Ibrahim Imam GENERAL, GENERAL NEUROLOGY, LISTENING POST

5 exciting developments in the management of Wilson’s disease

In all fairness, neurologists only very rarely come across patients with Wilson’s disease. This disorder of excessive copper deposition in tissues is however not vanishingly rare. And because it is one of the few curable neurological disorders, it is drummed into the brain of every neurologist to consider Wilson’s disease in any person, at any age, with any movement disorder. Dystonia is probably the most characteristic movement disorder in Wilson’s disease, and one of its classical signs is rhisus sardonicus, a fixed vacuous smile (which, by the way, may also be seen in tetanus). Other movement disorders of Wilson’s disease include parkinsonism, wing-beating tremor, ataxia, myoclonus, chorea, athetosis, stereotypies, tics, and restless legs syndrome. It is therefore not surprising that the disorder is named after one of neurology’s greats, Samuel Alexander Kinnier Wilson.

By Carl Vandyk – Carl Vandyk, Public Domain, https://commons.wikimedia.org/w/index.php?curid=11384670

The other name for Wilson’s disease is hepatolenticular degeneration. ‘Lenticular’ in this context refers to the favoured brain targets of Wilson’s disease, the lentiform nuclei. These are the putamen and globus pallidus, which, along with the caudate nucleus, make up the basal ganglia. The basal ganglia are very important in the coordination of movement, and are also dysfunctional in disorders such as Huntington’s disease and Parkinson’s disease.

By Niubrad at the English Wikipedia, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19495297

Wilson’s disease is however more than a brain disorder because it is, quintessentially, multi-systemic. The monicker hepatolenticular, for example, hints at the prominent and varied involvement of the liver in Wilson’s disease. Liver dysfunction here ranges from mild elevation of liver enzymes, to frank hepatic failure requiring liver transplantation. The eye is another important organ targeted by Wilson’s disease, and the neurologist is ever searching for the tell-tale but elusive Kayser-Fleischer ring. This is a brownish tinge seen around the iris caused by copper deposition, and named after the German ophthalmologists Bernhard Kayser and Bruno Fleischer. Another distinctive eye sign in Wilson’s disease is the sunflower cataract. The long reach of Wilson’s disease however extends to almost every organ system.

By Herbert L. Fred, MD, Hendrik A. van Dijk – http://cnx.org/content/m15007/latest/, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=2746925

Wilson’s disease is all about the ‘C’ words. The first ‘C’, Copper, is of course the essential element recognised as Cu, with atomic number 29, and snugly occupying group 4 in the periodic table. An autosomal recessive genetic mutation in ATP7B, the copper transporter gene, means some people are unable to move copper around the body. It therefore accumulates, and is eventually deposited, in almost every organ. Oh, and it also overflows in high amounts in urine.

Copper crystals. James St John on Flickr. https://www.flickr.com/photos/jsjgeology/17127538489

The other ‘C’ word is Ceruloplasmin, the blood protein that binds up the dangerous free-floating copper in the blood. The blood level of ceruloplasmin is low in Wilson’s disease because it is overwhelmed by the massive amounts of copper. The classical laboratory features of Wilson’s disease are therefore raised blood copper, low blood ceruloplasmin, and elevated 24 hour urinary copper excretion. The diagnosis of Wilson’s disease may also involve a liver biopsy to confirm copper accumulation, but this is rarely required. Long-term treatment depends on one of several therapeutic options for chelating or binding copper. Surveillance requires a tight monitoring regime to monitor the metabolic profile of the disease, and the complications its treatment.

By own work – adapted from http://www.pdb.org/pdb/files/1kcw.pdb using PyMOL, Public Domain, https://commons.wikimedia.org/w/index.php?curid=4982229

Is it however not all and dusted for Wilson’s disease. Not at all. There are advances being made to simplify the diagnosis and monitoring of this devastating disease, and below are 5 exciting developments in the management of Wilson’s disease.

Exchangeable copper

I learnt of this from a paper published in the European Journal of Neurology titled Exchangeable copper: a reflection of the neurological severity in Wilson’s disease. The authors, Aurelia Poujois and colleagues, investigated this new technique of measuring exchangeable copper (CuEXC) as an aid to the diagnosis of Wilson’s disease, and as an indicator of the severity of extra-hepatic damage. They studied 48 newly diagnosed subjects and found that CuEXC is a reliable test for making the diagnosis, and a cut-off value of >2.08 μmol/l is a marker of severe organ damage. Other papers have confirmed the value of exchangeable copper, even if they call it relative exchangeable copper.

