Author: Michelle C.

Brain Under Pressure – Understanding Intracranial Hypertension [UPDATED]

Published: 1 November 2024
Written by Michelle C.
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Categories: Empty Sella Syndrome, Hydrocephalus, Idiopathic Intracranial Hypertension, Intracranial Hypertension
INTRACRANIAL HYPERTENSION (IH) MEANS HIGH PRESSURE INSIDE THE SKULL

Intracranial Pressure (ICP) is measured in millimeters of mercury (mmHg). Most scholars agree that on average:

  • Intracranial pressures (ICP) between 5-15 mmHg, are considered Normal pressure
  • Intracranial pressures (ICP) between 20-30 mmHg, are considered Mild to moderate intracranial hypertension which “requires treatment in most circumstances”,

When high intracranial pressure is left untreated, it creates a “pushing effect” towards the only natural escape at the base of the skull (the foramen magnum), and the cerebellar tonsils in the pathway are pushed through the foramen magnum. [2]

Understanding the Monro-Kellie Doctrine (the pressure-volume relationship)

The association between IH/IIH and Chiari Malformation appears to be a malicious intricate pathological circle. The cranium (skull) consists of brain matter, cerebrospinal fluid, and both venous and arterial blood. A hypothesis, referred to as the Monro-Kellie Hypothesis (now better known as the Monro-Kellie Doctrine), states, “The sum of volumes of the brain, CSF, and intracranial blood is constant. An increase in one should cause a decrease in one or both of the remaining two.” Therefore, if an abundance of cerebrospinal fluid (IIH or hydrocephalus), both cranial blood volume and brain matter should be forced to deplete. This depletion is usually directed in the path of least resistance – through the foramen magnum and into the spinal canal. When the brain matter closest to the bottom of the skull (cerebellar tonsils) is pushed through the foramen magnum and into the spinal canal (an Acquired Chiari Malformation), the tonsils act like a cork and blocks the flow of cerebrospinal fluid (regardless of the size of the tonsillar descent), which in turn, continues to raise intracranial pressure.[3]

Venous Hypertension

When an etiological cofactor exists (such as a space-occupying mass), it is considered Secondary Intracranial Hypertension (SIH); when no other cause was identified, it is known as Idiopathic Intracranial Hypertension (IIH) formerly known as Pseudotumor Cerebri. However, recent studies on the connection between Intracranial Hypertension and Venous Hypertension might put an end to the “idiopathic” theory.

Oxygen-rich blood travels from the heart to the rest of the body through the arterial system, then the oxygen-depleted blood returns to the heart through the venous system. We have a host of small veins in our head and they dump into a series of large veins, called sinuses.

Dural Venous Sinus Stenosis occurs when there is a narrowing of one or more of the venous sinuses (most commonly seen in the transverse sinuses or transverse/sigmoid sinus junction, but can also occur anywhere within these sinuses or in the jugular). This narrowing compromises cerebral venous outflow through the jugular vein (stenosis/compression of the jugular vein can also result in elevated intracranial pressure [4]). Transverse Sinus Stenosis (TSS) is most common what was initially assumed to be “Idiopathic Intracranial Hypertension (IIH), formerly known as Pseudotumor Cerebri (PTC). Depending on the study that you are reading, it is proving to be present in 90-100% of IIH patients [5]. While its connection might sound obscure, if you look at it from a Monro-Kellie perspective – the blood going into the head, cannot get out at the same speed (because of the narrowed sinus). When this inflow of blood remains constant and the outflow is hindered, the transverse sinus on that side (we have two transverse sinuses, one on each side) enlarges, forcing the CSF and brain matter to reduce to maintain the volume equilibrium. This reciprocation can happen when any of the sinuses or jugular narrow (stenosis). While scholars continue to debate whether TSS is a cause or consequence of IIH, surgeons continue to decompress us without checking our pressures or decompress (the most invasive treatment) in hopes that it will lower our pressures, and patients are left with untreated high pressure still causing a “pushing down effect” and an enlarged foramen magnum for our brains to be pushed down. [2] The sagging brain once again obstructs the flow of cerebrospinal fluid by plugging the foramen magnum, and that in turn raises the intracranial pressure even more. Or, the untreated high pressure blows through the duraplasty and causes a post-operative leak, known as a pseudomeningocele.

Reducing the Risks of Post-Op IH/IIH Complications by Identifying Potential Problems Early:

Brain MRIs often show indicators of Intracranial Hypertension (IH/IIH), therefore, we recommend that all Chiari patients have full brain MRIs and not just cervical MRIs.

  • When the pressure builds inside of the dura mater the pressure pushes the dura and fluid inside of the crevice that holds the pituitary gland (the sella turcica or pituitary fossa). When the amount of fluid is equal to or greater than 50% and the pituitary gland size is 2mm, the condition is known as Empty Sella Syndrome. (Doctors now recognize that < 50% (where the pituitary gland size is 3-7mm) can also cause symptoms and they now refer to that as a partially empty sella.) [8]
  • Low lying or herniated tonsils (often diagnosed as a Chiari Malformation). [2]

Ideas BEFORE DECOMPRESSION is considered:

If you have symptoms of IH/IIH accompanied by any of the MRI indicators mentioned above, it is both reasonable and prudent to ask your neurosurgeon to investigate further BEFORE DECOMPRESSION.

  • See a neuro-ophthalmologist to check for signs of papilledema, including Optical Coherence Tomography and Ultrasonographic B-scanning. [8]
  • Magnetic Resonance Venography (MRV, preferably with the ATECO technique) to check for venous stenosis of any of the cranial sinuses and/or jugular vein. Stenosis is not exclusive to the transverse sinus and it can happen in multiple sinuses simultaneously.
  • If overweight, consider trying to lose weight. Studies show that a weight loss of 5-10% of one’s overall body weight, when accompanied by a low-salt diet, can offer some to IH/IIH symptoms.[9]
  • Request a lumbar puncture (spinal tap) to test your opening pressures. We recommend that it’s guided with fluoroscopy with a small gauge needle (and not the standard 22 gauge) that they allow to drip (as opposed to syringe pull) and ensure that someone is available to perform an epidural blood patch if necessary. Time should be allotted afterward to lay flat for several hours immediately following the procedure and for several days once returning home. The potential for CSF leaks is high for the EDS/Chiari patient. A doctor that marginalizes the risks ahead of time, will generally marginalize your symptoms when you are actively leaking.
  • ICP Bolt Monitoring can record the differences experienced in pressure over time, and how different positions affect ICP.

Note: When the intracranial pressure gets high enough, it can cause a cranial leak. This is especially true for the Ehlers-Danlos patient where the dura mater is thin and fragile. When a cranial leak decreases the intracranial pressure, the papilledema, empty sella, stenosis, and high-pressure headaches can sometimes start to revert to normal or near-normal, and the leak will affect any attempts to check intracranial pressure (reducing the pressure from what it was before the leak occurred), however, the tonsillar herniation will usually remain if the pressure gets too low. [10]

TREATMENT OPTIONS:

  • If you have IH/IIH, ask your doctor to help you reduce the ICP before decompression! This can be done medicinally using Topamax or Diamox. If that doesn’t work, a shunt or stent should be considered.
  • An MRV is recommended for all IH/IIH patients. If it indicates venous stenosis, stenting should be considered, as leaving the sinus/jugular stenosed can post other health risks, and stenting can be successful for many with fewer complications that often require revisions.

