Diagnostic and therapeutic value of intracellular biomarker testing in chronic pain

Aim: Micronutrient and metabolic compound supplementation as a method of treating chronic pain is not well understood. Case: A 58 year-old woman presented with refractory painful neuropathy. She did not respond to conservative treatment and was seeking spinal cord stimulator implantation. She underwent a biomarker panel that revealed low intracellular levels of multiple compounds. As she supplemented her deficiencies, her symptoms fully resolved, and the implant was no longer indicated. Discussion: Micronutrient and metabolic compound testing could potentially expand non-invasive treatment options for patients with refractory chronic pain. Caution should be exercised given limited regulatory oversight in the supplement industry and actively ongoing nutritional research. Conclusion: Biomarker testing panels may be a useful adjunct in the management of refractory neuropathic pain.

Temporal characterization of acute pain and toxicity kinetics during radiation therapy for head and neck cancer. A retrospective study

Objectives

Pain during Radiation Therapy (RT) for oral cavity/oropharyngeal cancer (OC/OPC) is a clinical challenge due to its multifactorial etiology and variable management. The objective of this study was to define complex pain profiles through temporal characterization of pain descriptors, physiologic state, and RT-induced toxicities for pain trajectories understanding.

Materials and methods

Using an electronic health record registry, 351 OC/OPC patients treated with RT from 2013 to 2021 were included. Weekly numeric scale pain scores, pain descriptors, vital signs, physician-reported toxicities, and analgesics were analyzed using linear mixed effect models and Spearman's correlation. Area under the pain curve (AUCpain) was calculated to measure pain burden over time.

Results

Median pain scores increased from 0 during the weekly visit (WSV)-1 to 5 during WSV-7. By WSV-7, 60% and 74% of patients reported mouth and throat pain, respectively, with a median pain score of 5. Soreness and burning pain peaked during WSV-6/7 (51%). Median AUCpain was 16% (IQR (9.3-23)), and AUCpain significantly varied based on gender, tumor site, surgery, drug use history, and pre-RT pain. A temporal increase in mucositis and dermatitis, declining mean bodyweight (-7.1%; P < 0.001) and mean arterial pressure (MAP) 6.8 mmHg; P < 0.001 were detected. Pulse rate was positively associated while weight and MAP were negatively associated with pain over time (P < 0.001).

Conclusion

This study provides insight on in-depth characterization and associations between dynamic pain, physiologic, and toxicity kinetics. Our findings support further needs of optimized pain control through temporal data-driven clinical decision support systems for acute pain management.

Methylene Blue for the Treatment of Radiation-Induced Oral Mucositis during Head and Neck Cancer Treatment: An Uncontrolled Cohort

Pain from radiation-therapy-induced oral mucositis during head-neck cancer treatment is aggravated by concurrent chemotherapy and commonly fails traditional treatments. To explore safe and sustainable alternatives, we investigated methylene blue oral rinse to reduce radiation-therapy-related oral mucositis pain. For this, we conducted a retrospective observational cohort study in a tertiary-care academic care cancer center including 85 patients with refractory oral mucositis pain during radiation therapy for head-neck cancer. Changes in pain (scale 0-10), oral function burden (scale 0-6) and requirement for percutaneous endoscopic gastrostomy tube placement were measured. Among 58 patients, 60% received radiation therapy alone and 40% received concurrent chemotherapy-radiation therapy. Methylene blue oral rinse (MBOR) significantly decreased oral mucositis pain for at least 6.2 h (median + SD 8 ± 1.68 before vs. 2 ± 2.20 after; p < 0.0001) and oral function burden (3.5 ± 1.33 before vs. 0 ± 0.86 after; p < 0.0001). Eleven patients (19%) had percutaneous endoscopic gastrostomy tubes placed before using methylene blue oral rinse; subsequently, four (36%) resumed oral alimentation after methylene blue oral rinse. Two patients (3%) required percutaneous endoscopic gastrostomy tubes despite methylene blue oral rinse. Minimal adverse events were reported (n = 9, 15%). Our study showed that methylene blue oral rinse was an effective and safe topical treatment for opioid-refractory oral pain from oral mucositis associated with radiation therapy for head-neck cancer.

Methylene blue for intractable pain from oral mucositis related to cancer treatment: a randomized phase 2 clinical trial

BACKGROUND

Oral mucositis (OM) in patients receiving cancer therapy is thus far not well managed with standard approaches. We aimed to assess the safety and effectiveness of methylene blue (MB) oral rinse for OM pain in patients receiving cancer therapy.

METHODS

In this randomized, single-blind phase 2 clinical trial, patients were randomized to one of four arms: MB 0.025%+conventional therapy (CTx) (n = 15), MB 0.05%+CTx (n = 14), MB 0.1%+CTx (n = 15), or CTx alone (n = 16). Intervention groups received MB oral rinse every 6 h for 2 days with outcomes measured at days 1-2; safety was evaluated up to 30 days. The primary outcome measured change in the pain numeric rating scale (0-10) from baseline to day 2. Secondary outcome measured change in oral function burden scores from baseline to day 2, World Health Organization OM grades, morphine equivalent daily doses, and adverse events. The trial was registered with ClinicalTrials.gov ID: NCT03469284.

RESULTS

Sixty patients (mean age 43, range 22-62 years) completed the study. Compared with those who received CTx alone, those who received MB had a significant reduction of pain scores at day 2 of treatment (mean ± SD); 0.025%: 5.2 ± 2.9, 0.05%: 4.5 ± 2.9, 0.1%: 5.15 ± 2.6) and reduction of oral function burden scores (0.025%: 2.5 ± 1.55, 0.05%: 2.8 ± 1.7, 0.1%: 2.9 ± 1.60). No serious adverse events were noted, but eight patients reported burning sensation of the oral cavity with the first dose, and this caused one patient to discontinue therapy.

