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John E Madigan - One of the best experts on this subject based on the ideXlab platform.
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effects of magnesium with or without boron on Headshaking behavior in horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais RR; Weich, Kalie; Howey, Quinn; Madigan, John E | Abstract: BackgroundOral administration of magnesium and boron might have a beneficial effect on Headshaking behavior in horses.ObjectiveEvaluate the effects of oral magnesium alone or in combination with boron on Headshaking behavior in affected horses.AnimalsTwelve geldings (6 healthy controls and 6 affected).MethodsProspective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal-mediated Headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium-boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation.ResultsAll 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in Headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P l .001; 52% for M, IRR, 0.476; CI, 0.37, 0.62; P l .001; and 64% for MB, IRR, 0.358; CI, 0.27, 0.48; P l .001).Conclusions and clinical importanceMagnesium in combination with boron had the greatest decrease in Headshaking. Oral supplementation with magnesium or magnesium in combination with boron should be considered in horses affected with Headshaking.
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luteinizing hormone concentrations in healthy horses and horses with trigeminal mediated Headshaking over an 8 hour period
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Weich, Kalie M; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from a low threshold for firing of the trigeminal nerve. A seasonal component has been implicated in onset of clinical signs, which occur during the spring and summer months. Geldings are overrepresented in the affected population and hormonal differences as compared to a healthy control population of geldings might contribute to Headshaking. OBJECTIVE/HYPOTHESIS:To assess concentrations of luteinizing hormone (LH) over an 8-hour period in gelded healthy controls and horses affected with Headshaking. Our hypothesis was that geldings with seasonal Headshaking would have higher concentrations of LH over an 8-hour period compared to control horses during the summer when affected horses manifested Headshaking. ANIMALS:Twelve geldings (6 controls and 6 affected). METHODS:Prospective controlled trial. Blood samples were drawn every 15 minutes over an 8-hour time period during summer from all horses to measure circulating LH concentrations by using a radioimmunoassay for equine LH. All affected horses were actively affected by Headshaking at the time of sample collection. RESULTS:No statistically significant differences in LH concentrations were found throughout the study period in headshakers as compared to control horses. Time had no significant effect, but a slight decrease in LH concentrations was observed for all horses. The main limitation of the study was the low number of horses. CONCLUSIONS AND CLINICAL IMPORTANCE:Horses affected with Headshaking did not have significant differences in circulating LH during the late summer as compared to control horses.
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intravenous infusion of magnesium sulfate and its effect on horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from low-threshold firing of the trigeminal nerve resulting in apparent facial pain. Magnesium may have neuroprotective effects on nerve firing that potentially dampen signs of neuropathic pain. This hypothesis has not been investigated in horses with trigeminal-mediated Headshaking. OBJECTIVE:To investigate head-shaking behavior in affected horses after IV magnesium sulfate infusion. ANIMALS:Six geldings with trigeminal-mediated Headshaking. METHODS:Prospective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextrose solution (DS; control solution at 2 mL/kg body weight [BW]) and MgSO4 50% solution (MSS at 40 mg/kg BW). Head-shaking behavior was recorded at times T0 (baseline, before infusion) and T15, T30, T60, and T120 minutes post-infusion. Venous blood variables such as pH, HCO3 - , standard base excess (SBE), Na+ , Cl- , K+ , Ca2+ , Mg2+ , total magnesium (tMg), glucose, and lactate were measured; strong ion difference (SID) and anion gap (AG) were calculated for each time point. RESULTS:Blood variables including pH, Na+ , Cl- , K+ , SID, AG, lactate, Ca2+ , tMg, and Mg2+ had significant changes with MSS as compared to DS treatment. Glucose, SBE, and HCO3 - did not have significant changes. A 29% reduction in head-shaking rate occurred after MSS treatment but no change occurred after DS treatment. CONCLUSIONS AND CLINICAL IMPORTANCE:Administration of MSS IV increased plasma total and ionized magnesium concentrations and significantly decreased head-shaking behavior in horses with trigeminal-mediated Headshaking.