For the IH/IIH patient, herniated tonsils should be assumed an Acquired Chiari Malformation (even if a small posterior fossa is evident), and by correcting the high pressure before decompression, the decompression will be less likely to fail.

Helpful Tips:
If you have IH/IIH, it is best to avoid caffeine, avoid progestin based birth control, and all EDS patients should try to avoid the use of fluoroquinolones such as ciprofloxacin (Cipro), levofloxacin (Levaquin/Quixin), gatifloxacin (Tequin), moxifloxacin (Avelox), ofloxacin (Ocuflox/Floxin/Floxacin), norfloxacin (Noroxin), due to the increased risk of aneurysm.

References: 

1 Rangel-Castillo, Leonardo, et al. “Management of Intracranial Hypertension.” Rangel-Castilla, Leonardo et al. “Management of intracranial hypertension.” Neurologic clinics vol. 26,2 (2008): 521-41, x. doi:10.1016/j.ncl. Feb. 2008, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2452989/>.

2 Aiken, A.H., et al. “Incidence of Cerebellar Tonsillar Ectopia in Idiopathic Intracranial Hypertension: A Mimic of the Chiari I Malformation.” American Journal of Neuroradiology; Nov. 2012, <http://www.ajnr.org/content/33/10/1901>.

3 Mokri, B. “The Monro-Kellie Hypothesis: Applications in CSF Volume Depletion.” Neurology., U.S. National Library of Medicine, 26 June 2001, <https://www.ncbi.nlm.nih.gov/pubmed/11425944>.

4 Zhou, D., et al. “Intracranial hypertension induced by internal jugular vein stenosis can be resolved by stenting.” European Journal of Neurology, November 2017 <https://onlinelibrary.wiley.com/doi/abs/10.1111/ene.13512>.

5 Henderson, Fraser C., et al. “Neurological and Spinal Manifestations of the Ehlers–Danlos Syndromes.” American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 21 Feb. 2017, <www.onlinelibrary.wiley.com/doi/10.1002/ajmg.c.31549/full>.

6 Pietrangelo, Ann. “Empty Sella Syndrome.” Healthline, Oct. 2017, <https://www.healthline.com/health/empty-sella-syndrome>.

7 Hingwala, Divyata R., et al. “Imaging signs in idiopathic intracranial hypertension: Are these signs seen in secondary intracranial hypertension too?.” Annals of Indian Academy of Neurology vol. 16,2: 229-33. doi:10.4103/0972-2327.112476, June 2013, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724081/>.

8 Mollan, Susan P., et al. “A practical approach to, diagnosis, assessment and management of idiopathic intracranial hypertension.” Practical neurology vol. 14,6: 380-90. doi:10.1136/practneurol-2014-000821. May 2014, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4251443/>.

9 Thurtell, Matthew J., and Michael Wall. “Idiopathic Intracranial Hypertension (Pseudotumor Cerebri): Recognition, Treatment, and Ongoing Management.” Current Treatment Options in Neurology, U.S. National Library of Medicine, Feb. 2013, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3554852/>.

10 Pérez, Mario A., et al. “Primary spontaneous cerebrospinal fluid leaks and idiopathic intracranial hypertension.” Journal of neuro-ophthalmology : the official journal of the North American Neuro-Ophthalmology Society vol. 33,4: 330-7. doi:10.1097/WNO.0b013e318299c292, Dec. 2014, <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4040082/>.

Struggling Through the Holidays

Published: 12 November 2023
Written by Michelle C.
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Categories: Inspirational, To Family/Friends

‘Twas the night before Christmas and despite the sleeping spouse, there was still one stirring in the Chiarian’s house. The stockings were hung by the chimney with care as she hoped despite the pain, she’d be able to be there. The family was nestled all snug in their beds, while fear of disappointment danced through her head.

While everyone’s talking about holiday cheer and how there’s laughter in the air, for the chronic pain patient it’s not that easy to get into the holiday spirit. We remember the happier holidays of the past and all that people want to see in us, but there are so many thoughts acting as obstacles in our path.

Will I have the spoons (energy) that I need to make it through the day?
We speak of energy in terms of spoons (The Spoon Theory, by Christine Miserandino). We know what it was like to have normal levels of energy to accomplish tasks and how much more energy every task requires now that our bodies went crazy. You don’t appreciate the energy it takes to get ready for something until you need a nap after every shower you take.

What will I do if I experience a pain flare and how will everyone else respond to me if I do?
Almost worse than the pain itself is living in fear of the pain, especially when we know how it seems to ruin everything for everyone, not just us. For the patient and their family, they know far too well how pain can ruin even the most important of occasions. And for the patient, we know the look on the faces of those we love when we have to cancel or depart early. It’s one thing to see those faces a time or two in a lifetime, but it’s a lot harder when it happens time and time again, and there’s nothing you can do about it.

Will I be able to engage?
People rarely realize how much time we really spend alone (or at least alone in our thoughts). We think about so many things. Should I tell them about what I’m facing? Should I answer how I’m really feeling, or just say, “I’m fine”? Am I talking too much about my conditions? Is it just me and my brain, or is it them? Are my feelings about this even rational? Am I losing my mind? Most of these thoughts are actually healthy thoughts, but when we second guess engaging with the world and live in constant fear of offending, it becomes detrimental to the way we see our value on this earth.

How many days of pain will I experience after the holiday is over?
We’ve learned from those times that we’ve tried to “push through the pain,” that this will be a factor nearly 100% of the time. While the healthier us could push through the pain, that often backfires when it comes to chronic pain. After a few hours of festivities (no matter how light the festivities seem to be), our nervous systems usually respond to the stress with inflammation and pain (which can last several days or even weeks).

Will I live up to what’s expected of me or am I going to let down everyone I love, yet again?
Even when nobody around us expects much from us, there’s always a part of us that still longs to be like our former selves – to have the strength and energy that we once had. The truth is, despite everything we’ve been through, we want to be more for those that we love. Our lives were forever altered and reconciling that with a lifetime of dreams isn’t easy. We’re not feeling sorry for ourselves, we’re mourning and trying to adapt to the reality of all that we face. It hasn’t been easy on our families either, they’re in mourning too. Chiari/comorbids have stolen hopes and dreams from all of us, but we don’t have to let it dominate us. We can figure it all out together and be a stronger family for it!

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September Is Chiari Awareness Month

Published: 16 September 2023
Written by Michelle C.
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Categories: Acquired Chiari Malformation, Expressive Writings, WorthTheFight

It’s hard having a chronic illness that isn’t all that understood.

As patients, we have to fight on absolutely every level!

