Headshaking in horses is a condition characterized by involuntary, repetitive movements of the head, often described as shaking, flicking, or jerking motions. This behavior can occur spontaneously and is sometimes associated with specific triggers such as light, sound, or exercise. The underlying causes of headshaking are not fully understood but may involve neuropathic pain, particularly related to the trigeminal nerve. The condition can affect a horse's quality of life and performance. Various diagnostic approaches are employed to identify potential causes, and management strategies may include environmental modifications, medical treatments, and protective gear. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, diagnosis, and management of headshaking in horses.
Aleman M, Morales CJ.Idiopathic trigeminal-mediated headshaking is a painful neuropathic disorder characterized by sudden, violent, predominantly vertical head movements of unknown etiology. Clinical signs may be seasonal or persistent and triggered by light, sound, exercise, or tactile nasal stimulation. The pathophysiology is multifactorial, involving abnormal trigeminal nerve excitability influenced by hormonal, environmental, and dietary factors. Treatment is challenging and typically multimodal, aiming to reduce trigeminal hypersensitivity and improve quality of life.
Hartl B, Strohmayer C, Vali Y, Lyrakis M, Kneissl SM.Horses with hyoid bone disease may present with clinical symptoms such as exercise intolerance, resistance to ridden work, anorexia, or headshaking. This study aims to describe the computed tomographic (CT) signs and prevalence of hyoid disease and to evaluate their association with other CT changes of the head. Unassigned: In this study, four investigators conducted a retrospective analysis of their findings after reviewing the medical records of 200 horses that had undergone CT scans between 2009 and 2019. A total of 32 parameters were analyzed, and associations were evaluated between those ...
Heun F, Delarocque J, Feige K, Hellige M.Nerve atrophy results in trigeminal nerve (TN) asymmetry detectable by magnetic resonance imaging (MRI) in humans, but similar studies have not been performed in horses with idiopathic trigeminal-mediated headshaking (ITMHS). Objective: Horses with ITMHS show greater MRI-detected trigeminal-nerve asymmetry than controls. Methods: A total of 20 adult horses with ITMHS and six unaffected control horses. Methods: Retrospective case-control study of the TN cross-sectional area (TNCSA) based on 3-Tesla MRI scans of the equine brain. TNCSA and its side-to-side differences at four defined measurement...
de Preux M, Precht C, Becker R, Stieglitz L, Easley J, Koch C.Trigeminal-mediated headshaking is a neuropathic disorder in horses, characterized by signs of regional pain similar to trigeminal neuralgia in humans. The injection of glycerol into the trigeminal cistern to ablate pain-conducting nerve fibers within the trigeminal ganglion -known as glycerol rhizotomy- is a well-established treatment in human medicine. This study compares two approaches to the equine trigeminal cistern using a navigation system for guiding needle placement, a previously described ventral and a newly developed transmandibular lateral approach. The surgical accuracy and risk o...
Forni G, Ellero N, Mannini A, Scacco L, Freccero F.A 3-year-old Quarter Horse stallion was referred for headshaking (HS) syndrome of one month duration. The horse underwent complete HS workup. Physical examination revealed up-and-down head movements associated with nose snorting during lunging and riding, in the absence of other abnormalities at rest or in motion. Lameness, neurologic and behavioural evaluations were unremarkable. Endoscopic examination of the upper respiratory tract showed bilateral guttural pouches (GPs) inflammation. The mucosal surface was altered by the presence of areas of microbullous appearance coalescing into some bul...
Lloyd-Edwards RA, Mulders E, Sloet van Oldruitenborgh-Oosterbaan MM, Veraa S. Headshaking is a common condition in horses, most cases are presumed idiopathic/trigeminal-nerve mediated. Diagnostic work-up of a headshaking horse may involve computed tomography (CT) of the head to exclude causative structural pathology. The relevance of the presence and severity of hyoid apparatus findings at CT to headshaking is unknown. A retrospective analysis of CT changes in the hyoid apparatus in horses was carried out. Comparisons were performed between horses with signs of headshaking and a control population and a subgroup of horses with signs of headshaking and no other 'likely...