CONCLUSIONS

MB oral rinse showed significant pain reduction and improved oral functioning with minimal adverse effects.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT03469284.

Non-Invasive Pelvic Floor Rehabilitation in Cancer Population: An Incomplete Cohort

BACKGROUND

Pelvic floor dysfunction and its associated symptoms are a common clinical challenge in the cancer population. Despite the noninvasive nature of pelvic floor rehabilitation (PFR) for this condition and the promising clinical results observed with its use, PFR appears to be an underused therapy.

OBJECTIVES

The purpose of this study was to quantify the association between physical therapy of the pelvic floor and its effect on pain relief and the associated symptoms in cancer patients with pelvic floor dysfunction.

STUDY DESIGN

Retrospective cohort study.

METHODS

With the use of an electronic database in our pain medicine department, we retrospectively quantified the pain relief and symptom improvement in patients diagnosed as having chronic pelvic floor dysfunction who had undergone PFR.

RESULTS

Of the 68 patients available for analysis, 49 met the inclusion criteria. Baseline characteristics of included patients were generally similar. The duration of pelvic pain before PFR was 53.7 months (mean) (SD, 182.5 months; median, 12 months). Of the 49 study patients, 23 (47%) had bladder dysfunction, 24 (49%) had dyspareunia, 2 (4%) had erectile dysfunction, and one (2%) had rectal dysfunction. Most symptoms associated with pelvic floor dysfunction resolved after PFR.

LIMITATIONS

Single-center, small data, retrospective study.

CONCLUSIONS

PFR is an effective tool for treating the pain associated with pelvic floor dysfunction and its related symptoms. This conservative approach can contribute to lowering the use of opiate analgesics.

Methylene Blue for the Treatment of Intractable Pain From Oral Mucositis Related to Cancer Treatment: An Uncontrolled Cohort

BACKGROUND

Oral mucositis is a complication of cancer therapy, causing severe pain that affects oral functioning, nutrition, and quality of life, as well as therapy nonadherence or dose-limiting toxicity. Anecdotal experience has suggested that methylene blue (MB) oral rinse may be an effective and safe treatment of this oral pain.

METHODS

To evaluate the efficacy and safety of MB oral rinse for the treatment of oral pain due to mucositis in patients with cancer, we retrospectively evaluated patients who experienced refractory pain despite conventional therapy.

RESULTS

We identified 281 patients who received MB oral rinse. Most were receiving treatment for leukemia (n=85; 30.3%) and head and neck squamous cell carcinoma (n=84; 29.9%). The most common treatments were radiation therapy alone (n=108; 38.4%) and chemoradiation (n=86; 30.6%). Median duration of symptoms was 14 days. Mean (SD) numeric rating scale pain scores were 7.7 (1.83; median, 8) before MB oral rinse and 2.51 (2.76; median, 2) after MB oral rinse (P<.0001). Most patients achieved pain control within the first 3 doses. The effectiveness of MB oral rinse was independent of patient age, sex, cancer type, cancer stage, MB dilution, and pain duration or baseline pain scores. The lowest response to treatment was reported in individuals with esophageal mucositis. Few patients experienced adverse effects of MB oral rinse (n=13; 4.6%); 10 had a transient burning sensation, 2 had transient blue discoloration of the teeth and mouth, and 1 had increased pain.

CONCLUSIONS

MB oral rinse is an effective and safe treatment for refractory pain from oral mucositis related to cancer treatment.

Lack of association between angiotensin-converting enzyme inhibitors and angiotensin receptor blockers and pain improvement in patients with oral cancer

Background

There is a growing body of literature implicating angiotensin II in the modulation of tumour-associated inflammation and pain. However, the impact of angiotensin-converting enzyme inhibitors (ACEis) and angiotensin II receptor blockers (ARBs) on pain and inflammation has not yet been studied in oral cancers. The objective is to investigate the role of ACEi and ARB pharmacotherapy on preoperative pain and inflammatory biomarkers, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and monocyte-to-lymphocyte ratio (MLR), in patients with oral cancer.

Methods

We performed a retrospective study on patients who underwent oral cancer surgery. The Wilcoxon rank-sum test or Kruskal-Wallis analysis was used to evaluate differences in demographic, tumour-related and preoperative characteristics and amongst patients using ARBs, ACEis and no treatment. Multivariable analysis was fitted to estimate the effects of important covariates on severe preoperative pain.

Results

A total of 162 patients with oral malignancies were included in the study. After adjusting for significant covariates, patients with perineural invasion were found to have higher levels of pain (p = 0.0278). Similarly, patients taking ARBs were found to have lower levels of perineural invasion (p = 0.035). The analysis did not demonstrate a significant difference in pain levels when comparing ARBs or ACEis to the no treatment group (p = 0.250). Furthermore, the use of ARB or ACEi did not significantly alter preoperative NLR (p = 0.701) or MLR (p = 0.869).

Conclusions

When compared to no treatment, ARBs and ACEis are not associated with significant analgesic effect or decreased inflammatory scores (NLR, PLR and MLR).

