TED2011
Elliot Krane: The mystery of chronic pain
Filmed:
Readability: 4.4
2,012,954 views
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.
Elliot Krane - Pediatric anesthesiologist
At the Lucile Packard Children's Hospital at Stanford, Elliot Krane works on the problem of treating pain in children. Full bio
At the Lucile Packard Children's Hospital at Stanford, Elliot Krane works on the problem of treating pain in children. Full bio
Double-click the English transcript below to play the video.
00:15
I'm a pediatrician and an anesthesiologist,
0
0
2000
00:17
so I put children to sleep for a living.
1
2000
2000
00:19
(Laughter)
2
4000
2000
00:21
And I'm an academic, so I put audiences to sleep for free.
3
6000
3000
00:24
(Laughter)
4
9000
4000
00:28
But what I actually mostly do
5
13000
2000
00:30
is I manage the pain management service
6
15000
2000
00:32
at the Packard Children's Hospital up at Stanford in Palo Alto.
7
17000
3000
00:35
And it's from the experience
8
20000
2000
00:37
from about 20 or 25 years of doing that
9
22000
2000
00:39
that I want to bring to you the message this morning,
10
24000
2000
00:41
that pain is a disease.
11
26000
2000
00:43
Now most of the time,
12
28000
2000
00:45
you think of pain as a symptom of a disease,
13
30000
2000
00:47
and that's true most of the time.
14
32000
2000
00:49
It's the symptom of a tumor or an infection
15
34000
3000
00:52
or an inflammation or an operation.
16
37000
2000
00:54
But about 10 percent of the time,
17
39000
3000
00:57
after the patient has recovered from one of those events,
18
42000
3000
01:00
pain persists.
19
45000
2000
01:02
It persists for months
20
47000
2000
01:04
and oftentimes for years,
21
49000
2000
01:06
and when that happens,
22
51000
2000
01:08
it is its own disease.
23
53000
2000
01:10
And before I tell you about how it is that we think that happens
24
55000
3000
01:13
and what we can do about it,
25
58000
2000
01:15
I want to show you how it feels for my patients.
26
60000
3000
01:18
So imagine, if you will,
27
63000
2000
01:20
that I'm stroking your arm with this feather,
28
65000
2000
01:22
as I'm stroking my arm right now.
29
67000
3000
01:25
Now, I want you to imagine
30
70000
2000
01:27
that I'm stroking it with this.
31
72000
2000
01:29
Please keep your seat.
32
74000
2000
01:31
(Laughter)
33
76000
2000
01:33
A very different feeling.
34
78000
2000
01:35
Now what does it have to do with chronic pain?
35
80000
2000
01:37
Imagine, if you will, these two ideas together.
36
82000
3000
01:40
Imagine what your life would be like
37
85000
2000
01:42
if I were to stroke it with this feather,
38
87000
3000
01:45
but your brain was telling you
39
90000
2000
01:47
that this is what you are feeling --
40
92000
2000
01:49
and that is the experience of my patients with chronic pain.
41
94000
3000
01:52
In fact, imagine something even worse.
42
97000
2000
01:54
Imagine I were to stroke your child's arm with this feather,
43
99000
3000
01:57
and their brain [was] telling them
44
102000
2000
01:59
that they were feeling this hot torch.
45
104000
3000
02:02
That was the experience of my patient, Chandler,
46
107000
2000
02:04
whom you see in the photograph.
47
109000
2000
02:06
As you can see, she's a beautiful, young woman.
48
111000
2000
02:08
She was 16 years old last year when I met her,
49
113000
2000
02:10
and she aspired to be a professional dancer.
50
115000
3000
02:13
And during the course of one of her dance rehearsals,
51
118000
2000
02:15
she fell on her outstretched arm and sprained her wrist.
52
120000
3000
02:18
Now you would probably imagine, as she did,
53
123000
2000
02:20
that a wrist sprain is a trivial event
54
125000
2000
02:22
in a person's life.
55
127000
2000
02:24
Wrap it in an ACE bandage,
56
129000
2000
02:26
take some ibuprofen for a week or two,
57
131000
2000
02:28
and that's the end of the story.
58
133000
2000
02:30
But in Chandler's case, that was the beginning of the story.