Franzen V, Reisbeck D, Leibl Y, Schoster A, May A.While there is agreement that horses experience pain during the actual headshaking attacks, there is still a lack of research about the time between the individual episodes in this species. Objective: To evaluate the signs of pain in horses with TMHS at rest in the absence of common triggering factors. Methods: Twenty TMHS horses (not head shaking at the time of pain assessment), 20 horses with colic, and 20 clinically healthy horses. Methods: Descriptive study assessing pain in TMHS horses during the absence of clinical signs using the Horse Grimace scale (HGS). To grade the pain shown with T...
Witt P, Stas EKL, Hardeman LC, van Proosdij ER, Weerts EAWS, Lloyd-Edwards RA, Veraa S, Kranenburg LC, van den Boom R.A sixteen-year-old Friesian mare was admitted to the university clinic with the following clinical signs: anorexia, weight loss, fever, bilateral nasal discharge, unilateral facial paralysis and a non-healing corneal lesion. Endoscopic examination of the upper airways showed thickening of the proximal portion of the right stylohyoid bone. Computed tomography imaging showed pneumocephalus due to grade 3 unilateral temporohyoid osteoarthropathy (THO) with fracture of the petrous temporal bone. The horse did not improve following medical treatment. Surgical intervention was declined by the owner ...
Franzen V, Gruber NA, Klußmann S, Schoster A, May A.Trigeminal-mediated headshaking is a neuropathic facial pain condition in horses. No treatment has been entirely successful. Repetitive transcranial magnetic stimulation (rTMS) is used in human medicine as a treatment for various neuropathic pain conditions, and good results have been achieved in cases of trigeminal neuralgia. Objective: Apply rTMS to horses with trigeminal-mediated headshaking (TMHS) and to evaluate tolerability, application of the setting, and success rate. Methods: Seventeen horses with nonseasonal signs of TMHS. Methods: Other underlying causes of headshaking were ruled ou...
Beldeanu S, Tay MCA, Daniel C, Dosi MCM, Hahn CN, James O, Townsend NB, Liuti T, Schwarz T, Parkinson NJ.Fractures of the paracondylar process of the occipital bone may cause headshaking, neck pain and neurologic deficits. The condition is being recognised more frequently with increasing availability of computed tomography. However, to date only limited information is available as to presentation, treatment, surgical approach and outcome. Objective: To describe the clinical signs, imaging findings, treatment, surgical approach and outcome in three horses diagnosed with paracondylar process fracture. Methods: Retrospective case series. Methods: Clinical records and diagnostic images of affected ca...
Becker R, Haenssgen K, Precht C, Khoma OZ, Hlushchuk R, Koch C, Kaessmeyer S, de Preux M.Equine trigeminal-mediated headshaking is a painful neuropathic disorder comparable to trigeminal neuralgia in humans. The selective destruction of pain fibers within the trigeminal ganglion, called rhizotomy, is the surgical treatment of choice for idiopathic trigeminal neuralgia refractory to medical treatment in humans. The human trigeminal ganglion is enclosed by a dural recess called the Meckel's or trigeminal cave, in which the ganglion is surrounded by a cerebrospinal fluid (CSF)-filled subarachnoid space. During glycerol rhizotomy, glycerol is percutaneously injected in this CSF-filled...
Pickles KJ, Marlin DJ, Williams JM, Roberts VLH.Equine trigeminal-mediated (TGM) headshaking (HS) is a neuropathic facial pain syndrome characterised by varying intensity and frequencies of head movements and signs of nasal irritation. An accurate method for quantification and/or characterisation of HS severity is lacking. Objective: To develop and validate an objective measure of TGMHS. Methods: Prospective case control study. Methods: Horses presenting for investigation of HS were recruited alongside those presenting for forelimb lameness (LAME) and pre-purchase examination as well as healthy controls (CONTROL). Head movement data were co...
Nessler JN, Delarocque J, Kloock T, Twele L, Neudeck S, Meyerhoff N, Riese F, Cavalleri JV, Tipold A, Feige K, Niebuhr T.To determine whether sensory nerve conduction stimulus threshold measurements of the infraorbital nerve are able to differentiate horses with idiopathic trigeminal-mediated headshaking (i-TMHS) from healthy horses and from horses with secondary trigeminal-mediated headshaking (s-TMHS). In a prospective trial, headshaking horses were examined using a standardized diagnostic protocol, including advanced diagnostics such as computed tomography and 3-Tesla-magnetic resonance imaging (MRI), to differentiate s-TMHS from i-TMHS. Clinically healthy horses served as controls. Within this process, patie...
