The utility of a point-of-care sural nerve conduction device for detection of diabetic polyneuropathy: A cross-sectional study

Introduction: Rapid and accessible methods for diagnosing diabetic polyneuropathy (DPN) have been developed, but not validated, in large cohorts of people with diabetes. Methods: The performance of a point-of-care device (POCD) was studied in 168 patients with type 2 diabetes, estimating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) compared with conventional sural nerve conduction studies (NCS). Results: A POCD amplitude limit of 6 µV increased the sensitivity (96%) and NPV (98%), but decreased the specificity (71%) and PPV (54%) compared with the 4-µV limit, which had values of 78%, 92%, 89%, and 71%, respectively. POCD on both legs showed better performance than on 1 leg. POCD amplitudes and conduction velocities correlated significantly with conventional sural NCS, but POCD values were underestimated compared with NCS. Discussion: The POCD may be used as a suitable screening tool for detection of DPN. Patients with abnormal and borderline results should undergo conventional NCS. Muscle Nerve 59 :187–193, 2019     

Intravenous lidocaine relieves spinal cord injury pain: a randomized controlled trial

BACKGROUND: Neuropathic pain in spinal cord injury is a common challenging therapeutic condition. The current study examines the analgesic effect of the sodium channel blocker lidocaine on neuropathic pain in patients with spinal cord injury and the predictive role of concomitant evoked pain on pain relief with lidocaine. METHODS: Twenty-four spinal cord injury patients with neuropathic pain at or below the level of injury were randomized and completed a double-blind crossover trial of 5 mg/kg lidocaine and placebo infused over 30 min. Twelve patients reported evoked pain, and 12 patients had no evoked pain. Spontaneous and evoked pains were assessed using a visual analog scale and quantitative sensory testing. RESULTS: Lidocaine significantly reduced spontaneous pain in all patients (P < 0.01) and in each of the two groups with (P < 0.01) and without (P = 0.048) evoked pain, with no difference in number of responders (pain reduction > or = 33%) between the patients with (n = 6) and without (n = 5) evoked pain. Lidocaine significantly relieved both at-level and below-level neuropathic pain and decreased brush-evoked dysesthesia but not cold allodynia, pinprick hyperalgesia, or pain evoked by repetitive pinprick. CONCLUSIONS: Lidocaine reduced neuropathic pain at and below the level of injury irrespective of the presence or absence of evoked pain. Results are consistent with a central-acting effect of sodium channel blockers acting on neuronal hyperexcitability. Agents (such as anticonvulsants or antiarrhythmics) with sodium channel-blocking properties may be a treatment option for spinal cord injury pain.     

Mitral or aortic regurgitation: quantification of regurgitant volumes with cine MR imaging

A new, rapid magnetic resonance (MR) imaging method, cine MR imaging, was used to determine the regurgitant fraction (RF) in patients with left-sided regurgitant lesions. Right and left ventricular stroke volumes were determined with cine MR imaging and a modified Simpson formula in ten healthy volunteers and 23 patients known to have either predominant mitral (n = 17) or aortic (n = 6) regurgitation. RFs evaluated at cine MR imaging were compared in healthy persons and patients with mild, moderate, or severe regurgitation demonstrated at angiography (n = 10) and Doppler echocardiography (n = 13). Cine MR imaging depicted regurgitant blood flow in all 29 regurgitant lesions in 23 patients as areas of low signal intensity within the regurgitant chamber. The RF was 4% +/- 7% in healthy subjects and 12% +/- 12% in those with mild, 35% +/- 14% in those with moderate, and 63% +/- 5% in those with severe regurgitation. The RFs determined by two observers were similar.     

Intravesical therapy of noninvasive bladder tumors (stage Ta) with doxorubicin: initial treatment results and the long-term course

A total of 64 consecutive patients with noninvasive bladder tumors (stage Ta) between 1977 and 1983 underwent treatment with intravesical instillation of doxorubicin. The total response rate was 85 per cent and 57 per cent of the patients had a complete response after 16 weekly instillations. Half of the patients with a complete response had recurrences within 12 to 16 months. Ten per cent of all patients had an invasive tumor during the observation period. We conclude that doxorubicin can render some patients with noninvasive bladder tumors (stage Ta) free of disease but there currently is nothing to indicate that the same results could not be obtained by transurethral resection.     

