Alaa Abd-Elsayed

KCNQ channels in nociceptive cold-sensing trigeminal ganglion neurons as therapeutic targets for treating orofacial cold hyperalgesia

BackgroundHyperexcitability of nociceptive afferent fibers is an underlying mechanism of neuropathic pain and ion channels involved in neuronal excitability are potentially therapeutic targets. KCNQ channels, a subfamily of voltage-gated K+ channels mediating M-currents, play a key role in neuronal excitability. It is unknown whether KCNQ channels are involved in the excitability of nociceptive cold-sensing trigeminal afferent fibers and if so, whether they are therapeutic targets for orofacial cold hyperalgesia, an intractable trigeminal neuropathic pain.MethodsPatch-clamp recording technique was used to study M-currents and neuronal excitability of cold-sensing trigeminal ganglion neurons. Orofacial operant behavioral assessment was performed in animals with trigeminal neuropathic pain induced by oxaliplatin or by infraorbital nerve chronic constrictive injury.ResultsWe showed that KCNQ channels were expressed on and mediated M-currents in rat nociceptive cold-sensing trigeminal ganglion (TG) neurons. The channels were involved in setting both resting membrane potentials and rheobase for firing action potentials in these cold-sensing TG neurons. Inhibition of KCNQ channels by linopirdine significantly decreased resting membrane potentials and the rheobase of these TG neurons. Linopirdine directly induced orofacial cold hyperalgesia when the KCNQ inhibitor was subcutaneously injected into rat orofacial regions. On the other hand, retigabine, a KCNQ channel potentiator, suppressed the excitability of nociceptive cold-sensing TG neurons. We further determined whether KCNQ channel could be a therapeutic target for orofacial cold hyperalgesia. Orofacial cold hyperalgesia was induced in rats either by the administration of oxaliplatin or by infraorbital nerve chronic constrictive injury. Using the orofacial operant test, we showed that retigabine dose-dependently alleviated orofacial cold hyperalgesia in both animal models.ConclusionTaken together, these findings indicate that KCNQ channel plays a significant role in controlling cold sensitivity and is a therapeutic target for alleviating trigeminal neuropathic pain that manifests orofacial cold hyperalgesia.

Identification of location of nerve catheters using pumping maneuver and M-Mode—a novel technique☆☆☆★

BACKGROUND Optimum positioning of the nerve catheter is crucial for a successful nerve block. We present a novel technique for confirmation of catheter position. METHODS We are describing a novel technique for localization of the shaft and tip of the peripheral nerve catheter. After introduction of the catheter 3 to 5 cm beyond the needle tip and removal of the needle, the guide wire was reintroduced and was moved inward and outward rapidly. This movement produced the color Doppler effect along the track of the catheter and the catheter tip that helped us verify the proper positioning of the catheter. RESULTS We used our technique in a cadaveric study for bilateral supraclavicular brachial plexus block, followed by a series of 5 patients undergoing femoral, sciatic (anterior approach), popliteal (2 patients), and brachial plexus blocks. Catheters were also identified on M-Mode sonography during pumping maneuver and during the injection of medications. CONCLUSION Pumping maneuver and M-Mode can be additional tools in the array of modalities applied to verify proper positioning of a nerve catheter.

Does Opioid Use Cause Angiogenesis and Metastasis

Objective. To provide a comprehensive overview of the potential for morphine to lead to angiogenesis and metastasis. Background. Morphine is often the treatment of choice for severe cancer-related pain. Small studies have been emerging that indicate that opioids may influence angiogenesis and metastasis, but this has not yet been comprehensively synthesized. Purpose. To highlight morphine’s relationship with angiogenesis and metastasis in in vitro models. Methods. A review of the literature was conducted using PubMed (1966 to 2015) and Cochrane Library (1987 to 2015) electronic databases. The search, as well as consultation with experts, yielded 84 articles for initial review, 12 of which met inclusion for review. Possible theories of the underlying etiology of the metastasis and angiogenesis were recorded. Results. All studies were assessed using the PRISMA checklist. Conclusion. This systematic review demonstrates that morphine has a potential causal relationship with angiogenesis and metastasis. This is likely due to multiple etiologies, including immunosuppressive, pro-inflammatory, and pro-angiogenetic.

Some Non-FDA Approved Uses for Neuromodulation: A Review of the Evidence

Neuromodulation, including spinal cord stimulation and peripheral nerve field stimulation, has been used with success in treating several painful conditions. The FDA approved the use of neuromodulation for a few indications. We review evidence for neuromodulation in treating some important painful conditions that are not currently FDA approved.

The Cleveland Clinic Experience with Supraclavicular and Popliteal Ambulatory Nerve Catheters

Continuous peripheral nerve blocks (CPNB) are commonly used for intraoperative and postoperative analgesia. Our study aimed at describing our experience with ambulatory peripheral nerve catheters. After Institutional Review Board approval, records for all patients discharged with supraclavicular or popliteal catheters between January 1, 2009 and December 31, 2011 were reviewed. A licensed practitioner provided verbal and written instructions to the patients prior to discharge. Daily follow-up phone calls were conducted. Patients either removed their catheters at home with real-time simultaneous telephone guidance by a member of the Acute Pain Service or had them removed by the surgeon during a regular office visit. The primary outcome of this analysis was the incidence of complications, categorized as pharmacologic, infectious, or other. The secondary outcome measure was the average daily pain score. Our study included a total of 1059 patients with ambulatory catheters (769 supraclavicular, 290 popliteal). The median infusion duration was 5 days for both groups. Forty-two possible complications were identified: 13 infectious, 23 pharmacologic, and 6 labeled as other. Two patients had retained catheters, 2 had catheter leakage, and 2 had shortness of breath. Our study showed that prolonged use of ambulatory catheters for a median period of 5 days did not lead to an increased incidence of complications.