Spiesshofer P, Hawkins AE, Berner D, Previdelli RL, Fiske-Jackson AR.To describe, in detail, the relevant anatomy and surgical approach to access the paracondylar process (PCP) and report its application in a clinical case of headshaking. Methods: A seven-year-old, mixed breed mare. Methods: Experimental study/case report. Methods: A seven-year-old mixed breed mare was presented for investigation of acute onset progressing violent headshaking, resulting in the horse falling on multiple occasions. The horse was highly reactive to palpation over the right PCP. Standing computed tomographic (CT) investigation and ultrasonographic examination of the head detected a...
Kloock T, Hellige M, Kloock A, Feige K, Niebuhr T.Horses with trigeminal-mediated headshaking (TMHS) exhibit different headshaking patterns (HSPs), electric shock-like jerking, signs of nasal irritation, and painful facial expressions. The History Rest and Exercise Score (HRE-S) was developed to objectively clarify the severity of the condition in affected horses. This score considers the history and severity of clinical signs at rest and exercise. This study aimed to assess the frequency of different clinical signs and their individual associations with diagnosis, treatment, and outcome in horses diagnosed with TMHS.The clinical records of h...
Bell T, Kyriazopoulou P, Mowbray C, Murphy BA.Equine headshaking syndrome is a poorly understood neuropathic pain condition presenting as uncontrollable shaking, flicking, or striking of the head. Therapeutic options are limited, and treatments are only partially successful. Currently, epidemiological information on headshaking in the Southern Hemisphere is lacking. An online survey was circulated to Australian owners of headshaking horses to collect information on triggers, symptoms, seasonality, treatments, and perceived treatment efficacy. The responses (n = 216) showed the mean age at symptom onset as 9.6 (±4.7) years. More geldings ...
Maier J, Rosenstand MG, Thim P, Aalund M.Introduction Imaging experience made us suspect an overrepresentation of ponytails in riders admitted as polytrauma after falling from their horse. Methods In a single-centre case-control study conducted over three months, we reviewed the records of all admitted polytraumatised patients for trauma mechanism and presence of ponytail on CT. Cerebral CTs were reviewed in the three standard imaging planes using a bone or lung window. Ponytail was diagnosed if most or all of the hair on the head was gathered and secured at the back of the head with a hair tie. Data were analysed with Fisher's exact...
Kloock T, Pickles KJ, Roberts V, Uhlendorf F, Twele L, Wilkens HL, Stehle E, Feige K, Niebuhr T.In horses with trigeminal-mediated headshaking (TMHS), clinical signs are likely to be expression of neuropathic facial pain. Currently, subjective assessment of disease severity is used as measure of compromise of animal's welfare. Objective: To develop and validate a precise scoring system for TMHS: History, Rest and Exercise Score (HRE-S). The HRE-S consists of three subscores: history score (H-S), resting score (R-S) and exercise score (E-S). Methods: Retrospective observational study. Methods: Seven masked observers with different experience used HRE-S to score 40 video recordings taken d...
Labbe KA, Allshouse KA, Gilmour LJ, Arnold CE, Whitfield-Cargile CM, Griffin CE.Sinusitis is a common disease of horses yet there are a limited number of reports in the literature that describe the prevalence of infraorbital canal (IOC) pathology and headshaking behaviour in horses diagnosed specifically with primary sinusitis and secondary dental sinusitis. Given the impact that these behaviours can have on horses' intended athletic use, investigation is warranted. Objective: To determine the occurrence of IOC pathology in horses with concurrent primary or secondary dental sinusitis based on computed tomography (CT) findings and to assess whether the frequency of headsha...
Carter BT, Richardson MD.The aim of the study was to examine helmet use, incidence of injury, and patient outcomes in a rural cohort of equestrian accidents. Unassigned: EHR records of patients admitted to a Level II ACS trauma center in the North-west United States were reviewed for helmet use. Injuries were categorized according to International Classification of Diseases-9/10 code. Unassigned: Of 53 identified cases, helmets only reduced superficial injury (χ (1) = 4.837, = 0.028). Intracranial injury rates were not different between those with and without helmets ( > 0.05). Unassigned: In equine related injur...
