The 7 most hazardous occupations to the nervous system

A critical part of history taking in medicine is establishing the occupation of the patient. This is because occupational activities and work place exposures are often major contributors to the disease. Furthermore, at the end of the medical process, the eventual diagnosis may have an impact on the patient’s ability to return to work. To be relevant, the occupational history must be exhaustive – it must establish current and past occupations, the tasks carried out, the risk of toxic exposure, and the use of personal protective equipment (PPE). The occupational history is so important to neurology that a whole subspecialty, occupational neuroscience, has emerged to evaluate “the effects of complex environmental and occupational exposure on working people”.

By Ford Madox Brown1QG5Dp3Ti29BxA at Google Cultural Institute, zoom level maximum, Public Domain, Link

So what are the occupational hazards that may lead a patient to the neurologist? Below are my 7 most hazardous occupations to the nervous system

Working together for the commune. Jrwooley6 on Flickr. https://www.flickr.com/photos/jordan_wooley/3861487721

Typing

Previously an occupational hazard restricted to professional typists, carpal tunnel syndrome (CTS) now threatens anyone who uses a computer. CTS develops when the median nerve is entrapped at the wrist, and it manifests as weakness and sensory disturbances over the thumb, the index finger, the middle finger, and half of the ring finger. Whilst desk work is the main risk of CTS, manual workers are not spared the peril because the occupations that increase the risk of CTS include assembly work, food processing and packing, and the use of hand-help powered vibratory tools. And, by the way, vibrating tools also predispose to cubital tunnel syndrome, entrapment of the ulnar nerve at the elbow which presents as weakness and sensory impairment of the little finger, and half of the ring finger (you now know why it was chosen for the wedding ring). Cubital tunnel syndrome, again by the way, also happens to be an occupational hazard of truck drivers, baseball pitchers, and golfers. Just saying.   

Tele typist (ghostwriter). Matthew Hurst on Flickr. https://www.flickr.com/photos/skewgee/4858837387

Farming 

Farming is actually a relatively innocent bystander with this occupational risk, the neurological hazard arising from exposure to pesticides. And the neurological consequence of pesticide use is Parkinson’s disease (PD), a threat that is established without any equivocation. All pesticides carry the same degree of PD risk, but the badge of ignominy surely belongs to organophosphates and carbamates. The risk of PD is however not all-or-none because it is proportional to the duration of exposure. And, as if PD wasn’t enough, pesticides also seem to increase the risk of developing Alzheimer’s disease (AD). I’m just the messenger!

By Manly MacDonaldhttps://www.warmuseum.ca/collections/artifact/1016823, Public Domain, Link

Welding

An almost iconic neurological occupational risk-relationship is the association of welding and Parkinson’s disease (PD). Along with the related tasks of galvanizing and grinding, welding releases fumes of manganese (Mn), the metal that is suspected to be the PD-trigger in this case. As with pesticides, the risk appears to be proportional to the degree of exposure. But unlike pesticides, the reported PD risk of manganese is equivocal because some studies have not found any relationship between welding fumes and PD; indeed one found an inverse relationship between the two, reporting that welding reduces the risk of PD. Surely there are no fumes without fire, but in spite of this minor controversy, or because of it, neurologists are forever vigilant for manganese fumes when they make a diagnosis of PD; they are aware, after all, that only more data will clear the fumes. As an addendum, many other occupations, from teaching to computer programming, reportedly increase the risk of developing PD – presumably because of occupational stress!

By DoriOwn work, CC BY-SA 3.0 us, Link

Smelting

Just as welding conferred notoriety on manganese, so has smelting endowed lead (Pb) with infamy. And the metal’s neurological ignominy is the peripheral neuropathy it evokes. The classical but rarer form of lead neuropathy, is a subacute motor neuropathy which is a manifestation of lead-induced porphyria. Far more common is a chronic sensory neuropathy which is considered to be the direct result of lead toxicity. Beyond neuropathy, chronic lead exposure has garnered disrepute for its reported links with motor neurone disease (MND), although this risk association is contested. In fairness to Pb, other periodic table elements such as thallium (Tl) and arsenic (As) also pose significant occupational risks of neuropathy. And whilst still on metals, it is worth pointing out the report that occupational exposure to iron (Fe) may be a risk factor for meningiomas. Dmitri Mendeleev must be turning in his grave!

By Alfred T. Palmer – This image is available from the United States Library of Congress‘s Prints and Photographs divisionunder the digital ID fsac.1a35280.This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information., Public Domain, Link

Music

Neurologists, particularly of the movement disorder fraternity, listen to the occupational history of their patients with very keen ears, which literally prick up when they hear that the patient is a musician. This is because a large swathe of musical instruments predispose musicians to career-threatening task-specific dystonia, a form of dystonia which targets muscles that are most frequently exerted, especially in performing delicate actions. Whilst this umbrella diagnosis embraces such non-musical disorders as writer’s cramp, runner’s dystonia, and croupier’s cramp, it is musician’s dystonia that constitutes the widest spectrum of task-specific dystonia. And the reason is not far-fetched: playing musical instruments professionally requires the repetitive performance of very exquisite motor skills over long periods of time. Initially, the dystonia is only evident whilst playing the musical instrument, but it eventually manifests during unrelated tasks, and even at rest. The diversity of symptoms of musician’s dystonia is rivalled only by the number of instruments in the music ensemble, ranging from finger incoordination to upper lip tremor. Singers are also at risk of dysphonia, a form of voice dystonia which they share with teachers, telemarketers and aerobic instructors – all potential victims of hoarseness and voice fatigue.

Musical instrument sculpture in MAMAC in Nice, France. Karen Bryan on Flickr. https://www.flickr.com/photos/europealacarte/17700661556/

Sports

Unsurprisingly, competitive sports takes a heavy toll on the nervous system. At the fairly benign end of the spectrum is the compression of nerves, the innocent victims of grotesquely enlarged, almost mythically Herculean, muscles. Many nerves may be stretched or trapped by a long list of risky sports which includes archery, ballet, baseball, basketball, bowling, football, golf, hockey, tennis, weightlifting, gymnastics, and wrestling. And the classic sport-related nerve entrapment is that of the long thoracic nerve which manifests as scapular winging. Unfortunately, many sporting-related neurological hazards lie at the malign end of the spectrum, with such appalling diseases as chronic traumatic encephalopathy (CTE) from repetitive contact sports; Parkinson’s disease from the boxing related head injuries; and motor neurone disease (MND) especially from professional football. As with most such risks, the evidence for some sports-related neurological hazards is often anecdotal, but very difficult to dismiss in a neurology clinic.