High-flow oxygen and pro-serotonin agents for non-interventional treatment of post-dural-puncture headache

OBJECTIVE

Post dural puncture headache (PDPH) is a common complication in patients following diagnostic or therapeutic lumbar puncture, procedures requiring epidural access, and spinal surgery. Epidural blood patch (EBP), the gold standard for the treatment of this pathology requires training not provided to emergency physicians. In addition, the presence of concomitant pathology and abnormal laboratory values are contraindications to perform EBP. In presence of these limitations, we sought for a non-interventional management of PDPH utilizing high-flow oxygen and pro-serotonin agents. We reviewed the mechanism of action of this therapy METHODS: To illustrate our proposal, we report a series of twelve consecutive patients with PDPH treated with high-flow oxygen therapy at 12 L/min via a non-rebreathing mask and intravenous metoclopramide.

RESULTS

All patients were treated with this conservative therapy, no adverse reactions were observed. After the intervention, the headache resolved without further indications for PDPH.

CONCLUSION

Our series suggests that combining high-flow oxygen and pro-serotonin agents such metoclopramide in the ED might be a feasible option as effective as the invasive methods used in treating PDPH. This therapy appears to be efficient and to minimize risk, cost and side effects. It presents an easily accessible alternative that should be considered when PDPH is not a viable option.

Sacroiliitis in cancer patients: a review of current literature

The sacroiliac (SI) joint can be directly jeopardized by malignancy and indirectly by ergonomic changes of pelvic obliquity that introduces uneven weight distribution. Cancer treatment can exacerbate preexisting arthritis and cause diffuse arthropathies, but these are unlikely to be isolated to the SI joint. The cancer population is exposed to unique stressors that might facilitate development of SI joint pain that includes cancer itself and therapy-related complications. Like the general population, cancer patients are subject to aging and BMI and musculoskeletal structural changes that affect symmetric body functioning and posturing. No frank association between sacroiliitis and cancer has been identified. Therefore, we believe there is a need to characterize any relationship between cancer and SI joint dysfunction and pain.

Normal Saline Trigger Point Injections vs Conventional Active Drug Mix for Myofascial Pain Syndromes

BACKGROUND

Myofascial pain syndrome (MPS) originates in the muscle and fascia. MPS presents with referred pain specific for each muscle and a trigger point that reproduces the symptoms. Trigger-point-injection (TPI) is an effective approach to treating MPS. Some TPI agents, however, are associated with systemic and local side effects.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of TPI with a conventional active drug mixture (CADM) vs. that with normal saline solution (NS) alone in patients with MPS presenting to the emergency department (ED).

METHODS

Adults with MPS diagnosed in the ED, participants were randomly assigned to receive TPI with NS or with CADM. Pain intensity was scored using a 0-10 numeric rating scale prior to and after TPI, before discharge and 2 weeks after TPI.

RESULTS

Among 48 patients analyzed, 23 received TPI with NS. The mean pain scores were as follows: immediately before TPI, 7.59 (NS) and 7.44 (CADM); immediately after TPI, 2.22 (NS) and 1.76 (CADM); prior to discharge, 1.52 (NS) and 1.76 (CADM). At 2-week follow up, the mean pain scores were 4.29 (NS) and 4.14 (CADM). Pain was significantly reduced after TPI in both groups. At 2 weeks, the mean pain scores were similar between the groups. No adverse events were reported.

CONCLUSION

In cases of MPS in the ED, pain can be controlled with TPI independent of the injectate. TPI with NS may be preferred over CADM because of its lower cost and more favorable side effect profile.

Sacroiliac joint pain following iliac-bone marrow aspiration and biopsy: a cohort study

Background: Sacroiliac joint (SIJ) pain is a common source of lower back pain; the factors associated have not been studied in cancer patients. Observing patients with bone marrow aspiration and biopsy (BMAB) who subsequently developed SIJ-pain led to this investigation. Aim: To investigate this possible relationship. Methods: A cohort study of cancer patients diagnosed with SIJ pain. The association of BMAB with SIJ pain was evaluated, as were variables that differed between the groups. Results: The prevalence of SIJ pain was 4.95% (231/4669). Among 231 patients with SIJ pain, 34% (78/231) did not have prior history of lower back pain and had undergone BMAB prior to their diagnosis of SIJ pain. A statistically significant association between BMAB-SIJ-pain was found (p < 0.01). Conclusion: We found linear correlation between BMAB and subsequent SIJ pain.

Recurrence of complex regional pain syndrome after administration of adenosine

Background: The effects of adenosine in acute chronic pain are not clear. Literature supports both a pronociceptive/inflammatory role of the A2aR/A2bR and antihyperalgesia/allodynia with A1Rs/A3Rs. Adenosine could participate in the reactivation of chronic regional pain syndrome (CRPS) through inflammatory pathways and via A2Rs. Plastic changes in the brain CRPS-related overlap with those seen in systemic inflammation and persist even after symptoms of CRPS resolve. Aim: To illustrate the hypothesis that intravenous adenosine can reactivate dormant CRPS. Case report: An individual with successfully treated CRPS developed supraventricular tachycardia, he was treated with intravenous adenosine. Shortly after a second dose, he developed severe pain at a lower limb from relapsed CRPS. Treatment included lumbar sympathetic block, physical therapy and pharmacological agents. Conclusion: Intravenous adenosine can reactivate dormant CRPS. Its potential pronociceptive role in CRPS calls for further studies to better elucidate the underlying mechanisms.

Oral pain associated with cancer therapy, a pain medicine perspective

Cancer therapy-induced oral mucositis (CTIOM) can cause intolerable oral pain resulting in difficulty in chewing, swallowing and speaking. Thus, leading to patients requiring aggressive measures, such as parenteral feeding, the placement of gastric feeding tubes and discontinuation of oncologic treatments. Although, pain is the debilitating symptom, current efforts seem to focus independently in the histological damage, not in pain and symptom care. Current strategies for managing pain from CTIOM entail maintaining oral hygiene and the use of oral rinses, topical anesthetics, prophylactic antimicrobials and systemic analgesics such as opioids. Novel therapies, such as methylene blue oral rinse, are being investigated, with positive outcomes. Therefore, there is a need to identify treatment modalities for pain of CTIOM. Ideally, this should be noninvasive, safe and cost-effective, while providing sustained analgesia.