Kloock T, Hellige M, Kloock A, Feige K, Niebuhr T.Most horses affected by headshaking (HS) are diagnosed with idiopathic trigeminal-mediated headshaking (i-TMHS) when no underlying disease is found. Diagnosis is made by the exclusion of differentials considering history, clinical signs, and diagnostic investigations. Therefore, in horses presented with headshaking, many diagnostic procedures and therapies are conducted. Retrospectively, the digital patient records of 240 horses with HS were analysed regarding the impact of diagnostic procedures on diagnosis, therapy, and outcome. Horses were extensively examined using a standardised protocol ...
Perrier M, Manso-Díaz G, Dunkel B.Trigeminal nerve-mediated head-shaking (TNMH) in horses is a diagnosis made by exclusion. Computed tomography (CT) is frequently used to identify any disease process that could cause the clinical signs of head-shaking. Although abnormalities are frequently identified, it is unknown whether treatment of these conditions improves clinical signs. Objective: To ascertain the clinical significance of CT findings in horses presented with a complaint of head-shaking. Methods: Retrospective case series. Methods: CT and patient records were reviewed and all abnormal findings and any treatments subseque...
Stange LM, Krieter J, Czycholl I.Equine headshaking syndrome (EHS) is characterised as non-physical and involuntary movement of the horse's head and neck. Although EHS is clinically simple to diagnose, its aetiopathogenesis often remains unclear. The aim of this study was to gain an overview of signalment and therapy possibilities used in France and Switzerland. To do this, an online survey was developed and distributed via newsletters. A total of 933 complete, answered surveys from France ( = 804) and Switzerland ( = 129) were evaluated. The median age in France was 12.4 years (CH = 14.3). Mostly geldings were affected (58.5...
Aleman M, Sheldon SA, Jospin G, Coil D, Stratton-Phelps M, Eisen J.Trigeminal-mediated headshaking (TMHS) in horses is a form of neuropathic pain of undetermined cause that often results in euthanasia. The role of microbiota in TMHS has not been investigated in diseased horses. To investigate if gastrointestinal microbiota in the cecum is different in horses with TMHS compared to a control population, during a summer season with clinical manifestations of disease. Ten castrated horses: five with TMHS and five neurologically normal controls. All horses were sourced from our institution and kept under the same husbandry and dietary conditions. All horses were f...
Paulussen E, Decloedt A, Vera L, Lefere L, van Loon G.Venous stenosis, a possible cause of jugular dilatation and congestion, is well known in human medicine but has poorly been described in horses. Objective: To report unilateral jugular vein stenosis as a cause of jugular vein dilatation in horses and describe treatment by percutaneous transluminal angioplasty (PTA). Methods: Case report. Methods: Details of horses diagnosed with unilateral jugular stenosis were retrieved from medical records. Results: Five horses were presented with a non-painful, unilateral dilatation of the jugular vein of which two horses showed headshaking during exercise....
Stange LM, Krieter J, Czycholl I.Equine headshaking syndrome is a problematic behavior that has been described in literature for more than 100 years. The signs of headshaking syndrome appear frequently and violently so that riding the horse can be dangerous. The aim of this research was to gain an overview of the underlying causes of equine headshaking syndrome to identify effective treatment options, reduce the distress of horses and, in a second step, potentially improve therapeutic possibilities for horse owners and veterinarians. Most studies on prevalence originate from Anglo-American countries, so this research was to ...
Toft K, Kjeldsen ST, Otten ND, van Galen G, Fjeldborg J, Sinding M, Hansen S.Flexion of the horse's head and neck during dressage riding reduces the pharyngeal lumen with the risk of increased upper airway resistance and upper airway obstructions. According to the Fédération Equestre Internationale, hyperflexion is achieved through force, whereas the position low-deep-round is nonforced. The objectives of this study were to evaluate (1) applied rein tension and (2) dynamic structural disorders in the upper airways in dressage horses in different gaits and different head-neck positions (HNPs). Overground endoscopy (OGE) and rein tension were evaluated in 13 clinically...
Schwarz B, Klang A, Schwendenwein I.A 14-year-old Zweibrücker Warmblood gelding was presented for evaluation of lethargy and headshaking. The horse had a history of bouts of lameness in different limbs and back problems. It also had many mild colic episodes in the past. Results of repeat laboratory tests had shown persistent hypercalcemia (4.8 mmol/L; reference interval [RI]: 2.0-3.2 mmol/L) for 1.5 years and later on hypophosphatemia (0.4 mmol/L; RI: 0.5-1.3 mmol/L) and mild hypermagnesemia (1.0 mmol/L; RI: 0.5-0.9 mmol/L). Parathyroid hormone (PTH) concentration was within the RI. Other causes of hypercalcemia, such as...