Leicestershire. Ann and David on Flickr. https://www.flickr.com/photos/annedavid2012/42872566454

Shift work

This is, of course, a no brainer as every shift worker knows. Sleep disruption is the most prominent, but by far not the most serious hazard of burning the midnight candle at work. It is common knowledge that shift work reduces alertness, thereby compromising work performance. But more seriously, shift work increases the risk of several neurological disorders such as stroke, epilepsy, Parkinson’s disease (PD), Alzheimer’s disease (AD), and even multiple sclerosis (MS). As if these are not enough, shift work also predisposes to malignancies such as breast cancer and colon cancer, apart from impairing the function of many organs. Indeed the number of disorders now grouped under the remit of shift work sleep disorder (SWSD) is mind-numbing (apologies, I can’t conjure up a better pun). The reason shift work is such a medical nuisance is that it disrupts the brain’s critical circadian rhythm, thereby impairing the production of melatonin, a hormone that plays a hugely critical neuroprotective role. So think twice before taking that next lucrative night shift!

Insomnia. Joana Coccarelli on Flickr. https://www.flickr.com/photos/narghee-la/7294549116

***

I suppose the key message of this blog post is…choose your profession wisely!

The cutting-edge applications of ultrasound in neurology

Imaging is central to neurological practice. It doesn’t take much to tempt a neurologist to ‘order’ or ‘request’ an MRI or a CT. In appropriate circumstances the imaging is a DAT scan, and with a bit more savvy, exciting imaging modalities such as amyloid scans and tau PET scans. In the playpen of the neurologist, the more ‘high tech’ the imaging technology, the more cutting-edge it feels-even if it doesn’t make much of a difference to the patient. Ultrasound on the other hand is the mongrel of imaging technologies. Too simple, too cheap, too available, too unsophisticated-not better than good old X-rays. It is safe to assume that the pen of the neurologist hardly ever ticks the ultrasound box. What for?
prd brain scan. Patrick Denker on Flickr. https://www.flickr.com/photos/pdenker/74684051
And yet, ultrasound has an established, even if poorly appreciated, place in neurological imaging. It is perhaps best known for its usefulness in assessing carpal tunnel syndrome at the wrist. But, for the neurologist, CTS is sorted out by wrist splints, steroid injections, and decompression surgery-forgetting that there may just be a ganglion, a cyst, or a lipoma lurking in there. Ultrasound also has a place in the assessment of muscle disorders, picking up anomalies and detecting distinctive muscle disease patterns. The only problem is that, even when radiologists and neurologists put their heads together, they struggle to understand what the patterns actually mean. And since the first pass of this blog post, I was reminded of the place of ultrasound-guided lumbar puncture in improving the safety and accuracy of this otherwise blind procedure. And there are even guidelines to help takers. My guess is that most neurologists prefer the thrill of hit-and-miss that goes with conventional LP. For many reasons therefore, the ultrasound box remains un-ticked.
By RSatUSZ – PACS UniversitätsSpitalZürich, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=11272585
Despite these limitations, the place of ultrasound remains entrenched in neurological practice. Indeed, ultrasound has been spreading its wings to exotic places, broadening its range, and asserting its presence. Perhaps it is time to reconsider the humble ultrasound, and to catch up with what it has been up to. Here then are 3 emerging roles of ultrasound in neurology

Therapeutic ultrasound

The role of ultrasound in treatment is reviewed in the excellent paper in Nature Neurology titled Ultrasound treatment of neurological diseases-current and emerging applications. And the emphasis is on trans-cranial MR-guided focused ultrasound (tcMRgFUS). tcMRgFUS is making waves in the treatment of essential tremor (ET), Parkinson’s disease (PD), and central pain. The benefit for PD is already filtering out into the popular press such as this article in STAT titled New treatment offers some hope for an unshakable tremorUltrasound is also rapidly emerging as an option in the ablation of brain tumours, and in the treatment of stroke (sonothrombolysis). 

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Drug delivery into the brain

The blood brain barrier is a rigidly selective barricade against most things that venture to approach the brain-even if their intentions are noble. This is a huge impediment to getting drugs to reach the brain where they are badly needed. It is therefore humbling that it is the simple ultrasound that is promising to smuggle benevolent drugs across the blockade to aid afflicted brains. This was reported in the journal Science Translational Medicine, and the article is titled Clinical trial of blood-brain barrier disruption by pulsed ultrasound. The trial subjects were people with the notorious brain tumour, glioblastoma. They were injected with their conventional chemotherapy drugs, delivered along with microbubbles. The blood brain barrier was then repeatedly ‘pelted’ with pulsed ultrasound waves; this seem to leapfrog the drugs into the brain in greater than usual concentrations, enough to do a much better job. This surely makes films such as Fantastic Voyage and Inner Space not far-off pipe-dreams.

Bubbles. Jeff Kubina on Flickr. https://www.flickr.com/photos/kubina/153871892

Treatment of coma

Some of the emerging neurological applications of ultrasound are even more Sci-Fi than pulsed ultrasound. And a sign of this Sci-Neuro world is this report titled UCLA scientists use ultrasound to jump-start a man’s brain after coma. One is tempted to dismiss this as ‘fake news’ but it is a proper case report, in a proper scientific journal, Brain Stimulation, and with a proper scientific title, Non-Invasive Ultrasonic Thalamic Stimulation in Disorders of Consciousness after Severe Brain Injury: A First-in-Man Report. By targeting ultrasounds to the subject’s thalamus, the authors assert, the subject just woke up (and presumably asked for a hot cup of tea!). A word of caution is however needed; the authors rightly point out that it may have all been…coincidental!

The awakening (arm). Jeff Kubina on Flickr. https://www.flickr.com/photos/kubina/153871892

Ultrasound is clearly humble no more.

Big ambition trumps humble beginnings.

What is the state of gene therapy for Parkinson’s disease?

First, some basic science to lay the groundwork for this blog post. Parkinson’s disease (PD) is all about dopamine, the chemical neurotransmitter that makes our movements smooth. It is produced by cells in the substantia nigra, a structure in the midbrain. The substantia nigra nerves project to the putamen, one of the structures that make up the basal ganglia, somewhere deep in the brain. The substantia nigra nerves are also called the nigrostriatal nerves because the putamen, along with the caudate nucleus and the nucleus accumbens, form a body called the corpus striatum. The work of these so-called nigrostriatal nerves is to produce and deliver dopamine to the putamen. In summary, the putamen is the playpen of dopamine; it is here that it does its work of smoothening our movements.

By BruceBlausOwn work, CC BY-SA 4.0, Link

In Parkinson’s disease, the nogrostriatal system slowly degenerates, therefore becoming unable to supply enough dopamine to the putamen. The obvious solution is to find an alternative supply of dopamine for the putamen. The obvious way again would be to deliver dopamine orally as a tablet, but dopamine unfortunately does not cross the blood brain barrier. However, the similar but more pliant levodopa is able to do so. Once in the brain, levodopa is then converted to the active dopamine by an enzyme called aromatic L‐amino acid decarboxylase (AADC). Because this strategy is reasonably efficient, levodopa has become the foundation of PD treatment. But this strategy is totally dependent on the presence of enough AADC to convert levodopa to dopamine. And this is a vulnerability that PD explores to the full.