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Effects of magnesium with or without boron on Headshaking behavior in horses with trigeminal‐mediated Headshaking
Wiley, 2019Co-Authors: Shara A Sheldon, Lais Rr Costa, Kalie Weich, Quinn Howey, Monica Aleman, John E MadiganAbstract:Abstract Background Oral administration of magnesium and boron might have a beneficial effect on Headshaking behavior in horses. Objective Evaluate the effects of oral magnesium alone or in combination with boron on Headshaking behavior in affected horses. Animals Twelve geldings (6 healthy controls and 6 affected). Methods Prospective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal‐mediated Headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium‐boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation. Results All 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in Headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P
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alterations in metabolic status and Headshaking behavior following intravenous administration of hypertonic solutions in horses with trigeminal mediated Headshaking
Animal, 2018Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Cristina A Santoyo, John E MadiganAbstract:Trigeminal-nerve-mediated Headshaking represents a major welfare challenge for owners and veterinarians and is caused by a low threshold firing of the trigeminal nerve resulting in pain manifested as violent head jerking that often terminates the horse’s career and life due to poor quality of life and suffering. As metabolic changes such as acid–base status and electrolytes play a role in nerve firing, this study sought to assess the effects following administration of hypertonic solutions on Headshaking behavior in affected horses. This prospective randomized controlled crossover design utilized six horses affected with trigeminal-mediated Headshaking and three treatment groups receiving intravenous administration of 5% dextrose solution at 2 mL/kg bwt (DS), NaCl 7.5% at 4 mL/kg bwt (HS), or NaHCO3 8.4% at 2 mmol/kg bwt (HB). Horses were assessed for Headshaking behavior changes at times T0 (baseline, before infusion) and T15, 30, 60, 120 min post infusion. Venous blood variables: pH, HCO3−, standard base excess (SBE), Na+, Cl−, K+, Ca2+, Mg2+, total magnesium (tMg), glucose, and lactate were measured at T0 (baseline, before infusion) and T5, 15, 30, 60, 120 min post infusion. Strong ion difference (SID) and anion gap (AG) were calculated for each time point. With HB treatment, there was greater than 50% reduction in Headshaking rate. There was an effect of time on increasing Headshaking rate. There was an effect of breed on Headshaking rate. Changes in blood parameters following DS were virtually absent. Infusion of HS caused mild changes and did not vary much from baseline except for SID and AG. Only infusion of HB caused blood pH and HCO3− to be outside of the physiologic range (alkalemia and metabolic alkalosis, respectively), SBE to double or triple, AG to decrease, and SID to increase compared to baseline. Infusion of DS was followed by increase in blood glucose and decrease in blood Na+. Infusion of HS was followed by increase in Na+ and Cl− and decrease in Mg2+. Infusion of HB was followed by decrease in Mg2+. Blood tMg, K+, and Ca2+ decreased slightly, but did not vary greatly from baseline following any of the treatments, remaining within physiologic ranges. Changes in blood composition were transient. Among all treatments, only HB had an effect on Headshaking rate. The limited effects following these fluids were likely due to normal mechanisms of regulation of blood levels of pH and electrolytes. Further investigations of changes in electrolytes that might affect nerve firing should be explored.
V. L. H. Roberts - One of the best experts on this subject based on the ideXlab platform.
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the safety and efficacy of neuromodulation using percutaneous electrical nerve stimulation for the management of trigeminal mediated Headshaking in 168 horses
Equine Veterinary Journal, 2020Co-Authors: V. L. H. Roberts, Mick Bailey, Nik PatelAbstract:BACKGROUND Early results from the use of neuromodulation by percutaneous electrical nerve stimulation for the management of trigeminal-mediated Headshaking in horses were promising but lacked sufficient case numbers and long-term follow-up. The neuromodulatory procedure has since been established as EquiPENS™. OBJECTIVES The aim of this study was to report long-term results from a larger number of cases and to investigate for predictors of outcome. STUDY DESIGN Prospective case series using international, multi-centre data. METHODS Eligible cases were horses with a veterinary diagnosis of trigeminal-mediated Headshaking, which received EquiPENS™ neuromodulation at trained centres between August 2013 and November 2017. The standard protocol was an initial three-procedure course, with additional procedures should a horse go into remission but then relapse. Data collected included signalment, history, diagnostic tests performed, details of any complications, whether horses had gone into remission and the length of remission. RESULTS Results were obtained from 168 horses, with 530 procedures. The complication rate was 8.8% of procedures. In all but one case, complications were mild and transient, without self-trauma. Remission of Headshaking following the initial course occurred in 53% (72/136) of horses. Median length of time recorded in remission was 9.5 weeks (range 2 days to 156 weeks ongoing). Where signs recurred, most horses went back into remission following additional procedures, usually for longer than from the previous procedure. No predictors for outcome were determined. MAIN LIMITATIONS No placebo or control group, owner-assessed results. CONCLUSIONS EquiPENS™ neuromodulation can be an effective and safe treatment for the management of trigeminal-mediated Headshaking in some horses. An increased understanding of neuromodulation could help optimise the technique. Advances in treatment for trigeminal-mediated Headshaking will remain limited until there is a greater understanding of the aetiopathogenesis of the condition.