Subclinical Peripheral Neuropathy in Patients with Head and Neck Cancer: A Quantitative Sensory Testing (QST) Study

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and chronic complication associated with cancer treatment. Prior investigations have demonstrated the presence of subclinical peripheral neuropathy in patients with colorectal cancer even before the patients had received chemotherapy. Objective: To investigate subclinical peripheral neuropathy of the upper limbs in patients with squamous cell carcinoma (SCC) of the head and neck which developed before their exposure to neurotoxic anticancer agents. Study Design: Retrospective analysis. Methods: With the use of our quantitative sensory testing (QST) data bank, we retrospectively assessed the afferent fiber function of 25 patients with SCC of the head and neck before they had received chemotherapy (the patient group) and compared our findings with those from 23 healthy control patients. Skin temperature, sensorimotor function, sharpness detection, thermal detection, and touch detection (using both von Frey monofilaments and the Bumps detection test) were measured. Results: Touch thresholds were statistically higher in the patient group than in the healthy volunteer group at the palm (mean [± SD], 0.54 g [± 0.07 g] and 0.27 g [± 0.05 g], respectively [P < 0.01]) and at the forearm (0.74 g [± 0.12 g] and 0.41 g [± 0.08 g] [P < 0.05]). There was also a clear deficit in touch sensation as indicated by a Bumps detection threshold in patients of 6.5 µm ± 0.8 µm and in controls of 3.7 µm ± 0.5 µm. This yields an elevation in threshold to 165% in the patients relative to that of the control volunteers. The grooved pegboard test showed delayed completion times for patients compared with controls, with differences of 18.65 seconds in the dominant hand and of 23.36 seconds in the nondominant hand. The sharpness detection thresholds did not differ between patients and volunteers. Limitations: Inadequacies in the original data acquisition and documentation of the QST and the medical records could not be addressed due to the retrospective nature of the study. In addition, based on available information, we did not find an objective parameter able to correlate the QST findings with pre-pain levels. Conclusion: Patients with SCC were found to have deficits in sensory function before undergoing treatment, suggesting that cancer itself alters peripheral nerve function and may contribute to the development of CIPN. These results confirm the sensitivity of the Bumps detection test and highlight its potential role in early detection of peripheral neuropathy, especially in cancer patients for whom chemotherapies associated with CIPN have been prescribed. Key words: Peripheral neuropathy, head and neck cancer, quantitative sensory testing

Subclinical Peripheral Neuropathy in Patients with Head and Neck Cancer: A Quantitative Sensory Testing (QST) Study

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is a common and chronic complication associated with cancer treatment. Prior investigations have demonstrated the presence of subclinical peripheral neuropathy in patients with colorectal cancer even before the patients had received chemotherapy.

OBJECTIVE

To investigate subclinical peripheral neuropathy of the upper limbs in patients with squamous cell carcinoma (SCC) of the head and neck which developed before their exposure to neurotoxic anticancer agents.

STUDY DESIGN

Retrospective analysis.

METHODS

With the use of our quantitative sensory testing (QST) data bank, we retrospectively assessed the afferent fiber function of 25 patients with SCC of the head and neck before they had received chemotherapy (the patient group) and compared our findings with those from 23 healthy control patients. Skin temperature, sensorimotor function, sharpness detection, thermal detection, and touch detection (using both von Frey monofilaments and the Bumps detection test) were measured.

RESULTS

Touch thresholds were statistically higher in the patient group than in the healthy volunteer group at the palm (mean [± SD], 0.54 g [± 0.07 g] and 0.27 g [± 0.05 g], respectively [P < 0.01]) and at the forearm (0.74 g [± 0.12 g] and 0.41 g [± 0.08 g] [P < 0.05]). There was also a clear deficit in touch sensation as indicated by a Bumps detection threshold in patients of 6.5 µm ± 0.8 µm and in controls of 3.7 µm ± 0.5 µm. This yields an elevation in threshold to 165% in the patients relative to that of the control volunteers. The grooved pegboard test showed delayed completion times for patients compared with controls, with differences of 18.65 seconds in the dominant hand and of 23.36 seconds in the nondominant hand. The sharpness detection thresholds did not differ between patients and volunteers.

LIMITATIONS

Inadequacies in the original data acquisition and documentation of the QST and the medical records could not be addressed due to the retrospective nature of the study. In addition, based on available information, we did not find an objective parameter able to correlate the QST findings with pre-pain levels.

CONCLUSION

Patients with SCC were found to have deficits in sensory function before undergoing treatment, suggesting that cancer itself alters peripheral nerve function and may contribute to the development of CIPN. These results confirm the sensitivity of the Bumps detection test and highlight its potential role in early detection of peripheral neuropathy, especially in cancer patients for whom chemotherapies associated with CIPN have been prescribed.

KEY WORDS

Peripheral neuropathy, head and neck cancer, quantitative sensory testing.

Randomized Controlled Double-blind Trial Comparing Haloperidol Combined With Conventional Therapy to Conventional Therapy Alone in Patients With Symptomatic Gastroparesis

OBJECTIVE

Gastroparesis is a debilitating condition that causes nausea, vomiting, and abdominal pain. Management includes analgesics and antiemetics, but symptoms are often refractory. Haloperidol has been utilized in the palliative care setting for similar symptoms. The study objective was to determine whether haloperidol as an adjunct to conventional therapy would improve symptoms in gastroparesis patients presenting to the emergency department (ED).