By Jynto (talk) – Own workThis image was created with Discovery Studio Visualizer., CC0, Link

Levodopa treatment is usually effective in the early stages of PD. But as the disease progresses, the degenerating nigrostriatal nerves increasingly struggle to produce enough AADC. Remember, AADC is essential for converting levodopa to the active dopamine. Without AADC, in other words, levodopa is useless. The declining ability to produce AADC is therefore the Achille’s heel of levodopa treatment. It is the reason people with advanced PD require increasingly higher doses of levodopa. It is the reason they get unpredictable treatment fluctuations. It is the reason they get abnormal movements called dyskinesias. To remedy this big flaw in the levodopa treatment strategy, and increase AADC levels in the putamen, neuroscientists have investigated the potential role of gene therapy. To unravel this topic, not a ride in the park by any means, I have relied on this excellent 2019 paper titled Magnetic resonance imaging–guided phase 1 trial of putaminal AADC gene therapy for Parkinson’s disease.

By Jynto (talk) – Own workThis image was created with Discovery Studio Visualizer., CC0, Link

If one group of cells becomes unable, or unwilling, to do its job, why not get another group of cells to take over the task? Indeed this simple concept lies at the heart of gene therapy for PD. And neuroscientists have identified the right type of cells to take over the job of producing AADC. These are the medium spiny neurones of the putamen which do not degenerate in PD. The brilliant strategy is to embed the gene for producing AADC into the DNA of the medium spiny neurones. A viral vector is required to carry the gene into the nerves, and the vector of choice here is adenovirus-associated virus (AAV). The vector ‘invades’ the medium spiny neurones and embeds the AADC gene into their DNA. The cells then start producing dopamine from levodopa. It is as simple as that in theory. It is easier said than done in reality.

By Thomas Splettstoesser (www.scistyle.com) – Own work, CC BY-SA 4.0, Link

The intricate steps involved in this strategy are outlined by Chadwick Christine and colleagues who carried out the phase 1 trial of AADC gene therapy. They infused the AAV viral vector directly into the putamen during neurosurgery, and they used magnetic resonance imaging to confirm that the injected material is delivered to the correct target. The detailed protocol refers to technical terms such as bilateral frontal burr holes, intraoperative delivery, neuro‐navigational systems, and the like. The whole affair however appears to be well-tolerated and reasonably successful; the authors reported a dose-dependent increase in AADC enzyme production, and their 15 subjects had more ‘on-time’, less troublesome treatment fluctuations, and required less levodopa. It is interesting that a similar benefit was demonstrated by Karin Kojima and colleagues when they used the same procedure in a genetic disorder called aromatic l-amino acid decarboxylase deficiency. In their paper titled Gene therapy improves motor and mental function of aromatic l-amino acid decarboxylase deficiency, the authors reported ‘remarkable’ motor improvement in all the six subjects they treated.

Public Domain, Link

An alternative approach to PD gene therapy is to use the AAV viral vector to deliver, not the gene for producing AADC this time, but the gene for producing glial cell line‐derived neurotrophic factor (GDNF). The idea behind this is, not to replace, but to flog the dying horse. The theory is that GDNF, a growth factor, should rejuvenate the flagging nigrostriatal nerves, thereby increasing their ability to produce dopamine. This approach was described by John Heiss and colleagues in their paper titled Trial of magnetic resonance–guided putaminal gene therapy for advanced Parkinson’s disease. The authors indeed demonstrated that GDNF-carrying adenovirus vectors can be safely infused into the putamen, and that the process is well-tolerated. They also demonstrated increased dopamine levels in the putamen in 12 of their 13 subjects.

Public Domain, Link

It is clearly early days, but there have been small successes along the way so far. Future trials, already underway, will tell us whether the hope is sustained or dashed. We must wait and see. In the meantime, you can read more about PD gene therapy in this update.

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3 exciting emerging interventional treatments for Parkinson’s disease

Parkinson’s disease (PD) is one of the bedrock disorders of neurology. It is common, universal, well-defined, usually easily diagnosed, and eminently treatable, even if not curable. PD is so important that I have visited it so many times on this blog. My previous blog posts on this topic include:

What are the drugs promising neuroprotection in PD?

What is the state of Parkinson’s disease biomarkers? 

The emerging research boosting Parkinson’s disease treatment.

PD is debilitating even when treated. This is because of the staggering number of motor and non-motor symptoms it provokes. And there is the long list of side effects the treatments induce, such as abnormal movements called dyskinesias. There is therefore a never-ending need for more effective and less agonising treatments for PD. And this blog has kept a keen eye on any advances that will make this disorder more bearable for the sufferers and their families, and less nerve-racking for the treating neurologist. It is therefore gratifying to know that there are many developments in the management of PD, and here I focus on 3 emerging interventional treatments.

By Marvin 101 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7533521

 

Magnetic resonance-guided focused ultrasound (MRgFUS)

MRgFUS is a technique that uses thermal heat to create lesions in the brain. This is a much less invasive approach than the current interventional treatments for PD which are surgery and deep brain stimulation (DBS). Surgical interventions for PD work by making therapeutic lesions in the globus pallidus (pallidotomy). In a first of its kind, Young Cheol Na and colleagues used MRgFUS to create similar pallidal lesions. They published their finding in 2015 in the journal Neurology under the title Unilateral magnetic resonance-guided focused ultrasound pallidotomy for Parkinson disease. They reported improvement in the motor symptoms of PD, and in drug-induced dyskinesias. But before MRgFUS pallidotomy will take off, it has to be as good as surgical pallidotomy which reduces dyskinesias for as long as 12 years!

Blue sonar. Gisela Giardino on Flickr. https://www.flickr.com/photos/gi/192984384

Repetitive transcranial magnetic stimulation (rTMS) 

In a reasonably large randomized trial published in 2016 in the journal Neurology, Miroslaw Brys and colleagues reported that rTMS improves motor symptoms in PD. Titled Multifocal repetitive TMS for motor and mood symptoms of Parkinson disease, the study reports that the benefit was significant. Indeed a systematic review and meta-analysis by Ying-hui Chou and colleagues in the journal JAMA Neurology, published just the year before, had established the benefit of rTMS in PD. The review, titled Effects of repetitive transcranial magnetic stimulation on motor symptoms in Parkinson disease, concluded with the hope that their findings “may guide treatment decisions and inform future research“. Hopefully it has, because a 2018 paper, published in the Journal of Clinical Neuroscience, has gone on to establish that the best results for rTMS are obtained with stimulation of the primary and supplementary motor cortex. That’s scientific progress.