Before diagnoses, we fight for someone to hear us when:

  • We explain to them that our neck is to weak to hold up our head.
  • We’re trying to hold our heads up with our hands when laying back isn’t an option.
  • Our necks start spasming to the point that we feel like we’ve been internally decapitated.
  • We have to ride in the front seat to try and minimize the car sickness.
  • We suddenly can’t balance to walk.
  • Our eyes start twitching beyond what could ever be considered normal.
  • We aren’t able to do what we could just a short time ago, or even a few hours ago.
  • That we want to scream and cry because of the pain, but we know it will only make it worse.
  • We go to say something and can’t find the right word because it just isn’t in our memory bank at that moment.
  • We spontaneously can’t read because we have double vision, blurred vision, or our eyes wont stop jerking around to focus, yet an hour later we’re fine.
  • We explain that doctors not knowing what’s wrong doesn’t mean that nothing is wrong (even when they say nothing is wrong).

Around diagnoses, we fight to:

  • Process the magnitude of what we’re facing.
  • Learn all we can so we’re prepared for the important decisions before us.
  • Find the right doctors who are knowledgeable and trained in our condition(s).
  • Fight to be stoic when we know that it’s not just our bodies enduring all of this – something is breaking in our souls and we’re fighting to not let it change us for the worse.

When our doctors continue to dismiss our symptoms, we need our friends and families to understand:

  • That we’re still the same wife/husband, mother/father, sister/brother, aunt/uncle, and/or friend that you’ve known and loved for all these years, and we need you now more than ever!
  • That decompression is not a cure! In fact it typically fails to relieve symptoms over the long term nearly 50% of the time when pathological conditions aren’t treated beforehand.

Testimonials

Published: 12 November 2022
Written by Michelle C.
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Categories: Testimonials

WTF! Online Support Group Meetings

Published: 13 November 2021
Written by Michelle C.
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Categories: Uncategorized

Ever feel alone in all you’re facing? It’s one thing to read what people are going through, but to see them as they share how they’re going through the same struggles that you are can be game-changing!

Starting in December, the tribe will be hosting online support meetings on the first and third Tuesdays of each month to share and learn about all we’re dealing with.

A valuable resource for patients and their families, looking for support and a sense of direction!

The Prayer of An EDS/Chiari/Comorbid Patient

Published: 21 June 2021
Written by Michelle C.
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Categories: Expressive Writings, Faith-based, Inspirational, Poetry
 
My sister asked me how she could pray for us specifically. Here’s what I’ve come up with.
 
 
 

As we lift up a warrior fighting EDS, Chiari, and/or Comorbids,
We are believing You for:

Knowledgeable doctors/surgeons
With hearts for the patients that are trusting them
Ears to hear them
And a willingness to unlearn and relearn

CSF leaks to seal
Cranial masses to disappear
Narrowed venous structures to widen
And cranial pressures restored to normal

Sticky filums to release
Stretched spinal cords to retract
Conus Medullaris’ to rise
And elongated medullas restored without consequence

Collagen restored without mutation
Intravertebral discs moving back into their rightful place
Laxity issues resolved
Straightened odontoids and clivus bones
And craniums to rise

Spines to straighten
Cerebellar tonsils to rise
CSF flow restored
And syringes (syrinxes) dissipated

Muscles reconditioned
Paralysis reversed
Vision completely restore
Ringing in the ears to cease

Habitual good night’s rests
No insomnia, painsomnia, chronic fatigue, or narcolepsy
Breathing issues corrected
Restless legs calmed

Nerves decompressed
Even vagus restored
Motility perfected
Inflammation gone
And pain a thing of the past

Depression replaced
Hearts seasoned with grace
Families restored
Where no one’s needs are ignored

Thank You, Father,
That despite all we’ve endured,
Your grace continues to be sufficient.
That none of this has taken You by surprise;
You knew all we’d face, yet You still chose each of us and call us Yours.
Our hope is in You and You alone,
The Author and Perfector of our faith,
We stand on Your promise that You still have a plan for each of us!
We might not know what it is or understand how we’ll get there,
but You are a good Father, and we trust You completely.

In Jesus’ Name, Amen!

(Note: This prayer was written to become a collaborative prayer, that we can add to as needed.)

From The Inside Out – Understanding Syringomyelia & Syringobulbia

Published: 26 February 2021
Written by Michelle C.
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Categories: Acquired Chiari Malformation, Comorbidities, Degenerative Disc Disease, Dysautonomia, Syringomyelia

WHEN A DOCTOR TALKS ABOUT THE “MOST SERIOUS” COMPLICATIONS SURROUNDING CHIARI MALFORMATION, THEY USUALLY SPEAK OF PARALYSIS OR DEATH. WHILE BOTH OF THESE ARE FAR LESS COMMON THAN THE ARRAY OF OTHER SYMPTOMS AND COMPLICATIONS, THEY BOTH CAN INVOLVE THAT OF A SYRINX.

The word syrinx (seer-inks), plural syringes  (seer-en-geez), means cavity or cyst. Syringomyelia (seer-ingo-my-el-lee-uh) is when the cyst forms in the spinal cord (myelo usually refers to the spinal cord), and when the cyst is in (or ascends up into) the bulbar region of the brainstem (the medulla oblongata) it is called Syringobulbia (seer-ingo-bulb-e-uh). While these cysts are technically the same cerebrospinal fluid-filled cysts, because they are damaging a different part of the body (each with a completely different function), the location of the syrinx has everything to do with the symptoms that it can cause.

Hydromyelia:
At the center of the spinal cord, there is a hole known as the central canal which runs from the fourth ventricle down the length of the cord. Its role is to carry a microscopic amount of cerebrospinal fluid down the center of the cord from the fourth ventricle. The small amount of fluid in the central canal is usually considered normal. When the central canal has too much cerebrospinal fluid coming in from the fourth ventricle it widens the canal and that abnormal widening that follows the central canal is known as hydromyelia (hydro-my-el-lee-uh) or syringohydromyelia (seer-ingo-hydro-my-el-lee-uh).

The Central Nervous System (CNS) is an amazingly complex network. The brain, brainstem, and spinal cord each play a role in communicating to coordinate everything that happens in our bodies (even when no cognitive thought is required). The messages to and from the brain are sent through the brainstem, down through the spinal cord, and out to our nerves. When that signal is blocked, it can cause interruption from that point down. When it’s thin, it interrupts the signal in the middle (gray matter), as it widens it interrupts the signal more and more, so it’s harder to get signal through the cord at the widest point of the syrinx.

The spinal cord runs through a canal known as the spinal canal. The spinal canal holds cerebrospinal fluid that among other things, nourishes the spinal cord and helps protect it from injury. A syrinx is generally known to be caused by a blockage of cerebrospinal fluid, which is why it is most commonly seen amongst those with Chiari Malformation. When the cerebellar tonsils descend into the spinal canal, like a cork the tonsils block the flow of cerebrospinal fluid. Even when the tonsils fail to descend, they can rest on top of the foramen magnum and still block the flow of cerebrospinal fluid (see Chiari Zero below). There are other conditions that can cause similar blockages as well, so it is not exclusive to Chiari malformations. Anything that causes stenosis (narrowing) of the spinal canal (the cord: canal ratio) can also block cerebrospinal fluid and lead to the formation of a syrinx – conditions such as bulging/herniated discs (from degenerative causes or trauma), spinal cysts/tumors, edema/inflammation of the spinal cord or surrounding membranes (from trauma or conditions like meningitis/arachnoiditis), and/or irregular curvatures of the spine (scoliosis).