By Alchemist-hp (pse-mendelejew.de) – Own work, CC BY-SA 3.0 de, https://commons.wikimedia.org/w/index.php?curid=6958463

X-ray fluorescence

Slávka Kaščáková and colleagues, in their paper published in the journal Pathology, touted X-ray fluorescence as a rapid way to quantify copper in tissues, thereby facilitating the diagnosis of Wilson’s disease. The rather technical paper, titled Rapid and reliable diagnosis of Wilson disease using X-ray fluorescence, describes the technique as ‘high‐resolution mapping of tissue sections’ which enables the measurement of ‘the intensity and the distribution of copper, iron and zinc while preserving the morphology’. This technique can, we have to accept, reliably distinguish Wilson’s disease from other diseases such as haemochromatosis and alcoholic cirrhosis. Not a bad deal, but the squeamish neurologist must realise it requires a liver biopsy!

X-ray Fluorescence Analyzer. IAEA Imagebank on Flickr. https://www.flickr.com/photos/iaea_imagebank/30483472557

Quantitative transcranial ultrasound

The typical method of ‘seeing’ the brain abnormalities of Wilson’s disease is by magnetic resonance imaging (MRI). Ultrasound is however much cheaper and easier, and would be a preferable option if it can be shown to be sensitive and specific. And this is what Gotthard Tribl and colleagues demonstrated in their paper published in the Journal of Neurological Sciences titled Quantitative transcranial sonography in Wilson’s disease and healthy controls: cut-off values and functional correlates. They reported that in Wilson’s disease, the lenticular nuclei (we are familiar with this now) and substantia nigra (literally a black substance in the midbrain) are hyperechogenic compared to normal control subjects. They also came up with reliable cut-off for normality. To make things better, the thalami and midbrain are also hyperechogenic. And to add the cherry on top, the third ventricle is enlarged. More than expected from a rather simple technology.

CC BY-SA 3.0, https://en.wikipedia.org/w/index.php?curid=19500021

Optical coherence tomography (OCT)

Hardly a day goes by that one doesn’t read a report on the applicability of optical coherence tomography (OCT) in one neurological disorder or the other. And Wilson’s disease is clearly not going to be the exception. OCT simply assesses the thickness or density of the retinal nerve fiber layer (RNFL), and this is reduced in many neurodegenerative diseases. In their paper titled Optical coherence tomography as a marker of neurodegeneration in patients with Wilson’s disease, Ewa Langwińska-Wośko and colleagues studied 58 subjects with Wilson’s disease. They reported that OCT can reliably measure the severity of Wilson’s disease, and it may reliably monitor disease progression. Another simple and non-invasive tool with big potential. 

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

Bis-choline tetrathiomolybdate

The treatment of Wilson’s disease centres on chelation or binding of copper. And the three major players here are  Penicillamine, Trientine, and Zinc, each with its own unique advantages and serious complications. They are however all rather cumbersome and inconvenient to administer and monitor. Into this unsatisfactory situation enters a study which promises to ease the burden for neurologist and patient. The trial is titled Bis-choline tetrathiomolybdate in patients with Wilson’s disease: an open-label, multicentre, phase 2 study, and it is published in the journal Lancet Gastroenterology and Hepatology. The authors, Karl Heinz Weiss and colleagues, investigated bis-choline tetrathiomolybdate (nicknamed WTX101), which they described as ‘an oral first-in-class copper-protein-binding molecule’. It binds up copper that is either stuck in the liver or swimming freely in blood. 70% of the 28 subjects they treated met the criteria for treatment success, and they were not unduly bothered by any nasty side effects. To add to this favourable profile, WTX101 has the convenience of a once daily dosing regime.

By I, Jonathan Zander, CC BY-SA 3.0, Link

 

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It is reassuring that so much as happening at the cutting edge of Wilson’s disease, and neurologists can’t wait to see when these will form part of their armamentarium.

Ibrahim Imam CUTTING EDGE, GENERAL NEUROLOGY

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.

