Diabetic Neuropathy - Diagnosis

Examination - updated: 15 March 2008

Symptoms

• Numbness (decreased or lost sensation to a body part)
• Diarrhea
• Constipation
• Loss of bladder control
• Impotence
• Facial drooping
• Drooping eyelid
• Drooping mouth
• Vision changes
• Dizziness
• Weakness
• Swallowing difficulty
• Speech impairment
• Muscle cramps

Signs and Tests

Physical examination, including neurological and sensory tests, may reveal many neuropathies. A common early finding is the absence of ankle reflexes.Health care providers often test for loss of sensation in the feet with a brush-like instrument called a monofilament.

How to better systematize the diagnosis of neuropathy?

Diabetes Metab. 2006 Sep;32(4):367-72

Gin H, Perlemoine C, Rigalleau V.

Two attitudes can be proposed, one consisting of making a diagnosis of neuropathy, the other seeking to grade the stage that it has reached in order to give a prognosis and above all determine the right way in which to educate the patient. In order to do this, it is important for the diagnosis to be thorough. It should be based both on listening to what the patient has to say and examining him/her. It is vital to listen to the patient because the warning signs are discreet, yet very evocative, and they will be a great help in making a positive diagnosis. They should not be confused with signs of arterial damage. They should then be interpreted by means of clinical examination and the tools that are available, i.e. essentially monitoring the osteo-tendinous reflexes and sensory signs. The sensory signs can only be studied with high-quality instruments, i.e. either a monofilament of proven technical quality and that should be used with care in line with good clinical practice recommendations, or by using a graduated tuning fork, or a neuroesthesiometer which will make it possible to obtained graduated responses, not simply binary responses of the "yes/no" variety. A whole series of scores have been put forward combining both functional and physical signs, making it possible to try to quantify the stage reached and the extent of the neuropathy. It is only by using a thorough and regularly applied routine that we can progress to establishing

Publication Types:

• Review

Validation of a novel screening device (NeuroQuick) for quantitative assessment of small nerve fiber dysfunction as an early feature of diabetic polyneuropathy

Diabetes Care. 2005 May;28(5):1169-74.

Ziegler D, Siekierka-Kleiser E, Meyer B, Schweers M.

OBJECTIVE: To validate a handheld screening device (NeuroQuick) for an early detection of diabetic distal symmetric polyneuropathy (DSP) by quantitative testing of cold sensation based on the wind chill factor (NeuroQuick threshold [NQT]). RESEARCH DESIGN AND METHODS: NQT was measured on the dorsum of the foot in 160 healthy subjects as well as 60 and 128 diabetic patients without and with DSP, respectively. DSP was diagnosed by a neurological examination, motor and sensory nerve conduction velocity, vibration perception threshold, and warm and cold thermal perception threshold (TPT) (TPT Medoc). In addition, a C-64 Hz tuning fork and TipTherm device were used as screening instruments. RESULTS: In the diabetic cohort, NQT correlated significantly with all nerve function tests, with the highest correlation coefficients being found on the foot versus Medoc warm TPT (r = 0.618, P < 0.001) and cold TPT (r = 0.529, P < 0.001). Among patients with DSP, NQT was abnormal, whereas Medoc warm TPT was normal in 34%, whereas only 5% showed the opposite constellation (P < 0.05). Likewise, the corresponding percentages for Medoc cold TPT were 32 and 11%, for TipTherm 47 and 2%, and for the tuning fork 29 and 10% (all P < 0.05), whereas no significant differences were noted when comparing NQT with peroneal motor nerve conduction velocity, sural sensory nerve conduction velocity, and malleolar vibration perception threshold. The coefficients of variation for repeated NQT measurements in 41 control and 41 diabetic subjects were 20.4 and 8.5%, respectively. CONCLUSIONS: The NeuroQuick is a valid and reliable screening tool for quantitative assessment of small nerve fiber dysfunction. This device appears to be more sensitive in detecting early diabetic polyneuropathy than both elaborate thermal testing and screening tests such as the tuning fork.