STUDY DESIGN AND METHODS

This was a randomized, double-blind, placebo-controlled trial of adult ED patients with acute exacerbation of previously diagnosed gastroparesis. The treatment group received 5 mg of haloperidol plus conventional therapy (determined by the treating physician). The control group received a placebo plus conventional therapy. The severity of each subject's abdominal pain and nausea were assessed before intervention and every 15 minutes thereafter for 1 hour using a 10-point scale for pain and a 5-point scale for nausea. Primary outcomes were decreased pain and nausea 1 hour after treatment.

RESULTS

Of the 33 study patients, 15 were randomized to receive haloperidol. Before treatment, the mean intensity of pain was 8.5 in the haloperidol group and 8.28 in the placebo group; mean pretreatment nausea scores were 4.53 and 4.11, respectively. One hour after therapy, the mean pain and nausea scores in the haloperidol group were 3.13 and 1.83 compared to 7.17 and 3.39 in the placebo group. The reduction in mean pain intensity therapy was 5.37 in the haloperidol group (p ≤ 0.001) compared to 1.11 in the placebo group (p = 0.11). The reduction in mean nausea score was 2.70 in the haloperidol group (p ≤ 0.001) and 0.72 in the placebo group (p = 0.05). Therefore, the reductions in symptom scores were statistically significant in the haloperidol group but not in the placebo group. No adverse events were reported.

CONCLUSIONS

Haloperidol as an adjunctive therapy is superior to placebo for acute gastroparesis symptoms.

Unilateral Lower Extremity Pain Due to Malignancy Managed With Cordotomy: A Case Report

Cancer pain management is comprehensive, and it generally begins with pharmacotherapy in a step-wise approach per analgesic guidelines established decades ago by the World Health Organization. This analgesic ladder involves the prescribing of co-analgesics, adjuvants, and opioids, with each step depending on pain severity. Although the majority of cancer pain responds to this strategy, there exist patients who do not respond adequately or experience significant side effects or intolerance to pain medications. It is in these patients whom clinicians consider interventional approaches. One approach to manage unremitting unilateral malignant pain includes evaluation for cordotomy, which is an approach that has been effective in such cases. We present a patient with breast cancer metastatic to the pelvis, with associated severe pelvic and right lower limb pain. Due to progressive disease, her pain worsened despite aggressive opioid dose escalations. She ultimately underwent percutaneous left anterolateral cervical cordotomy for malignant right leg pain, resulting in complete resolution of leg pain. We propose that, in select patients with neoplasm-related pain, cordotomy may prove very effective.

LEVEL OF EVIDENCE

V.

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers Modulate the Function of Myelinated Fibers after Chemotherapy: A Quantitative Sensory Testing Study

Background: Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) have sufficient scientific support for their use as tissue protectors. Preliminary studies suggest that their angiotensin-II type 2 receptor (AT2R)-blocking properties have a beneficial profile in the treatment of neuropathic pain. Objectives: The purpose of the current study was to quantify the extent of the somatosensory effects of ACEI and ARB in cancer patients with chemotherapy-induced peripheral neuropathy. Study Design: We performed a retrospective review of cancer patients with peripheral neuropathy of the upper limbs induced by known neurotoxic anti-cancer agents. Setting: Pain Medicine department at academic tertiary care cancer center. Methods: Using our quantitative sensory testing (QST) data bank, we retrospectively compared the tactile function and the touch, sharp, and thermal thresholds of patients who were previously receiving ACEI or ARB for high blood pressure with these variables in controls who were not receiving ACEI or ARB. Results: Of the 209 patients available for analysis, 145 met inclusion criteria. Baseline characteristics of patients included were generally similar. We identified 29 patients who were receiving AT2R inhibitors prior to starting chemotherapy. Touch thresholds were statistically lower in the thenar aspect of hand in the study group (patients who received AT2R inhibitors) than in the control group [mean (± SD), median 3.03 g (± 11.05), median 0.56 g and 6.75 g (± 18.28), 0.56 g, respectively (P = 0.0441)]. Similarly, the cold pain threshold was statistically higher at the thenar area for the study group [mean (± SD), median 13.23°C (± 8.02), 11.73°C] than for controls [9.89°C (± 6.62), 10.05°C (P = 0.0369)]. Limitations: Inadequacies in the original data acquisition and documentation of the QST and the medical records could not be addressed due to the retrospective nature of the study. Similarly, a discrepancy on the size of the comparison groups could not be reconciled. In addition, based on the available information and the lack of documented concomitant pain levels, we did not find an objective parameter able to correlate the QST findings with pain levels. Conclusions: AT2R inhibitors might offer partial and selective neuroprotective qualities of the myelinated fibers A-β and A-δ in cancer patients who receive neurotoxic chemotherapy. Key words: Quantitative sensory testing, chemotherapy-induced peripheral neuropathy, angiotensin-II type 2 receptor (AT2R)

Angiotensin-Converting Enzyme Inhibitors and Angiotensin Receptor Blockers Modulate the Function of Myelinated Fibers after Chemotherapy: A Quantitative Sensory Testing Study

BACKGROUND

Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) have sufficient scientific support for their use as tissue protectors. Preliminary studies suggest that their angiotensin-II type 2 receptor (AT2R)-blocking properties have a beneficial profile in the treatment of neuropathic pain.

OBJECTIVES

The purpose of the current study was to quantify the extent of the somatosensory effects of ACEI and ARB in cancer patients with chemotherapy-induced peripheral neuropathy.