By Images are generated by Life Science Databases(LSDB). – from Anatomography, website maintained by Life Science Databases(LSDB).You can get and edit 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・編集できますURL., CC BY-SA 2.1 jp, https://commons.wikimedia.org/w/index.php?curid=7932266

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

Ibrahim Imam CONTROVERSIAL, CUTTING EDGE, GENERAL, GENERAL NEUROLOGY

Are parasites the simple solution to the problem of MS?

In medicine, microbes are notorious for causing disease. In neurology particularly, infection is the direct cause of serious diseases such as meningitis and encephalitis. Infections may also act as  catalysts for neurological disorders, for example when they trigger Guillain Barre syndrome (GBS). Infection is therefore a villain, a scoundrel to be apprehended and disarmed whenever it rears its head. But this picture may not hold true when it comes to multiple sclerosis (MS) where a contrary story is emerging, a narrative which holds infection as the hero, the daredevil that will save the day. The premise is simple: MS has very little presence in the regions of the world where infections reign supreme. Just look at any world prevalence map of MS to be convinced.

By MS_Risk_no_legend.svg: *MS_Risk.svg: Dekoderderivative work: Faigl.ladislav (talk)derivative work: Gabby8228 (talk) – MS_Risk_no_legend.svg, Public Domain, https://commons.wikimedia.org/w/index.php?curid=15917004

How strong is this inverse relationship between infection and MS? It all boils down to the so-called hygeine hypothesis of autoimmune diseases. This suggests that the human immune system becomes dysregulated when it is not primed by infections, and this dysregulation results in autoimmune disorders. This point was strongly argued by Aakanksha Dixit and colleagues in their paper published in the International Journal of Molecular Science, titled Novel Therapeutics for Multiple Sclerosis Designed by Parasitic Worms. They contend that the relationship between parasitic infections and autoimmune diseases is “most compelling“, going on to assert that helminthic infections “may be the protective environmental factor against the development of MS”.

By Doc. RNDr. Josef Reischig, CSc. – Archiv autora, CC BY 3.0, Link

To support the hygiene theory of MS, that helminthic infections play a role in banishing MS, three levels of evidence are offered.

  1. The prevalence of MS steadily increases when the frequency of infections in a community is reduces.
  2. People with MS who also have helminthic infections have fewer relapses and slower disease progression.
  3. MS patients who are treated for their helminthic infections develop more relapses and have a more active disease course. 
Diversity and prevalence of gastrointestinal parasites in seven non-human primates of the Taï National Park, Côte d’Ivoire. Parasite, 2015, 22, 1.doi:10.1051/parasite/2015001, CC BY 4.0, Link

Toxoplasma gondii, the cause of toxoplasmosis, is perhaps the major parasite investigated in relation to MS. Asli Koskderelioglu and colleagues, for example, reported that exposure to T.gondii is less frequent in people with MS than in healthy control subjects. In their 2017 paper titled Is Toxoplasma gondii infection protective against multiple sclerosis risk?, published in Multiple Sclerosis and Related Disorders, they found that MS subjects who have higher toxoplasma antibody levels experience fewer relapses and less severe disease courses. This finding is corroborated by a 2015 paper in the Journal of Neuroimmunology titled Toxoplasma gondii seropositivity is negatively associated with multiple sclerosis.

CC BY 4.0, Link

Neurologists are however very cynical people, and they never believe what single trials tell them. After all, many microbes, such as Ebstein Barr virus (EBV), are touted as MS risk factors. For the sceptical neurologist, only systematic reviews and meta-analyses will do; these are the stuff of our dreams, the essence of our daily existence. So it is with a huge cheer that neurologists welcomed a 2018 systematic review and meta-analysis published in the Journal of Neuroimmunology and titled Is toxoplasma gondii playing a positive role in multiple sclerosis risk? The paper poured very cold water on the beautiful hygiene hypothesis. Whilst the authors, Reza Saberi and colleagues, confirmed that MS subjects had a lower risk of exposure to T. gondii, they found no relationship between this parasite and the development of MS. Wither a theory when it hits the reality of cold statistical analysis.

