TED2011

Elliot Krane: The mystery of chronic pain

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We think of pain as a symptom, but there are cases where the nervous system develops feedback loops and pain becomes a terrifying disease in itself. Starting with the story of a girl whose sprained wrist turned into a nightmare, Elliot Krane talks about the complex mystery of chronic pain, and reviews the facts we're just learning about how it works and how to treat it.

- Pediatric anesthesiologist
At the Lucile Packard Children's Hospital at Stanford, Elliot Krane works on the problem of treating pain in children. Full bio

I'm a pediatrician and an anesthesiologist,
00:15
so I put children to sleep for a living.
00:17
(Laughter)
00:19
And I'm an academic, so I put audiences to sleep for free.
00:21
(Laughter)
00:24
But what I actually mostly do
00:28
is I manage the pain management service
00:30
at the Packard Children's Hospital up at Stanford in Palo Alto.
00:32
And it's from the experience
00:35
from about 20 or 25 years of doing that
00:37
that I want to bring to you the message this morning,
00:39
that pain is a disease.
00:41
Now most of the time,
00:43
you think of pain as a symptom of a disease,
00:45
and that's true most of the time.
00:47
It's the symptom of a tumor or an infection
00:49
or an inflammation or an operation.
00:52
But about 10 percent of the time,
00:54
after the patient has recovered from one of those events,
00:57
pain persists.
01:00
It persists for months
01:02
and oftentimes for years,
01:04
and when that happens,
01:06
it is its own disease.
01:08
And before I tell you about how it is that we think that happens
01:10
and what we can do about it,
01:13
I want to show you how it feels for my patients.
01:15
So imagine, if you will,
01:18
that I'm stroking your arm with this feather,
01:20
as I'm stroking my arm right now.
01:22
Now, I want you to imagine
01:25
that I'm stroking it with this.
01:27
Please keep your seat.
01:29
(Laughter)
01:31
A very different feeling.
01:33
Now what does it have to do with chronic pain?
01:35
Imagine, if you will, these two ideas together.
01:37
Imagine what your life would be like
01:40
if I were to stroke it with this feather,
01:42
but your brain was telling you
01:45
that this is what you are feeling --
01:47
and that is the experience of my patients with chronic pain.
01:49
In fact, imagine something even worse.
01:52
Imagine I were to stroke your child's arm with this feather,
01:54
and their brain [was] telling them
01:57
that they were feeling this hot torch.
01:59
That was the experience of my patient, Chandler,
02:02
whom you see in the photograph.
02:04
As you can see, she's a beautiful, young woman.
02:06
She was 16 years old last year when I met her,
02:08
and she aspired to be a professional dancer.
02:10
And during the course of one of her dance rehearsals,
02:13
she fell on her outstretched arm and sprained her wrist.
02:15
Now you would probably imagine, as she did,
02:18
that a wrist sprain is a trivial event
02:20
in a person's life.
02:22
Wrap it in an ACE bandage,
02:24
take some ibuprofen for a week or two,
02:26
and that's the end of the story.
02:28
But in Chandler's case, that was the beginning of the story.
02:30
This is what her arm looked like
02:34
when she came to my clinic about three months after her sprain.
02:36
You can see that the arm is discolored,
02:39
purplish in color.
02:41
It was cadaverically cold to the touch.
02:43
The muscles were frozen, paralyzed --
02:45
dystonic is how we refer to that.
02:47
The pain had spread from her wrist to her hands,
02:50
to her fingertips, from her wrist up to her elbow,
02:53
almost all the way to her shoulder.
02:56
But the worst part was,
02:58
not the spontaneous pain that was there 24 hours a day.
03:00
The worst part was that she had allodynia,
03:03
the medical term for the phenomenon that I just illustrated
03:06
with the feather and with the torch.
03:09
The lightest touch of her arm --
03:11
the touch of a hand,
03:13
the touch even of a sleeve, of a garment, as she put it on --
03:15
caused excruciating, burning pain.
03:18
How can the nervous system get this so wrong?
03:22
How can the nervous system
03:25
misinterpret an innocent sensation
03:27
like the touch of a hand
03:29
and turn it into the malevolent sensation
03:31
of the touch of the flame?
03:34
Well you probably imagine that the nervous system in the body
03:36
is hardwired like your house.
03:39
In your house, wires run in the wall,
03:41
from the light switch to a junction box in the ceiling
03:43
and from the junction box to the light bulb.
03:46
And when you turn the switch on, the light goes on.
03:49
And when you turn the switch off, the light goes off.
03:51
So people imagine the nervous system is just like that.
03:54
If you hit your thumb with a hammer,
03:58
these wires in your arm -- that, of course, we call nerves --
04:00