STUDY DESIGN

We performed a retrospective review of cancer patients with peripheral neuropathy of the upper limbs induced by known neurotoxic anti-cancer agents.

SETTING

Pain Medicine department at academic tertiary care cancer center.

METHODS

Using our quantitative sensory testing (QST) data bank, we retrospectively compared the tactile function and the touch, sharp, and thermal thresholds of patients who were previously receiving ACEI or ARB for high blood pressure with these variables in controls who were not receiving ACEI or ARB.

RESULTS

Of the 209 patients available for analysis, 145 met inclusion criteria. Baseline characteristics of patients included were generally similar. We identified 29 patients who were receiving AT2R inhibitors prior to starting chemotherapy. Touch thresholds were statistically lower in the thenar aspect of hand in the study group (patients who received AT2R inhibitors) than in the control group [mean (± SD), median 3.03 g (± 11.05), median 0.56 g and 6.75 g (± 18.28), 0.56 g, respectively (P = 0.0441)]. Similarly, the cold pain threshold was statistically higher at the thenar area for the study group [mean (± SD), median 13.23°C (± 8.02), 11.73°C] than for controls [9.89°C (± 6.62), 10.05°C (P = 0.0369)].

LIMITATIONS

Inadequacies in the original data acquisition and documentation of the QST and the medical records could not be addressed due to the retrospective nature of the study. Similarly, a discrepancy on the size of the comparison groups could not be reconciled. In addition, based on the available information and the lack of documented concomitant pain levels, we did not find an objective parameter able to correlate the QST findings with pain levels.

CONCLUSIONS

AT2R inhibitors might offer partial and selective neuroprotective qualities of the myelinated fibers A-beta; and A-delta in cancer patients who receive neurotoxic chemotherapy.

Methylene Blue for the Treatment of Intractable Pain Associated with Oral Mucositis

Oral mucositis is a common and often debilitating complication among cancer patients receiving radiation therapy to the head and neck or chemotherapy agents, or undergoing hematopoietic stem cell transplantation. Pain and decreased oral function associated with oral mucositis may persist long after the conclusion of therapy. Although most patients respond to conservative management, a subset of patients develops intractable pain with severe consequences. For some, the use of total parenteral nutrition with insertion of percutaneous endoscopic gastrostomy feeding tubes is the only alternative. Current recommendations to treat mucositis and its related pain include basic oral care, bland oral rinses, topical anesthetics, and systemic analgesics. We believe that chemical neurolysis of the affected areas with methylene blue used as an oral rinse is a noninvasive, efficient, safe, and cost-effective alternative that can provide prolonged analgesia in patients with intractable pain of oral mucositis. The benefits of this therapy are reflected in its improvement of patients' quality of life by enabling oral feeding and controlling pain. We report a series of 5 consecutive patients with intractable oral mucositis-related pain despite conventional treatment with systemic opiates. All 5 patients responded well to the use of 0.05% methylene blue as mouth rinse, demonstrating sustained analgesia over 3 weeks. The treatment was tolerated well, and overall patient satisfaction was very high. We also observed that methylene blue rinse significantly reduced the total opioid requirement, as demonstrated by reductions in the patients' morphine equivalent daily dose scores after its use. Our case series suggests that 0.5% methylene blue oral rinse therapy is an effective and inexpensive modality that can be used safely to palliate intractable oral pain in patients with mucositis associated with cancer treatment. To our knowledge, this is the first report using this therapy to treat pain from oral mucositis.

Iliocostalis Thoracis-Lumborum Myofascial Pain: Reviewing a Subgroup of a Prospective, Randomized, Blinded Trial. A Challenging Diagnosis with Clinical Implications

Background: Pain of myofascial origin is a well-recognized pathology characterized by the presence of two components: referred pain; which is often distant from its source and specific to each muscle, and the trigger point, a localized hyperirritable band present in the affected muscle and able to reproduce the referred pain when stimulated. Myofascial pain (MP) commonly coexists in patients with acute or chronic pain of other etiologies. The uniqueness of the clinical presentation of some MPs and the lack of training of most specialties represent a clinical challenge. Thus, many patients with MPS receive less than optimal management of this condition. Objective: Pain at the anterior torso, originating at the posterior torso, can mimic common pathologies that correlate with the same anatomical area such as cardiac and intra-abdominal conditions. These clinical characteristics could be caused by MP of the iliocostalis thoracis-lumborum (ITL) muscle. However, this entity has not been well addressed in the medical literature. In this report we characterize the manifestations, diagnosis, and clinical implications of ITL MP. Study Design: Observational assessment. Setting: Two university-based academic emergency medicine departments (ED) in an urban setting in the United States. Methods: A convenience sample of 43 patients who presented to the ED with pain at the anterior aspect of the torso (chest, abdomen, or pelvis) and clinical evidence of MP originated in the ITL muscle. Of a clinical trial of patients with MP, we describe a subgroup of patients with MP of the ITL which was clinically evident by the presence of a trigger point (TP) in its ability to reproduce the referred pain present at the anterior aspect of the torso. Patients received a TP injection. In this trial we intend to demonstrate that TP injections using particulate steroids mixed with a local are no more effective than saline alone to treat MP. The primary outcome was pain control (decrease in intensity of 50% or more below baseline numeric pain rating). A follow-up telephone interview was performed by third-party abstractors. Results: Forty-three patients presented with pain of the anterior torso and ipsilateral back, both correlating with the level of the TP of the ITL muscle. The pain had been present from 2 days to 7 years. The most common locations of pain were the right-lower quadrant and the left side of the chest. In many of them a pattern of missed diagnosis was evident despite extensive workups and consultations. Only 17 patients were able to identify the precipitating event; the most common was coughing. Two weeks after TP injection, all patients still had satisfactory pain control. After treatment, no missed pathology or returns to the ED were reported. Limitations: This descriptive portion of the ongoing study does not affect the integrity of the trial itself but could be subject to the introduction of subject selection and selective reporting bias. Similarly, this convenience sample does not establish the incidence of this pathology and challenges the external validity to other clinical settings. Conclusions: Anterior torso pain often resulted in extensive workups before ITL myofascial pain was diagnosed. TP injections were diagnostic and therapeutic of ITL myofascial pain. Key words: Iliocostalis thoracis-lumborum muscle, myofascial pain, referred pain, trigger point injection