Cloudburst. Liz West on Flickr. https://www.flickr.com/photos/calliope/28825267500

Notwithstanding the systematic review, the helminth hypothesis marches on. It has even reached the stage of therapeutic trials where, as distasteful as it sounds, subjects ingest parasites by mouth! And the fancied parasite is not Toxoplasma gondii but Trichuris suis ova (TSO). It all began with a small observational trial in 10 people which proved that TSO is safe and well-tolerated (phew), but it had no value whatsoever in treating MS. Not discouraged, the hypothesis entered the slightly larger HINT 2 trial; this again confirmed good tolerability in 16 subjects, but any benefit in reversing MS was questionable. Undeterred, the hypothesis has gone for a bigger study in the form of the TRIOMS trial. This is a randomized, placebo-controlled study of 50 people with MS or clinically isolated syndrome (CIS) in which subjects will be ingesting 2,500 Trichuris suis eggs every two weeks. We wait with bated breaths for the results.

By Universidad de Córdoba – http://www.uco.es/dptos/zoologia/zoolobiolo_archivos/practicas/practica_4/practica4_botton.htm, Public Domain, Link

Before leaving this subject, we must know that helminths are not the only game in town; they have strong competition from their cousins, bacteria. And the standout character in this arena is Helicobacter pylori. We learnt this from a study published in 2015 in the Journal of Neurology Neurosurgery and Psychiatry. Titled Helicobacter pylori infection as a protective factor against multiple sclerosis risk in females, the paper reported that people with MS were less likely than controls to have been exposed to H. pylori. Two meta-analyses have also reviewed the relationship of H. pylori and MS, arguing strongly that, in Western countries, there is an inverse relationship between H pylori and MS. And they assert that H. pylori may be protective against MS. If it feels like déjà vu, it is.

Helicobacter pylori. AJC21 on Flickr. https://www.flickr.com/photos/ajc1/6946417103

We have surely not heard the last of bugs and MS. However, for now, the foundations of the hygiene theory are a bit shaky, and the future rather hazy.

By Doc. RNDr. Josef Reischig, CSc. – Archiv autora, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17268274

 

Ibrahim Imam GENERAL, GENERAL NEUROLOGY

What is the last word on migraine and PFOs?

This is surely one of neurology’s bug bears, the old chestnut. Just when one generation of neurologists thinks it has buried and sealed it in an impervious crypt, it resurrects to haunt the next breed. This cyclical and macabre dance of migraine and PFOs evokes a sense of deja vu every time it comes around. And each spawn of neurologists predictably picks up the gauntlet, answers the call to arms, and sets out to slaughter the ghost of migraines past.

By Lille1982 – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9682382

But let’s take a step back to basics with some definitions. The foramen ovale is just a ‘hole in the heart‘ between the right and left atria, or upper heart chambers. It is essential in foetal life because it enables circulating blood to bypass the superfluous foetal lungs (apologies to readers across the Atlantic for the superfluous ‘o’!). However, after birth, when blood needs to circulate through the now indispensable lungs, the foramen ovale becomes irrelevant. In most people, the foramen ovale humbly accepts its fate, crawls to a corner, and closes shop. But foramen ovales in some people are recalcitrant; standing their ground, they endure and survive as PFOs.

By DrJanaOfficial – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50477765

It is not clear how the myth started, but stories of migraine cure following surgical closure of PFO spread rapidly and widely. Very soon, migraineurs where demanding echocardiograms to check if they have PFOs lurking in their tickers. Research trials investigating this issue started as a trickle, and very soon become a flood. But rather than shed light, the conflicting results intensified the darkness. That is, until some indignant and determined neurologists and cardiologists set out to settle the matter once and for all. And the onslaught came in three waves of studies.

MIGRAINE. aka Tman on Flickr. https://www.flickr.com/photos/rundwolf/331545021

The first wave in the attempt to slay the beast of migraine and PFO was a trial published in the journal Headache. Davinia Larrosa and colleagues studied 183 people with migraine and found that, whilst PFOs were larger and more permanent in people with migraine, there was no relationship between patent foramen ovale and migraine frequency.

Migraine spectrum. JoanDragonfly on Flickr. https://www.flickr.com/photos/joandragonfly/26221136058

The second wave was a study published in the European Heart Journal by Heinrich Mattle and colleagues. In their PRIMA trial (Percutaneous Closure of PFO in Migraine with Aura), they blindly allocated or randomized half of their subjects with refractory migraine and PFO to have PFO closure surgery. And their verdict was, PFO closure did nothing to reduce the frequency of migraine.