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trigeminal mediated Headshaking in horses prevalence impact and management strategies
Veterinary Medicine : Research and Reports, 2019Co-Authors: V. L. H. RobertsAbstract:Trigeminal-mediated Headshaking is a little-understood neuropathic facial pain condition of the horse. The condition may affect around 1% of the equine population to a degree of severity sufficient to require veterinary attention. As a pain condition, this represents a significant welfare issue. Horses are usually more severely affected at exercise which can leave them unable to perform, or even dangerous to ride and handle. With little known about the condition and variable response to treatments, severely affected horses are often euthanized. This review article considers the literature on trigeminal-mediated Headshaking, focusing on what is known, and indeed not known, about the prevalence of the condition and its impact. The current published management options are considered, along with their challenges and limitations.
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prevalence of Headshaking within the equine population in the uk
Equine Veterinary Journal, 2018Co-Authors: Sarah Ross, Jane Murray, V. L. H. RobertsAbstract:SummaryBackground Headshaking in horses has been reported to be most commonly due to idiopathic neuropathic facial pain (trigeminal-mediated Headshaking). The prevalence of Headshaking in horses in the UK is unknown. Objectives To estimate owner-reported prevalence of Headshaking in horses in the UK and to report their signalment and disease characteristics, as reported by owners. Study design Cross-sectional web based owner questionnaire. Methods The questionnaire was advertised online via social media, horse forums, veterinary websites and equestrian magazines from 17 June 2016, until greater than 1,000 responses had been obtained. All UK horse owners were eligible to complete the questionnaire, however only one questionnaire could be completed per owner. Results The estimated prevalence of owner-reported Headshaking in the sample population of horses (n = 1014), within the last year, was 4.6% (95% CI 3.5, 6.1), whereas 6.2% (95% CI 4.9, 7.9) of horses were reported by their owners to have shown signs of Headshaking at any time-point since ownership. There was no association of sex or breed. Nineteen percent of Headshaking horses were reported to show Headshaking at rest. Fewer than one-third (30.2%, n = 19) of Headshaking horses had been examined by a veterinarian for Headshaking. Of horses seen by a veterinarian, the cause for Headshaking remained unknown in the majority of cases (57.9% responses) and trigeminal-mediated Headshaking was reported as a diagnosis in just one case. Main limitations The accuracy in data reporting by horse owners was not verified in this study. There may be a potential for bias towards over-reporting due to the nature of survey participation. Conclusions Within this sample, owner-reported prevalence of signs of Headshaking within the last year, in horses in the UK was 4.6%. Over two-thirds of owners of Headshaking horses did not seek veterinary intervention for Headshaking. Trigeminal-mediated Headshaking was rarely reported by owners as a diagnosis. This article is protected by copyright. All rights reserved.
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trigeminal nerve root demyelination not seen in six horses diagnosed with trigeminal mediated Headshaking
Frontiers in Veterinary Science, 2017Co-Authors: V. L. H. Roberts, D Fews, Jennifer M Mcnamara, Seth LoveAbstract:Abstract: Trigeminal-mediated Headshaking is an idiopathic neuropathic facial pain syndrome in horses. There are clinical similarities to trigeminal neuralgia, a neuropathic facial pain syndrome in man, which is usually caused by demyelination of trigeminal sensory fibres within either the nerve root or, less commonly, the brainstem. Our hypothesis was that the neuropathological substrate of Headshaking in horses is similar to that of trigeminal neuralgia in man. Trigeminal nerves, nerve roots, ganglia, infraorbital and caudal nasal nerves from horse abattoir specimens and from horses euthanased due to trigeminal-mediated Headshaking were removed, fixed and processed for histological assessment by a veterinary pathologist and a neuropathologist with particular experience of trigeminal neuralgia histology. No histological differences were detected between samples from horses with Headshaking and those from normal horses. These results suggest that trigeminal-mediated Headshaking may have a different pathological substrate from trigeminal neuralgia in man.
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Short Communication Accuracy of needle
2016Co-Authors: S. Wilmink, C. M. R. Warren-smith, V. L. H. RobertsAbstract:placement in diagnostic local analgesia of the maxillary nerve for investigation of trigeminally mediated Headshaking in horse
Monica R Aleman - One of the best experts on this subject based on the ideXlab platform.
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effects of magnesium with or without boron on Headshaking behavior in horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais RR; Weich, Kalie; Howey, Quinn; Madigan, John E | Abstract: BackgroundOral administration of magnesium and boron might have a beneficial effect on Headshaking behavior in horses.ObjectiveEvaluate the effects of oral magnesium alone or in combination with boron on Headshaking behavior in affected horses.AnimalsTwelve geldings (6 healthy controls and 6 affected).MethodsProspective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal-mediated Headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium-boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation.ResultsAll 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in Headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P l .001; 52% for M, IRR, 0.476; CI, 0.37, 0.62; P l .001; and 64% for MB, IRR, 0.358; CI, 0.27, 0.48; P l .001).Conclusions and clinical importanceMagnesium in combination with boron had the greatest decrease in Headshaking. Oral supplementation with magnesium or magnesium in combination with boron should be considered in horses affected with Headshaking.