Magnetic Fields-15. Windell Oskay on Flickr. https://www.flickr.com/photos/oskay/4581194252

Spinal cord stimulation 

It appears counterintuitive to think of the spinal cord in the context of PD, which is after all a disease of the brain. That is until you remember that walking impairment is a major problem in PD, and the spinal cord is the gateway for gait. Inspired by this insight, Carolina Pinto de Souza and colleagues stimulated the spinal cords of people with PD who have already undergone deep brain stimulation surgery. They published their findings in the journal Movement Disorders with the title Spinal cord stimulation improves gait in patients with Parkinson’s disease previously treated with deep brain stimulation. A clear title like this leaves little room for commentary. The authors however studied only four subjects, a number clearly missing from the paper’s title, but the benefit is an encouraging 50-65% improvement in gait. The omission is forgiven.

Spinal cord 8. GreenFlames09 on Flickr. https://www.flickr.com/photos/greenflames09/116396804

Taking things a step further, Reon Kobayashi and colleagues, writing in the journal Parkinsonism and Related Disorders, reported that a new mode of spinal cord stimulation called BurstDR, does a much better job than conventional stimulation. Again, the title of the paper is self-explanatory: New mode of burst spinal cord stimulation improved mental status as well as motor function in a patient with Parkinson’s disease.

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Surely the future must be bright with all these developments in the field of PD.

15 more creative and catchy neurology headlines for 2019

Regular visitors to this blog know that we love catchy article titles. It is always heartwarming to see how some authors create imaginative and inventive headlines. This skill involves the ability to play with words, and the capacity to be double-edged. This is why this blog keeps a lookout for fascinating neurology titles. And in line with this tradition, and in no particular order of inventiveness, here are 15 more catchy neurology titles!

By Andrikkos – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=33725735

15. Who do they think we are? Public perceptions of psychiatrists and psychologists

This paper, for some unfathomable reason, set out to ask if the public knows the difference between what psychiatrists and psychologists actually do. And the authors discovered that “there is a lack of clarity in the public mind about our roles”. More worryingly, or reassuringly (depending on your perspective), they also found out that “psychologists were perceived as friendlier and having a better rapport“. Not earth-shattering discoveries, but what a great title!

By Laurens van Lieshout – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2059674

14. OCT as a window to the MS brain: the view becomes slightly clearer

Optical coherence tomography (OCT) is a cool tool which measures the thickness of the retinal fiber layer (RFL). And it has the habit of popping its head up in many neurological specialties. In this case, the specialty is multiple sclerosis, and the subject is how OCT influences its diagnosis and surveillance. Surely a window into the brain is easier to achieve than one into the soul.

Optical coherence tomography of my retina. Brewbooks on Flickr. https://www.flickr.com/photos/brewbooks/8463332137

13. A little man of some importance 

The homonculus is the grotesque representation of the body on the surface or cortex of the brain. This paper reviews how formidable neurosurgeons such as Wilder Penfield worked out the disproportionate dimensions of this diminutive but influential man. He (always a man for some reason) has giant hands, a super-sized mouth, very small legs, and a miniature trunk. The clever brain doesn’t readily allocate its resources to large body parts that perform no complex functions! But be warned, this article is no light-weight reading!

The Homunculus in Crystal Palace (Moncton). Mark Blevis on Flickr. https://www.flickr.com/photos/electricsky/1298772544

12. Brain-focussed ultrasound: what’s the “FUS” all about? 

This title is a play on words around MR-guided focussed ultrasound surgery (MRgFUS), an emerging technique for treating disorders such as essential tremor and Parkinson’s disease (PD). This review looks at the controversial fuss that this technique has evoked.

By Luis Lima89989 – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19162929

11. The Masks of Identities: Who’s Who? Delusional Misidentification Syndromes

This paper explores the interesting subject of delusional misidentification syndromes (DMSs). The authors argue that few concepts in psychiatry can be as confusing as DMSs. And they did an excellent job of clearing our befuddlement around delusions such as Capgras and Fregoli. Very apt title, very interesting read.

no identity. HaPe-Gera on Flickr. https://www.flickr.com/photos/hape_gera/2929195528

 

10. Waking up to sleeping sickness.

This title belongs to a review of trypanosomiasis, aka sleeping sickness. It is a superb play on words, one that evokes several levels of meaning. It is simple and yet complex at the same time. Great imagination.

https://picryl.com/media/the-sleeping-sickness-gordon-ross

09. Brains and Brawn: Toxoplasma Infections of the Central Nervous System and Skeletal Muscle

This paper discusses two parts of nervous system that are affected by toxoplasmosis. Playing on the symbolic  contradiction between intellect and strength, the authors show how toxoplasmosis is an ecumenical abuser: it metes out the same fate to both brain and brawn.

Brain vs. Brawn. Yau Hoong Tang on Flickr. https://www.flickr.com/photos/tangyauhoong/4474921735

08. Shedding light on photophobia

A slightly paradoxical title this one. Ponder on it just a little more! And then explore the excellent paper shedding light on a condition that is averse to light.

Photophobia (light sensitivity). Joana Roja on Flickr. https://www.flickr.com/photos/cats_mom/2772386028/

07. No laughing matter: subacute degeneration of the spinal cord due to nitrous oxide inhalation

Nitrous oxide, or laughing gas, is now “the seventh most commonly used recreational drug”. But those who pop it do so oblivious of the risk of subacute combined degeneration. This damage to the upper spinal cord results from nitrous oxide-induced depletion of Vitamin B1 (thiamine). Not a laughing matter at all!

Empty Laughing Gas Canisters. Promo Cymru on Flickr. https://www.flickr.com/photos/promocymru/18957223365

06. To scan or not to scan: DaT is the question

Dopamine transport (DaT) scan is a useful brain imaging tests that helps to support the diagnosis of Parkinson’s disease and other disorders which disrupt the dopamine pathways in the brain. It is particularly helpful in ruling out mimics of Parkinson’s disease such as essential tremor. When to request a DaT scan is however a tricky question in practice. This paper, with its Shakespearean twist, looks at the reliability of DaT scans.

Dopamine. John Lester on Flickr. https://www.flickr.com/photos/pathfinderlinden/211882099

05. TauBI or not TauBI: what was the question?

It should be no surprise if Shakespeare rears his head more than once in this blog post. Not when the wordsmith is such a veritable source of inspiration for those struggling to invent catchy titles. This paper looks at taupathy, a neurodegeneration as tragic as Hamlet. It particularly comments on an unusual taupathy, one induced by traumatic brain injury. Curious.

By Lafayette Photo, London – This image is available from the United States Library of Congress‘s Prints and Photographs divisionunder the digital ID cph.3g06529.This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information., Public Domain, Link

04. Mind the Brain: Stroke Risk in Young Adults With Coarctation of the Aorta

What better way to call attention to a serious complication than a catchy title like this one. This paper highlights the neurological complications of coarctation of the aorta, a serious congenital cardiovascular disease. And the key concerns here are the risks of stroke and cerebral aneurysms. Cardiologists, mind the brain!

Own work assumed (based on copyright claims)., Public Domain, https://commons.wikimedia.org/w/index.php?curid=803943

03. Diabetes and Parkinson disease: a sweet spot?

This paper reviews the unexpected biochemical links between diabetes and Parkinson’s disease. And this relationship is assuming a rather large dimension. Why, for example, are there so many insulin receptors in the power house of Parkinson’s disease, the substantia nigra? A sweet curiosity.

