Toxic effects of epidural analgesia with ropivacaine 0.2% in a diabetic patient

Do you mind the role of spinal sensory block duration in a crucial endocrine disorder of diabetes mellitus? A prospective observational study

OBJECTIVE

Diabetes mellitus, per se, is a global health concern, which is often accompanied by complications such as diabetic neuropathy. This prospective observational study purposed to assess the durations of spinal sensory block and motor blocks in individuals with and without diabetes mellitus who had undergone spinal anesthesia.

METHODS

This study incorporated 80 cases, which were evenly divided into spinal sensory block without diabetes mellitus and spinal sensory block with diabetes mellitus. Various parameters were recorded at different time points, including heart rate, mean arterial blood pressure, SpO2, and spinal block characteristics. Notable measures included maximum spinal sensory block onset time, time to reach the 10th thoracic vertebra (T10), maximal spinal sensory block, time for Bromage scores, and block regression while controlling for age-related variations.

RESULTS

Patients in the diabetic group exhibited extended block durations, with significant differences in heart rate noted at specific time points. Regarding the spinal block characteristics, the "maximum onset of SSB" and the "time to reach the T10" were more prolonged in the SSBwDM without significance. Maximum sensory spinal sensory block did not differ. However, some cases in the SSBwDM displayed blocks extending up to the T6. The times to achieve Bromage motor block scores 1-3 were shorter in SSBwDM and lost significance regarding age. Notably, the regression time was longer in SSBwDM, which held significance for both parameters.

CONCLUSION

Diabetic cases commonly encounter prolonged block durations post-subarachnoid intervention, potentially linked to nerve sensitivity, age-related changes, and glycemic control. As such, attenuated local doses for diabetic neuropathic cases may enhance early mobilization, attenuate thromboembolic events, and expedite gastrointestinal recovery.

[Arachnoiditis following spinal anesthesia-Case report and review of the literature]

A 61-year-old woman underwent a tension-free vaginal tape (TVT) operation due to stress incontinence. After technically difficult spinal anesthesia with two attempts the patient developed symptoms of nerve irritation, complained about neckache and headache and showed signs of agitation. The regimen was shifted to general anesthesia and surgery was performed. Because of postoperatively persistent headache and sensory disturbances an MRI scan of the lumbar spine was performed on the first postoperative day without pathological findings. The patient was able to leave the hospital after 1 week with significant relief of symptoms but 3 weeks later she developed neurocognitive impairment with memory deficits. A second MRI scan of the head now showed signs of disturbance of CSF circulation with hydrocephalus. Treatment was performed with drainage and ventriculoperitoneal shunt. Further evaluation showed a severe, multisegmental arachnoiditis and the patient developed a progressive paraparesis. The patient presented her case for assessment to a commission on medical malpractice 13 months after anesthesia. The commission detected no treatment errors. In connection to the case report a literature review of characteristics and etiologies of chronic adhesive arachnoiditis is given, which is a known but very rare complication of spinal anesthesia or similar procedures.

Effect of ropivacaine on peripheral neuropathy in streptozocin diabetes-induced rats through TRPV1-CGRP pathway

Objective To determine the effect of ropivacaine on peripheral neuropathy in diabetic rats and its possible mechanism.

Methods Forty-eight Sprague–Dawley rats were randomly divided into six groups: nondiabetic control group, nondiabetic group A (0.25% ropivacaine), nondiabetic group B (0.75% ropivacaine), diabetic control group (diabetic peripheral neuropathy (DPN) +artificial cerebrospinal fluid), diabetic group A (DPN+0.25% ropivacaine), and diabetic group B (DPN + 0.75% ropivacaine), with eight rats in each group. Within an hour of the last administration, the sciatic motor nerve conduction velocity (MNCV) of each group was measured, and the morphological changes of rat sciatic nerve were observed by HE, Weil’s staining and electron microscopy. The expression of transient receptor potential vanilloid (TRPV1) in the spinal cord dorsal horn of rats was analyzed by immunohistochemistry, and the expression of Calcitonin gene-related peptide (CGRP) protein in the spinal cord was analyzed by Western blot.