transmit the information into the junction box in the spinal cord
04:03
where new wires, new nerves,
04:06
take the information up to the brain
04:08
where you become consciously aware that your thumb is now hurt.
04:10
But the situation, of course, in the human body
04:14
is far more complicated than that.
04:16
Instead of it being the case
04:19
that that junction box in the spinal cord
04:21
is just simple where one nerve connects with the next nerve
04:23
by releasing these little brown packets
04:26
of chemical information called neurotransmitters
04:28
in a linear one-on-one fashion,
04:31
in fact, what happens
04:34
is the neurotransmitters spill out in three dimensions --
04:36
laterally, vertically, up and down in the spinal cord --
04:38
and they start interacting
04:41
with other adjacent cells.
04:43
These cells, called glial cells,
04:46
were once thought to be
04:48
unimportant structural elements of the spinal cord
04:50
that did nothing more than hold all the important things together,
04:52
like the nerves.
04:54
But it turns out
04:56
the glial cells have a vital role
04:58
in the modulation, amplification
05:00
and, in the case of pain, the distortion
05:02
of sensory experiences.
05:05
These glial cells become activated.
05:08
Their DNA starts to synthesize new proteins,
05:10
which spill out
05:12
and interact with adjacent nerves,
05:14
and they start releasing their neurotransmitters,
05:16
and those neurotransmitters spill out
05:19
and activate adjacent glial cells, and so on and so forth,
05:21
until what we have
05:24
is a positive feedback loop.
05:26
It's almost as if somebody came into your home
05:28
and rewired your walls
05:30
so that the next time you turned on the light switch,
05:32
the toilet flushed three doors down,
05:34
or your dishwasher went on,
05:36
or your computer monitor turned off.
05:38
That's crazy,
05:40
but that's, in fact, what happens
05:42
with chronic pain.
05:44
And that's why pain becomes its own disease.
05:46
The nervous system has plasticity.
05:49
It changes, and it morphs
05:51
in response to stimuli.
05:53
Well, what do we do about that?
05:55
What can we do in a case like Chandler's?
05:57
We treat these patients in a rather crude fashion
06:00
at this point in time.
06:02
We treat them with symptom-modifying drugs --
06:04
painkillers --
06:07
which are, frankly, not very effective
06:09
for this kind of pain.
06:11
We take nerves that are noisy and active
06:13
that should be quiet,
06:15
and we put them to sleep with local anesthetics.
06:17
And most importantly, what we do
06:19
is we use a rigorous, and often uncomfortable, process
06:22
of physical therapy and occupational therapy
06:26
to retrain the nerves in the nervous system
06:29
to respond normally
06:32
to the activities and sensory experiences
06:35
that are part of everyday life.
06:38
And we support all of that
06:40
with an intensive psychotherapy program
06:42
to address the despondency, despair and depression
06:45
that always accompanies
06:48
severe, chronic pain.
06:50
It's successful,
06:52
as you can see from this video of Chandler,
06:54
who, two months after we first met her,
06:56
is now doings a back flip.
06:58
And I had lunch with her yesterday
07:00
because she's a college student studying dance at Long Beach here,
07:02
and she's doing absolutely fantastic.
07:05
But the future is actually even brighter.
07:07
The future holds the promise
07:11
that new drugs will be developed
07:14
that are not symptom-modifying drugs
07:16
that simply mask the problem,
07:19
as we have now,
07:21
but that will be disease-modifying drugs
07:23
that will actually go right to the root of the problem
07:26
and attack those glial cells,
07:28
or those pernicious proteins
07:30
that the glial cells elaborate,
07:32
that spill over and cause this central nervous system wind-up,
07:35
or plasticity,
07:38
that so is capable
07:40
of distorting and amplifying
07:42
the sensory experience that we call pain.
07:44
So I have hope
07:46
that in the future,
07:48
the prophetic words of George Carlin will be realized,
07:50
who said, "My philosophy:
07:53
No pain, no pain."
07:55
Thank you very much.
07:59
(Applause)
08:01

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About the Speaker:

Elliot Krane - Pediatric anesthesiologist
At the Lucile Packard Children's Hospital at Stanford, Elliot Krane works on the problem of treating pain in children.

Why you should listen

It's an awful problem to contemplate: How do you help a young child in pain? As director of Pain Management Services at Lucile Packard Children's Hospital at Stanford, Elliot Krane works on solving this problem, studying and treating kids who are undergoing surgeries, suffering from complications of diabetes -- and kids suffering "neuropathic pain" resulting from injury to the nervous system itself.

More profile about the speaker
Elliot Krane | Speaker | TED.com