1 Assessing Sensory Neuropathy Assessing Sensory Neuropathy Sanjeev Kelkar Conjoint Lecturer Faculty of health University of Newcastle Australia

2 MotorSensoryAutonom Myelinated Thinly myelinated Un- myelinated Thinly myelinated Un- myelinated A  A  /  A  C A  C LARGE SMALL Muscle control Touch, vibration, position perception Cold perception, pain Warm perception, pain Heart rate, blood pressure, sweating, GIT function A simplified view of the peripheral nervous system. GIT, gastrointestinal tract.

3 Clinical presentation of large-fibre neuropathies Clinical presentation of large-fibre neuropathies Impaired vibration perception (often the first objective evidence) and position sense. Impaired vibration perception (often the first objective evidence) and position sense. Depressed tendon reflexes. Depressed tendon reflexes. A  type deep-seated gnawing, dull, like a toothache in the bones of the feet or even crushing or cramp-like pain. A  type deep-seated gnawing, dull, like a toothache in the bones of the feet or even crushing or cramp-like pain.

4 Clinical presentation of large-fibre neuropathies Clinical presentation of large-fibre neuropathies Sensory ataxia (waddling like a duck) Sensory ataxia (waddling like a duck) Wasting of small muscles of feet with hammertoes (intrinsic minus feet and hands) with weakness of hands and feet. Wasting of small muscles of feet with hammertoes (intrinsic minus feet and hands) with weakness of hands and feet. Shortening of the achilles tendon with pes equinus. Shortening of the achilles tendon with pes equinus. Increased blood flow (hot foot). Increased blood flow (hot foot).

5 Need to Detect, Quantify and Prevent Neuropathy In Diabetes. Foot Ulceration GangreneAmputation

6 Androclese and the lion After identifying lions foot/paw problem, Androcleas removed the thorn in his paw. Treated his ulcers and may be they lived happily ever after…….!!!! After identifying lions foot/paw problem, Androcleas removed the thorn in his paw. Treated his ulcers and may be they lived happily ever after…….!!!!

7 Pay back All patients of diabetes of some duration need testing. Every third person is likely to be a neuropathic. We must know his relative risk to prevent ulceration A worthwhile investment, likely to pay back more than usual. Androcleas says every third lion diabetic has the painless thorn of neuropathy. He needs quantification. The third Lion

8 Factors and markers of low-risk versus high- risk diabetic feet Low-risk foot High-risk foot All of the following: One or more of the following: following: Intact protective sensation Loss of protective sensation sensation Pedal pulses present Absent pedal pulses No severe deformity Significant foot deformity deformity

9 Factors and markers of low-risk versus high- risk diabetic feet Low-risk foot High-risk foot All of the following: One or more of the following: following: No prior foot ulcer History of foot ulcer or callus pre-ulcerative callus No amputation Prior amputation Normal joint mobility. Limited joint mobility

10 What do we have to assess Neuropathy? Need to assess associated risk of ulceration in a neuropathic Need to distinguish Neuropathic and non neuropathic patients Need to establish wide range of quantitated gradation of sensory deficits for comparison on Follow up Need simple testing equipment

11 Tuning fork - 1 The sensory exam should be done in a quiet and relaxed setting. First apply the tuning fork on the patient’s wrists (of elbow, or clavicula) so that patient knows what to expect. The sensory exam should be done in a quiet and relaxed setting. First apply the tuning fork on the patient’s wrists (of elbow, or clavicula) so that patient knows what to expect. The patient must not be able to see if and where the examiner applies the tuning fork. The tuning fork is applied on a bony part on the dorsal side of the distal phalanx of the first toe. The patient must not be able to see if and where the examiner applies the tuning fork. The tuning fork is applied on a bony part on the dorsal side of the distal phalanx of the first toe. It should be applied perpendicularly with a constant pressure. It should be applied perpendicularly with a constant pressure.

12 Tuning fork - 2 Repeat this applications twice, but alternate this with at least one “sham” application, in which the tuning fork is not vibrating. Repeat this applications twice, but alternate this with at least one “sham” application, in which the tuning fork is not vibrating. The test is positive if the patient correctly answered at least two out of three applications, and negative (at risk for ulceration) with two out of three incorrect answers. The test is positive if the patient correctly answered at least two out of three applications, and negative (at risk for ulceration) with two out of three incorrect answers. If the patient is unable to sense the vibrations at the big toe, the test is repeated more proximally (malleolus, tibial tuberositas). If the patient is unable to sense the vibrations at the big toe, the test is repeated more proximally (malleolus, tibial tuberositas). Encourage the patient during testing. Encourage the patient during testing.

13 Vibration perception assessed with 128 Hz tuning fork

14 The Rydel Seiffer tuning fork : An inexpensive device for screening diabetic patients with high risk foot. Vijay Viswanathan et al. Pract. Diab. Int.(In print). It is a 128HZ graduated tuning fork which allows quantifiable assessment of vibration perception in the feet of diabetic patients.

15 Differing methods to measure VPT Method Technique Usefulness 128-Hz tuning fork Sensation normal(cf.hand/ Only to detect presence forehead,reduce or absent or absence of neuropathy Reidell-Seiffer graduated tuning fork Ascending method Coefficient of variation compares (Firma Martin, favorably with more complex Tuttlingen, Germany) techniques below Biothesiometer (Biomedical Instrument Ascending method Largely superseded by Newbury, OH) Neurothesiometer Neurothesiometer (Arnold Howrwell, Ascending method Currently most widely used. London) Interobserver and intersubje coefficient of variation ~ 10%.