Results Compared with the nondiabetic control group, elevated blood glucose, decreased weight and reduced average mechanical withdrawal threshold (MWT), additionally, the sciatic nerves showed significantly slowed conduction velocity (both P<0.001) and damaged pathological structure, the expression of TRPV1 and CGRP were decreased (both P<0.001) in the diabetic groups. Compared with the diabetic control group, down-regulation of TRPV1 and CGRP in spinal cord was significant for the diabetic groups A and B treated with 0.25 and 0.75% ropivacaine, the higher concentration of ropivacaine correlated with a greater change.

Conclusion Ropivacaine can significantly block sciatic nerve conduction velocity in DPN rats in a concentration-dependent manner, which may be related to the expression of the TRPV1-CGRP pathway.

The role of DRP1 in ropivacaine-induced mitochondrial dysfunction and neurotoxicity

Ropivacaine is a commonly used local anaesthetic, but its side effects remain largely unknown. In the present study, we investigated the side effects of ropivacaine in human neuronal SH-5Y5Y cells. We show that 0.5% and 1% ropivacaine could cause fission-like mitochondrial morphological changes. Ropivacaine exclusively induces mitochondrial fission protein DRP1, generation of ROS and causes mitochondrial dysfunction including decreasing mitochondrial membrane potential, the activity of cytochrome C oxidase and ATP production. The side effects of ropivacaine appear to be dependent on DRP1 expression as silencing of DRP1 in neuronal cells abolishes ropivacaine-induced morphological changes and mitochondrial dysfunction. Silencing of DRP1 prevents ropivacaine-induced cellular LDH release and cell death. Moreover, DRP1-deficient neuronal cells are resistant to ropivacaine-induced apoptosis and silencing of DRP1 rescues the activity of cytochrome C oxidase and cellular ATP production. Collectively, our data indicate that imbalances in mitochondrial dynamics, mitochondrial dysfunction and cell death resulting from ropivacaine are all dependent on DRP1 expression. Our study provides valuable data to assess the safety of ropivacaine.

High glucose and bupivacaine‑induced cytotoxicity is mediated by enhanced apoptosis and impaired autophagy via the PERK‑ATF4‑CHOP and IRE1‑TRAF2 signaling pathways

Bupivacaine has previously been reported to induce neurotoxicity, which is further enhanced by high glucose levels. In the present study, the underlying molecular mechanisms via which bupivacaine induces cytotoxicity under high glucose conditions were investigated in cultured human SH-SY5Y cells. In order to identify the optimal concentrations of glucose and bupivacaine that induced cytotoxicity, SH-SY5Y cells were treated with 30–100 mM glucose and 0.5–1.0 mM bupivacaine. Based on the dose response experiments, 50 mM glucose and 0.5 mM bupivacaine was used in the present study. The effects that 3-MA (autophagy inhibitor) and rapamycin (RAPA; autophagy inducer) exerted on cell apoptosis, autophagy and the expression of protein kinase R-like endoplasmic reticulum kinase (PERK)-activating transcription factor 4 (ATF4)-C/EBP-homologous protein (CHOP) and inositol-requiring enzyme 1 (IRE1)-tumor necrosis factor receptor associated factor 2 (TRAF2) signaling proteins were measured in high glucose and bupivacaine-treated cells. Cell viability was measured using a Cell Counting Kit-8 assay, cell apoptosis was assessed using flow cytometry, and protein expression was determined using western blot analyses. Compared with the control group, high glucose and bupivacaine significantly increased ATF4, CHOP and caspase-12 expression, increased apoptosis, and decreased p-IRE1, TRAF2, LC3-II/LC3-I and Beclin1 expression. Promoting autophagy with RAPA partly reversed the high glucose and bupivacaine-induced changes in p-PERK, CHOP, TRAF2, Beclin1, caspase-12 and apoptosis, while inhibiting autophagy with 3-MA further enhanced the changes in ATF4, CHOP, p-IRE1, TRAF2 and apoptosis. High glucose and bupivacaine induced cytotoxicity in SH-SY5Y cells, at least in part, through enhancing cell apoptosis and inhibiting autophagy via the PERK-ATF4-CHOP and IRE1-TRAF2 signaling pathways.