Open the key to your heart. Maria Eklind on Flickr. https://www.flickr.com/photos/mariaeklind/24659701809

The third wave, launched by Nauman Tariq and colleagues, took a different tack. They carried out a detailed review of practically all the studies that had addressed the subject. Their brilliantly titled paper, “Patent foramen ovale and migraine: closing the debate“, reflected their ambition to settle the question once and for all. After an arduous trawl through the literature, and a mind-blowing crunching of statistics, the authors came to the conclusions that “there is no good quality evidence to support a link between migraine and PFO“, and “closure of PFO for migraine prevention does not significantly reduce the intensity and severity of migraine“.

By Patrick J. Lynch, medical illustrator – Patrick J. Lynch, medical illustrator, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=1488277

The final word therefore is, leave PFOs alone! But there is a big caveat. There is one situation where PFO is associated with migraine, and that is when it is accompanied by another heart anomaly called an atrial septal aneurysm (ASA). The evidence for this comes from Roel Snijder and colleagues, and the title of their paper says it all: Patent foramen ovale with atrial septal aneurysm is strongly associated with migraine with aura: a large observational study. We already knew that PFO associated with ASA increases the risk of stroke; we can now add to this, the risk of migraine with aura.

By H. Airy – Flatau 1912 “Migrena” monograph after previous publication of H. Airy, Public Domain, https://commons.wikimedia.org/w/index.php?curid=7814450

The debate is now hopefully sealed and settled. But don’t hold your breath for too long: the phantom of migraine and PFO may just rear its hideous head again at a neuroscience centre near you.

 

Ibrahim Imam GENERAL NEUROLOGY, NEW SYNDROMES

The 9 neurological manifestations of anti MOG antibody disorder

Autoimmune disorders are probably the most proliferative field of neurology. It seems like there is a blazing headline every week announcing a new antibody disease. Many of these antibodies are esoteric, but some shake the foundations of medical practice. Anti-MOG antibody is one of those which requires you to stop and pay attention, and it has significantly affected neurological practice in a very big way.

By Simon Caulton – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20522656

Perhaps the most important thing about anti-MOG antibody disease is that, like the chameleon, it presents in many guises. For the neurologist therefore, the first thing is to recognise these varied manifestations. Here then is a quick list of the 9 manifestations of anti MOG antibody disorder.

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1. Optic neuritis (ON)

2. Neuromyelitis optica spectrum disorders (NMOSD)

3. Multiple sclerosis (MS)

4. Acute disseminated encephalomyelitis (ADEM)

5. Multiphasic disseminated encephalomyelitis (MDEM)

6. Isolated transverse myelitis (TM)

7. Leukodystrophy-like phenotype

8. Cerebral cortical encephalitis

9. Combined central and peripheral demyelinating syndrome (CCPD)

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Optic Nerve Side View. Francisco Bengoa on Flikr. https://www.flickr.com/photos/frecuenciamedicafb/7404373800

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You can explore anti MOG antibody disorder further in Neurochecklists under the following titles:

Image from page 400 of “Diseases of the nervous system” (1910). Internet Archive Book Images on Flickr. https://www.flickr.com/photos/internetarchivebookimages/14586405720/

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For a detailed review and guidance, check this paper in Journal of Neuroinflammation:

 MOG encephalomyelitis: international recommendations on diagnosis and antibody testing.

By Pecatum – Own work, CC BY-SA 4.0, Link
Ibrahim Imam GENERAL, GENERAL NEUROLOGY

What are the pitfalls and perils of intracranial pressure?

Crudely speaking, the nervous system is made up of two parts. The peripheral nervous system, composed of nerves and muscles, is rather robust and roams free, exposed to the elements. On the other hand, the central nervous system, consisting of the brain and spinal cord, is delicate and fragile. It is therefore protectively cocooned in a rigid skull and a hardy vertebral skeleton. But even this tough fortress isn’t secure enough for these dainty neurones; they are, after all, the command and control system for the whole body. Therefore, to further insulate them from the physical and physiological perturbations that continuously threaten them, nature has further sequestered them within a very exquisitely regulated irrigation system, the cerebrospinal fluid (CSF).

Internet Archive book Images on Flickr. https://www.flickr.com/photos/internetarchivebookimages/14769907251/

The CSF is actually a fine filtrate of the blood that flows in the arteries. The sieve is the very forbidding blood-brain barrier (BBB) which turns away all the blood cells, and carefully sets a target on how much protein and glucose to let in. The pressure within the CSF is also very finely tuned, not too high…and not too low; that is how the neurones like it.