59
135000
3000
02:34
This is what her arm looked like
60
139000
2000
02:36
when she came to my clinic about three months after her sprain.
61
141000
3000
02:39
You can see that the arm is discolored,
62
144000
2000
02:41
purplish in color.
63
146000
2000
02:43
It was cadaverically cold to the touch.
64
148000
2000
02:45
The muscles were frozen, paralyzed --
65
150000
2000
02:47
dystonic is how we refer to that.
66
152000
3000
02:50
The pain had spread from her wrist to her hands,
67
155000
3000
02:53
to her fingertips, from her wrist up to her elbow,
68
158000
3000
02:56
almost all the way to her shoulder.
69
161000
2000
02:58
But the worst part was,
70
163000
2000
03:00
not the spontaneous pain that was there 24 hours a day.
71
165000
3000
03:03
The worst part was that she had allodynia,
72
168000
3000
03:06
the medical term for the phenomenon that I just illustrated
73
171000
3000
03:09
with the feather and with the torch.
74
174000
2000
03:11
The lightest touch of her arm --
75
176000
2000
03:13
the touch of a hand,
76
178000
2000
03:15
the touch even of a sleeve, of a garment, as she put it on --
77
180000
3000
03:18
caused excruciating, burning pain.
78
183000
4000
03:22
How can the nervous system get this so wrong?
79
187000
3000
03:25
How can the nervous system
80
190000
2000
03:27
misinterpret an innocent sensation
81
192000
2000
03:29
like the touch of a hand
82
194000
2000
03:31
and turn it into the malevolent sensation
83
196000
3000
03:34
of the touch of the flame?
84
199000
2000
03:36
Well you probably imagine that the nervous system in the body
85
201000
3000
03:39
is hardwired like your house.
86
204000
2000
03:41
In your house, wires run in the wall,
87
206000
2000
03:43
from the light switch to a junction box in the ceiling
88
208000
3000
03:46
and from the junction box to the light bulb.
89
211000
3000
03:49
And when you turn the switch on, the light goes on.
90
214000
2000
03:51
And when you turn the switch off, the light goes off.
91
216000
3000
03:54
So people imagine the nervous system is just like that.
92
219000
4000
03:58
If you hit your thumb with a hammer,
93
223000
2000
04:00
these wires in your arm -- that, of course, we call nerves --
94
225000
3000
04:03
transmit the information into the junction box in the spinal cord
95
228000
3000
04:06
where new wires, new nerves,
96
231000
2000
04:08
take the information up to the brain
97
233000
2000
04:10
where you become consciously aware that your thumb is now hurt.
98
235000
4000
04:14
But the situation, of course, in the human body
99
239000
2000
04:16
is far more complicated than that.
100
241000
3000
04:19
Instead of it being the case
101
244000
2000
04:21
that that junction box in the spinal cord
102
246000
2000
04:23
is just simple where one nerve connects with the next nerve
103
248000
3000
04:26
by releasing these little brown packets
104
251000
2000
04:28
of chemical information called neurotransmitters
105
253000
3000
04:31
in a linear one-on-one fashion,
106
256000
3000
04:34
in fact, what happens
107
259000
2000
04:36
is the neurotransmitters spill out in three dimensions --
108
261000
2000
04:38
laterally, vertically, up and down in the spinal cord --
109
263000
3000
04:41
and they start interacting
110
266000
2000
04:43
with other adjacent cells.
111
268000
3000
04:46
These cells, called glial cells,
112
271000
2000
04:48
were once thought to be
113
273000
2000
04:50
unimportant structural elements of the spinal cord
114
275000
2000
04:52
that did nothing more than hold all the important things together,
115
277000
2000
04:54
like the nerves.
116
279000
2000
04:56
But it turns out
117
281000
2000
04:58
the glial cells have a vital role
118
283000
2000
05:00
in the modulation, amplification
119
285000
2000
05:02
and, in the case of pain, the distortion
120
287000
3000
05:05
of sensory experiences.
121
290000
3000
05:08
These glial cells become activated.
122
293000
2000
05:10
Their DNA starts to synthesize new proteins,
123
295000
2000
05:12
which spill out
124
297000
2000
05:14
and interact with adjacent nerves,
125
299000
2000
05:16
and they start releasing their neurotransmitters,
126
301000
3000
05:19
and those neurotransmitters spill out
127
304000
2000
05:21
and activate adjacent glial cells, and so on and so forth,
128
306000
3000
05:24
until what we have
129
309000
2000
05:26
is a positive feedback loop.