Insulin bubble. Sprogz on Flickr. https://www.flickr.com/photos/sprogz/5606839532

02. PFO closure for secondary stroke prevention: is the discussion closed?

The foraman ovale is a physiological hole-in-the-heart which should close up once a baby is born. A patent foramen ovale (PFO) results when this hole refuses to shut up. PFOs enable leg clots to traverse the heart and cause strokes in the brain. This paper reviews the evidence that surgically closing PFOs prevents stroke. Common sense says it should, but science demands proof. And the authors assert that they have it all nicely tied up. Hmmm.

By Kjetil Lenes – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=3705964

01. Closure of patent foramen ovale in “cryptogenic” stroke: Has the story come to an end?

Not to be beaten in the catchy title race is another brilliant PFO review article. Why do I feel the answer here is ‘no’? This is science after all.

https://www.flickr.com/photos/fliegender/293340835

 

Do statins really increase the risk of Parkinson’s disease?

Statins are famous, and their fame lies in their ability to bust cholesterol, the villain in many medical disorders such as heart attack (myocardial infarction) and stroke. Some may add that statins are infamous, and this is partly because of their side effects such as muscle pain. Love them or hate them, we can’t get away from statins…even as the debate rages about their benefits and downsides.

By ChiltepinsterOwn work, CC BY-SA 3.0, Link

It is not surprising therefore that the statin debate will filter into neurology. The sticking point here however has nothing to do with cholesterol busting, but all to do with whether statins increase or reduce the risk of developing Parkinson’s disease (PD). Strange as it may seem, statins and PD have a long history. And a positive one generally, I hasten to add. There is a large body of evidence to suggest a protective effect of statins on PD as reflected in the following studies:

  1. Confounding of the association between statins and Parkinson disease: systematic review and meta-analysis 
  2. Statin therapy prevents the onset of Parkinson disease in patients with diabetes
  3. Statin use and risk of Parkinson’s disease: A meta-analysis 
  4. Statin use and its association with essential tremor and Parkinson’s disease
  5. Statin use and the risk of Parkinson’s disease: an updated meta-analysis
  6. Long-term statin use and the risk of Parkinson’s disease
  7. Discontinuation of statin therapy associated with Parkinson’s disease
Modeling the Molecular Basis of Parkinson’s Disease. Argonne National Laboratory on Flikr https://www.flickr.com/photos/argonne/4192798573

It was therefore with some consternation that a recent study, published in the journal Movement Disorders, really put the cat among the pigeons. The paper is titled:

Statins may facilitate Parkinson’s disease: insight gained from a large, national claims database,

The authors of this paper set out to investigate ‘the controversy surrounding the role of statins in Parkinson’s disease’. In this retrospective analysis of over 2,000 people with PD, and a similar number of control subjects, the authors found that statins significantly increased the risk of developing PD. This is clearly a conclusion looking for a fight!

By Col. Albert S. Evans – internet archives, Public Domain, Link

I must admit I was totally unaware there was any controversy about statins and PD. I was therefore curious to find out what studies are out there fuelling it. Which other trials have bucked the trend and reported an increased risk of PD from statins? And where best to find the answers but in PubMed, the repository of all human knowledge! And I found that there were only a few studies that did not report a protective effect of statins on PD, and these studies concluded, quite reasonably, that they found no relationship between PD and statins. Here are a few of the studies:

  1. Statin adherence and the risk of Parkinson’s disease: A population-based cohort study. 
  2. Use of statins and the risk of Parkinson’s disease: a retrospective case-control study in the UK. 
  3. Statin use and the risk of Parkinson disease: a nested case control study. 

These papers reporting the absence of evidence seem happy to engage in an amicable debate to resolve the question.

By DavidKF1949Own work, CC BY-SA 3.0, Link

One study however stood out like a sore thumb because it positively reported a negative effect of statins on PD (try and work that out!). This 2015 study, also published in Movement Disorders, is titled Statins, plasma cholesterol, and risk of Parkinson’s disease: a prospective study. The paper concludes that “statin use may be associated with a higher PD risk, whereas higher total cholesterol may be associated with lower risk“. Not only are the authors arguing that statins are bad for PD, they are also suggesting that cholesterol is good! This is a paper that was itching for fisticuffs.

By Jan SteenWeb Gallery of Art:   Image  Info about artwork, Public Domain, Link

What is a jobbing neurologist to do? What are the millions of people on statins to do? Whilst awaiting further studies, I will say stay put. Go with the bulk of the evidence! And keep track of The Simvastatin Trial, funded by The Cure Parkinson’s Trust. This trial is looking at the benefit of statins in slowing down PD. And surely, very soon, the science will lead to a resolution of the argument-all you need to do is keep track of everything PD in Neurochecklists.

By Léon Augustin Lhermittehttp://wellcomeimages.org/indexplus/obf_images/fc/7f/643258ab30237374aaea5ac15757.jpgGallery: http://wellcomeimages.org/indexplus/image/L0006244.html, CC BY 4.0, Link

 

Quelling the frenzy of restless legs syndrome

Restless legs syndrome (RLS) does what it says on the can. Victims need to only sit or lie down for a few seconds before creepy-crawly sensations literally drive them up the wall. The discomfort is as insatiable as the urge to move is uncontrollable. It is, literally again, a nightmare; a frantic evening quickly followed by a frenetic night.

The Colour Economy: Frantic on Vimeo. Jer Thorp on Flikr. https://www.flickr.com/photos/blprnt/2542831577/
The Colour Economy: Frantic on Vimeo. Jer Thorp on Flikr. https://www.flickr.com/photos/blprnt/2542831577/

Neurologists rarely struggle to make the diagnosis of RLS. And with the efforts of support groups such as the RLS foundation, patients are now well-informed about the diagnosis. To the chagrin of the neurologists, patients often come with a list of medications they have tried, and failed.

Frantic future. Jim Choate on Flikr. https://www.flickr.com/photos/137864562@N06/27938018674
Frantic future. Jim Choate on Flikr. https://www.flickr.com/photos/137864562@N06/27938018674

The list of RLS risk factors is quite long. Some of these are modifiable, and the ‘must-exclude’ condition here, iron deficiency, requires checking the level of ferritin in blood. Other modifiable risk factors are quite diverse such as obesity, migraine, and even, surprisingly, myasthenia gravis (MG). Most RLS risk factors, such as peripheral neuropathy and Parkinson’s disease (PD), are unfortunately irreversible; in these cases some form of treatment is required.

Frantic Face Sculpture. Eric Kilby on Flikr. https://www.flickr.com/photos/ekilby/14875258474
Frantic Face Sculpture. Eric Kilby on Flikr. https://www.flickr.com/photos/ekilby/14875258474

But what really works in RLS? And what is the evidence? To the rescue come the latest Practice guideline summary: Treatment of restless legs syndrome in adults, published in the journal Neurology. Below, in summary, are the interventions that work in RLS.