 

By Dr. Johannes Sobotta – Atlas and Text-book of Human Anatomy Volume III Vascular System, Lymphatic system, Nervous system and Sense Organs, Public Domain, https://commons.wikimedia.org/w/index.php?curid=29135482

 

Alas, as with all systems, the CSF is vulnerable to external miscreants; infections such as meningitis,  encephalitis, and brain abscesses which cause brain swelling or cerebral edema. The CSF is also largely defenceless to internal insurgents, fifth columnists, such as a brain tumours, haematomas (bleeds), and cerebral vein thrombosis (venous clots). The smooth flow of the CSF may also be obstructed, resulting in hydrocephalus or enlargement of the brain’s ventricular system. In all these circumstances, the intracranial pressure is often elevated, a situation aptly dubbed intracranial hypertension. Very often, intracranial hypertension may occur without any obvious cause, and this condition is referred to as idiopathic intracranial hypertension (IIH). Because IIH threatens vision, neurologists have abandoned its old and misleading name, benign intracranial hypertension (BIH).

By BruceBlaus. When using this image in external sources it can be cited as:Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014“. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436. – Own work, CC BY 3.0, Link

Intracranial hypertension is no walk in the park as it portends disaster, whatever its cause. As it is a  potentially fatal state, the early warning signs are drilled into all doctors in medical school…when their brains are still malleable. These red flag features are severe headache, impaired consciousness, progressive visual loss, dilated or blown pupils, papilledema (swelling of the optic nerve head), and neck stiffness. The standard operating procedure for intracranial hypertension is to deflate the pressure as quickly as possible, by hook or by crook. This may be medical, with infusions such as mannitol, or surgical, with procedures such as decompressive craniectomy (removal of part of the skull). The terminal stage of intracranial hypertension, the most ominous neurological emergency, is cerebral herniation: this is the catastrophic compression of the brainstem into the narrow and tight spinal canal: a physical state that is incompatible with life.

By Ambika S., Arjundas D., Noronha V. – https://openi.nlm.nih.gov/detailedresult.php?img=2859586_AIAN-13-37-g001&query=papilledema&it=xg&req=4&npos=2, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=47658492

As with all waves, intracranial pressure also has its lows, and it is a no-brainer that neurologists call this intracranial hypotension. This is not as hazardous as intracranial hypertension, but it is worthy of respect in view of its devastating morbidity. The usual cause, and again no prizes for guessing this, is a leak. The puncture in this case is often iatrogenic, in other words, the whodunnit is the doctor. This may be deliberate, such as when the doctor attempts to remove some CSF to test, via a procedure called a  lumbar puncture (LP). It may also be accidental, such as when your friendly anaesthetist performs an epidural to relieve pain. In both situations, the dura protecting the CSF is perforated, causing spinal fluid leakage. This manifests as postural or orthostatic headache; by definition, this is a headache that sets in within 15 minutes of standing up, and resolves within 15 minutes of lying down flat. The treatment in such cases is strict bed rest, drinking loads of fluids, including caffeinated drinks, and waiting for the dura to heal itself…usually within one week. If this does not happen, then an intravenous caffeine infusion may be required. An epidural blood patch may also be carried out, again by your friendly anaesthetist, who squirts a little of the victims blood around the site of the leak, to, well, ‘patch it up’. In extremis, surgery may be needed to seal the leak, but this is way beyond my pay grade.

By Paul Anthony Stewart – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=75808444

Intracranial hypotension may however develop without any apparent cause, and this is called spontaneous intracranial hypotension (SIH). The causes of SIH include unpredictable dural tears, ruptured meningeal diveticuli (outpouchings of the dura), and direct CSF-venous fistulae (don’t ask!) There are a variety of risk factors for SIH such as connective tissue diseases and bariatric surgery. It is very helpful that SIH leaves characteristic tell-tale clues on brain MRI scans, and these include subdural hygroma (plain fluid collections under the dura); subdural haematoma (blood under the dura); meningeal enhancement with contrast dye; engorgement of the pons and pituitary; and the interesting dinosaur tail sign on fat suppression T2 MRI (FST2WI). The gold standard test to localise the site of leakage in SIH is radionuclide cisternography. In the absence of this rather sophisticated test, a CT myelogram may be considered. Treatment is similar to that of other forms of intracranial hypotension, but other measures that may be required to seal the leak, including the use of fibrin sealeant.