The LDIflare: a novel test of C-fiber function demonstrates early neuropathy in type 2 diabetes

Diabetes Care. 2004 Dec;27(12):2930-5

Krishnan ST, Rayman G.

OBJECTIVE: The aim of this study was to evaluate a novel method for assessing the axon reflex and to determine its value in detecting neuropathy in type 2 diabetes. RESEARCH DESIGN AND METHODS: The neurogenic flare response to nociceptive stimuli is mediated by an axon reflex involving small unmyelinated C-fibers. We developed a method to assess this reflex involving skin heating to 44 degrees C to evoke the flare followed by scanning the site using a laser Doppler imager (LDI) to measure the area; we termed this method LDIflare. To confirm its neurogenic nature, we examined the LDIflare in eight healthy subjects before and after topical administration of anesthesia. We used this technique to detect C-fiber neuropathy in people with type 2 diabetes. A total of 36 subjects were studied: 12 subjects with neuropathy (group DN), 12 subjects without neuropathy (group DC), and 12 age- and sex-matched control subjects (group NC). For comparison, small-fiber function was also assessed using the Computer Aided Sensory Evaluator-IV (CASE IV) (WR Medical Electronics, Stillwater, MN). RESULTS: In the eight healthy control subjects, LDIflare was markedly reduced after topical administration of anesthesia (1.62 [1.45-1.72] vs. 5.2 cm2 [3.9-5.9], P <0.0001), confirming its neurogenic nature. Similarly, in neuropathic subjects, LDIflare was significantly smaller compared with normal and diabetic control subjects (LDIflare area: DN 1.3 cm2 [0.9-1.8], NC 5.5 cm2 [3.9-5.8], and DC 2.8 cm2 [2.5-3.8]; P <0.0001 and P=0.01, respectively). The group without neuropathy (DC) also demonstrated a reduced flare compared with the NC group (P=0.01). In contrast, C-fiber function assessed by evaluating the quantitative thermal thresholds (CASE IV) did not detect a difference between the latter two groups. CONCLUSIONS: This study confirms the neurogenic nature of the LDIflare and clearly demonstrates loss of C-fiber function in neuropathic subjects with type 2 diabetes. Moreover, it demonstrates C-fiber dysfunction before its detection by other currently available methods, including CASE IV. The LDIflare seems to be a simple objective method to detect early neuropathy and may be of value in assessing therapeutic interventions aimed at preventing or reversing C-fiber dysfunction.

The Rochester Diabetic Neuropathy Study

NEUROLOGY 1992;42:1164

P. J. Dyck, MD, J. L. Karnes, MS, P. C. O'Brien, PhD, W. J. Litchy, MD, P. A. Low, MD and L. J. Melton, III, MD

We evaluated the initial assessments of the 380 diabetic patients with and without polyneuropathy in the Rochester Diabetic Neuropathy Study for (1) associations among neuropathy test results, (2) usefulness of different tests for diagnosing and staging polyneuropathy, (3) appropriateness of different minimal criteria for the diagnosis of polyneuropathy, and (4) significant differences in test results with increasing stage of polyneuropathy. Nerve conduction ([NC]; abnormality in two or more nerves) and quantitative autonomic examination ([QAE]; decreased heartbeat response to deep breathing [DB] or the Valsalva maneuver [VAL]) were the most sensitive and objective and were especially suitable for detection of subclinical neuropathy. We propose the following minimal criteria for the diagnosis of diabetic polyneuropathy: =" src="/math/ges.gif" border=0 abnormal evaluations (from among neuropathic symptoms, neuropathic deficits, NC, quantitative sensory examination [QSE], and QAE) with one of the two being abnormality of NC or QAE (DB or VAL). Neuropathy Symptom Score, Neuropathy Disability Score, QSE (vibratory or cooling detection threshold), and summated compound muscle action potential of ulnar, peroneal, and tibial nerves were best for judging severity. Inability to walk on heels provided a discrete separation of diabetic patients into those with mild and those with more severe neuropathy—a separation helpful in staging.

Publication Types:

• Review