Taishet; the Cerebral Angiogram

As much as possible, we’ve been trying to make our Johns Hopkins trips family outings as much as they are trips to check on Christopher’s brain.  This usually means booking a hotel on Hotwire (Scott’s pretty awesome at getting great rooms for good deals) and staying overnight so we aren’t pressured by the Capital Beltway—I95—395 traffic gauntlet.  After our first visit with Dr. Groves, we all went to the Baltimore Science Center for the first time.  Since cerebral angiograms are officially “minimally invasive” outpatient procedures, we booked a hotel for two nights, this time as well.  The idea was that I’d take Christopher to Hopkins at o’ dawn-thirty while Scott took the other two children to the Science Center for another field trip.  The next day, we’d all go to the National Aquarium together.

Image 1--The Children's Tower at Johns Hopkins University

Christopher displayed no nerves whatsoever either in driving to Hopkins from our hotel or while in PACU awaiting his procedure.  In fact, the same incredibly charming demeanor he’d had at Inova Children’s in April was on display.  I asked him about it afterwards, commenting, “I thought you hated hospitals and needles?”

“Well, yeah, but hospitals actually do stuff.  Doctors’ appointments just ask lots of questions without fixing anything.”

Image 2--Smelling anesthesia flavors; he chose cherry.

Out of the mouths of babes.  He’s not necessarily wrong.  The anesthesiologists were quite concerned that his headaches were still getting worse even though Dr. Bernier had adjusted his dose to 20mg amitriptyline two weeks’ prior.  So they decided they’d try to give him some extra fentanyl during the angiogram to see if they couldn’t relieve the headache.  We also got a full description of the cerebral angiogram and how it works by the pediatric interventional neuroradiology resident.  Say that ten times fast.  He asked if we knew what it meant, Christopher said no.  I told him, “Interventional Neuroradiology” means they use radiation like X-rays and gamma to actually treat and fix the diseased tissue inside of you, not just image it.  Pediatric means they only treat kids.”  I got a gold star for the day.   And then it was time to wheel him back to the angiography suite, the anesthesiologists cracking horrible potty humor jokes the whole time.  They put on the mask, I gave him a kiss just before he lost consciousness, and then I went to the waiting room.  

Image 3--Ready to Go, calm as a cucumber; the anesthesiologist is pictured on the left.  I tried to remember his name, I've failed, but he was awesome.

Dr. Monica Pearl, the interventional neuroradiologist performing the procedure, walked me down the hall, since she’d been at the weekly neurovascular conference and hadn’t seen us earlier.  I felt, at that point, that everything was coming together.  When we’d seen Dr. Bernier for his headache follow-up, she had told us we should seek out a second opinion regardless of what Dr. Ahn told us regarding the AVM, just because it’s such a big thing.  When I asked who at Children’s National she recommended, I was told all the complicated cases are referred to Johns Hopkins, and Dr. Monica Pearl is the best. 

Waiting is hard.  Luckily, I was at the climax to The Maltese Falcon, but even then is was difficult to remain focused.  Also, that hospital is cold.  Even in a sweater.  Finally, I got a phone call from the nurse saying they were taking him back to PACU and everything had gone well.  Next I got a call from Dr. Pearl wanting to know where to find me so we could discuss his results.

As much as I was hoping for Option 1 or 2, as outlined by Dr. Ahn, I didn’t really expect it.  From the very, very little I’d allowed myself to research on AVMs, Christopher had enough symptoms it didn’t seem likely this was a nothing.  And yet, we were all still hoping he was undergoing a very expensive procedure for a nothing diagnosis.  Dr. Pearl, however, quietly told me that there is, indeed, a true AVM in Christopher’s brain.  It is small, just under 2 cubic centimeters in volume, it isn’t hiding an aneurysm, it has only superficial veinous drainage, all good things.  But it has to come out.  It’s in prime real estate, so if it were to rupture, the damage would be catastrophic.  She had already taken the images for the gamma knife surgery, because she, too, thought it was inoperable.  And so I cried.  I was expecting this result, but the reality still caught me off guard.

And then I put myself together and went in to see Christopher around the corner in PACU.  Honestly, he wasn’t in great shape.  The breathing tube had scratched his throat pretty badly, so I spent the next several hours offering him sips of popsicle slushy every few minutes.  The first two hours of laying flat didn’t bother him at all, he was too preoccupied by the sore throat and I had his iPad monopolizing his attention with Zootopia.  The second two hours at a 30 degree incline weren’t too bad, either, although sometimes he slipped and we had to make adjustments.  By then, he’d moved on to Home.  The fentanyl they’d given him for the headache worked to lower its intensity the first part of recovery, but his headache was worse than usual by discharge and they’d given him IV Zofran for nausea.  But he did his laps around the unit just fine, the catheter site had no hematoma, and he was able to walk on his own to where I’d parked that morning.  