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luteinizing hormone concentrations in healthy horses and horses with trigeminal mediated Headshaking over an 8 hour period
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Weich, Kalie M; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from a low threshold for firing of the trigeminal nerve. A seasonal component has been implicated in onset of clinical signs, which occur during the spring and summer months. Geldings are overrepresented in the affected population and hormonal differences as compared to a healthy control population of geldings might contribute to Headshaking. OBJECTIVE/HYPOTHESIS:To assess concentrations of luteinizing hormone (LH) over an 8-hour period in gelded healthy controls and horses affected with Headshaking. Our hypothesis was that geldings with seasonal Headshaking would have higher concentrations of LH over an 8-hour period compared to control horses during the summer when affected horses manifested Headshaking. ANIMALS:Twelve geldings (6 controls and 6 affected). METHODS:Prospective controlled trial. Blood samples were drawn every 15 minutes over an 8-hour time period during summer from all horses to measure circulating LH concentrations by using a radioimmunoassay for equine LH. All affected horses were actively affected by Headshaking at the time of sample collection. RESULTS:No statistically significant differences in LH concentrations were found throughout the study period in headshakers as compared to control horses. Time had no significant effect, but a slight decrease in LH concentrations was observed for all horses. The main limitation of the study was the low number of horses. CONCLUSIONS AND CLINICAL IMPORTANCE:Horses affected with Headshaking did not have significant differences in circulating LH during the late summer as compared to control horses.
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intravenous infusion of magnesium sulfate and its effect on horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from low-threshold firing of the trigeminal nerve resulting in apparent facial pain. Magnesium may have neuroprotective effects on nerve firing that potentially dampen signs of neuropathic pain. This hypothesis has not been investigated in horses with trigeminal-mediated Headshaking. OBJECTIVE:To investigate head-shaking behavior in affected horses after IV magnesium sulfate infusion. ANIMALS:Six geldings with trigeminal-mediated Headshaking. METHODS:Prospective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextrose solution (DS; control solution at 2 mL/kg body weight [BW]) and MgSO4 50% solution (MSS at 40 mg/kg BW). Head-shaking behavior was recorded at times T0 (baseline, before infusion) and T15, T30, T60, and T120 minutes post-infusion. Venous blood variables such as pH, HCO3 - , standard base excess (SBE), Na+ , Cl- , K+ , Ca2+ , Mg2+ , total magnesium (tMg), glucose, and lactate were measured; strong ion difference (SID) and anion gap (AG) were calculated for each time point. RESULTS:Blood variables including pH, Na+ , Cl- , K+ , SID, AG, lactate, Ca2+ , tMg, and Mg2+ had significant changes with MSS as compared to DS treatment. Glucose, SBE, and HCO3 - did not have significant changes. A 29% reduction in head-shaking rate occurred after MSS treatment but no change occurred after DS treatment. CONCLUSIONS AND CLINICAL IMPORTANCE:Administration of MSS IV increased plasma total and ionized magnesium concentrations and significantly decreased head-shaking behavior in horses with trigeminal-mediated Headshaking.
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alterations in metabolic status and Headshaking behavior following intravenous administration of hypertonic solutions in horses with trigeminal mediated Headshaking
Animal, 2018Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Cristina A Santoyo, John E MadiganAbstract:Trigeminal-nerve-mediated Headshaking represents a major welfare challenge for owners and veterinarians and is caused by a low threshold firing of the trigeminal nerve resulting in pain manifested as violent head jerking that often terminates the horse’s career and life due to poor quality of life and suffering. As metabolic changes such as acid–base status and electrolytes play a role in nerve firing, this study sought to assess the effects following administration of hypertonic solutions on Headshaking behavior in affected horses. This prospective randomized controlled crossover design utilized six horses affected with trigeminal-mediated Headshaking and three treatment groups receiving intravenous administration of 5% dextrose solution at 2 mL/kg bwt (DS), NaCl 7.5% at 4 mL/kg bwt (HS), or NaHCO3 8.4% at 2 mmol/kg bwt (HB). Horses were assessed for Headshaking behavior changes at times T0 (baseline, before infusion) and T15, 30, 60, 120 min post infusion. Venous blood variables: pH, HCO3−, standard base excess (SBE), Na+, Cl−, K+, Ca2+, Mg2+, total magnesium (tMg), glucose, and lactate were measured at T0 (baseline, before infusion) and T5, 15, 30, 60, 120 min post infusion. Strong ion difference (SID) and anion gap (AG) were calculated for each time point. With HB treatment, there was greater than 50% reduction in Headshaking rate. There was an effect of time on increasing Headshaking rate. There was an effect of breed on Headshaking rate. Changes in blood parameters following DS were virtually absent. Infusion of HS caused mild changes and did not vary much from baseline except for SID and AG. Only infusion of HB caused blood pH and HCO3− to be outside of the physiologic range (alkalemia and metabolic alkalosis, respectively), SBE to double or triple, AG to decrease, and SID to increase compared to baseline. Infusion of DS was followed by increase in blood glucose and decrease in blood Na+. Infusion of HS was followed by increase in Na+ and Cl− and decrease in Mg2+. Infusion of HB was followed by decrease in Mg2+. Blood tMg, K+, and Ca2+ decreased slightly, but did not vary greatly from baseline following any of the treatments, remaining within physiologic ranges. Changes in blood composition were transient. Among all treatments, only HB had an effect on Headshaking rate. The limited effects following these fluids were likely due to normal mechanisms of regulation of blood levels of pH and electrolytes. Further investigations of changes in electrolytes that might affect nerve firing should be explored.