Syringomyelia:
Syringomyelia does not usually run the entire length of the spinal cord like the central canal (but it can). Instead, it often seems to spontaneously appear. As the CSF increases in a syrinx, it can either lengthen or widen. The length doesn’t matter much (radiologists note the location because they report what they see and try to be precise). But a neurosurgeon that knows about syringes, knows that what really matters is the diameter of a syrinx (which is where the risk of paralysis can come into play). Symptoms tend to vary based on where the syrinx is located in the spinal cord. The highest point of the syrinx (where the initial disruption starts) and the widest point of the syrinx (location of the greatest disruption) should always be considered because there are different nerves branching from the spinal cord at different intervals. A syrinx interrupts the communication from the top of the syrinx down, so a syrinx that is higher in the spinal cord can have an impact on a larger range of the body. Someone with a syrinx in the lumbar region of the spinal cord will usually have communication problems from the waist down, but someone with a cervical syrinx is likely to have problems from the neck down. A syrinx in the upper thoracic spinal cord (or above) will often include the arms since the peripheral nerves that lead to the arms branch off around the T1 vertebra. The wider the syrinx, the greater the interruption of communication. Therefore, a syrinx should always be gauged by its diameter and not its length. Symptoms generally include (from the syrinx down): muscle weakness, pain, and spasms in legs; pain, tingling, burning of arms; muscle wasting (atrophy); loss of reflexes; loss of pain senses, loss of temperature sensation, numbness, pain, and stiffness in back/shoulders/upper chest (cape-like area); stiffness of muscles; muscle contractions (fasciculations); bowel & bladder dysfunction; scoliosis; paralysis (rare).

Syringobulbia:
Syringobulbia exists when a syrinx forms in the medulla oblongata (the bulbar region of the brainstem) OR when a syrinx in the cervical cord extends upward into the medulla. A syrinx in the medulla can cause medullary issues or in extreme cases, death (since the medulla is responsible for things that happen autonomically (automatically) for survival – such as breathing, heart rate, swallowing, gag reflex, etc.). Dysautonomia is an umbrella term used to describe any dysfunction of the Autonomic Nervous System (ANS), both Sympathetic and Parasympathetic divisions, often accompany any damage to the medulla. When talking about Dysautonomia, many tend to think of Postural Orthostatic Tachycardia Syndrome (POTS), but POTS is but one symptom of Dysautonomia in a long list. The damage from Syringobulbia is not generally isolated to the medulla, but to the cervicomedullary junction (where the cervical spine meets the medulla), it can also affect the cranial nerves causing symptoms such as facial sensory loss (unilateral or bilateral); extraocular muscle palsy; nystagmus; palatal palsy; atrophy of the tongue; dysphonia (vocal cord paralysis); slurred speech; indistinct speech; drooling; tongue fibrillation; oropharyngeal dysphagia; impaired gag reflex; hearing loss; tinnitus (ringing in the ears); alveolar hypoventilation; Sleep-Disordered Breathing (SDB); Central and obstructive sleep apnea; Anhidrosis (inability to sweat normally); Inability to burp (Retrograde Cricopharyngeal Dysfunction – RCP-D).

Common Treatment Options:

Monitoring The Syrinx:
Both Syringomyelia and Syringobulbia tend to be progressive, but in some cases, patients report having no symptoms and imaging proves it to be relatively stable in size. In this case, monitoring is generally recommended. A neurologist or neurosurgeon should carefully monitor these patients to track changes in the diameter of the syrinx (which should include regular imaging) and/or any evolution in related symptoms.

Surgical Treatment Of The Underlying Cause:
For symptomatic patients, or when the syrinx is progressing in diameter, or when the syrinx is so wide in diameter that it is stretching the diameter of the spinal cord from the inside out, treatment is essential. This generally involves treating the cause of the blockage of cerebrospinal fluid. When syrinx exists in a symptomatic patient with Chiari Malformation, a posterior fossa decompression surgery is usually recommended, with the desired result being to re-establish the flow of the cerebrospinal fluid to the spinal canal (so it no longer reroutes to the spinal cord and/or low-lying medulla).

Surgically Draining The Syrinx:
A surgical shunt is commonly used to surgically treat a syrinx when: the underlying cause is unknown or when treating the underlying cause has proven ineffective at reducing the size of the syrinx in a patient that is symptomatic.

Brain Under Pressure – Understanding Intracranial Hypertension [Archived]

Published: 26 October 2018
Written by Michelle C.
1 Comment
Categories: Comorbidities, Ehlers-Danlos Syndromes, Empty Sella Syndrome, Etiological Co-Factors, Hydrocephalus, Idiopathic Intracranial Hypertension, Intracranial Hypertension

INTRACRANIAL HYPERTENSION (IH) AND IDIOPATHIC INTRACRANIAL HYPERTENSION (IIH) ARE CONNECTED, BUT ARE NOT THE SAME THING AND THEREFORE SHOULD NOT BE USED INTERCHANGEABLY.

Intracranial Hypertension (IH) means high pressure inside the skull. Intracranial Pressure (ICP) is measured in millimeters of mercury (mmHg). Most scholars agree that on average, “normal pressure” should be between 5-15 mmHg and that 20-25 mmHg is when the ICP crosses the line into being IH. Pressure can be brought on by several different means: space-occupying masses such as hydrocephalus and cranial cysts/tumors; cranial edema (Encephalitis); trauma; stroke; aneurysm; certain infections/diseases (Meningitis), liver failure[1], kidney failure[2]; or as a side-effect of certain medications (such as: Tetracycline[3][5], Sulfasalazine[4], Lithium[5], excess amounts of Vitamin A, steroid use[6], growth hormone treatments[6], and the hormonal Intrauterine Device (IUD), “Mirena”[7]); however, sometimes the cause of the pressure is completely unknown. When an etiological cofactor exists, it is considered Secondary Intracranial Hypertension (SIH); when no other cause is identified, it is known as Idiopathic Intracranial Hypertension (IIH) or Primary Intracranial Hypertension (PIH).

“Idiopathic Intracranial Hypertension (IIH) was first noticed in 1893, by the German physician Heinrich Quincke, who named it Serous Meningitis. As its absence of space occupying masses/lesions began to draw more thought, it was renamed Pseudotumor Cerebri (PTC) by Max Nonne in 1904. Sometime later, the term “Benign Intracranial Hypertension” began being used interchangeably with Pseudotumor Cerebri, to describe the fact that while it is sharing some of the same characteristics that a cranial tumor would cause, it is benign (not harmful), but arguments were made against it in that blindness is not indicative of being benign.”[6] The name finally settled as “Idiopathic Intracranial Hypertension,” which means IH of an unknown cause. No matter what you choose to call it, the pain and damage remains the same for those who have it.

