[«Apuntes en Neurologia» (Notes in Neurology): a synthesis of the evidence on common paroxysmal neurological disorders and on neurodegenerative disorders]

«Apuntes en Neurologia» is an initiative in which prominent national and international leaders, with broad academic recognition, came together to synthesise the most outstanding clinical aspects within their area of interest and to discuss the latest developments in a more accessible language. Understanding the factors that affect the onset and progression of any neurological disease through a review is important to be able to develop strategies to reduce the burden of these diseases. Moreover, knowledge of the clinical aspects is essential to solve the problems of daily clinical practice. The data collected here reflect the weight of evidence and some of them anticipate a promising future in the treatment of these diseases. This first edition focuses on common paroxysmal neurological disorders such as migraine, epilepsy and sleep disorders, as well as neurodegenerative disorders such as Parkinson's disease and cognitive impairment. These are clearly different pathologies, although some of them such as migraine and epilepsy, may share clinical symptoms. Sleep disorders, however, are important manifestations of neurodegenerative diseases that are sometimes clinically apparent long before the onset of other neurological symptoms. After recalling pathophysiology and diagnosis, the current review focuses on bringing together the main advances in five of the major neurological diseases.

Peripheral neuropathy in Parkinson's disease: levodopa exposure and implications for duodenal delivery

In advanced Parkinson's disease (PD) patients, continuous intra-duodenal infusion of levodopa/carbidopa intestinal gel (LCIG) is an established approach in the management of motor complications that cannot be further improved by conventional oral therapy. In general, tolerability of LCIG has resembled that of oral dopaminergic therapy; however, cases of symptomatic peripheral neuropathy (PN), sometimes severe, have been reported in patients receiving LCIG. Cases are generally a sensorimotor polyneuropathy with both subacute and chronic onsets, often associated with vitamin B12 and/or B6 deficiency. Rare cases clinically resemble Guillain-Barré syndrome. In the absence of prospectively collected data on possible associations between LCIG and PN, it is prudent to explore potential mechanisms that may explain a possible relationship. The PN may be linked to use of high-dose levodopa, promoting high levels of homocysteine and methylmalonic acid or reduced absorption of vitamins essential for homocysteine metabolism. Cases of LCIG-associated PN often have responded to vitamin supplementation without need for LCIG cessation, although LCIG cessation is sometimes necessary. It may be advisable to monitor vitamin B12/B6 status before and after patients start LCIG and be vigilant for signs of PN. Prospective, large-scale, long-term studies are needed to clarify whether vitamin supplementation and routine use of a catechol-O-methyltransferase inhibitor may help prevent PN in LCIG recipients and whether these measures should be routine practice in patients with PD on high-dose oral levodopa.

[Levodopa in the treatment of Parkinson's disease: myths and realties]

In recent years we have witnessed a growing tendency to opt for the use of dopamine agonists (DA) as treatment for Parkinson's disease (PD), with the aim of delaying as far as possible the development of fluctuations and dyskinesias. Yet, levodopa continues to be the most effective antiparkinson drug and is probably the one that improves the greatest number of symptoms of the disease. This article reports on the results of a comprehensive review of the literature dealing with the benefits and risks of levodopa treatment in patients with PD which was conducted by a group of expert neurologists and members of the Spanish Neurology Society's Movement Disorder Group. The main conclusion reached in this article is that levodopa continues to be the most effective treatment for PD. Although the risk and incidence of developing dyskinesias remains at a lower level in the group initially treated with DA, the number of patients who develop disabling dyskinesias is very low in all the studies and is similar for DA and for levodopa. Scores on the quality of life scales are also similar in the two groups, which casts some doubt on the impact that these motor complications have on the quality of life of patients with PD. In view of these findings, we should consider whether there is any real justification for depriving patients of the good control of their symptoms offered by levodopa owing to the fear of developing dyskinesias or mild motor fluctuations that are not really going to have any negative effect on their quality of life. There is also the possibility of their developing severe side effects, which are more frequent with the use of DA.

[Subcutaneous continuous apomorphine infusion: treatment initiation and follow up]

Continuous apomorphine infusion has been an established treatment for advanced Parkinson's disease for over two decades. This article reviews the different methods for starting treatment and propose a consensus methodology for it, as well as for the modification of prior treatment, in order to standardize and reduce the variability of clinical practice.