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

 

 

Is thrombolysis effective 9 hours after stroke?

Thrombolysis guided by perfusion imaging up to 9 hours after onset of stroke. Ma H, Campbell BCV, Parsons MW, et al; EXTEND Investigators. N Engl J Med 2019; 380:1795-1803. Abstract BACKGROUND: The time to initiate intravenous thrombolysis for acute ischemic stroke is generally limited to within 4.5 hours after the onset of symptoms. Some trials […]

via Is thrombolysis effective 9 hours after stroke? — Neurochecklists Blog

Is migraine a risk for suicide?

Association of suicide risk with headache frequency among migraine patients with and without aura. Lin YK, Liang CS, Lee JT, et al. Front Neurol 2019; 10:228. Abstract Background: Migraines with aura have been associated with suicide in adolescents and young adults, but the association between suicide and migraine frequency has not been determined. This study investigated suicidal ideation and suicide attempts among patients with varying […]

via Is migraine a risk for suicide? — Neurochecklists Blog

A few more catchy titles from the world of neurology

Here we go again. Neurologists can’t seem to stop spinning them, and we can’t help weaving them into blog posts. If you are late to the game, you may catch up with our previous catchy titles:

The art of spinning catchy titles
The art of spinning catchy neurology headlines
A few more catchy neurology article titles to start the year
15 more creative and catchy neurology headlines for 2019

Now that you are up-to-date, here are 10 more catchy neurology article titles to make your day: 

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Optic neuritis in the diagnosis of MS: more than meets the eye

This article looks at a common symptom of multiple sclerosis (MS), and makes the strong case that we need to do more to diagnose optic neuritis. And it is a very catchy way to make the point.

Optic nerve fron view. Francisco Bengoa on Flickr. https://www.flickr.com/photos/frecuenciamedicafb/7404373518/

The many faces of oral-facial-digital syndrome

This is not something neurologists often come across, but it comes close enough to the specialty. Oral-facial-digital-syndrome is typified by facial deformities, but more importantly, the title makes it clear that it is a syndrome with diverse subtypes. A catchy title for a rare disorder, and this paper reveals all.

Ben Eine – The Strangest Week. Bob Bob on Flickr. https://www.flickr.com/photos/bobaliciouslondon/5196843736

The new concussion in sport guidelines are here. But how do we get them out there?

Not all catchy titles are convoluted. This one is simple but yet very inspired. It refers to the 2016 Consensus Statement on Concussion in Sport. As for all guidelines, it is all well and good to develop them, but a herculean task to get anyone to take notice. It is therefore very ingenious to use a catchy editorial to do the job.

By shgmom56 on Flickr – Originally posted to Flickr as “DSC02769”, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=4231521

The great escape: a neuropsychological study of psychogenic amnesia

This is just a case report of fugue state, but it comes with a great title. The perspective of psychological amnesia as an escape is appropriate, and to the point.

By Wassily Kandinski – http://www.abcgallery.com/K/kandinsky/kandinsky73.html, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2174133

When the past is lost: focal retrograde amnesia

Another one on amnesia, and what a great title. It is a report of 13 cases of focal retrograde amnesia, all typified by loss of autobiographical memory. The amnesia is severe enough in some cases “to erase the knowledge of their own identity”.

By scanned by Open Clip Art Library user Johnny Automatic – http://openclipart.org/detail/168137/head-scratcher-by-johnny_automatic, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18732522

What gnaws at the heart and gets on the nerves

This inspired title clearly took some thinking to conjure. It is on the subject of transthyretin-related amyloidosis (ATTR), a hereditary disorder that equally maims the heart and the brain. Typical features are small fiber neuropathy, autonomic neuropathy, and ventricular hypertrophy. And the treatment, incidentally, requires transplanting a third organ, the liver.

Amyloidosis, Node, Congo Red. Ed Uthman on Flickr. https://www.flickr.com/photos/euthman/377559787

Hand up! Yawn and raise your arm

Now here is a title to pique anyone’s neurological curiosity. It is about a peculiar disorder, parakinesia brachialis oscitans. There is really no cat to be let out of the bag here; the paper’s abstract reveals all. In some cases of hemiplegia, the abstract says, yawning is associated with involuntary raising of the paralysed arm”. Read all about it!

By Joseph Ducreux – MQG0zXDvoSnYDg at Google Cultural Institute maximum zoom level, Public Domain, https://commons.wikimedia.org/w/index.php?curid=22178664

A sleep medicine medical school curriculum: time for us to wake up

This simple but catchy title is an excellent play on words. It is clearly about the contrariness of the acts of sleep and waking in one headline. This editorial is more than just a catchy title; it is a strong call to action!

Wake up! Simon Bleasdale on Flickr. https://www.flickr.com/photos/simonbleasdale/9562433956

Burnout in neurology: extinguishing the embers and rekindling the joy in practice

It takes great imagination to come up with a title that contains burnout, embers and kindling. And the result is catchy. Burnout is a serious issue that threatens neurological practice, and this editorial flags the concern very forcefully: “the message for all is clear: medicine must identify the root causes of burnout, and more importantly, put the joy back in medicine. It is time to see the light!

Burnout! Dennis Skley on Flickr. https://www.flickr.com/photos/dskley/14692471997

Warts and all: Fingolimod and unusual HPV-associated lesions

Probably not the catchiest title one could come up with, but it is catchy enough to attract attention. The title refers to fingolimod, the multiple sclerosis drug which predisposes to treatment-resistant warts. Simple verruca is bad enough, but the human papilloma virus (HPV) which causes it happens to trigger more sinister diseases: cervical and anogenital cancer. Therefore, with fingolimod, we must pay attention to warts and all!