Efficacy of Transversus Abdominis Plane Steroid Injection for Treating Chronic Abdominal Pain

Historically, transversus abdominis plane (TAP) block has been performed to treat acute abdominal pain that accompanies a variety of surgical procedures. This study represents an innovative approach in which the TAP block was performed on patients experiencing chronic abdominal pain who had failed other forms of pain management.

Amputation as an Unusual Treatment for Therapy-Resistant Complex Regional Pain Syndrome, Type 1

BACKGROUND Complex regional pain syndrome, type 1 (CRPS-1) causes severe pain that can be resistant to multiple treatment modalities. Amputation as a form of long-term treatment for therapy-resistant CRPS-1 is controversial. CASE REPORT We report the case of a 38-year-old man who failed all treatment modalities for CRPS-1, including medication, steroid injections, and spinal cord stimulator implantation. Below-the-knee amputation to relieve intractable foot and ankle pain resulted in a favorable outcome for this patient. CONCLUSION Select patients with severe CRPS-1 who are unresponsive to all forms of treatment for pain may benefit from amputation as a last option for relief of suffering. Larger studies are needed to prove the efficacy of amputation.

A severe interaction between Tizanidine and Ciprofloxacin

Tizanidine is a commonly prescribedmedication formuscle spasms [1]. The pharmacokinetics of Tizanidine are altered by the use of CYP1A2 inhibitors as Ciprofloxacin in healthy subjects; elevation of Tizanidine levels leads to a decrease in psychomotor activity and hemodynamic changes which are manifested as a decrease in blood pressure and heart rate [2,3]. A 51-year-old woman with chronic low back pain was on treatment with Oxycodone 5/325 mg 3 times daily as needed, Oxycontin 10 mg twice daily, and Tizanidine 4 mg three times daily as needed. The patient was prescribed Ciprofloxacin 500 mg twice daily andMetronidazole 500mg three times daily for diverticulitis by her primary care physician. Four days after starting treatment the patient developed severe abdominal pain, nausea, and vomiting. The patient was admitted to the hospital, had abdominal computed tomography and ultrasound which showed an enlarged gall bladder. The gastroenterology team and gynecology team were consulted, and they both excluded the gastrointestinal tract and genitourinary tract, respectively, to have any disease condition that caused this pain. The patient was afebrile on presentation and her white blood cell count was 5.9. The patient also presented with acute kidney dysfunction, thrombocytopenia, orthostatic hypotension, dizziness, and headache. She was also diagnosed with Clostridium difficile infection. The abdominal pain in this patient can be attributed to the infection with C difficile or the interaction between Ciprofloxacin and Metronidazole. Tizanidine is a common medication to be prescribed by a pain physician for treating muscle spasms. It is very important to check the patient

Treatment of Occipital Neuralgia by Thermal Radiofrequency Ablation

Background: Occipital neuralgia is an uncommon disorder characterized by severe pain involving the posterior scalp in the distribution of the greater and lesser occipital nerves. In cases refractory to pharmacotherapy, invasive treatment options may be warranted. The aim of the present study was to examine the effects of thermal radiofrequency ablation (TRF) on occipital neuralgia. We hypothesized that this procedure would result in long-term pain relief. Methods: All patients who underwent TRF of the greater and lesser occipital nerves between January 1, 2013 and March 23, 2016 were identified. Medical records were reviewed for preprocedure pain score, 1-month postprocedure pain score, patient-defined percent pain relief according to the visual analog scale (on which zero equals no pain and 10 represents the worst pain imaginable), and length of pain relief. The primary outcomes were the differences between preprocedure and 1-month postprocedure pain scores (mean change from baseline), percent pain relief, and patient-reported length of relief. Results: A total of 50 patients were identified; 4 patients were excluded because of insufficient data as a result of loss to follow-up. A significant difference was found between preprocedure and postprocedure patient-reported pain scores (6.7 vs 2.7, respectively; P < 0.001), equating to a mean reduction in pain scores 1-month postprocedure of 4.0 ± 3.3. The mean patient-defined percent pain relief was 76.3% ± 25.0%. The mean patient-reported length of relief was 6.5 ± 5.1 months. Conclusion: This study suggests that TRF may reduce pain scores for approximately 6 months.

Naloxone Academic Detailing: Role of Community Outreach Teaching

Purpose of ReviewTesting the efficacy of academic detailing in improving the practice of prescribing naloxone for patients on high-dose opioids.Recent FindingsAcademic detailing has been identified as an effective method for improving health care practices through focused community education.SummaryWe found that academic detailing is an effective method in improving health care providers’ knowledge about the importance of prescribing naloxone for patients on high-dose opioids. We also found that prescribers prescribed more naloxone after our education program. This study reflects the importance of education and academic detailing in resolving health problems. Academic detailing can provide effective preventive tools that can reduce the incidence of health problems we encounter.