Diagnostic accuracy of the 5.07 monofilament test for diabetes polyneuropathy: influence of age, sex, neuropathic pain and neuropathy severity.

INTRODUCTION: There is a need for simple and cheap diagnostic tools for diabetic polyneuropathy (DPN). We aimed to assess the diagnostic accuracy of the 5.07/10 g monofilament test in patients referred to polyneuropathy assessments, as well as to examine how disease severity, age, sex and neuropathic pain (NP) impact diagnostic accuracy. RESEARCH DESIGN AND METHODS: Five Norwegian university hospitals recruited patients with diabetes aged 18-70 referred to neurological outpatient clinics for polyneuropathy assessments. The 5.07/10 g Semmes-Weinstein monofilament examination (SWME) was validated against the Toronto consensus for diagnosing diabetic neuropathies; the results were stratified by age, sex and NP. Disease severity was graded by a combined nerve conduction study (NCS) Z-score, and logistic regression was applied to assess whether disease severity was a predictor of diagnostic accuracy. RESULTS: In total, 506 patients were included in the study. Global sensitivity was 0.60 (95% CI 0.55, 0.66), specificity 0.82 (95% CI 0.75, 0.87), positive and negative predictive values were 0.86 (95% CI 0.81, 0.90) and 0.52 (95% CI 0.46, 0.58), respectively, positive and negative likelihood ratios were 3.28 (95% CI 2.37, 4.53) and 0.49 (95% CI 0.42, 0.57), respectively. The SWME was less sensitive in females (0.43), had lower specificity in patients with NP (0.56), and performed worse in patients ≥50 years. NCS-based disease severity did not affect diagnostic accuracy (OR 1.15, 95% CI 0.95, 1.40). CONCLUSIONS: This multicenter study demonstrates poor diagnostic performance for the 5.07/10 g SWME in patients with diabetes referred to polyneuropathy assessments; it is particularly unsuited for female patients and those with NP. The diagnostic accuracy of the SWME was not influenced by NCS-based disease severity, demonstrating that it does not perform better in patients with later stages of DPN. We do not recommend the use of the 5.07/10 g monofilament in the evaluation of patients with diabetes referred to polyneuropathy assessments.

Accuracy of neuropathic pain measurements in patients with symptoms of polyneuropathy: validation of painDETECT, Self-Completed Leeds Assessment of Neuropathic Symptoms and Signs, and Douleur Neuropathique 4.

ABSTRACT: Pain is a common symptom in patients referred to polyneuropathy assessment. Diagnostic evaluation and choice of treatment may depend on whether the pain is likely to be neuropathic or not. This study aimed to investigate the diagnostic accuracy of 3 tools commonly used to differentiate between neuropathic and nonneuropathic pain. To accomplish this, we included patients with bilateral distal lower extremity pain, referred to neurological outpatient clinics at 5 Norwegian University hospitals for polyneuropathy assessment. The patients filled in Norwegian versions of painDETECT, the Self-Completed Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), and the clinician-rated Douleur Neuropathique 4 (DN4). All patients underwent a clinical examination and nerve conduction measurements and were classified according to the NeuPSIG neuropathic pain criteria (reference standard). In total, 729 patients were included, of which 63% had neuropathic pain by the reference standard. Only DN4 demonstrated high sensitivity (0.87), whereas all 3 tools had low specificity (≤0.65). Importantly, the tools' predictive ability was unsatisfactory; The probability of getting a correct test result was 3 quarters at best, and at worst, no better than two fifths. Consequently, we show that neither DN4, painDETECT, nor S-LANSS can be confidently used to assess neuropathic pain in a neurological outpatient population with symptoms of polyneuropathy.

Case report: Pain in anti-DPPX encephalitis.

Encephalitis due to antibodies targeting dipeptidyl-peptidase-like protein 6 (DPPX), a potassium channel subunit, is rare. The illness is typically characterized by a triad of weight loss, CNS hyperexcitability and cognitive symptoms, but recent reports suggest that the clinical picture may be more heterogeneous. Here, we describe the case of a 63-year-old female who was admitted to the hospital with severe extremity pain, which had been preceded by diarrhea and weight loss. She later developed cognitive changes, and her general condition rapidly deteriorated. Extensive workup did not reveal gastrointestinal illness or underlying malignancies. MRI of the brain was normal. Analyses of blood and cerebrospinal fluid showed normal cell counts but high titres of DPPX antibodies in blood and cerebrospinal fluid. The patient was treated with intravenous methylprednisolone followed by rituximab. At 1-year follow-up, she was without pain and had completely recovered. In this case, DPPX-associated autoimmune encephalitis was dominated by severe extremity pain, illustrating that sensory symptoms may be one of the main complaints in these patients. It is important for clinicians to be aware of the heterogeneous clinical picture in this serious condition, since correct diagnosis and treatment with immunosuppressants are associated with favorable prognosis.

Combined variants in reading epilepsy; coexisting anterior and posterior variants camouflaged as heat cramps where the patient finds his own diagnosis searching the internet.

Reading epilepsy is a form of reflex-induced seizures. Two entities are postulated as part of a clinical spectrum; one anterior variant with jaw jerks and orofacial myoclonia and another posterior variant with visual symptoms and alexia or dyslexia. We present a case with suggestible evidence of both conditions coexisting within the same patient, a finding that, to our knowledge, has not been previously reported. The diagnosis in this specific case was contributed to by the patient searching the internet.

Insulin-induced hypoglycemia stimulates gastric vagal activity and motor function without increasing cardiac vagal activity.

BACKGROUND/AIMS: We investigated whether increasing the efferent vagal activity by insulin-induced hypoglycemia would enhance gastric emptying and volumes in healthy subjects. METHODS: Twenty healthy volunteers (10 males) were examined with and without vagal stimulation by insulin-induced hypoglycemia using a glucose clamp technique. Stomach function was tested by drinking meat soup (0.04 kcal ml(-1)) at a rate of 100 ml min(-1) until maximal capacity. Intragastric volume at maximal drinking capacity was determined by three-dimensional ultrasound. Respiratory sinus arrhythmia (RSA) was used as an index of cardiac vagal activity and plasma pancreatic polypeptide (PP) as a measure of gastric vagal activity, and skin conductance (SC) as a measure of sympathetic tone. RESULTS: Insulin-induced hypoglycaemia increased drinking capacity (p = 0.002), gastric emptying (p = 0.02), PP (p = 0.004) and SC (p = 0.004), while intragastric volume was unchanged (p = 0.7) and RSA decreased (p = 0.03). CONCLUSION: Enhancement of gastric vagal activity by insulin-induced hypoglycemia increased drinking capacity and gastric emptying similarly, resulting in an unchanged intragastric volume. Enhanced efferent vagal activity to the stomach (as measured by PP) was not associated by enhanced cardiac vagal activity (as measured by RSA), possibly a consequence of stress-induced sympathetic activation during the procedure.