Severe back pain following epidural analgesia in patients with spinocerebellar ataxia: a report of two cases

Two patients with spinocerebellar ataxia received epidural analgesia with no exacerbation of their symptoms. The patients developed transient, but extremely severe, low back pain as a result of the epidural analgesia.

Repeated Intrathecal Administration of Ropivacaine Causes Neurotoxicity in Rats

Previous studies suggest that ropivacaine causes the least neurotoxicity among local anaesthetics. Most data derive from a single injection of ropivacaine into the subarachnoid space. The histological changes and behavioural effects of repeated intrathecal administration have yet to be studied. We examined the possible neurotoxicity of multiple doses of intrathecal ropivacaine in rats.

Rats received 0.12 ml/kg body weight ropivacaine in normal saline at concentrations of 0.25%, 0.5%, 0.75% and 1.0% at 90-minute intervals via an implanted intrathecal catheter (ID 0.12 mm, OD 0.35 mm) for 48 hours. At L3, the spinal cord and posterior roots were examined by light and electron microscopy. We performed in situ TUNEL assay to evaluate apoptosis in the spinal cord. Sensory threshold to noxious stimulation along with behavioural change were also studied.

Both 0.75% and 1.0% ropivacaine induced neuronal injury characterised by infiltration of inflammatory cells, vacuolation of myelin sheaths and axons, abnormal morphology of neurons and apoptosis in the spinal cord, mainly in posterior roots and the adjacent posterior white matter. Compared to controls, the percentage of maximum possible effect did not show any significant differences between the rats treated with variable concentrations of ropivacaine or tested with either heat or mechanical stimulation. As expected, the recovery time to normal ambulation was prolonged as the ropivacaine concentration was increased.

Ropivacaine can induce neurotoxicity and trigger apoptosis in a dose-dependent manner after repeated intrathecal administration. Although the clinical safety profile of ropivacaine appears favourable compared with other local anaesthetics, it is possible our findings have clinical significance.

In vitro, inhibition of mitogen-activated protein kinase pathways protects against bupivacaine- and ropivacaine-induced neurotoxicity

BACKGROUND

Animal models show us that specific activation of the p38 mitogen-activated protein kinase (MAPK) may be a pivotal step in lidocaine neurotoxicity, but this has not been investigated in the case of two very widely used local anesthetics, bupivacaine and ropivacaine. We investigated the hypotheses that these drugs (A) are less neurotoxic than the prototype local anesthetic, lidocaine (B) are selectively toxic for subcategories of dorsal root ganglion neurons and (C) induce activation of either p38 MAPK or related enzymes, such as the c-jun terminal N-kinase (JNK) and extracellular signal-regulated kinase (ERK).

METHODS

We incubated primary sensory neuron cultures with doses of lidocaine, bupivacaine, and ropivacaine equipotent at blocking sodium currents. Next, we sought to determine potential selectivity of bupivacaine and ropivacaine toxicity on neuron categories defined by immunohistochemical staining, or size. Subsequently, the involvement of p38 MAPK, JNK, and ERK was tested using enzyme-linked immunosorbent assays. Finally, the relevance of MAPK pathways in bupivacaine- and ropivacaine-induced neurotoxicity was determined by selectively inhibiting activity of p38 MAPK, JNK, and ERK.

RESULTS

We found that the neurotoxic potency of bupivacaine and ropivacaine is dose-dependent and similar in vitro, but is not selective for any of the investigated subgroups of neurons. Neurotoxicity of bupivacaine and ropivacaine was mediated, at least in part, by MAPKs. Specifically, we demonstrated the relevance of both p38 MAPK and JNK pathways for the neurotoxicity of bupivacaine and characterized the involvement of the p38 MAPK pathway in the neurotoxicity of ropivacaine.

CONCLUSIONS

Given equipotent doses, the neurotoxic potential of lidocaine does not appear to be significantly different from that of bupivacaine and ropivacaine in vitro. Moreover, bupivacaine and ropivacaine do not exert their neurotoxicity differently on specific subsets of dorsal root ganglion neurons. Their neurotoxic effects are brought about through the activation of specific MAPKs; the specific pharmacologic inhibition of these kinases attenuates toxicity in vitro.