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idiopathic Headshaking is it still idiopathic
Veterinary Journal, 2014Co-Authors: Kirstie Pickles, John E Madigan, Monica R AlemanAbstract:The clinical syndrome of equine idiopathic Headshaking (HSK) was first described in the veterinary literature over 100 years ago, and the disorder continues to be a cause of substantial distress for the horse, frustration for the owner and therapeutic challenge for the veterinarian. This review presents a summary of the current knowledge of clinical signs, signalment, aetiopathogenesis, anatomy, diagnosis and treatment of idiopathic HSK. Recent advances in understanding the pathogenesis of the disease will be discussed with reference to human trigeminal neuralgia, along with the implications this may have for potential therapies.
Derek C. Knottenbelt - One of the best experts on this subject based on the ideXlab platform.
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a randomised blinded crossover study to assess the efficacy of a feed supplement in alleviating the clinical signs of Headshaking in 32 horses
Equine Veterinary Journal, 2013Co-Authors: W A Talbot, Derek C. Knottenbelt, G L Pinchbeck, H Graham, S. A. MckaneAbstract:Summary Reasons for performing study: Feed supplements are commonly used by owners to alleviate Headshaking; however, randomised, controlled trials are required to assess their efficacy. Objective: To determine the efficacy of a feed supplement for alleviation of the clinical signs of Headshaking using a randomised, blinded, placebo-controlled trial. Methods: Using a crossover design, 44 horses previously diagnosed with chronic idiopathic Headshaking received both the supplement and a matching placebo per os for 28 days with a washout period between of 14 days. Video recordings were taken at rest and exercise prior to the study and at the end of both periods of treatment. The degree of Headshaking was assessed in a blinded, randomised manner by 2 veterinary surgeons. At the same time points, owners completed a questionnaire to assess the severity of Headshaking signs. A Wilcoxon signed rank test was used to compare the scores while on supplement and placebo. Results: Using the video assessments, there was no significant difference between scores while on supplement compared with placebo (P = 0.7). Using the questionnaire responses, there was no significant difference between scores for any activity when the placebo and the supplement were compared with each other. However, owners reported significant improvement during all activities for both placebo and supplement compared with pretreatment scores. Conclusions and potential relevance: The supplement offered no benefit over a placebo in alleviating the clinical signs of Headshaking. There appeared to be a significant proxy placebo effect when the outcome was based on subjective owner perception of clinical signs. This study demonstrated no beneficial effect of this supplement on the clinical signs of Headshaking. The study did show a significant placebo effect, thereby highlighting the necessity of properly conducted, randomised controlled trials, with blinding, to assess true treatment effects in trials in animals.