Antidepressants in the treatment of neuropathic pain

Neuropathic pain is due to lesion or dysfunction of the peripheral or central nervous system. Tricyclic antidepressants and anticonvulsants have long been the mainstay of treatment of this type of pain. Tricyclic antidepressants may relieve neuropathic pain by their unique ability to inhibit presynaptic reuptake of the biogenic amines serotonin and noradrenaline, but other mechanisms such as N-methyl-D-aspartate receptor and ion channel blockade probably also play a role in their pain-relieving effect. The effect of tricyclic antidepressants in neuropathic pain in man has been demonstrated in numerous randomised, controlled trials, and a few trials have shown that serotonin noradrenaline and selective serotonin reuptake inhibitor antidepressants also relieve neuropathic pain although with lower efficacy. Tricyclic antidepressants will relieve one in every 2-3 patients with peripheral neuropathic pain, serotonin noradrenaline reuptake inhibitors one in every 4-5 and selective serotonin reuptake inhibitors one in every 7 patients. Thus, based on efficacy measures such as numbers needed to treat, tricyclic antidepressants tend to work better than the anticonvulsant gabapentin and treatment options such as tramadol and oxycodone, whereas the serotonin noradrenaline reuptake inhibitor venlafaxine appears to be equally effective with these drugs and selective serotonin reuptake inhibitors apparently have lower efficacy. Head-to-head comparisons between antidepressants and the other analgesics are lacking. Contraindications towards the use of tricyclic antidepressants and low tolerability in general of this drug class--may among the antidepressants--favour the use of the serotonin noradrenaline reuptake inhibitors. A recent study on bupropion, which is a noradrenaline and dopamine uptake inhibitor, indicated a surprisingly high efficacy of this drug in peripheral neuropathic pain. In conclusion, antidepressants represent useful tools in neuropathic pain treatment and must still be considered as first line treatments of neuropathic pain. However, without head-to-head comparisons between antidepressants and other analgesics, it is not possible to provide real evidence-based treatment algorithms for neuropathic pain.     

Oral capsules of tetra-hydro-cannabinol (THC), cannabidiol (CBD) and their combination in peripheral neuropathic pain treatment

Background

Cannabinoids are often prescribed for neuropathic pain, but the evidence-based recommendation is ‘weak against’.

Objectives

The aim was to examine the effect of two cannabinoids and their combination in peripheral neuropathic pain.

Methods

This was a randomized, double-blind, trial with treatment arms for cannabidiol (CBD), tetra-hydro-cannabinol (THC), CBD and THC combination (CBD/THC), and placebo in a 1:1:1:1 ratio and flexible drug doses (CBD 5–50 mg, THC 2.5–25 mg, and CBD/THC 5 mg/2.5 mg–50 mg/25 mg). Treatment periods of 8-week duration were proceeded by 1 week for baseline observations. Patients with painful polyneuropathy, post-herpetic neuralgia and peripheral nerve injury (traumatic or surgical) failing at least one previous evidence-based pharmacological treatment were eligible for inclusion. The primary outcome was the change in weekly average of daily pain measured with a numeric rating scale (NRS). Trail Making Test (TMT) was used as one of the tests of mental functioning.

Results

In all, 145 patients were included in the study of which 118 were randomized and 115 included in the intention-to-treat analysis. None of the treatments reduced pain compared to placebo (p = 0.04–0.60). Effect sizes as estimated in week 8 (positive values worse and negative better than placebo) were CBD mean 1.14 NRS points (95% CI 0.11–2.19), THC 0.38 (CI −0.65 to 1.4) and CBD/THC −0.12 (−1.13 to 0.89).

Conclusions

CBD, THC and their combination did not relieve peripheral neuropathic pain in patients failing at least one previous evidence-based treatment for neuropathic pain.