Iliocostalis Thoracis-Lumborum Myofascial Pain: Reviewing a Subgroup of a Prospective, Randomized, Blinded Trial. A Challenging Diagnosis with Clinical Implications

BACKGROUND

Pain of myofascial origin is a well-recognized pathology characterized by the presence of two components: referred pain; which is often distant from its source and specific to each muscle, and the trigger point, a localized hyperirritable band present in the affected muscle and able to reproduce the referred pain when stimulated. Myofascial pain (MP) commonly coexists in patients with acute or chronic pain of other etiologies. The uniqueness of the clinical presentation of some MPs and the lack of training of most specialties represent a clinical challenge. Thus, many patients with MPS receive less than optimal management of this condition.

OBJECTIVE

Pain at the anterior torso, originating at the posterior torso, can mimic common pathologies that correlate with the same anatomical area such as cardiac and intra-abdominal conditions. These clinical characteristics could be caused by MP of the iliocostalis thoracis-lumborum (ITL) muscle. However, this entity has not been well addressed in the medical literature. In this report we characterize the manifestations, diagnosis, and clinical implications of ITL MP.

STUDY DESIGN

Observational assessment.

SETTING

Two university-based academic emergency medicine departments (ED) in an urban setting in the United States.

METHODS

A convenience sample of 43 patients who presented to the ED with pain at the anterior aspect of the torso (chest, abdomen, or pelvis) and clinical evidence of MP originated in the ITL muscle.Of a clinical trial of patients with MP, we describe a subgroup of patients with MP of the ITL which was clinically evident by the presence of a trigger point (TP) in its ability to reproduce the referred pain present at the anterior aspect of the torso. Patients received a TP injection. In this trial we intend to demonstrate that TP injections using particulate steroids mixed with a local are no more effective than saline alone to treat MP. The primary outcome was pain control (decrease in intensity of 50% or more below baseline numeric pain rating). A follow-up telephone interview was performed by third-party abstractors.

RESULTS

Forty-three patients presented with pain of the anterior torso and ipsilateral back, both correlating with the level of the TP of the ITL muscle. The pain had been present from 2 days to 7 years. The most common locations of pain were the right-lower quadrant and the left side of the chest. In many of them a pattern of missed diagnosis was evident despite extensive workups and consultations. Only 17 patients were able to identify the precipitating event; the most common was coughing. Two weeks after TP injection, all patients still had satisfactory pain control. After treatment, no missed pathology or returns to the ED were reported.

LIMITATIONS

This descriptive portion of the ongoing study does not affect the integrity of the trial itself but could be subject to the introduction of subject selection and selective reporting bias. Similarly, this convenience sample does not establish the incidence of this pathology and challenges the external validity to other clinical settings.

CONCLUSIONS

Anterior torso pain often resulted in extensive workups before ITL myofascial pain was diagnosed. TP injections were diagnostic and therapeutic of ITL myofascial pain.

Quantitative sensory testing in pain management

Quantitative sensory testing (QST), a set of noninvasive methods used to assess sensory and pain perception, has been used for three decades. The precision of the instruments and the uninvasiveness encouraged many QST-based trials. The developments made have benefited multiple disciplines. QST relies on analysis of an individual's response to external stimuli, reflecting the integrity of the PNS and the sensory pathway. The sensory pathway cannot be assessed in isolation from the affective and cognitive characteristics of patients or testers. Many variables potentially affect the reliability and reproducibility of QST, which after all, is designed for the testing of individuals by other individuals. Several decades of QST research have yielded exciting contributions, but the future of QST cannot be fully known.

Phenytoin toxicity from cocaine adulteration

The use of phenytoin (PHT) as a cocaine adulterant was reported decades ago; that practice is still current. Ironically PHT has also been used for the treatment of cocaine dependence. A drug smuggler developed PHT toxicity after swallowing several rocks of crack. We investigated the current trends of PHT as a cocaine adulterant and its toxicological implications. We also reviewed the clinical use of PTH in relation to cocaine. The use of PHT as cocaine cut is a current practice. This may affect the clinical manifestations and the management of the cocaine-related visits to the emergency department.

