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.

Polyneuropathy in Adolescent Childhood Cancer Survivors: The PACCS Study.

BACKGROUND: Childhood cancer survivors (CCS) are at risk of polyneuropathy due to chemotherapy, but studies in young survivors are scarce and diagnosis is challenging. We aimed to study the presence of polyneuropathy and the possible effect of cumulative doses of chemotherapeutic agents in a representative group of adolescent survivors. METHODS: CCS aged nine to 18 years and age- and sex-matched controls were recruited from the cross-sectional Physical Activity and Fitness among Childhood Cancer Survivors (PACCS) study. CCS with various cancer diagnoses who had ended cancer treatment one year or more before study were included. Polyneuropathy was evaluated clinically and with nerve conduction studies (NCSs) in three motor and five sensory nerves. We used mixed-effects linear regression models to compare CCS and controls, and investigate possible associations between cumulative chemotherapy doses and NCS amplitudes. RESULTS: A total of 127 CCS and 87 controls were included, with 14% CCS having probable or confirmed polyneuropathy. NCS amplitudes were lower in survivors compared with controls in all nerves. The largest mean difference was 3.47 µV (95% confidence interval [CI], 2.18 to 4.75) in the tibial plantar medial sensory and 1.91 mV (95% CI, 0.78 to 3.04) in the tibial motor nerve. The cumulative dose of platinum derivatives was associated with lower tibial motor nerve amplitude (-0.20; 95% CI, -0.35 to -0.04 mV for 100 mg/m2 dose increase) but not in other nerves. We found no significant associations between vinca alkaloids cumulative dose and amplitudes. CONCLUSIONS: CCS without clinical signs or symptoms of polyneuropathy may have subtle nerve affection. The clinical long-term impact of this novel observation should be evaluated in larger, longitudinal studies.

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.

Cryoneurolysis for cervicogenic headache - a double blinded randomized controlled study.

Background and aims Cervicogenic headache (CEH) is a debilitating condition and analgesics have limited effect. Percutaneous cryoneurolysis is thus still in use although the clinical evidence is lacking. We present a randomized, controlled study to assess the clinical efficacy of cryoneurolysis compared with a corticosteroid combined with a local anaesthetic. Methods In a university-based outpatient pain clinic we performed a randomized, double blinded, comparative study with an 18-week follow-up. After positive diagnostic test blocks 52 eligible patients were randomly allocated in a ratio of 3:2, 31 participants to occipital cryoneurolysis and 21 participants to injections of 1 mL methylprednisolone 40 mg/mL (Depo-Medrol®) combined with 1 mL bupivacaine 5 mg/mL. Results We observed a significant pain reduction of more than 50% in both treatment groups, slightly improved neck function and reduced number of opioid consumers. After 6-7-weeks, however, pain intensity increased gradually, but did not reach baseline within 18 weeks. Although cryoneurolysis provided a more prolonged effect, the group differences did not reach statistical significance. Health related quality of life and psychological distress improved minimally. A large number reported minor and transient side effects, but we found no significant group differences. After 18 weeks, 29% rated the headache as much improved, and 12 (24%) somewhat improved, but a large proportion (78%) reported need for further intervention/treatment. Conclusions Cryoneurolysis provided substantial, but temporary pain relief, and the effect was not significantly different from injections of a corticosteroid combined with a local anaesthetic. Participants were selected by a single test block, and the neurolytic procedure was guided by anatomical landmarks and nerve stimulation. A stricter patient selection and an ultrasound-guided technique might have improved the results. Cryoneurolysis provides temporary pain relief not significantly superior to corticosteroid injection, and the results question the value of occipital cryoneurolysis for a chronic pain condition like CEH. Implications Occipital cryoneurolysis may be considered when non-invasive treatments appear insufficient, but only for patients who have responded substantially to test blocks. A risk of local scar and neuroma formation by repeated cryoneurolysis, leading to neuropathic pain has been discussed by other researchers.

A painful foot with diagnostic and therapeutic consequences.

Background A wide range of patients are referred to multidisciplinary pain clinics. An important part of the work-up is a thorough pain analysis that might reveal a specific cause for chronic pain. Method We describe a patient with chronic pain in one foot after a light trauma and repeated surgery. However, careful examination revealed symptoms and clinical finings in both feet. This led to referral to a University Hospital and the diagnosis of a chronic neurologic condition explaining both symptoms and findings. The diagnosis of this condition has implications both for further follow-up for this patient and possibly also other family members. Implications Professionals working in the pain-field should be aware of diagnosis that might partly explain increased pain or complications after surgery.