Moss PS, Wan A, Whitlock MR.To describe the demographics and nature of injuries occurring on or around horses, to examine the nature of protective clothing in relation to these injuries, and to compare our data with previously published work in this area. Methods: Patients were identified using the term "sports injury-horse riding" from the departmental database for one calendar year from February 2000. Data were collected regarding demographics, injuries, protective clothing, and outcome. The data were then analysed and compared with the previously published literature. Results: 260 patients' records were analysed. The ...
Aleman M, Williams DC, Brosnan RJ, Nieto JE, Pickles KJ, Berger J, Lecouteur RA, Holliday TA, Madigan JE.Idiopathic headshaking (HSK) in horses is a distressing disorder in which the etiology and pathophysiology are unknown. Objective: Differences in sensory function of the trigeminal nerve exist between healthy and affected horses. Methods: Six healthy mature geldings and 6 mature geldings with idiopathic HSK. Methods: Prospective study. Sensory nerve action and somatosensory evoked potentials studies were performed. The stimulus site comprised the gingival mucosa dorsal to the maxillary canine. A pair of recording electrodes was placed along the sensory pathway of the trigeminal complex at the ...
Newton SA, Knottenbelt DC, Eldridge PR.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 appa...
Guyton K, Houchen-Wise E, Peck E, Mayberry J.Horse-related injury can be severe and disabling. We investigated the causes, severity, and costs of equestrian injury with the goal of injury prevention. A retrospective review of horse-related injuries from 2001 to 2008 identified 231 patients with a mean age of 38 years and a mean Injury Severity Score of 11 (range, 1 to 45). Mean length of stay was 5.5 days. Fifty-nine patients (25%) required 84 surgeries. Helmet use was 20 per cent and of the 172 patients not wearing a helmet while mounted, 38 per cent received potentially preventable head injuries. There were three deaths of which two we...
Madigan JE, Bell SA.To determine signalment, history, clinical signs, duration, seasonality, and response to various treatments reported by owners for headshaking in horses. Methods: Owner survey. Methods: 109 horses with headshaking. Methods: Owners of affected horses completed a survey questionnaire. Results: 78 affected horses were geldings, 29 were mares, and 2 were stallions. Mean age of onset was 9 years. Headshaking in 64 horses had a seasonal component, and for most horses, headshaking began in spring and ceased in late summer or fall. The most common clinical signs were shaking the head in a vertical pla...
Talbot WA, Pinchbeck GL, Knottenbelt DC, Graham H, McKane SA.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 an...
Madigan JE, Bell SA.Headshaking is a maturity onset condition with the most commonly reported clinical signs being 'flipping' of the nose, nose rubbing, snorting or sneezing, and acting like a bee is flying up the nostril. A questionnaire was completed by owners of 31 horses with headshaking syndrome. The history, time of onset, clinical presentation and treatment of this condition were reported. Headshaking appeared to be light-stimulated in approximately 60% of the horses. The condition is seasonal and recurring in the majority of horses. Treatment with cyproheptadine produced improvement of symptoms in 76% of ...
Lane JG, Mair TS.The clinical records of 100 cases of headshaking in horses were reviewed. Possible causes of the abnormal behaviour were identified in 11 animals; these included ear mite infestation, otitis interna, cranial nerve dysfunction, cervical injury, ocular disease, guttural pouch mycosis, dental periapical osteitis and suspected vasomotor rhinitis. However, in only two of these could it be shown that correction of the abnormality led to elimination of the headshaking. The additional clinical signs exhibited by the other idiopathic cases of headshaking included evidence of nasal irritation, sneezing ...
Roberts VL, Perkins JD, Skärlina E, Gorvy DA, Tremaine WH, Williams A, McKane SA, White I, Knottenbelt DC.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. Objective: 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 c...
Ross SE, Murray JK, Roberts VLH.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. Objective: To estimate owner-reported prevalence of headshaking in horses in the UK and to report their case background and disease characteristics, as reported by owners. Methods: Cross-sectional web based owner questionnaire. Methods: The questionnaire was advertised online via social media, horse forums, veterinary websites and equestrian magazines from 17th June 2016, until >1000 responses had ...