 

UNDERSTANDING IDIOPATHIC INTRACRANIAL HYPERTENSION
IIH is a neurological disorder where the cerebrospinal fluid within the skull is elevated, without the presence of a space-occupying mass, edema (brought on by things such as trauma, infection, or disease), or any adverse reactions to certain medications. Studies show that IIH is more common amongst women between the ages of 20 and 50,[8] and there is a slight increase amongst those that are overweight. Some studies also suggest a connection between obstructive sleep apnea and transverse cerebral venous sinus stenosis.[9] Amongst the general population, IIH is believed to exist in 1/100,000 (0.00001). Amongst those that are 10% above their ideal body weight, the numbers increase to 13/100,000 (0.00013), and rising to 19/100,000 (0.00019) in those 20% above their ideal body weight.[10] Although doctors often tend to pass this off as merely a side effect of weight gain, the increase is slim and seems to decrease as the percentage of weight gain above ideal weight continues to rise above the 10% margin. Additionally, the weight factor excludes men and children under the age of 10, which may simply be because women are more likely than men to have comorbid conditions that would lead to Intracranial Hypertension. Studies show that the women to men ratio for Chiari Malformation is believed to be 3:1 and those with both Chiari Malformation and Ehlers-Danlos Syndromes 9:1[11]). However weight is not irrelevant with IIH, the overweight/obese patient population report finding improvement of some symptoms when weight loss of 5-10% of one’s overall body weight, when accompanied by a low-salt diet[12]. 

 

UNDERSTANDING THE IH/IIH CONNECTION: THE MONRO-KELLIE DOCTRINE
The association between IH/IIH and Chiari Malformation, appears to be a malicious intricate pathological circle. The cranium (skull) consists of brain matter, cerebrospinal fluid, and both venous and arterial blood. A hypothesis, referred to as the Monro-Kellie Hypothesis (or Monro-Kellie Doctrine), states, “The sum of volumes of brain, CSF, and intracranial blood is constant. An increase in one should cause a decrease in one or both of the remaining two.”[13] Therefore, if there is an abundance of cerebrospinal fluid (IIH or hydrocephalus), both cranial blood volume and brain matter should be forced to deplete. This depletion is usually directed in the path of least resistance – through the foramen magnum and into the spinal canal. When the cranial brain matter closest to the bottom of the skull (cerebellar tonsils) goes through the foramen magnum and into the spinal canal (an Acquired Chiari Malformation), it blocks the flow of cerebrospinal fluid, which in turn, continues to raise intracranial pressure.

 

SYMPTOMS OF INTRACRANIAL HYPERTENSION
Intracranial Hypertension (IH) can be either acute or chronic and comes with a variety of symptoms, many of which can help distinguish IH pain from typical pain associated with Chiari Malformation. A typical Chiari headache originates at the back of the skull (at the occiput), but IH headaches are usually described as pressure at the top of the head, that radiates downward. Headaches tend to be worse when laying down (which is opposite of low pressure headaches that are often relieved by laying down). Those that suffer from IH, often report waking up from sleep with a bad headache, and often a slight incline can help alleviate the headache pain. Pulsatile Tinnitus occurs when you hear a ringing in your ears that coincides with your heart beat. The tale-tell symptom of IH involves the damage done to the optical nerves.  Papilledema is when the optic discs swell in response to the increased cranial pressure.[14] Symptoms of Papilledema include: headaches behind the eyes, blurred vision, fleeting vision, dimmed vision, double vision, visual obscurations, decreased peripheral vision, and photopsia. Another source of IH damage is seen in the pituitary gland and is known as Empty Sella Syndrome (ESS). As the high intracranial pressure (ICP) tries to take over, cerebrospinal fluid finds its way to the sella turcica and starts filling it with spinal fluid (partially or completely)[15]. The intruding CSF attempts to envelope this depression in the sphenoid bone, and squeezes the pituitary gland, flattening it until it appears “empty.” While some initially suffer no symptoms of the damage done to the pituitary gland, most eventually develop a variety of hormonal issues, known as hypopituitarism.

 

DIAGNOSIS CRITERIA
Diagnosis of Intracranial Hypertension usually begins with investigating either the headaches or the vision problems. The least invasive test is having a neuro-ophthalmologist check behind your eyes for Papilledema. It is not considered conclusive in testing for IH, but it is essential in determining the extent of the damage to the optical nerves. Magnetic Resonance Imaging (MRI) of the brain can be useful in showing signs of Intracranial Hypertension. In cases where one or more space-occupying masses exists, further imaging and often biopsy may be required. The type of mass, its exact location, and the amount of damage that it is believed to be doing, will be used to determine the best treatment. If imaging gives an indication that the intracranial pressure is high, but no space-occupying mass exists, additional testing is usually necessary to confirm, some of which can be potentially be dangerous for those with Heritable Disorders of Connective Tissue (HDCT), such as Ehlers-Danlos Syndromes (EDS). Lumbar punctures (LP), also known as a spinal tap, are often used to test the opening CSF pressure, but by puncturing the dura (which is thinner than normal with Connective Tissue Disorders), the risk of a CSF leak is high. When an LP causes a CSF leak, the first indication is usually a post-dural-puncture headache (PLPH) and eventually, the intracranial hypertension will decrease, as the leak causes intracranial hypotension.[16] CSF leaks can escalate very quickly and can be difficult to identify and treat; therefore, we recommend that LPs be done only when absolutely necessary, and that they be done only under fluoroscopy, by qualified surgeons that fully understand the likelihood of Connective Tissue Disorders, the symptoms of leaks, and have a plan of action should those symptoms occur. Sometimes, ICP can fluctuate and have high spikes that cause problems, rendering LPs useless unless they are done at the precise time. When these spikes are suspected ICP monitoring bolts might be the better option, but still poses a risk of leaks.[17] 

 

TRANSVERSE SINUS STENOSIS (TSS)

Transverse sinus stenosis (TSS) occurs when there is a narrowing of the transverse sinus (dural venous sinus), which in turn can compromise cerebral venous outflow. TSS is common in idiopathic intracranial hypertension (IIH). Depending on the study that you are reading, it is proving to be present in 65-100% of those diagnosed specifically with IIH. Its direct connection seems relatively obscure, and there is no indication of its prevalence in intracranial hypertension (IH), but it is worth looking for and treating if found. While scholars remain undecided as to whether TSS is a cause or consequence of IH, if it does prove to be a cause of high pressure, IIH will likely no longer have an idiopathic element to it and it will become another etiology of Intracranial Hypertension. TSS can often be undetectable with standard Magnetic Resonance Imaging (MRI). The correct procedure would be Magnetic Resonance Venography (MRV, with the ATECO technique [18]), specifically looking for signs of stenosis, to include looking for fistula(s) and aneurysm(s). The lack of a fistula or aneurysms however, does not exclude the possibility of a TSS existing (remember it’s being found in 65-100% of those with IIH). Even with MRV, TSS can often be misinterpreted as “flow-related artifacts.” [18] Because the prevalence of TSS in IIH patients is high (some studies call it “universal”) [19], we recommend that all IIH patients have a MRV with the ATECO technique done before surgical treatment and that venous stenting be considered as a viable surgical treatment.

