diagnosing dpn

1. • Process of Diagnosis of diabetic neuropathy
Sanjeev Kelkar
Secretary DFSI

2. Process of Diagnosis
• DIAGNOSING DIABETIC
NEUROPATHY
• ISSUES, VEXATIONS AND
LIMITATIONS
• TECHNIQUES

3. Process of Diagnosis
• Volunteered symptoms – unreliable,
insensate feet will have no complaints
• Tallying from case records – likely to have
been missed / may not have been asked
• NSS - Neuropathic Symptom Score –
Should be asked from a check list –
1 point given to each either present or
absent, severity of symptoms does not count

4. Process of Diagnosis
• Profiling Neuropathic Symptoms
Not useful in DPN, the technique is at
variance with other techniques
• Assessing severity of and change in the
neuropathic symptoms
Done on visual analogue pain scale

5. Assessing Severity
• Descriptive terms are used, symptoms
cluster around descriptive terms,
eg; Pain, burning parasthesias, numbness,
these terms need to be explained to the
patients;
• Intensity - absent, slight, moderate, severe,
• Frequency – occasional, frequent,
continuous,

6. Assessing Severity
• Interpretation of symptoms subjective,
mixed, hence unreliable
• Maximum points 0 to 14.64
• Descriptive terms are given visual analogue
scale giving rise to graphic rating

7. Assessing Severity
• Neuropathic Symptom Change (NSC) –
recommended by Dyke and Thomas
• NSC – change and severity – better measures to
detect worsening or improvement
• NIS, NC, VPT, CASE IV – if changes are large,
all of them move in the same direction, if changes
are small discrepancies occur
• What is NIS?

8. Neuropathic Impairment Score
• It is a single value provided as cut off
• Indicates presence of neuropathy
• Only lower limbs are measured
• Eliminates noise from or dilution of other
normal neurological studies in diabetes eg
upper limbs

9. Neuropathic Impairment Score
• Scoring is NIS LL + 7
• 99th
percentile - 1 point
• 99 to 99.9 percentile - 2 points
• > or = to 99.9 - 3 points

10. Neuropathic Impairment Score
Scoring on QST, Quantitative Sensory
Testing
• < 95 percentile 0 points,
• 95 to 99 percentile 1 point,
• > or = to 99th
to 99.9 percentile 2 points,
• > or = to 99.9 percentile 3 points

11. Sural Nerve Morphometry
Cut sections – quantitative , allows statistical
analysis of even large data sets
Reduces observer bias
Can assess myelinated, unmyelinated fibers,
blood vessels
Adaptable to computerization of image
processing and analysis

12. Sural Nerve Morphometry
On teased fiber technique – Could be normal,
Detects – Excessive myelin irregularities
Segmental, nodal demyelination
Thinly myelinated internodes indicating
remyelination
Focal myelin thickening

13. Sural Nerve Morphometry
On teased fiber technique –
Normally myelinated internodes with
superimposed myelin ovoids indicating
fiber regenration
Several normal proximal internodes adjacent
to arow of myelin ovoids indicating
Wallerian degenration

14. Sural Nerve Morphometry
Objections:
Ovoids mistaken as normal fibers
Myelinated fibers may be non functional
Benefits are not outweighed by the morbidity
and cost o procedure

15. Nerve Endings in Punch
Skin Biopsies
Questionable – how well does it detect all
nerve fibers?
Counted nerve fibers may not be functional
Difficult to correlate what degree of change is
meaningful for a clinical change

16. Conclusion
Neuropathy research is complex,
Choice of method to record data important
Calls for meticulous questioning from well trained
staff
Variable methods, difficulties in comparing with
other studies
limitations of various techniques be known