Strong evidence (Level A)

  • Pramipexole
  • Rotigotine
  • Cabergoline (but beware of cardiac risks)
  • Gabapentin enacarbil

Moderate evidence (level B)

  • Ropinirole
  • Pregabalin
  • Ferric carboxymaltose 
  • Pneumatic compression

Weak evidence (level C)

  • Levodopa
  • Oxycodone/naloxone (prolonged release)
  • Near-infrared spectroscopy
  • Transcranial magnetic stimulation (TMS)
  • Vibrating pads (to improve subjective sleep)

Add-on treatments in haemodialysed patients

  • Vitamin C 
  • Vitamin E 

Enough to guarantee a well-deserved nighttime sleep!

https://pixabay.com/en/bed-cornfield-sleep-good-night-921061/
https://pixabay.com/en/bed-cornfield-sleep-good-night-921061/

You may wish to look at another set of RLS guidelines also recently published in the journal Sleep titled Guidelines for the first-line treatment of restless legs syndrome/Willis–Ekbom disease, prevention and treatment of dopaminergic augmentation: a combined task force of the IRLSSG, EURLSSG, and the RLS-foundation

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The emerging research boosting Parkinson’s disease treatment

Parkinson’s disease (PD) is probably the most iconic neurological disorder. It has diverse manifestations, typical of many neurological diseases. PD is a result of brain dopamine deficiency, and its clinical picture is dominated by motor symptoms- tremor, rigidity and bradykinesia (slowing of movements). It however also manifests with a variety of non-motor symptoms which rival the motor symptoms in their impact. PD is responsive to treatment with several oral medications such as levodopa, infusions such as apomorphine, and interventions such as deep brain stimulation (DBS).

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Regardless of the intervention used, PD is a neurodegenerative disorder that grinds, slowly and steadily, along a chronic progressive course. This often manifests with disabling features such as freezing, hallucinations, and dyskinesias (drug-induced writhing movements). These symptoms creep or barge in unannounced, challenging the wits of the neurologist, and pushing the resolve of patients and their families to the limit. What hope does research offer to smooth the journey for people with PD? Here are my top 7.

1. Increasing evidence for the benefit of exercise

jogging-1529803_1280

OK, not every advance has to be groundbreaking. It is self-evident that exercise is beneficial for many chronic disorders, but proving this has been difficult…until now that is. Researchers, publishing in the journal Movement Disorders, looked at the benefits of exercise on cognitive function in PD, and their verdict is-yes, it works! The study, titled Exercise improves cognition in Parkinson’s disease: The PRET-PD randomized, clinical trial, comes with strings attached- you have to keep at the exercise for 2 years! A review  in the same journal indicates that exercise also improves mood and sleep in PD.

2. Lithium for treatment of dyskinesias

By Dnn87 - Self-photographed, CC BY 3.0, Link
By Dnn87Self-photographed, CC BY 3.0, Link

Dyskinesias are abnormal, fidgety movements that develop as side effects of the drugs used to treat PD. Most people with dyskinesias are not overly concerned about the movements because the alternative, disabling freezing and immobility, is worse. Dyskinesias are however energy-sapping, and are distressing for family members. Amantadine is one drug neurologists add-on to improve dyskinesias, but many people do not tolerate or benefit from this. The suggestion that lithium may help dyskinesias is therefore welcome news. The report comes from a study in mice reported in the journal Brain Research titled The combination of lithium and l-Dopa/Carbidopa reduces MPTP-induced abnormal involuntary movements (AIMs). A long way to go yet, but hope.

3. Transcranial magnetic stimulation (TMS)

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

Transcranial magnetic stimulation (TMS) is playing an increasing role in neurology as I discussed in a previous post titled Are magnets transforming neurology? It is almost inevitable therefore that TMS will crop up in attempts to treat PD. And so it has, going by a meta-analysis and systematic review published in JAMA Neurology. The paper is titled Effects of repetitive transcranial magnetic stimulation on motor symptoms in Parkinson disease. The reviewers passed the judgement that repetitive TMS improves motor symptoms in PD. Perhaps time to invest in TMS!

4. MRI guided focused ultrasound (MRgFUS)

By Frmir - Own work, CC BY-SA 3.0, Link
By FrmirOwn work, CC BY-SA 3.0, Link

MRI guided ultrasound (MRgFUS) is not new to medicine. It is used, for example, in the treatment of solid tumours and uterine fibroids. It is however innovative in the treatment of tremor and dyskinesia in PD. This came to my attention via a press release from University of Maryland titled Metabolic Imaging Center uses new ultrasound technology to target deep structures of the brain. MRgFUS non-invasively transmits ultrasound waves to the globus pallidus, one of the deep brain structures involved in PD. How this works still remains fuzzy to me, but it is exciting enough to generate a lot of research activity with articles such as MRI guided focused ultrasound thalamotomy for moderate-to-severe tremor in Parkinson’s disease in the journal Parkinson’s Disease; and Unilateral magnetic resonance-guided focused ultrasound pallidotomy for Parkinson disease, published in Neurology. Watch out, deep brain stimulation!

5. Nasal mucosal grafting

Big Nose Strikes Again. Bazusa on Flikr. https://www.flickr.com/photos/bazusa/260401471
Big Nose Strikes Again. Bazusa on Flikr. https://www.flickr.com/photos/bazusa/260401471

What a great thing, the blood-brain barrier, protecting the brain from all the bugs and toxins running amok in the bloodstream. This iron-clad fence unfortunately also effectively keeps out, or limits the entrance of, many beneficial drugs which need to get to the brain to act. As with all borders however, there are always people ready to break through, without leaving any tracks behind. And the people in this case are neurosurgeons who have successfully bypassed the blood brain barrier, and safely ‘transported’ PD drugs in to the brain. They did this by removing a portion of the blood brain barrier of mice, and replaced it with a piece of the tissue which lines the inside of the nose, a procedure called nasal mucosal grafting. They then delivered glial derived neurotrophic factor (GDNF), a protein that treats PD in mice, across the graft. The neurosurgeons explained all this in their paper titled Heterotopic mucosal grafting enables the delivery of therapeutic neuropeptides across the blood brain barrier. You may however prefer the simpler version from the Boston Business Journal (can you believe it!) titled A new way to treat Parkinson’s disease may be through your nose. It will however take time before human trials of nasal mucosal grafting…this is science after all, not science fiction!