 

TREATMENT OPTIONS
Treatments for Idiopathic Intracranial Hypertension usually starts with weight loss and/or medicinal options; Diamox (Acetazolamide) and Topamax (Topiramate) are most frequently prescribed. Those with IH/IIH should avoid consuming caffeine, as it can increase pressure and therefore is counter-productive to treatment measures. Diamox is a carbonic anhydrase inhibitor and Topamax can also inhibit carbonic anhydrase, but is an anticonvulsant, often prescribed for the treatment of neuropathy and seizure disorders. Both are believed to successfully lower the production of cerebrospinal fluid. Topamax can also help suppress the appetite, which can help with weight loss, but it also comes with many side-effects like all nerve meds do. When medication fails to decrease ICP, a Ventriculoperitoneal Shunt (VP Shunt) or Ventriculoatrial Shunt (VA Shunt) are surgically placed to drain cerebrospinal fluid straight from the ventricle. Shunts are known for failing and often need a multitude of revisions. Venous stenting is not a new procedure, yet it is not readily offered. While there are studies indicating that the successful reduction of intracranial pressure can help with TSS. Stenting is not only a surgical treatment for the stenosis (which could significantly reduce the possibility of a life-threatening aneurysm in patients with a connective tissue disorder), but it is also a surgical treatment for intracranial hypertension as it “improves CSF resorption in the venous system.” [18] Therefore, it seems illogical to shunt (just dealing with the pressure) and leave such a potentially life-threatening condition untreated. [20] Studies are indicating as high as a 94% of patients being cured of all IIH symptoms as a direct result of venous stenting. [18] While all surgeries pose a risk of complications, and the statistics for stenting are likely inflated and skewed (like that of decompression surgeries), these statistics on stenting are definitely encouraging!

Intracranial Hypertension is a complex issue that should be explored whenever a Chiari Malformation exists, before a decompression surgery is performed. When both Intracranial Hypertension and Chiari Malformation are found to co-exist, the treatment should be in consideration of the correlation of the two, as they both are pathological co-factors of one another. Failure to recognize and treat Intracranial Hypertension before or soon after decompression surgery, will increase the likelihood of a failed decompression. While a decompression surgery can lower Intracranial Hypertension, as cerebrospinal fluid is once again allowed to flow, if space-occupying masses or a case of Idiopathic Intracranial Hypertension (where too much cerebrospinal fluid is being created) are left untreated, those problems will still exist after decompression surgery and the high pressure is likely to cause the cerebellar tonsils to fall once again.

*Revised October 2018

 

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References:

1 Jalan, R. “Intracranial Hypertension in Acute Liver Failure: Pathophysiological Basis of Rational Management.” Seminars in Liver Disease., U.S. National Library of Medicine, Aug. 2003, <www.ncbi.nlm.nih.gov/pubmed/14523680>.

2 Chang, D, et al. “Benign Intracranial Hypertension and Chronic Renal Failure.” Cleveland Clinic Journal of Medicine., U.S. National Library of Medicine, <www.ncbi.nlm.nih.gov/pubmed/1525975>.

3 Holst, Anders Vedel, et al. “A Severe Case of Tetracycline-Induced Intracranial Hypertension.”Dermatology Reports, PAGEPress Publications, 31 Jan. 2011, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4211491/>.

4 Sevgi, E, et al. “Drug Induced Intracranial Hypertension Associated with Sulphasalazine Treatment.” Headache., U.S. National Library of Medicine, Feb. 2008, <www.ncbi.nlm.nih.gov/pubmed/18070060>.

5 Kelly, S J, et al. “Pseudotumor Cerebri Associated with Lithium Use in an 11-Year-Old Boy.”Journal of AAPOS : the Official Publication of the American Association for Pediatric Ophthalmology and Strabismus., U.S. National Library of Medicine, Apr. 2009, <www.ncbi.nlm.nih.gov/pubmed/19393521>.

6 Aylward, Shawn C. “Intracranial Hypertension: Is It Primary, Secondary, or Idiopathic?”Journal of Neurosciences in Rural Practice, Medknow Publications & Media Pvt Ltd, 2014, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4173226/>.

7 Etminan, Mahyar, et al. “Risk of Intracranial Hypertension with Intrauterine Levonorgestrel.”Therapeutic Advances in Drug Safety, SAGE Publications, June 2015, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4519742/>.

8  “Pseudotumor Cerebri Information Page.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, <www.ninds.nih.gov/Disorders/All-Disorders/Pseudotumor-Cerebri-Information-Page>.

9 Thurtell, Matthew J., et al. “An Update on Idiopathic Intracranial Hypertension.” Reviews in Neurological Diseases, U.S. National Library of Medicine, 2010, <www.ncbi.nlm.nih.gov/pmc/articles/PMC3674489/>.

10 Wani, Irfan Yousuf, et al. “Complete Ophthalmoplegia: A Rare Presentation of Idiopathic Intracranial Hypertension.” Annals of Indian Academy of Neurology, Medknow Publications & Media Pvt Ltd, 2015, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4683894/>.

11 Henderson, Fraser C., et al. “Neurological and Spinal Manifestations of the Ehlers–Danlos Syndromes.” American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 21 Feb. 2017, <www.onlinelibrary.wiley.com/doi/10.1002/ajmg.c.31549/full>.

12 Thurtell, Matthew J., and Michael Wall. “Idiopathic Intracranial Hypertension (Pseudotumor Cerebri): Recognition, Treatment, and Ongoing Management.” Current Treatment Options in Neurology, U.S. National Library of Medicine, Feb. 2013,<www.ncbi.nlm.nih.gov/pmc/articles/PMC3554852/>.

13 Mokri, B. “The Monro-Kellie Hypothesis: Applications in CSF Volume Depletion.” Neurology., U.S. National Library of Medicine, 26 June 2001, <www.ncbi.nlm.nih.gov/pubmed/11425944>.

14 Schirmer, Clemens M, and Thomas R Hedges. “Mechanisms of Visual Loss in Papilledema.”Journal of Neurosurgery, <www.thejns.org/doi/full/10.3171/FOC-07/11/E5>.

15 “Empty Sella Syndrome Information Page.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, <www.ninds.nih.gov/Disorders/All-Disorders/Empty-Sella-Syndrome-Information-Page>.

16 Panikkath, Ragesh, et al. “Intracranial Hypertension and Intracranial Hypotension Causing Headache in the Same Patient.” Proceedings (Baylor University. Medical Center), Baylor Health Care System, July 2014, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4059569/>.

17 Abraham, Mary, and Vasudha Singhal. “Intracranial Pressure Monitoring.” Journal of Neuroanaesthesiology,  <www.jnaccjournal.org/article.asp?issn=2348-0548;year=2015;volume=2;issue=3;spage=193;epage=203;aulast=Abraham>.

18 Ahmed, Wilkinson, et al. “Transverse Sinus Stenting for Idiopathic Intracranial Hypertension: A Review of 52 Patients and of Model Prediction.” American Society of Neuroradiology, July 2011. <www.ajnr.org/content/32/8/1408.long>.

19 Riggeal, Bruce, et al. “Clinical course of idiopathic intracranial hypertension with transverse sinus stenosis.” American Academy of Neurology, 2012. <www.ncbi.nlm.nih.gov/pmc/articles/PMC3589184/>.

20 Patel, et al. “Evaluating and treating venous outflow stenoses is necessary for the successful open surgical treatment of arteriovenous fistula aneurysms.” Society for Clinical Vascular Surgery, Volume 61, Issue 2. February 2015. <www.sciencedirect.com/science/article/pii/S0741521414014116>.

