placebo and tolcapone, respectively (p = 0.5). Liver transaminase values returned to normal in 65% of placebo and 80% of tolcapone treated patients. No instances of serious hepatotoxicity were seen. Diarrhoea was the most commonly reported AE-36/342 (11.0%) placebo v 98/335 (29.0%) tolcapone-and caused discontinuation in 9.9% of tolcapone treated patients. Overall, study discontinuation due to adverse effects was 2.9% in the placebo group and 17.3% in the tolcapone group.

CONCLUSIONS

Tolcapone seemed to be safe and was generally well tolerated as an adjunctive treatment in patients starting treatment with carbidopa/levodopa for symptomatic PD. Mild increases in transaminase levels--< 3 times the ULN--occurred commonly in both placebo and tolcapone treated patients, whereas potentially serious increases of up to > or = 3 times the ULN were infrequent.

[Advances in the treatment of multiple sclerosis?]

The natural course of multiple sclerosis (MS) is probably more favourable than previously assumed years ago. Since the introduction of interferons in Germany, the establishment and further development of new diagnostic criteria (McDonald criteria), the causal and symptomatic treatment possibilities and initiation of therapy early in the course of the disease have led to a considerable change in the treatment of MS. MS attacks are usually treated with the intravenous administration of high-dosed steroids. When the attack symptoms do not sufficiently subside, plasmapheresis can be considered. For long-term treatment of MS, beta interferon, glatirameracetate and natalizumab are available as basic causal therapy and natalizumab and mitoxantrone are available for escalation therapy. Frequently occurring spasticity, chronic fatigue syndrome, depression, cognitive disturbances, incontinence, pain, ataxia and sexual disorders must be treated symptomatically. Overall, the outpatient treatment of MS is complex and should be carried out with close cooperation between the family doctor, neurological practices and outpatient departments specialized in treating MS.

Olfactory dysfunction in patients with narcolepsy with and without REM sleep behaviour disorder

Patients with idiopathic rapid eye movement sleep behaviour disorder (RBD) frequently develop Parkinson's disease and the majority present with hyposmia, which is a potential preclinical non-motor sign of Parkinson's disease. Accordingly, it has been proposed that the clinical symptoms of hyposmia and RBD in combination have to be considered as very early symptoms of Parkinson's disease. Since not only patients with idiopathic RBD but also patients in whom RBD is associated with narcolepsy present with an olfactory dysfunction we investigated if hyposmia in RBD patients with concomitant narcolepsy is RBD specific or if narcolepsy per se is associated with olfactory dysfunction. We studied olfactory function in 20 narcoleptic patients each with RBD (9 male and 11 female; mean age 45.4 +/- 14.0 years, range 20-75 years) and without associated RBD (8 male and 12 female; mean age 44.4 +/- 13.40 years, range 20-70 years) and 40 age- and gender-matched healthy control subjects using standardized 'Sniffin' Sticks'. Both, narcoleptics with (Narc/+RBD) and without RBD (Narc/-RBD) had a significantly higher olfactory threshold (Narc/+RBD, P = 0.0001; Narc/-RBD, P = 0.0001), lower discrimination scores (P = 0.001; P = 0.014) and lower identification scores (P = 0.057; P = 0.003) than controls. There were no symptoms or signs for early parkinsonism in both patient groups. Our results show for the first time that narcolepsy per se is associated with olfactory dysfunction. In contrast to patients with idiopathic RBD, hyposmia in patients with RBD associated with narcolepsy is unlikely to be a predictor for developing parkinsonism.

Atypical parkinsonism in Guadeloupe: a common risk factor for two closely related phenotypes?

In Guadeloupe, there is an abnormally high frequency of atypical parkinsonism. Only one-third of the patients that develop parkinsonian symptoms were reported to present the classical features of idiopathic Parkinson disease and one-third a syndrome resembling progressive supranuclear palsy (PSP). The others were unclassifiable, according to established criteria. We carried out a cross-sectional study of 160 parkinsonian patients to: (i) define more precisely the clinical phenotypes of the PSP-like syndrome and the parkinsonism that was considered unclassifiable in comparison with previously known disorders; (ii) define the neuropsychological and brain imaging features of these patients; (iii) evaluate to what extent a candidate aetiological factor, the mitochondrial complex I inhibitor annonacin contained in the fruit and leaves of the tropical plant Annona muricata (soursop) plays a role in the neurological syndrome. Neuropsychological tests and MRI were used to classify the patients into those with Parkinson's disease (31%), Guadeloupean PSP-like syndrome (32%), Guadeloupean parkinsonism-dementia complex (PDC, 31%) and other parkinsonism-related disorders (6%). Patients with a PSP-like syndrome developed levodopa-resistant parkinsonism, associated with early postural instability and supranuclear oculomotor dysfunction. They differed, however, from classical PSP patients by the frequency of tremor (>50%), dysautonomia (50%) and the occurrence of hallucinations (59%). PDC patients had levodopa-resistant parkinsonism associated with frontosubcortical dementia, 52% of these patients had hallucinations, but, importantly, none had oculomotor dysfunction. The pattern of neuropsychological deficits was similar in both subgroups. Cerebral atrophy was seen in the majority of the PSP-like and PDC patients, with enlargement of the third ventricle and marked T2-hypointensity in the basal ganglia, particularly the substantia nigra. Consumption of soursop was significantly greater in both PSP-like and PDC patients than in controls and Parkinson's disease patients. In conclusion, atypical Guadeloupean parkinsonism comprises two forms of parkinsonism and dementia that differ clinically by the presence of oculomotor signs, but have similar cognitive profiles and neuroimaging features, suggesting that they may constitute a single disease entity, and both were similarly exposed to annonaceous neurotoxins, notably annonacin.

CNS involvement in hereditary neuropathy with pressure palsies (HNPP)

We assessed seven patients with hereditary neuropathy with liability to pressure palsies (HNPP) with 16 electrophysiological tests and cranial MRI for CNS abnormalities. Mean latencies differed between patients with HNPP and controls for the blink reflex, the jaw-opening reflex, and acoustic evoked potentials. MRI abnormalities were observed in four patients. Our study suggests subclinical but functionally relevant CNS myelin damage in HNPP.