By Hellerhoff – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18946727

If you have reached the end of this blog post, then you deserve a prize. Four prizes actually: recent interesting reports in the field of SIH to explore:

  1. The use of transorbital ultrasound in making a diagnosis.
  2. Treatment of complicated SIH with intrathecal saline infusion.
  3. SIH complicated by superficial siderosis.
  4. Severe SIH complicated by sagging brain causing causing postural loss of consciousness.
By © Nevit Dilmen, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=45660723

 

 

Ibrahim Imam CONTROVERSIAL, GENERAL, GENERAL NEUROLOGY

Clipping the wings of cerebral aneurysms: is the pendulum swinging back?

This is a follow up to my previous blog post, What should we really know about cerebral aneurysms? In that post, I discussed the nature and presentations of cerebral aneurysms. In this post I will look at the two major treatments for cerebral aneurysms, exploring their pros and cons, and looking at some emerging challenges to the conventional wisdom. 

By Tiago Etiene Queiroz – Own work, CC BY-SA 3.0, Link

The first question to answer regarding treatment of aneurysms is whether they need any treatment at all. In other words, are they best left well alone? In principle, aneurysms that have ruptured require treatment, irrespective of their size. On the other hand, aneurysms that are discovered incidentally, before they rupture, may not need surgical treatment unless they are large (usually 7mm or more in diameter), or they are associated with high-risk features/locations. Low-risk aneurysms that do not require treatment however need long-term surveillance with intermittent brain imaging. To limit the growth of such aneurysms, people harbouring them are advised to stop smoking, and if they have hypertension, to ensure that this is well-controlled.

By Professor Dr. O. Bollinger. – LEHMANN’S MEDICIN. HAND ATLANTEN Atlas und Grundrissder PATHOLOGISCHENANATOMIE 1901, Public Domain, Link

There are two treatment approaches to ruptured aneurysms and high-risk unruptured aneurysms. The first is invasive and neurosurgical; the cranium is opened, the aneurysm located, and a surgical clip is put around its neck, sequestering it from its parent vessel. In this way, with its wing literally clipped, the aneurysm is disarmed, its potential for growth and rupture severely restricted. 

By Roberto Stefini – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47226273

The other procedure, younger and safer than clipping, is endovascular coiling or coil embolisation. This procedure, performed by an interventional neuroradiologist, involves tunnelling a fine wire or coil through blood vessels until it reaches the aneurysm. The aneurysm space is then filled up with the coil until it is totally obliterated. Unable to fill up with blood or expand, the aneurysm is rendered impotent. Both coiling and clipping however carry a small failure risk, resulting in aneurysm recurrence or re-rupture.

By 77giallo77 – Own work, CC BY-SA 4.0, Link

This is the conventional wisdom of cerebral aneurysm treatment. But there are advocates out there who are pushing the case for clipping over coiling. One reason they put forward is the emerging observation that clipping results in better recovery of function of the third cranial or oculomotor nerve. The oculomotor nerve is critical to the movement of the eye and eyelid, and it is vulnerable to compression by the posterior communicating artery (PCOM) aneurysm. A compressed third cranial nerve results in a droopy eyelid (ptosis) and double vision (diplopia); recovery of function of the oculomotor nerve is therefore an important goal in the treatment of aneurysms.

Автор: Patrick J. Lynch, medical illustrator – Patrick J. Lynch, medical illustrator, CC BY 2.5, Посилання

There are now at least four systematic reviews and/or meta-analyses that show that recovery of the oculomotor nerve function is better achieved by clipping than by coiling. These are:

Another meta-analysis, titled Clinical outcome after surgical clipping or endovascular coiling for cerebral aneurysms, goes further to argue that clipping results in better chances of survival and independent living than coiling. 

By Hellerhoff – Own work, CC BY-SA 3.0, Link

These may be the last-gasp attempts of clippers to have one up over coilers, but the consensus still remains dominantly in favour of endovascular coiling. We however need to keep a close eye on this pendulum-it may just swing back unexpectedly.

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Why not check out these related blog posts:

How does aspirin influence the rupture risk of cerebral aneurysms?

Is the growth of cerebral aneurysms predictable?