 

 

Overview: Chiari Malformation [Revised]

Published: 4 October 2018
Written by Michelle C.
3 Comments
Categories: Acquired Chiari Malformation, General Information

CHIARI MALFORMATIONS (PRONOUNCED: KEE-AH-REE) ARE STRUCTURAL DEFECTS IN WHICH THE CEREBELLUM, THE HIND PART OF THE BRAIN, DESCENDS BELOW THE FORAMEN MAGNUM INTO THE SPINAL CANAL.

While Arnold Chiari Malformation (Type 2) was first identified in the late 19th century by the Austrian pathologist Hans Chiari, much of the current medical knowledge has developed since 1985 with the expanded use of Magnetic Resonance Imaging (MRI). The number of patients diagnosed with Chiari malformations continues to increase, and with that increase Chiari Malformation is getting some of the attention the condition has always demanded.

Chiari malformations (“CMs”) are neurological disorders in which the cerebellum extends out of the skull and into the spinal canal, which in turn blocks the flow of cerebrospinal fluid, puts pressure on the brainstem and spine, and may result in varying degrees of nerve compression. Once thought to occur in 1 in 1000 people, it is now believed to be much more frequent of an occurrence. A 2016 pediatric study found it to occur in 1 in 100 children[1]. However, since the most common type (Type 1) tends to become symptomatic during late teens and early adulthood, it is likely to be much more common when adults are factored in. Females are more likely than males to have a Chiari Malformation (at a ratio of 3:1), and significantly higher amongst those with both Chiari Malformation and Ehlers-Danlos Syndrome (9:1)[2]. We affectionately refer to those that live with this condition, including the attendant pain and frequent disregard from the medical community, as Chiarians (regardless of whether they have had surgical intervention or not).

While some Chiarians are symptomatic throughout their lifetime, the vast majority of Chiarians (those with Type 1) develop symptoms in their late teens or early adulthood. Those symptoms can range from mild to crippling, and can become severe enough to cause paralysis (often associated with syringomyelia) or death.


WHAT CAUSES A CHIARI MALFORMATION?

Multiple factors have been identified which can either cause or attribute to Chiari malformations. Although they too were once thought to be rare, Acquired Chiari malformations are now being diagnosed in increasing numbers. A brief overview of what each of these labels entail, together with a summary of the different types of CM’s, is provided below:

SEVEN TYPES OF CHIARI MALFORMATIONS WORTH DISCUSSING (asterisks “*” indicate commonly known types)

Chiari Zero:  The lower part of the cerebellum (the cerebral tonsils) are blocking the foramen magnum, but are not descended through. Because of the cerebellum’s position, it blocks the flow of cerebrospinal fluid and all the effects of that blockage are comparable to Type 1.

Diagnosis Requirements: Symptomology; MRI showing no herniation but the low-lying tonsils that are pressing against the top of the foramen magnum; MRI showing a syrinx (despite the name, Chiari Zero is classified under Syringomyelia and not Chiari Malformation – so a syrinx is technically required for diagnoses). [6][7]

Treatment Options: With few symptoms, non-surgical treatments might be recommended. When a syrinx is present, a decompression is often recommended before the syrinx has a chance to further develop and cause additional damage to the spine. However, even when a syrinx is present, all pathological cofactors should be explored and addressed prior to decompression surgery.

Chiari 0.5: In cases of Chiari 0.5, the lower part of the cerebellum (the cerebral tonsils) are descended through the foramen magnum, but descends < 5mm (which is the measurement that some doctors use to define Chiari). Usually labeled “tonsillar ectopia” on radiology reports, the symptoms and effects of the obstruction are generally the same as those experienced with Type 1 or Chiari 1.5.[3]

Diagnosis Requirements: Symptomology; MRI showing a herniation of < 5mm, unless already properly diagnosed with a Type 1 or Chiari 1.5; presence of a syrinx is not “required” for diagnosis, but as with Chiari Zero, it illustrates that it is causing a problem obstructing the flow of cerebrospinal fluid and may be relevant when deciding between various courses of treatment.

Treatment Options: The same as Type 1 or Chiari 1.5, respectively.

*Chiari Malformation Type 1: The most common type of Chiari Malformation, Type 1 is diagnosed when the cerebral tonsils descend below the foramen magnum. Medical professionals unfamiliar with current research surrounding Chiari Zero and Chiari 0.5 (and the symptomology surrounding the blockage of cerebrospinal fluid), believe that a tonsillar herniation of less than 5mm is simply a tonsillar ectopia and only diagnose a Chiari Malformation when the descent is > 5mm. However, the 5mm requirement is controversial, and many doctors now base their diagnoses not solely on measurements, but rather on symptomology and a combination of other factors, including cine MRI’s, a patient’s symptoms, and other relevant factors.[6] Many people with a Chiari Zero, Chiari 0.5, or Type 1 can be asymptomatic for a lifetime: one large study found that approximately 30% of those with a CM measuring between 5-10mm were asymptomatic.[8] If symptoms develop, they often present in adolescence or early adulthood. Anecdotal evidence supports the proposition that once symptoms start, the symptoms often progress rapidly until the damage is stopped surgically.

Diagnosis Requirements: Symptomology; MRI indicating at least one herniated tonsil (without the brainstem descending as well).[9]

Treatment Options: Prior to surgery any/all comorbidities should be explored and treated especially if you are found to have a normal sized posterior fossa. However, if you have classic Chiari 1 Malformation with a small posterior fossa, the risks of surgery should be weighed against the severity of symptoms and the impact that symptoms are having on the patient’s quality of life. It is often recommended to treat mild symptoms with medication, with surgical options typically reserved for cases in which symptoms cause more serious medical and quality of life problems. However, symptoms do tend to progress, and studies have shown a correlation between successful decompression surgery and the amount of time between the onset of any symptoms and surgical intervention[10]. See “Decompression Surgery” below.

Chiari 1.5: This type of CM (often referred to as a “Complex Chiari”) is often acquired as opposed to congenital.  Chiari 1.5 should be the diagnosis when the tonsil(s) and all/part of the lower brainstem (the medulla oblongata) has descended past the foramen magnum. This is usually indicative of another comorbid condition pushing the brainstem downward from above or pulling downward from below.[5][11][12]

Diagnosis Requirements: symptomology; MRI indicating at least one herniated tonsil AND a downward displacement of all/part of the brainstem; without the other radiological findings associated with Type 2.

Treatment Options: Treatment options can vary significantly from patient to patient depending on the cause of the Chiari 1.5. While a variety of medical options might initially be used to treat symptoms, it is extremely important that all possible causes and/or comorbidities are thoroughly investigated and treated prior to the consideration of decompression surgery. Failure to identify and treat any such conditions can increase the likelihood of a failed decompression and further complications such as brain slumping, increased cervical instability, etc.