16 Pressure perception assessed with 5.07/10g Semmes- Weinstein monofilament. Plantar aspect of first and fifth metatarso- phalageal joints gives best sensitivity (80%) and specificity (86%) (McGill.M et al, 1999 – Diabetes Care)

17 In an recent study in an outpatient clinic, which examined the reproducibility of screening using a monofilament, biothesiometer and palpation of pedal pulses, only the monofilament gave adequately reproducible results (over 85%) for measurements repeated after 2 weeks. In an recent study in an outpatient clinic, which examined the reproducibility of screening using a monofilament, biothesiometer and palpation of pedal pulses, only the monofilament gave adequately reproducible results (over 85%) for measurements repeated after 2 weeks. [Klenerman L, et al. Diabet Med 1996].

18 Detection of neuropathy Identification of neuropathy based on insensitivity to a 10 gm (5.07) nylon monofilament is convenient and appears to be cost-effective. Identification of neuropathy based on insensitivity to a 10 gm (5.07) nylon monofilament is convenient and appears to be cost-effective. [Gadsby R, McInnes A. Diabet Med 1998]

19 Semmes-Weinstein monofilament - 1 Sensory examination should be done in a quiet and relaxed setting. First apply the monofilament on the patient’s hands (or elbow, or forehead) so the patients know what to expect. Sensory examination should be done in a quiet and relaxed setting. First apply the monofilament on the patient’s hands (or elbow, or forehead) so the patients know what to expect. The patient must not be able to see if and where the examiner applies the filament. The three sites to be tested on both feet are indicated. The patient must not be able to see if and where the examiner applies the filament. The three sites to be tested on both feet are indicated.

20 Semmes-Weinstein monofilament - 2 Apply the monofilament perpendicular to the skin surface. Apply the monofilament perpendicular to the skin surface. Apply sufficient force to cause the filament to bend or buckle. Apply sufficient force to cause the filament to bend or buckle. The total duration of the approach, skin contact, and removal or the filament should be approximately 2 seconds. The total duration of the approach, skin contact, and removal or the filament should be approximately 2 seconds.

21 Semmes-Weinstein monofilament - 3 Semmes-Weinstein monofilament - 3 Apply the filament along the perimeter of and not on an ulcer site, callus, scar or necrotic tissue. Do not allow the filament to slide across the skin or make repetitive contact at the test site. Apply the filament along the perimeter of and not on an ulcer site, callus, scar or necrotic tissue. Do not allow the filament to slide across the skin or make repetitive contact at the test site. Press the filament to the skin and ask the patient IF they feel the pressure applied (yes/no) and next WHERE they feel the pressure applied (left/right foot). Press the filament to the skin and ask the patient IF they feel the pressure applied (yes/no) and next WHERE they feel the pressure applied (left/right foot).

22 Semmes-Weinstein monofilament – 4 Semmes-Weinstein monofilament – 4 Repeat this application twice at the same site, but alternate this with at least one “sham” application, in which no filament is applied (total three questions per site). Repeat this application twice at the same site, but alternate this with at least one “sham” application, in which no filament is applied (total three questions per site). Protective sensation is present at each site if the patients correctly answers two out of three applications. Protective sensation is absent with two out of three incorrect answers, and the patient is then considered to be at risk of ulceration. Protective sensation is present at each site if the patients correctly answers two out of three applications. Protective sensation is absent with two out of three incorrect answers, and the patient is then considered to be at risk of ulceration. Encourage the patients during testing. Encourage the patients during testing.

23 Monofilaments to detect the foot at risk, That too for multiple use. Up to five patients can be tested with one Monofilament

24 Semmes-Weinstein monofilament - 5 Semmes-Weinstein monofilament - 5 Monofilament: When applied perpendicular to the foot it buckles at a force of 10 gms, tests touch & pressure Areas to be tested - metatarsal heads of first, third and fifth and the plantar surface of heel.

25 Semmes-Weinstein monofilament - 5 Semmes-Weinstein monofilament - 5 The validity of SW monofilament for predicting the neuropathy by nerve conduction study criteria are confirmed by Perkins BA, 2001, The validity of SW monofilament for predicting the neuropathy by nerve conduction study criteria are confirmed by Perkins BA, 2001,

26 Semmes-Weinstein monofilament - 5 Semmes-Weinstein monofilament - 5 SW Monofilament has a Sensitivity 77%, specificity 98% with a + ve and – ve likelihood ratios of 10.2 and 3.4 respectively for 4 to8 imperceptible stimuli on great toe bilaterally. (Perkins, BA 2001) SW Monofilament has a Sensitivity 77%, specificity 98% with a + ve and – ve likelihood ratios of 10.2 and 3.4 respectively for 4 to8 imperceptible stimuli on great toe bilaterally. (Perkins, BA 2001)

27 Semmes-Weinstein monofilament - 6 Semmes-Weinstein monofilament - 6 Monofilaments help classify foot at risk for touch pressure. (5.07/10gms) Diagnosed clinically by reduced sensitivity to 10 g Semmes Weinstein monofilament. and pricking sensation using the Waardenberg wheel or similar instrument testing sensation to light touch and pinprick - Sensitivity 71%

28 Semmes-Weinstein monofilament - 7 Semmes-Weinstein monofilament - 7 Filament not to be applied over the callus The advantage of the assessment with monofilaments is a foot at risk can be decided in 2 seconds and segregated for detailed analysis

29 Semi-Quantitative test for neuropathic assessment Semi-Quantitative test for neuropathic assessment Pricking sensation can be tested by using the Waardenberg wheel or similar instrument testing sensation to light touch and pinprick -