Pediatric Early Detection

Mylee GraceJust days after birth, Mylee Grace was admitted to the neonatal intensive care unit in severe distress. Diagnosed with aspiration pneumonia, she miraculously survived. But her battles were only beginning.

Mylee suffered from dysphagia (difficulty swallowing). Instead of traveling into her esophagus, food and liquids would go down the trachea into the lungs (called aspiration), which caused Mylee to suffer repeated episodes of life-threatening pneumonia during her first year of life.

What was causing Mylee’s troubling problems?

When an MRI scan was ordered for Mylee, it revealed a Chiari I malformation (a downward herniation of the cerebellar tonsils.

Children with Chiari I malformations under the age of 3 may present with some or all of these symptoms: failure to thrive, a history of difficulty feeding, problems swallowing, aspiration pneumonia, gastroesophageal reflux, and many undergo procedures such as Nissen fundoplication or tracheotomy.

Early identification is vital for children like Mylee. If your child has these symptoms, ask your doctor about screening for the Chiari I malformation. A surgical treatment could benefit your child.

The Chiari I Abnormality in Childhood

by Arnold H. Menezes, MD

The following article is a transcribed presentation from the 2004 ASAP Conference.

Abstract

The clinically symptomatic child with the hindbrain herniation syndrome (Chiari I) can differ significantly from the adult patient. A prospective analysis of these children has brought an understanding of the various presentations.

The primary symptoms below age 5 have been failure to thrive secondary to repeated aspirations, gastroesophageal reflux and headaches. Between ages 3-10 years, headaches and scoliosis were the main symptoms together with neurological abnormalities secondary to the cerebellar tonsillar impaction and syringohydromyelia.

The factors affecting treatment have been clinical symptoms/signs, posterior fossa volume, craniovertebral junction abnormalities and instability. Taken together, these substrates provide for successful outcome.

Transcribed Presentation Notes

Slide 1Good morning. I sound like a preacher dont I — expecting you to say good morning back again! I thought Id talk to you today about something thats always fascinated me, the problems that occur in the young child. I think most of us have come to the conclusion that the Chiari I malformation is not a nervous system neural abnormality per se, but rather that which is the result in the decrease in the housing space in the back of the head. We call that a mesodermal abnormality.

abnormality-children2But why should it happen in the very young, before the skull has fully formed and developed? And is there any way in which we can predict or help these children who come in with different forms of presentation? So in light of that, we reviewed– this is a prospective study thats been going on for many years– we reviewed our series and we thought wed focus on childhood.

Ive been at the University of Iowa since 1969 [see Figure 1] and my interest in terms of keeping a detailed log started out fairly early. We have a prospective data base and it looked at nearly 600 surgical patients, because of my interest in abnormalities of the skull base, bony abnormalities, about 2/5 of them, nearly half of them, were patients who had problems with skull base abnormalities. But when we focused on children below the age of 6 years, [see Figure 2] we thought that our reason for doing this would be, how did this defer in terms of presentation from the adults or anybody above that age? And why did we pick the age of 6? Because it begins to be statistically significantly. We wanted to achieve an early diagnosis, and more importantly, we need to educate medical practioners, such as pediatricians, family practioners, general practice, neurosurgeons too, and I think that that was something we needed to achieve. Once we came to some conclusions, we thought that our best bet was to have special meetings, instead of going ahead and presenting this at neurosurgical national meetings, which is what we do, but also to educate the pediatricians. The Journal of Pediatrics has a circulation of over 300,000 and its translated into 4 languages and goes out world wide.

Radiology in the diagnosis of the Chiari I malformation

by Victor Haughton, MD, University of WI-Madison

For some patients with the Chiari I malformation CSF flow studies may be helpful in determining if surgical management is appropriate. Some patients with a Chiari malformation may not need the flow studies.

The position of the tonsils can be evaluated by a routine MR scan or even a CT scan, making the identification of the Chiari I malformation simple. The definition of the Chiari I malformation for radiologists is the descent of the tonsils 5 mm below the foramen magnum. Although this amount of tonsilar malposition is found once in approximately every 150 scans, it is not always a finding that needs to be evaluated further or treated. In some cases it is an incidental finding, that is not related to the conditions or symptoms for which the scan was requested. In other cases the finding may explain the patient’s symptoms or conditions. For example, in patients with Valsalva-induced headaches (exertional headaches), syringomyelia (spinal cord cysts), apneic spells (temporary interruption of breathing pattern), the Chiari I malformation can be diagnosed as the cause of the symptoms with a high degree of confidence. In other patients, having MR because of a pituitary disorder for example, the low position of the tonsils does not likely relate to the patient’s symptoms. In many cases, the patient’s signs and symptoms may not be easily attributed to one cause and not confidently explained by the tonsil position. Such patents might include patients with less distinctive types of headaches for example.