*Chiari Malformation Type 2 (also known as Arnold Chiari Malformation): Type 2 involves a herniation of the cerebellar tonsils and lower part of the brainstem (the medulla oblongata). Unlike in Chiari 1.5, in Type 2 the fourth ventricle is usually herniated, all/part of the cerebellar vermis (the tissue connecting both halves of the cerebellum) is missing or herniated, the corpus callosum (nerve fibers connecting both hemispheres of the brain) is fully/partially absent (agenesis), and it is almost always accompanied by a myelomeningocele (the most serious form of Spina Bifida, a congenital neural tube defect where the spinal canal does not close properly).[13][14][15]

Diagnosis Requirements: While a myelomeningocele is usually evident and diagnosed at birth, a brain MRI should confirm the radiological aspects of Type 2.

Treatment Options: Myelomeningocele is usually treated surgically at birth. If other related problems develop, such as hydrocephalus and/or tethered cord, they are often dealt with surgically as they become problematic. While some with Type 2 are decompressed, anecdotal evidence reflects a general trend of an increased failure rate with decompression surgeries as compared to those with Type 1. Because of this, some neurosurgeons choose not to decompress those with Type 2.

*Chiari Malformation Type 3: Type 3 is a serious type of Chiari Malformation involving herniated cerebellar tonsils, brainstem, and fourth ventricle. However, in most cases of Type 3, a sac forms out of the back of the skull (encephalocele) that contains brain matter from the cerebellum and the meninges. Type 3 causes severe neurological problems that are evident at birth and has a high infant mortality rate.[16][17]

 *Chiari Malformation Type 4: Type 4 is the most severe type of Chiari Malformation, but does not involve a hindbrain herniation (and therefore arguments have been made that it is not a Chiari Malformation). Instead, it consists of an undeveloped or underdeveloped cerebellum. Most infants born with Type 4 die in infancy.[16][17]


SURGICAL INTERVENTION 

Decompression surgery is currently the only available means of attempting to stop the progression of symptoms of a congenital chiari (with no other pathological cofactors), but decompression is not a cure (not even close). Statistics show that up to 69% of decompressed patients find some measure of relief from surgery (usually headaches)[18]. Most neurosurgeons will give only a 50% chance of helping each individual symptom. Some of the symptoms are irreversible once they develop. Recent studies show that there is a correlation between early surgical intervention and positive post-surgical outcomes.[19] However, we cannot over emphasize the importance of your doctors taking time to find, diagnose, and treat co-morbid conditions BEFORE decompression surgery. If they are not willing to consider comorbidities, they are probably not the doctor for you!

 

 

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*Original version released January 2018, revised October 2018.

 

References:

1 Eltorai, Ibrahim M. “Rare Diseases and Syndromes of the Spinal Cord” Cham: Springer International Publishing: Imprint: Springer, 2016. Page 43, 15.2, <www.springer.com/us/book/9783319451466>.

2 Henderson, Fraser C., et al. “Neurological and Spinal Manifestations of the Ehlers–Danlos Syndromes.” American Journal of Medical Genetics Part C: Seminars in Medical Genetics, 21 Feb. 2017, <www.onlinelibrary.wiley.com/doi/10.1002/ajmg.c.31549/full>.

3 Sekula, Raymond F, et al. “Dimensions of the Posterior Fossa in Patients Symptomatic for Chiari I Malformation but without Cerebellar Tonsillar Descent.” Cerebrospinal Fluid Research, BioMed Central, 2005, <www.ncbi.nlm.nih.gov/pmc/articles/PMC1343586>.

4 Stagi, Stefano, et al. “The Ever-Expanding Conundrum of Primary Osteoporosis: Aetiopathogenesis, Diagnosis, and Treatment.” Italian Journal of Pediatrics, BioMed Central, 2014, <www.ncbi.nlm.nih.gov/pmc/articles/PMC4064514>.

5 Milhorat, Thomas H., et al. “Mechanisms of Cerebellar Tonsil Herniation in Patients with Chiari Malformations as Guide to Clinical Management.” Acta Neurochirurgica, Springer Vienna, July 2010, <www.ncbi.nlm.nih.gov/pmc/articles/PMC2887504>.

6 Isik, N, et al. “A New Entity: Chiari Zero Malformation and Its Surgical Method.” Turkish Neurosurgery., U.S. National Library of Medicine, <www.ncbi.nlm.nih.gov/pubmed/21534216>.

7 “JNS JOURNAL OF Neurosurgery OFFICIAL JOURNALS OF THE AANS since 1944.” The Resolution of Syringohydromyelia without Hindbrain Herniation after Posterior Fossa Decompression | Journal of Neurosurgery, Vol 89, No 2, <www.thejns.org/doi/abs/10.3171/jns.1998.89.2.0212?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed>.

8 Elster, A D, and M Y Chen. “Chiari I Malformations: Clinical and Radiologic Reappraisal.”Radiology., U.S. National Library of Medicine, May 1992, <www.ncbi.nlm.nih.gov/pubmed/1561334>.

9 Wilson, Eugene. “Chiari.” CEDSA Home, <www.cedsa.org/index.php/59-quick-reference/73-chiari.html>.

10 Hindawi. “Surgical Management of Patients with Chiari I Malformation.” International Journal of Pediatrics, Hindawi, 28 June 2012, <www.hindawi.com/journals/ijpedi/2012/640127>.

11 Kim, In-Kyeong, et al. “Chiari 1.5 Malformation : An Advanced Form of Chiari I Malformation.”Journal of Korean Neurosurgical Society, The Korean Neurosurgical Society, Oct. 2010, <www.ncbi.nlm.nih.gov/pmc/articles/PMC2982921>.

12 Malik, Amita, et al. Chiari 1.5: A Lesser Known Entity. Annals of Indian Academy of Neurology, <www.annalsofian.org/article.asp?issn=0972-2327;year=2015;volume=18;issue=4;spage=449;epage=450;aulast=Malik>.

13 Wolpert, Samuel M, et al. “Chiari II Malformation: MR Imaging.” American Journal of Roentgenology, <www.ajronline.org/doi/pdf/10.2214/ajr.149.5.1033>.

14 Yumer, M H, et al. “Chiari Type II Malformation: a Case Report and Review of Literature.”Folia Medica., U.S. National Library of Medicine, <www.ncbi.nlm.nih.gov/pubmed/16918056>.

15 Kim, Irene. “Chiari II Decompression in Patients with Myelomeningocele in the National Spina Bifida Patient Registry (NSBPR).” <http://spinabifidaassociation.org/sbworldcongress/wp-content/uploads/sites/10/2017/04/B.4-Kim-Neurosurgery.pdf>.

16 “Chiari Malformation Fact Sheet.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, <www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Chiari-Malformation-Fact-Sheet>.

17 “Chiari Malformations.” NORD (National Organization for Rare Disorders), <www.rarediseases.org/rare-diseases/chiari-malformations>.

18 14 Aliaga, L, et al. “A Novel Scoring System for Assessing Chiari Malformation Type I Treatment Outcomes.” Neurosurgery., U.S. National Library of Medicine, Mar. 2012, <www.ncbi.nlm.nih.gov/pubmed/21849925>.

19  Siasios, John, et al. “Surgical Management of Patients with Chiari I Malformation” International Journal of Pediatrics, Article ID 640127, Hindawi, 2012, <www.hindawi.com/journals/ijpedi/2012/640127>.

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