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caudal anaesthesia of the infraorbital nerve for diagnosis of idiopathic Headshaking and caudal compression of the infraorbital nerve for its treatment in 58 horses
Equine Veterinary Journal, 2013Co-Authors: V. L. H. Roberts, S. A. Mckane, A. Williams, Justin Perkins, W H Tremaine, E Skarlina, D A Gorvy, I White, Derek C. KnottenbeltAbstract:Summary Reasons for performing study: Idiopathic Headshaking is often a facial pain syndrome, but a diagnostic protocol has not been described. In a previous study, caudal compression of the infraorbital nerve for treatment offered a fair success rate, but low case numbers and short follow-up time were limitations. Objectives: To describe a diagnostic protocol for Headshaking, examining the role of bilateral local analgesia of the posterior ethmoidal nerve (PET block). To report longer-term follow-up after surgery of the original cases and further cases and to determine whether changes to the technique influence success rates and complications. Methods: Records of horses that had undergone PET block and caudal compression surgery at 3 hospitals were reviewed. Modifications to the surgical technique included placing additional coils into the infraorbital canal and/or performing concurrent laser cautery of the nerve. Follow-up information was obtained by telephone contact with owners. Results: The PET block was performed in 27 horses, with a positive result in 23 of 27 (85%). Surgery was performed in 58 horses. A successful outcome was initially achieved in 35 of 57 (63%) horses, but recurrence occurred between 9 and 30 months later in 9 (26%). Surgery was repeated in 10 of 31 (32%) horses. Final success rate, considering only response to the last performed surgery, was 28 of 57 (49%) horses with median follow-up time of 18 months (range 2–66 months). Nose-rubbing was reported post operatively in 30 of 48 (63%) horses. This resolved in all but 4 horses, which were subjected to euthanasia. Response to PET block or change in surgical technique did not appear to influence outcome or complications. Conclusions and potential relevance: The diagnostic protocol described is recommended for the investigation of headshakers. Caudal compression offers the best prognosis for a successful outcome compared with other treatments, for horses in which the only alternative is euthanasia. Surgical treatment of the disorder requires refinement, and the pathogenesis of the disorder requires investigation.
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Headshaking in horses possible aetiopathogenesis suggested by the results of diagnostic tests and several treatment regimes used in 20 cases
Equine Veterinary Journal, 2010Co-Authors: S A Newton, Derek C. Knottenbelt, P R EldridgeAbstract:Twenty mature horses with typical Headshaking of 2 week-7 year duration were studied. Clinical examinations included radiography of the head and nasopharyngeal endoscopy. All were assessed at rest and at exercise, both before and after fitting an occlusive nasal mask, application of tinted contact lenses and the perineural anaesthesia of the infraorbital and posterior ethmoidal branches of the trigeminal nerve. Infraorbital anaesthesia had no effect in 6/7 cases but 11/17 (65%) cases showed a 90-100% improvement following posterior ethmoidal nerve anaesthesia. Tinted contact lenses had no apparent long-term benefit, although 2 cases showed a transient improvement. We found no other evidence to suggest a photic aetiology in the current series of cases. Treatment regimens based on the results of the diagnostic investigative methods included sclerosis of the posterior ethmoidal branch of the trigeminal nerve. This was effective in some cases but the benefits were temporary. Cyproheptadine alone was ineffective but the addition of carbamazepine resulted in 80-100% improvement in 80% of cases. Carbemazepine alone was effective in 88% of cases but results were unpredictable at predefined dose rates. The positive response to carbamazepine, combined with the clinical features is consistent with involvement of the trigeminal nerve, particularly the more proximal branches such as the posterior ethmoidal nerve. Headshaking has some clinical features in common with trigeminal neuralgia in humans. As a result of the findings detailed in this paper, we conclude that a trigeminal neuritis or neuralgia may be the basis of the underlying aetiopathology of equine Headshaking. Initial observations of the positive response of headshakers to carbamazepine therapy is encouraging. However, future studies will include a more detailed investigation of dosages, duration of effectiveness (in some cases it appears short-lived) and other effects. In practice there is a realistic possibility of controlling but not curing Headshaking with carbamazepine therapy at the present time. Other future investigations will include details of the functional anatomy of the trigeminal nerve and the role of the P2 myelin protein in Headshaking and other neurological disease.
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Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic Headshaking and assessment of its efficacy in 24 horses.
Equine veterinary journal, 2009Co-Authors: V. L. H. Roberts, S. A. Mckane, A. Williams, Derek C. KnottenbeltAbstract:Summary Reasons for designing and reporting technique: Idiopathic Headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal location within the infraorbital canal and the technique requires validation. Hypothesis: Caudal compression of the infraorbital nerve with platinum coils, performed in horses diagnosed with idiopathic Headshaking, results in a decrease in clinical signs. Methods: Caudal compression of the infraorbital nerve, using platinum embolisation coils, was performed under fluoroscopic guidance. Clinical records of 24 idiopathic headshakers that had undergone this procedure were reviewed. Follow-up information was obtained by telephone questionnaire with the owner or referring veterinary surgeon. Results: All 24 horses had at least one surgical procedure. Median follow-up time was 6 months. There were 2 horses which had surgery 2 weeks before follow-up and these were excluded from the analysis of outcome. Following one surgery, 13/22 horses (59.0%) had a successful outcome. Of the 9 horses that did not improve, surgery was repeated in 6 cases. Two of these horses had a successful outcome. Overall, a successful outcome was obtained in 16/19 horses (84.2%). Conclusions: This surgical technique is likely to prevent input from the TgN at a more caudal location then the previously described infraorbital neurectomy. The technique requires refinement.