Image 4--For the record, cherry slushies look like a slasher movie when spilled in PACU.

Surprisingly, Christopher didn’t ask in PACU about his diagnosis.  I had decided I wouldn’t offer until he asked.  On the drive home, he asked.  I was as gentle as I could in saying he definitely had an AVM and they definitely wanted to remove it.  He crumpled in the backseat and started crying.  He almost never cries in all of this.  It didn’t last long, but he was definitely in a very bad mood as we entered the hotel room.  The leg was also bothering him from the short walks to and from the vehicle, and he was supposed to have a quiet afternoon to initiate his 7 days of limited activity and no swimming while the catheter site healed.  So, we curled up in one of the hotel room beds, watching Shark Week with the rest of our family, and ordering take-out  for dinner (mediterranean kabobs  and rice, one of his favorite meals).

I was up most of the night, finally doing my research and looking at the longitudinal studies on AVMs and treatment outcomes via peer reviewed papers.  I was feeling very grateful for my training as a research scientist at that point.  As hard as the formal AVM diagnosis was on Christopher, I took it better.  I think because at this point, I’d opened up to the most important people in my life and just about everybody knew what we’re facing.  Secrets are hard.

The next day we still went to the Aquarium, although it was one of our shorter trips because his leg was sore.  He had full laryngitis by then, and the sore throat was still raging, so we treated it with Tylenol and honey tea, which helped a good bit.  And then we went home and packed him off to 4-H camp, something he’d been excited about for months.  And they, very graciously, changed two of his classes at the last minute so to meet the activity restrictions we’d only just learned about.

Krasnoyarsk; What is an AVM, anyway?

As expected, Dr. Ahn told us Christopher needed a cerebral angiogram to know for certain what kind of tangle was in his brain.  But first he showed us what they were seeing in his MRI and what it meant.  In the very top layer of his brain, you see a few tiny black circles in the middle, just to the left, kind of like swiss cheese.  The next layer down—nothing.  

Image 1--View of the AVM in the top layer of Christopher's brain.  I added the labels.  Note that since the AVM is located in the right side of his brain, any deficits would occur on the left side of his body.  Also note that it is straddling the central sulcus, but in this view, appears to mostly be located in the pre-central gyrus, aka, the motor strip.

Dr. Ahn said those black circles could mean one of three things:  

1. A benign tangle of blood vessels that will never cause harm.
2. A true, but mild, arteriovenous malformation (AVM), where the arteries are hooked up directly to the veins without any intervening capillaries.  They’d monitor it yearly.
3. A true AVM that is deemed dangerous enough to remove.

Why are AVMs dangerous?  First, veins aren’t intended to take the pulsile flow of an artery, but since the blood flow slows WAAAAY down in the capillary beds, that isn’t an issue in normally wired blood vessels.  Second, the arteries in an AVM are missing a structural layer that causes the whole thing to wind up like a tangled ball of yarn.  

 Figure 1--Okay, so this is two figures I pulled off the braingletangle blog, but I like the visualization of an AVM compared to a normal artery--capillary bed--vein connection.

He also felt, based on what he saw on the MRI image of Christopher’s brain, that an AVM diagnosis would be physically inoperable and would require gamma knife surgery to remove.  Why?  Because they thought his AVM is in an area of the brain called the motor strip.  When you decide you want to move one of your skeletal muscles, the motor strip is responsible for sending that message down your spinal cord to the muscles required.  In the world of vascular neurosurgeons, it makes it “eloquent tissue”; to the layman, it’s “prime real estate”.  Just behind the motor strip is the sensory strip, which, as the name implies, is responsible for receiving the sensory input from various areas of the body.  Where the regions of the motor strip learn early which parts of the body to control and display little plasticity for taking on new roles later in life, the sensory strip is much more flexible.  Lying immediately between the two regions is a line called the central sulcus.

Figure 2--The pre-central gyrus, also known as the primary motor cortex or motor strip, is the area just in front of the central sulcus in this diagram.  The post-central gyrus, also known as the primary somatosensory cortex or sensory strip, is located immediately behind the central sulcus.  Image Courtesy of The Aneurysm and AVM Foundation.

Christopher's biggest concern about the angiogram, as usual, was whether or not he’d need an IV.  As soon as he heard the words “gamma irradiation”, however, he was all atwitter with questions about the nature and safety of the therapy.  Luckily, Dr. Ahn is a pediatric neurosurgeon and appeared more than happy to answer those questions.  He was also ready to explain how gamma irradiation shreds the DNA inside the targeted tissues, but since I spent several years in graduate school studying the DNA damage repair cycles, we were able to focus on Christopher’s questions.

With that information, we chose the first available date for a cerebral angiogram and awaited our arrival at the next station.