pain

1. Pain facts – 3
Dr. S. Parthasarathy
MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip.
Software statistics
PhD (physio)
Mahatma Gandhi medical college and research
institute – puducherry, India

2. Referred pain
• Pain perceived at a location other than the
site of the painful stimulus
• What is radiating pain ??
• What is referred pain ??

3. Radiation or referral
• Pain of myocardial infarction is located in the mid or
left side of the chest where the heart is actually
located. The pain can radiate to the left side of the
jaw and into the left arm.
• Referred pain is when the pain is located away from
or adjacent to the organ involved. Referred pain
would be when a person has pain only in their jaw or
left arm, but not in the chest

4. • Confusion still • ISSP does not clarify ??

5. Visceral pain
• Does it respond to clamp??
• No
• Ischemia
• Distension
• Active contractions
• Diffuse, referred, autonomic

6. Organs and site of referred pain

7. Characteristics
1. segmental
Renal colic – loin and scrotum
2. area of referral – tender hyperalgesic,
3. develops after sometime.

8. Mechanisms
• Morley ‘ s theory
• Axon reflex -= Sinclair
• Convergent-projection- Ruch
• Convergence-facilitation
• Hyperexcitability
• Thalamic-convergence

9. Morley ‘ s theory
• It states that the involvement of adjacent
somatic structures caused pain !!
• Simultaneous ?
• Can be the only symptom ?
• Put to disuse

10. Axon reflex theory
• primary sensory
neurones have widely
bifurcating axons and
innervate both
somatic and visceral
targets, thus
obscuring the source
of afferent activity,
and explaining the
segmental nature of
referred sensations.

11. Questions about axon theory
• No such axons
• No explanation to time delay
No explanation to referred hyperalgesia

12. Convergent-projection- Ruch
• visceral and somatic primary sensory
neurones converge onto common spinal
neurones
• This theory proposes that the activity in
ascending spinal pathways is misconstrued as
originating from somatic structures
ready explanation for the segmental nature
but issue of referred hyperalgesia.??

13. convergence-facilitation theory
• viscera were wholly insensitive and therefore that visceral
afferent activity never of itself gave rise to pain.
• He proposed instead that this activity was capable of creating
an “irritable focus” within the spinal cord, so that other,
segmentally appropriate, somatic inputs could now produce
abnormal and, of course, referred pain sensations.
• MacKenzie

14. convergence-facilitation theory
• NO general acceptance, in part because it implicitly
denied the existence of “true” visceral palm.
However, the theory offers an explanation for
referred hyperalgesia and, perhaps, the delay of
referred sensations.
• The concept of an irritable focus has more recently
been resurrected with another label—central
sensitization, which appears to be of major
importance in hyperalgesia from somatic and visceral
structures.

15. Supraspinal – theobald
• interactions at supra spinal levels lead to the
phenomenon.
• But are there separate systems ??

16. What happens if we block area referred
hyperalgesia lost tenderness lost ,
pain- loss – controversial

17. Summary
• Referred pain
• Features
• Theories

18. Phantom pain
• A phantom limb is the sensation that an amputated
or missing limb (even an organ, like the breast) is still
attached to the body and is moving appropriately
with other body parts
• Approximately 60 to 80% of individuals with an
amputation experience phantom sensations in their
amputated limb, and the majority of the sensations
are painful

19. Phantom pain

20. Or simply!!
• Painful sensations experienced in a missing
limb .
• Tooth and eye also possible
• Stump pain is different.

21. • phantom pains can also occur in people who
are born without limbs and people who are
paralyzed.
• So phantom limb, phantom pain, stump pain

22. History
• Ambrose Paire (1510)
• Military surgeon
• First explained
• Mitchell (1979) coined the term – phantom
pain

23. How frequent is it ??
• 4 – 90 %
• Innumerable studies
• Onset
• Usually first week after amputation
• Rarely months to years

24. Where is it ??
• Entire – 6%
• Proximal – 10%
• Distal – around 80 %
• Approx figures changes with duration !!

25. Quality - No proper studies
• Varied –Squeeze ,Clenching toes ,Nails digging
• The missing limb often feels shorter
• feel as distorted
• can be made worse by stress, anxiety, and
weather changes.
• usually intermittent.
• The frequency and intensity of attacks usually
declines with time 70 % ----35 % in 2 years

26. Preamputation pain
• Striking case reports
• Location and character similar –
• Vascular and traumatic amputees
• Pain memory ?
• Melzack (1990) – questioned the fact ??
• CNS lesions made pain disappear

27. Possible no relation
• Military Vs civilian
• Age, side,
• Sex
• Level of amputation

28. Etiology
• Peripheral
• Spinal
• Supraspinal

29. Peripheral
• Irritation in the severed nerve endings (called
"neuromas").
• Gallamine and Local injection
• Percussion of stump – increases pain
• Stump end pathology ends pain ends

30. Spinal and thereon
• Disinhibition of neurons at spinal level
• Nerve injury – sensitization – spinal plasticity
• In his 1989 paper,"Phantom Limbs, The Self
And The Brain“ Melzack proposed the theory
of the "neuromatrix.“

31. Mechanisms
• the experience of the body is created by a wide
network of interconnecting neural structures
• the primary somatosensory cortex undergoes
substantial reorganization after the loss of sensory
input.
• due to this reorganization in the somatosensory
cortex, which is located in the postcentral gyrus, and
which receives input from the limbs and body.
• Stroke the Face – phantom pain

32. Etiology
• Peripheral
• Spinal
• Supraspinal

33. Treatment
• Yes it a form of chronic pain
• Difficult to treat
• 68 treatment , 50 still in use !!
• TENS, massage, acupuncture,capsaicin ECT
• 75% Vs 44 % placebo
• mirror box visual feedback

34. Drugs
• Carbamazepine and newer anticonvulsants
• Antidepressants
• IV calcitonin
• Beta blockers
• Depression or original which is treated ??

35. Invasive techniques
• Stump revisions
• Neuroma excision
• Sympathectomy
• Dorsal root entry – zone lesions
• Spinal stimulation
• Brain stimulation
• Preemptive – role ??

36. What I do
• A very low dose IV ketamine as premed
• Always regional
• Add opioids

37. Villiyanur Ramachandran !!
Statement by an international
phantom pain authority
The fingers were illusory,
but the pain was real

38. If we give pain relief then

39. Is this phantom or real ?
• Thank you all