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Caudal compression of the infraorbital nerve: a novel surgical technique for treatment of idiopathic Headshaking and assessment of its efficacy in 24 horses.
'Wiley', 2009Co-Authors: Vl Roberts, S. A. Mckane, Williams A, Derek C. KnottenbeltAbstract:REASONS FOR DESIGNING AND REPORTING TECHNIQUE: Idiopathic Headshaking has remarkable similarities to human neuropathic facial pain syndromes associated with post herpetic and trigeminal neuralgia. These derive from abnormal sensory function within the peripheral or central pathways of the trigeminal nerve (TgN). Limiting input from the TgN can be helpful in controlling the perception of pain. Rhizotomy of the infraorbital branch of the TgN as it emerges from the infraorbital canal has been reported but has a poor efficacy. A novel technique involves compression of the nerve at a more caudal location within the infraorbital canal and the technique requires validation
Shara A Sheldon - One of the best experts on this subject based on the ideXlab platform.
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effects of magnesium with or without boron on Headshaking behavior in horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais RR; Weich, Kalie; Howey, Quinn; Madigan, John E | Abstract: BackgroundOral administration of magnesium and boron might have a beneficial effect on Headshaking behavior in horses.ObjectiveEvaluate the effects of oral magnesium alone or in combination with boron on Headshaking behavior in affected horses.AnimalsTwelve geldings (6 healthy controls and 6 affected).MethodsProspective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal-mediated Headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium-boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation.ResultsAll 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in Headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P l .001; 52% for M, IRR, 0.476; CI, 0.37, 0.62; P l .001; and 64% for MB, IRR, 0.358; CI, 0.27, 0.48; P l .001).Conclusions and clinical importanceMagnesium in combination with boron had the greatest decrease in Headshaking. Oral supplementation with magnesium or magnesium in combination with boron should be considered in horses affected with Headshaking.
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luteinizing hormone concentrations in healthy horses and horses with trigeminal mediated Headshaking over an 8 hour period
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Kalie Weich, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Weich, Kalie M; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from a low threshold for firing of the trigeminal nerve. A seasonal component has been implicated in onset of clinical signs, which occur during the spring and summer months. Geldings are overrepresented in the affected population and hormonal differences as compared to a healthy control population of geldings might contribute to Headshaking. OBJECTIVE/HYPOTHESIS:To assess concentrations of luteinizing hormone (LH) over an 8-hour period in gelded healthy controls and horses affected with Headshaking. Our hypothesis was that geldings with seasonal Headshaking would have higher concentrations of LH over an 8-hour period compared to control horses during the summer when affected horses manifested Headshaking. ANIMALS:Twelve geldings (6 controls and 6 affected). METHODS:Prospective controlled trial. Blood samples were drawn every 15 minutes over an 8-hour time period during summer from all horses to measure circulating LH concentrations by using a radioimmunoassay for equine LH. All affected horses were actively affected by Headshaking at the time of sample collection. RESULTS:No statistically significant differences in LH concentrations were found throughout the study period in headshakers as compared to control horses. Time had no significant effect, but a slight decrease in LH concentrations was observed for all horses. The main limitation of the study was the low number of horses. CONCLUSIONS AND CLINICAL IMPORTANCE:Horses affected with Headshaking did not have significant differences in circulating LH during the late summer as compared to control horses.
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intravenous infusion of magnesium sulfate and its effect on horses with trigeminal mediated Headshaking
Journal of Veterinary Internal Medicine, 2019Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Ana C Santoyo, John E MadiganAbstract:Author(s): Sheldon, Shara A; Aleman, Monica; Costa, Lais Rosa R; Santoyo, Ana C; Howey, Quinn; Madigan, John E | Abstract: BACKGROUND:Trigeminal-mediated Headshaking results from low-threshold firing of the trigeminal nerve resulting in apparent facial pain. Magnesium may have neuroprotective effects on nerve firing that potentially dampen signs of neuropathic pain. This hypothesis has not been investigated in horses with trigeminal-mediated Headshaking. OBJECTIVE:To investigate head-shaking behavior in affected horses after IV magnesium sulfate infusion. ANIMALS:Six geldings with trigeminal-mediated Headshaking. METHODS:Prospective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextrose solution (DS; control solution at 2 mL/kg body weight [BW]) and MgSO4 50% solution (MSS at 40 mg/kg BW). Head-shaking behavior was recorded at times T0 (baseline, before infusion) and T15, T30, T60, and T120 minutes post-infusion. Venous blood variables such as pH, HCO3 - , standard base excess (SBE), Na+ , Cl- , K+ , Ca2+ , Mg2+ , total magnesium (tMg), glucose, and lactate were measured; strong ion difference (SID) and anion gap (AG) were calculated for each time point. RESULTS:Blood variables including pH, Na+ , Cl- , K+ , SID, AG, lactate, Ca2+ , tMg, and Mg2+ had significant changes with MSS as compared to DS treatment. Glucose, SBE, and HCO3 - did not have significant changes. A 29% reduction in head-shaking rate occurred after MSS treatment but no change occurred after DS treatment. CONCLUSIONS AND CLINICAL IMPORTANCE:Administration of MSS IV increased plasma total and ionized magnesium concentrations and significantly decreased head-shaking behavior in horses with trigeminal-mediated Headshaking.