Human Papillomavirus (HPV) in Head and Neck Cancer. NIH Image Gallery on Flickr. https://www.flickr.com/photos/nihgov/29990958966

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Do you have any catchy titles up your sleeves? Do leave a comment.

Do statins increase the risk of intracerebral haemorrhage following stroke?

Statins and the risk of intracerebral haemorrhage in patients with stroke: systematic review and meta-analysis. Ziff OJ, Banerjee G, Ambler G, Werring DJ. JNNP 2019; 90:75-83. Abstract OBJECTIVE: Whether statins increase the risk of intracerebral haemorrhage (ICH) in patients with a previous stroke remains uncertain. This study addresses the evidence of statin therapy on ICH and other clinical outcomes in patients with previous ischaemic stroke (IS) or ICH. […]

via Do statins increase the risk of intracerebral haemorrhage following stroke? — Neurochecklists Blog

Mozart and epilepsy: the rhythm beats on

I can’t seem to get away from the theme of Mozart and epilepsy. When I first looked at this, in a blog post titled Mozart and seizures? The links between epilepsy and music, I took the topic rather lightly, more a subscript than a headline you may say. But I have since learnt to take the links between epilepsy and music more seriously. 

By Barbara KrafftThe Bridgeman Art Library, Object 574471, Public Domain, Link

The major trigger for my ‘road to Damascus’ conversion is a 2018 paper titled Study of the Mozart effect in children with epileptic electroencephalograms, published in the journal Seizure. The paper was an eye-opener because it gave a very helpful comprehensive context to the broader beneficial effect of music…not just in epilepsy, but in other neurological disorders such as Parkinson’s disease, dementia and sleep disorders. The authors, Elyza Grylls and colleagues, started on the established premise that Mozart’s music has a beneficial effect on epilepsy. What they wanted to know was if other forms of music have a similar settling effect on epilepsy, or if only Mozart’s music carries the magic touch. The authors therefore played Mozart’s Sonata for two pianos in D major (K448) to 40 children with epilepsy who were undergoing an EEG (electroencephalogram, or electrical brain wave test). They then compared this with the effect of playing other types of music. Remarkably, they found that only Mozart’s Sonata led to a significant reduction in EEG epileptic discharges.

Public Domain, Link

The authors concluded that there was indeed an anti-epileptic effect of Mozart’s music, the so-called  ‘Mozart therapy’. But what is so special about K448? They speculate that it has to do with the structure of Mozart’s music, containing as it does, long periodicities. Interestingly, the music of Yanni, which is similarly structured, has somewhat a similar effect on brain wave activity. On the contrary, and sorry to Beethoven fans, Fur Elise doesn’t have this effect.

By W.J. Baker (held the expired copyright on the photograph) – Library of Congress[1]Contrairement à une erreur fréquemment répandue le buste a été réalisé par Hugo Hagen, non pas à partir du masque mortuaire mais, comme de nombreux autres, d’après le masque réalisé en 1812 par Franz Klein pour un buste qu’il devait réaliser ensuite., Public Domain, Link
So what does the structure of Mozart’s music do to the brain? One suggestion is that Mozart’s music enhances the body’s parasympathetic drive; this reduces the heart rate, and thereby inhibits the brain’s propensity to epileptic seizures. The suppression of this parasympathetic drive is of course the theory behind using vagus nerve stimulation (VNS) to treat drug-resistant epilepsy. For more on VNS, see my previous blog, Vagus nerve stimulation: from neurology and beyond!

By Bionerd – MRI at Charite Mitte, Berlin (used with permission), CC BY 3.0, Link

You have surely wondered by now whether K448 is the only one of Mozart’s compositions to have an anti-epileptic effect. It doesn’t matter if you haven’t, because the authors of another interesting paper have. They titled their study, published in 2018, Mozart’s music in children with drug-refractory epileptic encephalopathies: comparison of two protocols. Published in the journal Epilepsy and Behaviour, the authors, Giangennaro Coppola and colleagues, compared the effect of K448 with a set of his other compositions. Intriguingly they found that the composition set actually had a greater effect in epilepsy than K448…by a wide margin of 70% to 20%! Furthermore, the set was better tolerated by the children; they were less irritable and had a better nighttime sleep quality.   

https://www.publicdomainpictures.net/en/view-image.php?image=76907&picture=dog-amp-child-painting

So, is it all rosy in the garden of music and the brain? No, it’s not! As every rose grows on a thorny tree, so do some forms of music trigger epileptic seizures. This so-called musicogenic epilepsy is well-recognised, and two recent culprits are the music of Sean Paul, discussed in the journal Scientific American , and the music of Ne Yo, explored by NME. Therefore you should craft your playlist wisely.

By CLASSICNEYOOwn work, CC BY-SA 4.0, Link

So, is it time for neurologists to start prescribing music?

Or is it too much of a double-edged sword?

Music is #SimplyIrresistible. Luca Florio on Flickr. https://www.flickr.com/photos/elle_florio/29516744480

Phantoms in the Brain

Phantoms in the Brain Authors: V. S. Ramachandran and Sandra Blakeslee Synopsis The author of this book, one the leading figures in neuroscience, unapologetically declared that his intention was to write ‘a popular book on the brain’. To accomplish this goal, he recounts seemingly endless ‘true-life stories‘ of fascinating neurological disorders (page xiii). Like a […]

via Phantoms in the Brain — The Doctors Bookshelf