6. Fetal stem cell transplantation

Marmoset embryonic stem cells forming neurons. NIH Image gallery on Flikr. https://www.flickr.com/photos/nihgov/27406746806
Marmoset embryonic stem cells forming neurons. NIH Image gallery on Flikr. https://www.flickr.com/photos/nihgov/27406746806

It doesn’t seem too long ago when all ethical hell broke loose because some scientists were transplanting fetal tissue into human brains. I thought the clamour had put this procedure into the locker, never to be resurrected. Apparently not; fetal stem cell transplantation (SCT) is back, reminiscent of Arnold Schwarzenegger in the Terminator films. Learn more of this comeback in this piece from New Scientist titled Fetal cells injected into a man’s brain to cure his Parkinson’s. The work is from Roger Barker‘s team at the University of Cambridge, and they are planning a big study into this named TRANSNEURO. Watch this space

7. Pluripotent stem cell transplantation

By Judyta Dulnik - Own work, CC BY-SA 4.0, Link
By Judyta DulnikOwn work, CC BY-SA 4.0, Link

The future of stem cell transplantation probably lies with pluripotent, rather than fetal cells. The idea is to induce skin cells, called fibroblasts, to transform into dopamine-producing cells. Fibroblasts can do this because they are pluripotent cells; that is they are capable of becoming whatever type of cells you want, so long as you know the magic words. In this case, the words are likely to be the transcription factors Mash1, Nurr1 and Lmx1a. Beatsopen sesame‘, and surely less controversial than fetal cells. Researchers are taking this procedure very seriously indeed, setting out ground rules in articles such as Direct generation of functional dopaminergic neurons from mouse and human fibroblasts. This was published in the journal Nature, but you may prefer the easier read in New Scientist titled Brain cells made from skin could treat Parkinson’s. But don’t get too excited…pluripotent stem cell transplantation is barely at the starting line yet.

 

Eu Sou. jeronimo sanz on Flikr. https://www.flickr.com/photos/jeronimooo/12069638595
Eu Sou. jeronimo sanz on Flikr. https://www.flickr.com/photos/jeronimooo/12069638595

There is so much more going on in the field of Parkinson’s disease to cover in one blog post. I will review neuroprotection in Parkinson’s disease in a coming post. In the meantime, here are links to 12 interesting articles and reviews on the future of PD:

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neurochecklists-image

What are the most iconic neurological disorders?

Neurology is a broad specialty covering a staggering variety of diseases. Some neurological disorders are vanishingly rare, but many are household names, or at least vaguely familiar to most people. These are the diseases which define neurology. Here, in alphabetical order, is my list of the top 60 iconic neurological diseases, with links to previous blog posts where available.

 

1. Alzheimer’s disease

By uncredited - Images from the History of Medicine (NLM) [1], Public Domain, https://commons.wikimedia.org/w/index.php?curid=11648572
By uncredited – Images from the History of Medicine (NLM) [1], Public Domain, https://commons.wikimedia.org/w/index.php?curid=11648572

2. Behcet’s disease

By Republic2011 - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17715921
By Republic2011Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17715921

3. Bell’s palsy

By http://wellcomeimages.org/indexplus/obf_images/69/f2/8d6c4130f4264b4b906960cf1f7e.jpgGallery: http://wellcomeimages.org/indexplus/image/M0011440.html, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=36350600
By http://wellcomeimages.org/indexplus/obf_images/69/f2/8d6c4130f4264b4b906960cf1f7e.jpgGallery: http://wellcomeimages.org/indexplus/image/M0011440.html, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=36350600

4. Brachial neuritis

5. Brain tumours

6. Carpal tunnel syndrome

7. Cerebral palsy (CP)

8. Cervical dystonia

9. Charcot Marie Tooth disease (CMT)

By http://wellcomeimages.org/indexplus/obf_images/66/09/4dfa424fe11bb8dc56b2058f04ba.jpgGallery: http://wellcomeimages.org/indexplus/image/V0026141.html, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=36578490
By http://wellcomeimages.org/indexplus/obf_images/66/09/4dfa424fe11bb8dc56b2058f04ba.jpgGallery: http://wellcomeimages.org/indexplus/image/V0026141.html, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=36578490

10. Chronic inflammatory demyelinating polyneuropathy (CIDP)

11. Cluster headache

12. Creutzfeldt-Jakob disease (CJD)

By Unknown - http://www.sammlungen.hu-berlin.de/dokumente/11727/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4008658
By Unknownhttp://www.sammlungen.hu-berlin.de/dokumente/11727/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4008658

13. Duchenne muscular dystrophy (DMD)

By G._Duchenne.jpg: unknown/anonymousderivative work: PawełMM (talk) - G._Duchenne.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9701531
By G._Duchenne.jpg: unknown/anonymousderivative work: PawełMM (talk) – G._Duchenne.jpg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9701531

14. Encephalitis

15. Epilepsy

16. Essential tremor

17. Friedreich’s ataxia

By Unknown - http://www.uic.edu/depts/mcne/founders/page0035.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3960759
By Unknownhttp://www.uic.edu/depts/mcne/founders/page0035.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=3960759

18. Frontotemporal dementia (FTD)

19. Guillain-Barre syndrome (GBS)

By Anonymous - Ouvrage : L'informateur des aliénistes et des neurologistes, Paris : Delarue, 1923, Public Domain, https://commons.wikimedia.org/w/index.php?curid=28242077
By Anonymous – Ouvrage : L’informateur des aliénistes et des neurologistes, Paris : Delarue, 1923, Public Domain, https://commons.wikimedia.org/w/index.php?curid=28242077

20. Hashimoto encephalopathy

21. Hemifacial spasm

22. Horner’s syndrome

By Unknown - http://ihm.nlm.nih.gov/images/B15207, Public Domain, https://commons.wikimedia.org/w/index.php?curid=19265414
By Unknownhttp://ihm.nlm.nih.gov/images/B15207, Public Domain, https://commons.wikimedia.org/w/index.php?curid=19265414

23. Huntington’s disease (HD)

https://en.wikipedia.org/wiki/George_Huntington#/media/File:George_Huntington.jpg
https://en.wikipedia.org/wiki/George_Huntington#/media/File:George_Huntington.jpg

24. Idiopathic intracranial hypertension (IIH)

25. Inclusion body myositis (IBM)

26. Kennedy disease

27. Korsakoff’s psychosis

28. Lambert-Eaton myasthenic syndrome (LEMS)

29. Leber’s optic neuropathy (LHON)

30. McArdles disease

31. Meningitis

32. Migraine

33. Miller-Fisher syndrome (MFS)

By J3D3 - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34315507
By J3D3Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=34315507

34. Motor neurone disease (MND)

35. Multiple sclerosis (MS)

36. Multiple system atrophy (MSA)

37. Myasthenia gravis (MG)

38. Myotonic dystrophy

39. Narcolepsy

40. Neurofibromatosis (NF)

41. Neuromyelitis optica (NMO)

42. Neurosarcoidosis

43. Neurosyphilis

44. Parkinson’s disease (PD)

45. Peripheral neuropathy (PN)

46. Peroneal neuropathy

47. Progressive supranuclear palsy (PSP)

48. Rabies

49. Restless legs syndrome (RLS)

50. Spinal muscular atrophy (SMA)

51. Stiff person syndrome (SPS)

52. Stroke

53. Subarachnoid haemorrhage (SAH)

54. Tension-type headache (TTH)

55. Tetanus

56. Transient global amnesia (TGA)

57. Trigeminal neuralgia

58. Tuberous sclerosis

59. Wernicke’s encephalopathy

By J.F. Lehmann, Muenchen - IHM, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9679254
By J.F. Lehmann, Muenchen – IHM, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9679254