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Effects of magnesium with or without boron on Headshaking behavior in horses with trigeminal‐mediated Headshaking
Wiley, 2019Co-Authors: Shara A Sheldon, Lais Rr Costa, Kalie Weich, Quinn Howey, Monica Aleman, John E MadiganAbstract:Abstract Background Oral administration of magnesium and boron might have a beneficial effect on Headshaking behavior in horses. Objective Evaluate the effects of oral magnesium alone or in combination with boron on Headshaking behavior in affected horses. Animals Twelve geldings (6 healthy controls and 6 affected). Methods Prospective randomized controlled dietary trial over 42 days in 12 horses (6 horses diagnosed with trigeminal‐mediated Headshaking and 6 unaffected healthy controls). All horses received a hay diet and were randomized into 3 treatment groups: pelleted feed combination (PF), pelleted feed combination with magnesium (M), and pelleted feed combination with magnesium‐boron (MB) with a week washout of hay only between treatments. Headshaking behavior and biochemical blood variables were assessed at baseline (hay only) and then after each week of supplementation. Results All 3 diet interventions increased blood ionized and total magnesium. Groups M and MB further increased Mg2+ when compared to PF. Horses receiving treatments had a significant reduction in Headshaking behavior, as measured by incidence rate ratio (IRR), when compared to unsupplemented hay diet (44% for PF, IRR, 0.558; CI, 0.44, 0.72; P
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alterations in metabolic status and Headshaking behavior following intravenous administration of hypertonic solutions in horses with trigeminal mediated Headshaking
Animal, 2018Co-Authors: Shara A Sheldon, Monica R Aleman, Lais Rr Costa, Quinn Howey, Cristina A Santoyo, John E MadiganAbstract:Trigeminal-nerve-mediated Headshaking represents a major welfare challenge for owners and veterinarians and is caused by a low threshold firing of the trigeminal nerve resulting in pain manifested as violent head jerking that often terminates the horse’s career and life due to poor quality of life and suffering. As metabolic changes such as acid–base status and electrolytes play a role in nerve firing, this study sought to assess the effects following administration of hypertonic solutions on Headshaking behavior in affected horses. This prospective randomized controlled crossover design utilized six horses affected with trigeminal-mediated Headshaking and three treatment groups receiving intravenous administration of 5% dextrose solution at 2 mL/kg bwt (DS), NaCl 7.5% at 4 mL/kg bwt (HS), or NaHCO3 8.4% at 2 mmol/kg bwt (HB). Horses were assessed for Headshaking behavior changes at times T0 (baseline, before infusion) and T15, 30, 60, 120 min post infusion. Venous blood variables: pH, HCO3−, standard base excess (SBE), Na+, Cl−, K+, Ca2+, Mg2+, total magnesium (tMg), glucose, and lactate were measured at T0 (baseline, before infusion) and T5, 15, 30, 60, 120 min post infusion. Strong ion difference (SID) and anion gap (AG) were calculated for each time point. With HB treatment, there was greater than 50% reduction in Headshaking rate. There was an effect of time on increasing Headshaking rate. There was an effect of breed on Headshaking rate. Changes in blood parameters following DS were virtually absent. Infusion of HS caused mild changes and did not vary much from baseline except for SID and AG. Only infusion of HB caused blood pH and HCO3− to be outside of the physiologic range (alkalemia and metabolic alkalosis, respectively), SBE to double or triple, AG to decrease, and SID to increase compared to baseline. Infusion of DS was followed by increase in blood glucose and decrease in blood Na+. Infusion of HS was followed by increase in Na+ and Cl− and decrease in Mg2+. Infusion of HB was followed by decrease in Mg2+. Blood tMg, K+, and Ca2+ decreased slightly, but did not vary greatly from baseline following any of the treatments, remaining within physiologic ranges. Changes in blood composition were transient. Among all treatments, only HB had an effect on Headshaking rate. The limited effects following these fluids were likely due to normal mechanisms of regulation of blood levels of pH and electrolytes. Further investigations of changes in electrolytes that might affect nerve firing should be explored.