Central Venous Catheter Intravascular Malpositioning: Causes, Prevention, Diagnosis, and Correction

Despite the level of skill of the operator and the use of ultrasound guidance, central venous catheter (CVC) placement can result in CVC malpositioning, an unintended placement of the catheter tip in an inadequate vessel. CVC malpositioning is not a complication of central line insertion; however, undiagnosed CVC malpositioning can be associated with significant morbidity and mortality. The objectives of this review were to describe factors associated with intravascular malpositioning of CVCs inserted via the neck and chest and to offer ways of preventing, identifying, and correcting such malpositioning. A literature search of PubMed, Cochrane Library, and MD Consult was performed in June 2014. By searching for “Central line malposition” and then for “Central venous catheters intravascular malposition,” we found 178 articles written in English. Of those, we found that 39 were relevant to our objectives and included them in our review. According to those articles, intravascular CVC malpositioning is associated with the presence of congenital and acquired anatomical variants, catheter insertion in left thoracic venous system, inappropriate bevel orientation upon needle insertion, and patient’s body habitus variants. Although plain chest radiography is the standard imaging modality for confirming catheter tip location, signs and symptoms of CVC malpositioning even in presence of normal or inconclusive conventional radiography findings should prompt the use of additional diagnostic methods to confirm or rule out CVC malpositioning. With very few exceptions, the recommendation in cases of intravascular CVC malpositioning is to remove and relocate the catheter. Knowing the mechanisms of CVC malpositioning and how to prevent, identify, and correct CVC malpositioning could decrease harm to patients with this condition.

Myofascial Pain Syndromes in the Emergency Department: What Are We Missing?

BACKGROUND

Myofascial pain syndrome (MPS), pain originating in the myofascial tissue, is a widely recognized pathology characterized by the presence of referred pain (often distant from its origin and specific to each muscle) that can resemble other pathologies and by the presence of a trigger point, a localized hyperirritable band able to reproduce the pain and its associated symptoms. Patients with acute or chronic MPS are commonly seen in the emergency department (ED), usually complaining of pain of undetermined origin. Traditionally, the emergency physician (EP) is not trained to diagnose and treat MPS, and many patients with MPS have received less than optimal management of this condition in the ED. Many types of treatments are known to be effective against MPS. Among these, trigger point injection (TPI) is considered a practical and rapid approach that can be carried out in the ED by EPs.

OBJECTIVE

This article reviews the current diagnostic methods, treatment options, and procedures for MPS patients seen in the ED to enable EPs to diagnose and successfully treat this condition.

DISCUSSION

This article discusses the clinical characteristics, etiology, diagnosis, and treatment of MPS in the ED, including a description of performing TPI.

CONCLUSIONS

MPS can mimic other clinical conditions commonly seen in the ED. MPS can be diagnosed on the basis of clinical findings; in many cases, no imaging or laboratory testing is needed. Therefore, MPS diagnosis and treatment can be successfully accomplished in the ED by EPs.

Magnetic fields and intrathecal pump malfunction

Medical technology has impacted the overall life expectancy. Many conditions traditionally considered fatal are now curable. Surviving chronic diseases and aging of the population have increased the number of people with chronic pain. Many devices are also available to manage severe refractory pain. As such, implantable drug-delivery system (IDDS) is a small battery-powered, programmable pump implanted under the subcutaneous tissue of the abdomen and connected to a small catheter tunneled into the spine. Implantable drug-delivery system is used for the administration of morphine, ziconotide, baclofen, or their mixtures into the cerebrospinal fluid. Like many medical devices, IDDS has technical glitch which limits its performance under certain conditions. Implantable drug-delivery system is susceptible to magnetic field such as a magnetic resonance imaging (MRI) which can temporarily stall the rotor of the pump motor and suspend drug delivery. We encountered a patient from out of town seen at emergency department with increased pain and symptoms of opiates withdrawal after intermittent IDDS malfunction. He denied any exposure to magnetic fields or MRI. However, the pump interrogation showed multiple motor stall events in the event log. After a detailed inquiry, the most likely cause of pump malfunction appears to be frequent placement of a laptop computer on his abdomen close to the pump. The magnets in the laptop speakers may have caused the rotor of the pump motor to stall during the computer use, and frequent stall has caused symptoms of withdrawal. No other mechanical failures were found. The patient was discharged home after the symptoms resolved, and the pump was reprogrammed.

Complications of new medications

Numerous mandibular pathologies are diagnosed in the emergency department (ED). We present the case of a woman with severe right-sided mandibular pain who was found to have a pathological fracture and osteonecrosis of the jaw (ONJ). The etiology of ONJ was found to be associated to previous use of zoledronic acid to treat osteoporosis. The aim of this case report is to discuss the etiology, diagnosis and treatment of ONJ secondary to the use of zoledronic acid and to outline a clinical condition rarely seen in the ED whose incidence might rise with the increasing use of bisphosphonates.

Longus colli tendonitis, clinical consequences of a misdiagnosis

Numerous pathologies diagnosed in the emergency department (ED) are treated with invasive procedures involving anesthetic and surgical risks. Retropharyngeal abscess is a serious condition requiring emergent treatment, often in need of trans-oral incision and drainage under general anesthesia. A misdiagnosis, especially after surgical treatment, might generate undesirable consequences, more so if the final diagnosis is a non-surgical pathology such as longus colli (LC) tendonitis. To discuss the etiology, differential diagnosis and treatment of LC tendonitis, a clinical condition still misdiagnosed despite advanced imaging techniques. A middle-aged man presented to a satellite ED with sore throat, neck pain and stiffness. A computed tomography (CT) scan of the neck with intravenous contrast was read as retropharyngeal abscess. He was transferred to our ED after acceptance by ear-nose-throat (ENT) surgery. He was scheduled for open incision and drainage under general anesthesia. A detailed evaluation by our ED staff revealed a nontoxic patient with no compromise of the airway. His physical exam was unrevealing and a second review of the CT demonstrated typical radiological signs for LC tendonitis. After a discussion with ENT the patient was discharged home on anti-inflammatory medications and oral steroids. He recovered well and no further intervention was needed. Longus colli tendonitis is a rare condition that mimics emergent surgical conditions. Emergency physicians are qualified to make a clinical and radiological diagnosis. While CT scan can provide a diagnosis, the primary evaluation tool is an adequate medical interview and physical exam.