Therefore CSF flow studies have been developed to provide a functional test of the effect of the tonsils, to distinguish the “symptomatic Chiari I” (with symptoms resulting from the tonsil position) from the “asymptomatic Chiari I” (with symptoms or symptoms unrelated to the tonsil position). The usual test of CSF flow is the cardiac-gated Phase Contrast MR study (PC MR). This study shows the pattern and measures the velocity of CSF flow. The study may be viewed as a cine loop showing the changes in CSF flow during the cardiac cycle, or it may be viewed as a series of images representing different phases in the cardiac cycle. The images may be analyzed to measure the velocity of the CSF and, with sophisticated mathematical techniques, the pressures, pressure waves, flow directions, and flow structure. PC MR shows different CSF flow patterns in Chiari I patients than in normal subjects. It shows different patterns in “symptomatic” than in “asymptomatic” patients). In PC MR, the symptomatic patients display “synchronous bidirectional flow” and greater CSF velocity magnitudes compared to the “asymptomatic patients. PC MR has good but not perfect accuracy (1). The PC MR test for abnormal CSF flow should include axial images at the tip of the tonsils and perhaps sagittal images.

New research suggests that the accuracy of the test may be improved by obtaining axial PC MR images at multiple levels. The goal of research is to define the critical CSF flow parameters that result necessarily in signs and symptoms. Sophisticated techniques, Computation Flow Design, are used by some investigators in attempt to explain how obstruction of CSF flow by the tonsils results in a syrinx, spinal cord cyst, inches below the obstruction. These studies are enhancing our understanding of CSF flow and promising to improve our diagnosis and care of the Chiari I malformation.

References

  1. Hofkes SK, Iskandar BJ, Turski PA, Gentry LR, McCue JB, Haughton VM. Differentiation between symptomatic Chiari I malformation and asymptomatic tonsilar ectopia by using cerebrospinal fluid flow imaging: initial estimate of imaging accuracy. Radiology. 2007 Nov;245(2):532-40. Epub 2007 Sep 21.

Current Synthesis

by John J. Oró, MD

Abstract

In papers published in 1891 and 1894, pathologist Dr. Hans von Chiari described a series of hindbrain malformations now known as the Chiari malformations. The traditional definitions went unchallenged for over 100 years. However, the marked advances in medicine over the past couple of decades have led to a new understanding of these malformations and proposed new definitions. We will review the pertinent neuroanatomy, pathology, clinical presentation, diagnosis, treatment, and outcome of patients with CMI with or without syringomyelia. Emphasis will be placed on new research findings, new concepts, and the current naming controversy.

Transcribed Presentation Notes

Figure 1

Figure 1

Well thank you, it’s always a great pleasure to be here annually at this meeting. We’re going to talk about the Chiari Malformation and syringomyelia. To get started we have to have a sense of the normal anatomy. Let’s start with the ventricular system here[see Figure 1].

Within the core of the brain there are fluid spaces called the ventricles and it is in these ventricles that spinal fluid is created and it has to flow a certain direction. These large two ventricles up here connect to this small little canal, into a third ventricle, down the Aqueduct of Sylvius, into the forth ventricle and then they drain out through three openings into the spaces on the outside of the brain and around the spinal canal. Here we have a cross sectional image [see Figure 2] showing the inside of the ventricles. This is the choroid plexus- it’s a tuft of vascular tissue.

Figure 2

Figure 2

With each pulsation an ultra filtrate is created of spinal fluid that again has to flow down these pathways into the forth ventricle and comes out- in particular in this foramen (opening) of Magendie, and two on the side; and here we have a cistern. This fluid filled space, is the cisterna magna, which we’ll talk some more about. It flows around the spinal canal on up and it has to find it’s way for the most part up into this area where it – through these little granulations as they’re called – gets backed into the venous system, and this happens with every heart beat, about 100,000 times a day.