130
311000
2000
05:28
It's almost as if somebody came into your home
131
313000
2000
05:30
and rewired your walls
132
315000
2000
05:32
so that the next time you turned on the light switch,
133
317000
2000
05:34
the toilet flushed three doors down,
134
319000
2000
05:36
or your dishwasher went on,
135
321000
2000
05:38
or your computer monitor turned off.
136
323000
2000
05:40
That's crazy,
137
325000
2000
05:42
but that's, in fact, what happens
138
327000
2000
05:44
with chronic pain.
139
329000
2000
05:46
And that's why pain becomes its own disease.
140
331000
3000
05:49
The nervous system has plasticity.
141
334000
2000
05:51
It changes, and it morphs
142
336000
2000
05:53
in response to stimuli.
143
338000
2000
05:55
Well, what do we do about that?
144
340000
2000
05:57
What can we do in a case like Chandler's?
145
342000
3000
06:00
We treat these patients in a rather crude fashion
146
345000
2000
06:02
at this point in time.
147
347000
2000
06:04
We treat them with symptom-modifying drugs --
148
349000
3000
06:07
painkillers --
149
352000
2000
06:09
which are, frankly, not very effective
150
354000
2000
06:11
for this kind of pain.
151
356000
2000
06:13
We take nerves that are noisy and active
152
358000
2000
06:15
that should be quiet,
153
360000
2000
06:17
and we put them to sleep with local anesthetics.
154
362000
2000
06:19
And most importantly, what we do
155
364000
3000
06:22
is we use a rigorous, and often uncomfortable, process
156
367000
4000
06:26
of physical therapy and occupational therapy
157
371000
3000
06:29
to retrain the nerves in the nervous system
158
374000
3000
06:32
to respond normally
159
377000
3000
06:35
to the activities and sensory experiences
160
380000
3000
06:38
that are part of everyday life.
161
383000
2000
06:40
And we support all of that
162
385000
2000
06:42
with an intensive psychotherapy program
163
387000
3000
06:45
to address the despondency, despair and depression
164
390000
3000
06:48
that always accompanies
165
393000
2000
06:50
severe, chronic pain.
166
395000
2000
06:52
It's successful,
167
397000
2000
06:54
as you can see from this video of Chandler,
168
399000
2000
06:56
who, two months after we first met her,
169
401000
2000
06:58
is now doings a back flip.
170
403000
2000
07:00
And I had lunch with her yesterday
171
405000
2000
07:02
because she's a college student studying dance at Long Beach here,
172
407000
3000
07:05
and she's doing absolutely fantastic.
173
410000
2000
07:07
But the future is actually even brighter.
174
412000
4000
07:11
The future holds the promise
175
416000
3000
07:14
that new drugs will be developed
176
419000
2000
07:16
that are not symptom-modifying drugs
177
421000
3000
07:19
that simply mask the problem,
178
424000
2000
07:21
as we have now,
179
426000
2000
07:23
but that will be disease-modifying drugs
180
428000
3000
07:26
that will actually go right to the root of the problem
181
431000
2000
07:28
and attack those glial cells,
182
433000
2000
07:30
or those pernicious proteins
183
435000
2000
07:32
that the glial cells elaborate,
184
437000
3000
07:35
that spill over and cause this central nervous system wind-up,
185
440000
3000
07:38
or plasticity,
186
443000
2000
07:40
that so is capable
187
445000
2000
07:42
of distorting and amplifying
188
447000
2000
07:44
the sensory experience that we call pain.
189
449000
2000
07:46
So I have hope
190
451000
2000
07:48
that in the future,
191
453000
2000
07:50
the prophetic words of George Carlin will be realized,
192
455000
3000
07:53
who said, "My philosophy:
193
458000
2000
07:55
No pain, no pain."
194
460000
3000
07:59
Thank you very much.
195
464000
2000
08:01
(Applause)
196
466000
6000
ABOUT THE SPEAKER
Elliot Krane - Pediatric anesthesiologistAt 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.
Elliot Krane | Speaker | TED.com