What are the most important neurological questions of 2020?

It is the season again for reflecting over the most important neurology papers published in the year. Because we keep a keen eye on the relevant journals and neurology headlines, we are well-placed at Neurochecklists to pinpoint those papers which asked the most pressing neurological questions, and either answered them, or pointed to where the wind […]

What are the most important neurological questions of 2020? — Neurochecklists Blog

Should unruptured brain AVMs be left alone?

Medical management with interventional therapy versus medical management alone for unruptured brain arteriovenous malformations (ARUBA): final follow-up of a multicentre, non-blinded, randomised controlled trial. Mohr JP, Overbey JR, Hartmann A, et al. Lancet Neurol 2020; 19:573-581. Abstract Background In A Randomized trial of Unruptured Brain Arteriovenous malformations (ARUBA), randomisation was halted at a mean follow-up […]

Should unruptured brain AVMs be left alone? — Neurochecklists Blog

What are the risk factors for progression of radiologically isolated syndrome?

Radiologically isolated syndrome: 10-year risk estimate of a clinical event. Lebrun-Frenay C, Kantarci O, Siva A, et al. Ann Neurol 2020 (Online ahead of print). Abstract Objective We have previously identified male sex, younger age, and the presence of spinal cord lesions as independent factors that increase the 5-year risk for evolution from radiologically isolated […]

What are the risk factors for progression of radiologically isolated syndrome? — Neurochecklists Blog

The appendix in Parkinson’s disease: hero or villain?

The brain-gut axis has become a well-recognised cliche, and for very good reasons. Possessing an  almost independent and complex nervous system, the gut is considered to be the ‘second brain‘. The gut of course coordinates things hand-in-hand with the brain with which it communicates via the vagus nerve; through this it not only determines our body balance or homeostasis, but also rules our emotions and guides our decision-making. But some scientists are beginning to think that the brain-gut axis, or more appropriately the gut-brain axis, has a dark side, and this is the simple idea that ‘very bad things‘ in the gut can smuggle their way into the brain by latching on to the vagus nerve. The gut-brain axis may therefore be the seditious agent of neurological ruin by acting as a Trojan horse which surreptitiously jumps over the brain’s elaborate defensive big wall.

By Marvin 101Own work, CC BY-SA 3.0, Link

Parkinson’s disease (PD) is perhaps the most illustrative example of the consequence of the treacherous behaviour of the gut-brain axis. Some researchers are now convinced that PD actually starts in the gut and, like an undesirable hitchhiker, fastens itself on the vagus nerve as it meanders its way up to the brain. This migration hypothesis is not a fanciful notion but an idea founded on sound facts. For example, take the observation that the guts of people with PD are riddled with α-synuclein, the misfolded protein that is thought to cause PD by disabling the basal ganglia. The story, according to researchers, is that α-synuclein first accumulates in the gut and, feeling cramped, seeks greener pastures. It therefore propagates up the vagus nerve, in ‘prion-like‘ fashion, to get to the brain. Further support for this theory is the observation that people who have had their vagus nerves resected (that’s another story) have a much lower risk of developing PD.

By Niubrad at the English Wikipedia, CC BY-SA 3.0, Link

That’s just as well you may say, but where does the appendix come into all this? I admit the so-called vermiform or worm-like appendix is not a structure that readily comes to mind when one thinks of the gut-brain axis. Apart from being the seat of the dreaded appendicitis, it was considered to be just a useless appendage, nature’s trick on anatomists and physiologists. As diminutive as it may be however, it is part of the gut, and as it turns out, it is heavily laden with α-synuclein in people with PD. Furthermore, it has been shown that people who have had an appendicectomy, or appendectomy if you prefer, have a much lower risk of developing PD. We know this because of researchers such as Bryan Killinger and colleagues who, in their paper titled The vermiform appendix impacts the risk of developing Parkinson’s disease, published in the journal Science Translational Medicine in 2018, found that “early removal of the appendix is associated with a reduced risk of developing PD”. And it all comes down to the powerful immune surveillance function of the appendix which, it seems, mops up all sorts of threats that find their way into our guts. You may say that the appendix is punching way beyond its weight class.

Appendectomy. msafari2425 on Flickr. https://www.flickr.com/photos/msafari/6020024188

As happens to all beautiful theories, they often come up against some immovable objections….and there are quite a few raised eyebrows at the appendix-PD hypothesis. For one, many studies have just not been able to confirm it. For example, take this paper published in the journal Movement Disorders in 2018, titled Appendectomy and risk of Parkinson’s disease in two large prospective cohorts of men and women; the authors disappointingly found little or no evidence for the association between having an appendectomy and the risk of developing Parkinson’s disease. Another paper published in the same journal in 2016, titled Appendectomy and risk of Parkinson’s disease: A nationwide cohort study with more than 10 years of follow‐up, further upturned the applecart because the authors found that having an appendectomy actually increased the risk of developing PD. Another paper from a 2017 issue of the Journal of Parkinson’s Disease was succinctly brutal in shooting down the appendix-PD connection with its title: Appendectomy history is not related to Parkinson’s disease. Even more damning to the “appendectomy is good against PD” theory is this 2019 study whose blazing headline is Parkinson’s disease is more prevalent in patients with appendectomies. Just when you were beginning to feel good about having your appendix removed all those year ago!

http://www.actaneurocomms.org/content/1/1/2., CC BY 2.5, Link

By Mikael Häggström, B jonasOwn work CC0, Link


25 updated practical neurology checklists

This is just a quick blog post to let you know of some of our recently revised checklists Alemtuzumab neurological complications Anti MOG antibody disease treatment Cavernomas clinical features Cenobamate Cerebral amyloid angiopathy related inflammation (CAA-ri) *** CIDP clinical features Cluster headache acute treatment Dravet syndrome management Duchenne muscular dystrophy genetic treatments Functional neurological disorders […]

25 updated practical neurology checklists — Neurochecklists Blog