60. Wilson’s disease

By Carl Vandyk (1851–1931) - [No authors listed] (July 1937). "S. A. Kinnier Wilson". Br J Ophthalmol 21 (7): 396–97. PMC: 1142821., Public Domain, https://commons.wikimedia.org/w/index.php?curid=11384670
By Carl Vandyk (1851–1931) – [No authors listed] (July 1937). “S. A. Kinnier Wilson“. Br J Ophthalmol 21 (7): 396–97. PMC: 1142821., Public Domain, https://commons.wikimedia.org/w/index.php?curid=11384670

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The Neurology Lounge has a way to go to address all these diseases, but they are all fully covered in neurochecklists. In a future post, I will look at the rare end of the neurological spectrum and list the 75 strangest and most exotic neurological disorders.

What’s happening at the cutting edge of MSA?

Multiple system atrophy (MSA) is a mimic of Parkinson’s disease (PD). Neurologists suspect MSA in people with apparent PD who, in addition, have other defining features. In many people with MSA their prominent symptoms are cerebellar dysfunction (MSA-C), and these have unsteadiness and incoordination of movements. In other people with MSA the predominant symptoms are of Parkinsonism, and this type is called MSA-P.

By Images are generated by Life Science Databases(LSDB). - from Anatomography[1] website maintained by Life Science Databases(LSDB).You can get this image through URL below. 次のアドレスからこのファイルで使用している画像を取得できますURL., CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=7769113
By Images are generated by Life Science Databases(LSDB). – from Anatomography[1] website maintained by Life Science Databases(LSDB).You can get this image through URL below. 次のアドレスからこのファイルで使用している画像を取得できますURL., CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=7769113

Making a diagnosis of MSA is gratifying, but treating it is frustrating. Only about a third of people with MSA respond to the standard PD medication, Levodopa. Furthermore, MSA confers a shortened life expectancy. It is therefore important that neurologists resolve the mystery of MSA, and they are indeed hacking away at its cutting-edge.

Genetics

The general assumption is that MSA is acquired rather than inherited. This assumption did not dissuade neurologists from looking for MSA genetic risk factors, and their quest has led to the discovery of a candidate MSA gene. This is called coenzyme Q2 4-hydroxybenzoate polyprenyltransferase, or simply the COQ2 gene. This gene was first touted in a 2013 paper in the New England Journal of Medicine titled Mutations in COQ2 in Familial and Sporadic Multiple-System Atrophy. Using whole genome sequencing, the authors identified COQ2 gene mutations in both sporadic and familial cases of MSA. Another paper in Neurology in 2016, titled New susceptible variant of COQ2 gene in Japanese patients with sporadic multiple system atrophy, reported that the COQ2 gene mutation is more likely in MSA-C than in other types of MSA.

You may explore the genetics of MSA further in this paper in Neurobiology of Aging titled Genetic players in multiple system atrophy: unfolding the nature of the beast.

Differential diagnoses

When neurologists are considering the diagnosis of MSA, they come up against many disorders jostling to confuse them. There are of course PD and related conditions such as progressive supranuclear palsy (PSP). There is also the endless list of conditions which cause either cerebellar or autonomic dysfunction. The neurologist is usually cautious to exclude these known differential diagnoses of MSA. But what happens when they come across a mimic that isn’t in the textbooks? Such is the situation with this case report published in Movement Disorders of Concomitant Facioscapulohumeral Muscular Dystrophy and Parkinsonism Mimicking Multiple System Atrophy.

This case defies the law of parsimony, Occam’s razor. To paraphrase, this law states that a single diagnosis is the most likely cause for a patient’s clinical features. Clearly in some cases such as this, the neurologist must disregard William of Occam, and make multiple diagnoses.

Investigations
Hot cross bun. Liliana Fuchs on Flikr. https://www.flickr.com/photos/akane86/5208128379
Hot cross bun. Liliana Fuchs on Flikr. https://www.flickr.com/photos/akane86/5208128379

Neurologists often request some tests to confirm their suspicion of MSA. The usual investigation is the painless but claustrophobic magnetic resonance imaging (MRI). In MSA, this shows shrinking or atrophy of the cerebellum. It may also show the hot cross bun sign, a characteristic pattern of shrinking of the chunky middle section of the brainstem, the pons.

Big MRI. liz west on Flikr. https://www.flickr.com/photos/calliope/223220955
Big MRI. liz west on Flikr. https://www.flickr.com/photos/calliope/223220955

Some neurologists are not satisfied with this culinary sign and have explored other radiological indicators of MSA. They studied an MRI technique called diffusion tensor imaging tractography (DTI tractography) and reported their findings in the Journal of Neurology. Their paper titled Characteristic diffusion tensor tractography in multiple system atrophy reports that DTI tractography appears to distinguish MSA-C from other causes of cerebellar dysfunction.

Biomarkers

Biomarkers again, so soon after my previous blog post, What is the state of parkinson’s disease biomarkers. The whole idea behind biomarkers is their potential to make for an easier and earlier diagnosis. They are all the rage in neurodegenerative diseases, and MSA can’t be an exception. The first potential MSA biomarker is α-synuclein, the abnormal protein that is found in the brains of people with PD, MSA and Lewy body disease (LBD), the so-called synucleopathies. Researchers have now discovered that α-synuclein also resides in the skin. They carried out skin biopsies in people with PD and MSA and found skin deposits of α-synuclein in both. Writing in the journal Movement Disorders, they showed that in PD, the deposits were mainly in autonomic nerve fibers, whilst in MSA they were in the larger somatic nerves. Time to brush up those skin biopsy skills!

The second potential biomarker is optical coherence tomography (OCT). This is reported in Movement Disorders in a paper titled Progressive retinal structure abnormalities in multiple system atrophy. The authors used OCT to measure the thickness of the retina of the eye. They demonstrated that the retina is thin in both PD and MSA, but the thinning advances more rapidly in MSA than in PD. If confirmed, this would be a handy, and painless, biomarker.

Potential treatments
Syringe and vaccine. Niaid on Flikr. https://www.flickr.com/photos/niaid/14329622976
Syringe and vaccine. Niaid on Flikr. https://www.flickr.com/photos/niaid/14329622976

The objective of all research is to arrive at effective treatments. There is unfortunately no bright treatment looming in the MSA horizon because the research so far have produced disappointing results. Such failures include Rifampicin, Fluoxetine and Lithium. There is however no scarcity of potential therapeutic candidates. The most exciting is a vaccine against MSA. For this and other research efforts read this excellent review in Advances in Clinical Neurology and Rehabilitation (ACNR) titled Updates on potential therapeutic targets in MSA.