1362405279 hcp
Post on 21-Jan-2018
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DM and HCP
Early Detection of Heat and Cold Perception in Diabetic Neuropathy Issues and Reasons Dhananjay Kelkar Dhansai Laboratory, Mumbai
Anatomy of Heat, Cold and Pain Perception Small Fibers sub-serve warm cold and
pain sensation – The C fibers C Fibers – Unmyelinated, without
specialized Nerve endings, lying naked in tissues
Distinct from A delta – deep aches and pain
Symptoms 1
Diabetic foot ulcers has great impact on morbidity and mortality of life
First symptoms to appear – pain, hyperesthesia, hyperalgesia, allodynia - that is contact pain
Abnormalities of C fibers supposedly responsible for early occurrence of symptoms
Symptoms 2
Other somatic sensations of pressure, touch, vibration, proprioception are likely as not, not affected at this stage
Makes more sense to detect HC thresholds Early pain and heat hyperalgesia and later
hypoalgesia>Further damage to C fibers Also impairs the warm thermal perceptions (Aron Vinik – Exp Clin Endocrinol Diabetes- 109 (2001) (Suppl 2)
Time of Damage
Other authors have also considered these to be the first fibers to be affected in diabetic neuropathy
(Jamal et al, 1987, Dyck, 1988, Hanson et al, 1992, as quoted by Vinik vide above)
Various symptoms occur when there is on going damage to the nerves initially
Time and Sequence of Damage
Pain of A delta – thinly myelinated is deep seated and gnawing,
Pain of C fibers is described in most vivid terms like burning, bursting, walking on hot pebbles and sand etc
Symptoms occur when structural damage has occurred - not without it
Some More Concerns
Diabetes affects rhythmic vasomotion of small arterioles due to sympathetic damage early in disease,
Loss of warm thermal threshold also occurs early with C fiber damage and correlates significantly to reduced vasomotion
(Vinik – ibid) Exact cause effect or association between
vasomotion and C fiber damage as a time relationship is not established (ibid)
Pathological Evidence
Skin biopsies in persons with Diabetes show – uniform depletion of substance P, CGRP and the cytoplasmic proteins PGP 9.5 for small fiber specificity
(Levy et al, 1992,Wallargren et al, 1995, Lauria et al, 1998,and others)
Glabrous skin of the foot is far more affected by Diabetes than that of hand
Can we do something? Detect early? Of what use? Cost effective? Other benefits? Can we stop progression? Can we reverse abnormalities? Is detection easy?
Can we do something? - 2
Can we stop progression? Can we reverse abnormalities? Enough medical evidence to say
yes to these questions – if the detection is early enough
Malady is – failure of early detection
Can we do something?- 3 Detect early? Yes. Sensitive and simple instrument for
detection, detects heat, cold, heat pain and cold pain thresholds,
Used by many – Further simplified on feedback after field study
Reliable and reproducible thresholds Needs grasp of the working of the instrument
Can we do something? - 4 Cost effective? Needs time, about 15 to 20 minutes of
technician, Used carefully – no maintenance cost, after sales service, no consumables required etc;
Can we do something? - 5 Other benefits? Indicates simultaneous
possibility of Autonomic dysfunction
Acts as motivator for better glucose control
Tissue Damage Heat pain threshold range is 42
to 45 0C Erythema takes place after an
hour at 45 0C Needs 10 second to a minute at
50 0C And just One second at 55 0C
A Little Physiology - 1 C fibers carry sensations slower, have a
period of latency of about 500 milliseconds before the impulse gets initiated
Consequently there is a further delay in reaching the sensation to the cortical areas as the velocities are slow, therefore
There is a further delay for the registration of the sensation and response to it
A Little Physiology - 2 These factors dictate the working of he
instrument These factors determine the rise of
temperature in degrees as well as the time taken to change the level of temperature
Applies also to the rate of fall of temperature in time
A Little Physiology - 3
A rate of one degree per second is generally recommended
For heat and cold thresholds the rate of rise or fall of temperature seems best at 1 degree Celsius over 4 seconds
This makes testing a little longer but gives precise thresholds, reduces the need for many readings, averaging etc
Needed
Early detection Early detection of the early
fibers that are affected HCP is an answer
Sensitometer-HCP Made in India
HCP Probe
A Little Physiology - 4
Concept of heat pain and cold pain should be understood; these thresholds are higher and lower than heat and cold respectively
Cool pain is sensation of coolness with an additional component of un-comfort
Heat pain is warmth plus pricking sensation It is the slight un-comfort and not, not the
ability to bear
A Little Physiology - 5 The rate of rise or fall of temperature to
detect Heat pain & Cool Pain also seems best at 1 degree Celsius over 4 seconds
Two additional thresholds make testing a little longer but gives precise thresholds,
Only cool and heat pain thresholds are enough for clinical practice
Operation of the instrument 1
Operation of the instrument 2
Normal range 32 to 34 oC is neutral zone Just bellow 32 oC & up to 30 oC is the Cool
threshold range -age dependant 27 to 25 oC Cool pain 36 to 38 oC warm And 42 to 45 oC Heat pain zone Above ranges are true for clinical practice in
an ambiant temperature of 27 to 37 oC
Other featchers It can be operated through PC Report can be generated through PC Data can be stored and retrieved for
future use Data can be picked by hospital/clinic
management system as well
Thank you for a patient hearing
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