Rohit Aiyer

A Systematic Review of NMDA Receptor Antagonists for Treatment of Neuropathic Pain in Clinical Practice

Objective: To investigate the efficacy of N-methyl-D-aspartate receptor (NMDAR) antagonists for neuropathic pain (NeuP) and review literature to determine if specific pharmacologic agents provide adequate NeuP relief. Methods: Literature was reviewed on PubMed using a variety of key words for 8 NMDAR antagonists. These key words include: “Ketamine and Neuropathy,” “Ketamine and Neuropathic Pain,” “Methadone and Neuropathy,” “Methadone and Neuropathic Pain,” “Memantine and Neuropathic pain,” “Memantine and Neuropathy,” “Amantadine and Neuropathic Pain,” “Amantadine and Neuropathy,” “Dextromethorphan and Neuropathic Pain,” “Dextromethorphan and Neuropathy,” “Carbamazepine and Neuropathic Pain,” “Carbamazepine and Neuropathy,” “Valproic Acid and Neuropathy,” “Valproic Acid and Neuropathic Pain,” “Phenytoin and Neuropathy,” and “Phenytoin and Neuropathic Pain.” With the results, the papers were reviewed using the PRISMA (Preferred Reporting in Systematic and Meta-Analyses) guideline. Results: A total of 58 randomized controlled trials were reviewed among 8 pharmacologic agents, which are organized by date and alphabetical order. Of the trials for ketamine, 15 showed some benefit for analgesia. Methadone had 3 positive trials, while amantadine and memantine each only had 2 trials showing NeuP analgesic properties. Dextromethorphan and valproic acid both had 4 randomized controlled trials that showed some NeuP treatment benefit while carbamazepine had over 8 trials showing efficacy. Finally, phenytoin only had 1 trial that showed clinical response in treatment. Conclusions: There are a variety of NMDAR antagonist agents that should be considered for treatment of NeuP. Nevertheless, continued and further investigation of the 8 pharmacologic agents is needed to continue to evaluate their efficacy for treatment of NeuP.

Dorsal thoracic arachnoid web presenting as neuropathic pain: 'Scalpel' sign found on MRI.

Dorsal thoracic arachnoid webs are due to a deformity in the formation of arachnoid membrane in the spinal arachnoid space. These webs usually occur in the upper thoracic spine and are viewed on imaging as a pathogonomic ‘scalpel’ sign because of the resemblance on sagittal MRI to a surgical scalpel. We describe a case of a patient with a neuropathic pain presentation. After MR imaging, a focal dorsal indentation of the upper thoracic spinal cord at the T3–T4 level with the scalpel sign was found. This sign indicates that the patient’s neuropathic pain was caused by the dorsal thoracic arachnoid web.

Treatment of Chronic Pain With Various Buprenorphine Formulations: A Systematic Review of Clinical Studies

Clinical studies demonstrate that buprenorphine is a pharmacologic agent that can be used for the treatment of various types of painful conditions. This study investigated the efficacy of 5 different types of buprenorphine formulations in the chronic pain population. The literature was reviewed on PubMed/MEDLINE, EMBASE, Cochrane Database, clinicaltrials.gov, and PROSPERO that dated from inception until June 30, 2017. Using the population, intervention, comparator, and outcomes method, 25 randomized controlled trials were reviewed involving 5 buprenorphine formulations in patients with chronic pain: intravenous buprenorphine, sublingual buprenorphine, sublingual buprenorphine/naloxone, buccal buprenorphine, and transdermal buprenorphine, with comparators consisting of opioid analgesics or placebo. Of the 25 studies reviewed, a total of 14 studies demonstrated clinically significant benefit with buprenorphine in the management of chronic pain: 1 study out of 6 sublingual and intravenous buprenorphine, the only sublingual buprenorphine/naloxone study, 2 out of 3 studies of buccal buprenorphine, and 10 out of 15 studies for transdermal buprenorphine showed significant reduction in pain against a comparator. No serious adverse effects were reported in any of the studies. We conclude that a transdermal buprenorphine formulation is an effective analgesic in patients with chronic pain, while buccal buprenorphine is also a promising formulation based on the limited number of studies.

An Overview of Arachnoid Webs

Arachnoid webs are abnormal formations of arachnoid membrane in the spinal subarachnoid space that prevents movement of cerebrospinal fluid (CSF) in the longitudinal direction1.These webs represent intradural extramedullary transverse bands of arachnoid tissue that extend to the dorsal surface of the spinal cord resulting in dorsal indentation2. These arachnoid webs may represent a variant of an arachnoid cyst3. However, they may also represent localized arachnoiditis3.