Figure 3

Figure 3

The area that we’re going to talk about today, which is this posterior fossa, this compartment down low here where we see the brain stem turning into the spinal cord and we see the cerebellum in this area. The posterior fossa: there is a lot of activity in the area. The cranial nerves, the nerves that run the eye movements, the facial movements, the tongue movements, et cetera, come out of the brain through the brain stem in this area here. Regulatory mechanisms for the heart and the lungs are in this area, and of course, the cerebellum, and all the highways coming up and down the spinal cord are traveling through this area. So it’s a very busy area. From our point of view, as far as the Chiari malformation is concerned, this is some anatomy [see Figure 3] that we want to kind of put into our brains, if you will, to help understand things. This is a side view of the posterior fossa and what you’re seeing here is some bone at the base of the skull and in the back of your skull, ending at this point, called the basion. This point is called the episthion, and that’s not that important, but the bottom line is the opening at the base of the skull. A line drawn from here to here (and it happens to be called the foramen, which we know is anopening) the foramen magnum (and magnum means large) the large foramen at the base of the skull. Normally what you’re supposed to have in this area is a cistern, a fluid pocket, if you will, and it’s large and when the ancients found this they gave it the term magna, again for large, so it’s the cisterna magna.

Spinal Taps

A lumbar puncture (spinal tap) is a procedure in which spinal fluid is removed from the subarachnoid space in the lumbar region of the spine. It is often ordered to check for infection, rule out certain diseases, or to detect and/or treat elevations in spinal fluid pressure.

Individuals often ask if a lumbar puncture is contraindicated in people diagnosed with Chiari malformation and/or syringomyelia. Some research shows that having a Chiari malformation may increase the risks associated with this procedure. Some authors have reported a worsening of symptoms or catastrophic results following the procedure, but these are considered very rare. In those patients who have been successfully surgically treated, these concerns are even less of an issue.

Make sure the ordering physician is aware of your diagnosis and that you discuss all potential benefits and risks of the procedure. If the situation is not an emergency, it is a good idea to discuss the procedure with the neurosurgeon as well. If the benefits outweigh the risks, your physician may decide to go ahead with the procedure. It is important to remember that some conditions such as meningitis can be fatal if not diagnosed and treated properly.

Dilated Central Canal

With the advancement of MRI technology, individuals are being diagnosed with very small syrinxes that we were unable to detect in years prior. Some people will be told they have a slit-like syrinx or dilated central canal. These are generally 1-2 mm wide in diameter and are often described as a “nonexpansile” syrinx. To understand why this small cavity is present, a review of normal anatomy is helpful.

The spinal cord forms as a tube. On the inside of the tube is a small fluid cavity called the central canal. This disappears during development or during infancy. When the central canal does not completely close, a small leftover of the canal can be seen on MRI and is referred to as a “persistent central canal”.  A radiology report may contain the phrase “a small syrinx versus a persistent central canal”.  A repeat MRI may be recommended in order to determine a definite diagnosis.  This often causes stress for the person waiting and hoping for a concrete diagnosis.   

Our current understanding leads us to recommend that if the dilation of the central canal is not associated with any other known cause of a syrinx (such as the Chiari malformation, a tethered spinal cord, or tumor) it is likely to be a benign finding that will not cause any symptoms and is not likely to grow or enlarge. To make sure, a follow up MRI is usually ordered. In cases where an underlying condition known to be associated with syrinx formation is present (such as a Chiari malformation) or if repeated imaging shows a change in the dilation, then it is more likely to be a true syrinx that should be evaluated and monitored accordingly.

Cine MRI

Cine MRICine MRI (as in cinema) is taken the same way a traditional MRI is, with the addition of either a wristband or EKG leads on the patient’s chest to measure the heart rate. Each time your heart beats, the cerebrospinal fluid is forced out of your brain, down toward the spine in response to the flow of blood that enters the brain with each beat. The MRI machine is equipped with an additional software package that allows the images to be put together, showing the flow of the cerebrospinal fluid (CSF) as it is moving.

Cine MRI’s are sometimes ordered for patients to help doctors determine the amount of CSF flow through the foramen magnum. It can be useful in cases of “borderline” Chiari Malformations or when the question of whether or not decompression is needed is not readily answered using a traditional MRI. A radiologist can determine the amount of fluid that is moving and compare that with normal subjects. Cine MRI’s are sometimes useful in showing other CSF blockages as well. Cine MRI’s are not readily available to all patients, and their practical use is still debated by physicians.

Pregnancy With CM/SM Seminar

Date: October 19, 2011
Time: 7:00 pm Eastern

Keynote speaker:
Dr. Diane M Mueller, ND,RN, FNP-BC
Neurosurgery Center of Colorado

Join Dr Mueller for a comprehensive seminar regarding pregnancy in patients diagnosed with Chiari and or syringomyelia. This is a telephone conference call. Attendees should call 1-800-839-9416 between 6:55 – 7:00 PM Eastern time. If you do not live in the Eastern time zone please verify the correct time for your zone. Participant Pin to enter call is 1698657. Attendee should submit questions in advance to Patrice Schaublin via email patrice_schaublin@ASAP.org. Registration not required