Process of Diagnosis of diabetic neuropathy Sanjeev Kelkar Secretary DFSI

Process of Diagnosisof diabetic neuropathy Sanjeev Kelkar Secretary DFSI

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

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

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

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,

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

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?

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

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

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

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

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

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

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

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

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

Process of Diagnosis of diabetic neuropathy Sanjeev Kelkar Secretary DFSI