A systematic review on the impact of psychotropic drugs on electroencephalogram waveforms in psychiatry

ABSTRACT Objectives: It is known that psychotropic medications have an impact on the readings found in Electroencephalogram (EEG). In the field of psychiatry, there are several psychotropics utilized by clinicians. This review seeks to investigate all the available data for psychotropic drugs and their impact on EEG changes. Methods: A systematic review of all the published and ongoing literature was conducted via PubMed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method was used for each search. Key words for searches include ‘EEG and Psychotropics’, ‘EEG and Mood Stabilizers’, ‘EEG and Clozapine’, ‘EEG and Bupropion’, ‘EEG and SSRI’, ‘EEG and Lamotrigine’, ‘EEG and Carbamazepine’, ‘EEG and Lithium’ and ‘EEG and Valproate’, ‘EEG and Haloperidol’, ‘EEG and Aripiprazole’, ‘EEG and Methylphenidate’, ‘EEG and Topiramate’, ‘EEG and Gabapentin’ and ‘EEG and Oxcarbamazepine’. After applying the inclusion criteria, 201 articles were eligible and reviewed. Results: Following an extensive review of selected studies from the 201 articles, the studies indicate that each of the psychotropic medications reviewed impact alpha, beta, delta and theta waves independently and differently from each other. Additionally, certain medications, particularly haloperidol and valproic acid, have dissimilar results exemplified in all waveforms. Conclusions: This PRISMA systematic review illustrates that while there is available data on psychotropic medications and their proposed effect on EEG activity, further research is needed to confirm these findings to help allow clinical correlations to be made between the patient’s response and the psychotropic agent.

Cervical Epidural Injection in the Management of Refractory Pain and Stiffness in Spondyloarthropathy: A Case Report Series

The primary objective of this case series was to report the use of cervical epidural steroid injection in the management of neck pain and stiffness secondary to spondyloarthropathy in cases refractory to conservative therapy.

Rare presentation of intrathecal morphine withdrawal psychosis

We report a case of a 57-year-old male patient with intrathecal morphine pump failure who presented with psychosis as part of a clinical presentation of opioid withdrawal. The patient was being treated for chronic back pain with an intrathecal morphine pump for several years. The patient spontaneously started to experience psychotic symptoms which included disorganized thinking, delusional thoughts, paranoia, auditory and visual hallucinations. Upon interrogation of intrathecal pump, it was found not to be functioning, thereby not delivering intrathecal morphine. After opioid rotation with administration of oral oxycodone, the patients psychosis improved dramatically within a few days, clinically confirming psychosis due to morphine withdrawal. Therefore, it is important for physicians to consider opioid withdrawal in patients experiencing isolated psychosis.

Postoperative transient blindness after general anesthesia and surgery: case report of conversion disorder

Postoperative acute visual loss due to organic pathology has been described after spinal surgery in the prone position. This report describes a case of transient postoperative blindness in a patient after general anesthesia and surgery in the prone position. Postoperative workup did not reveal any organic pathology. Unbeknown to the treating physicians, the patient had a comorbid untreated psychiatric history. Upon psychiatric consultation, the patient was diagnosed with conversion disorder as a cause of postoperative blindness. There was full recovery of vision after psychiatric intervention within a week.

Epidural hematoma development contralateral to dura after lumbar transforaminal epidural steroid injection

AIM To illustrate the anatomical and pathophysiological risks of epidural hematoma formation, other than direct needle trauma, after lumbar transforaminal epidural steroid injection in the setting of severe central canal stenosis. CASE REPORT This case report presents the development of an epidural hematoma after lumbar transforaminal epidural steroid injection in a patient who has anatomical risk factor of severe lumbar spinal stenosis. The anatomic location of epidural hematoma was at the injected level, but on the contralateral side of the dura at a distance from the needle path. Epidural vascular anatomy and the potential mechanisms of bleeding in the epidural space in the absence of direct needle trauma, including the importance of injection pressures are discussed. CONCLUSION This is the first reported case of an epidural hematoma on the contralateral side of the dura at a distance from the needle tip location, in the setting of severe central canal stenosis.

A Computed Tomography-Guided Demonstration of the Unilateral Distribution of Low-Volume Epidural Injectate

The primary objective of this case report was to demonstrate the unilateral distribution of the low volume injectate given in the epidural space when paramedian interlaminar approach is utilized under computed tomography guidance.