Mills DS, Cook S, Taylor K, Jones B.A national survey of headshaking in 254 horses was undertaken to describe the clinical signs of the condition as observed by horse owners. Principal component analysis was used to determine the underlying structure of 11 signs and the criteria by which the affected horses could be most effectively differentiated; the analysis suggested five components with a variance greater than one which together explained over 60 per cent of the total variance. Other analyses of the data indicated that headshaking could develop at any age and that twice as many males were affected as females; 64 per cent of...
Roberts V.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 t...
Roberts VL, McKane SA, Williams A, Knottenbelt DC.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 lo...
Mills DS, Taylor K.Thirty-six owners of seasonally headshaking horses took part in a trial to compare the effectiveness of three types of nose net, a traditional cylindrical net (full net) and two forms of larger mesh nets which cover only the nostrils and dorsorostral muzzle (half nets). Baseline data relating to the overall severity of the problem and 18 specific behaviours describing the nature of the problem were recorded on a check sheet by the owners. A within-subjects repeated measures design experiment, with each net used for a week before reassessment, was then used to assess the effect of the nets on t...
Fletcher J, Davies PT, Lewis T, Campbell MJ.Jockeys accept bony fractures and soft tissue injuries as occupational hazards. An average National Hunt jockey falls once in ten races with an injury rate of 4.25%. Head injury is a common cause of morbidity and the benefit of helmets is well recognized. Neck injuries are also common and usually musculoskeletal. Although rare, trauma to the neck arteries may go unnoticed yet have catastrophic consequences. Internal tears can allow arterial blood to dissect the layers of the arterial wall and obstruct the lumen. Severe obstruction may lead to cerebral ischaemia and infarction. An appreciation ...
Madigan JE, Kortz G, Murphy C, Rodger L.Seven horses with headshaking are described. No physical abnormalities were detected in any of the cases. Six of these horses had onset of clinical signs in the spring. The role of light was assessed by application of a blindfold or dark grey lens to the eyes, covering the eyes with a face mask and observing the horse in total darkness outdoors. Cessation of headshaking was observed with blindfolding (5/5 horses), night darkness outdoors (4/4 horses) and use of grey lenses (2/3 horses). Outdoor behaviour suggested efforts to avoid light in 4/4 cases. The photic sneeze in man is suggested as a ...
Fenner MF, Verwilghen D, Townsend N, Simhofer H, Schwarzer J, Zani DD, Bienert-Zeit A.Paranasal sinus cysts (PSC) are a common cause of equine secondary sinusitis. The outcome and associated complications have not been frequently reported. Objective: To review the associated clinical signs, associated morbidities and outcomes of horses treated for PSC. Methods: Retrospective multicentre case series. Methods: Retrospective analysis of case records and telephone follow up survey. Results: Subjects were 37 horses 1-24 years old that were presented with nasal discharge (n = 31), facial swelling (n = 25) and epiphora (n = 19). Radiography and computed tomography allowed identificati...
Pickles KJ, Berger J, Davies R, Roser J, Madigan JE.The aim of this study was to investigate the use of a gonadotrophin-releasing hormone (GnRH) vaccine in the treatment of headshaking in horses. Fifteen geldings received two doses of the GnRH vaccine four weeks apart. Serum was collected before and after vaccination to measure concentrations of luteinising hormone (LH) (10 horses) and follicle-stimulating hormone (FSH) (six horses). Owners recorded the frequency of seven common headshaking behaviours using a visual analogue scale (VAS) before vaccination and at two, four, eight, 12, 16 and 20 weeks after vaccination. Serum LH (P=0.008) and FSH...
Aleman M, Pickles KJ, Simonek G, Madigan JE.Trigeminal neuralgia or neuropathic pain has been regarded as a putative cause of idiopathic headshaking in horses. Equine herpesvirus-1 (EHV-1) infection and resultant postherpetic pain have been suggested as a possible cause of such neuropathic pain. Objective: To determine the presence of EHV-1 in the trigeminal ganglia of horses with idiopathic headshaking. Methods: Nineteen horses: control (n = 11, 9 geldings, 2 mares, median age 11 years) and headshaking (n = 8, all geldings, median age 11.5 years) horses were sourced from the equine research herd and caseload at the Veterinary Medical T...
Schwarz BC, Sallmutter T, Nell B.A 6-year-old 680-kg (1,496-lb) German Warmblood gelding was evaluated because of bilateral blepharospasm and head shaking. Results: Moderate blepharospasm was evident bilaterally, and both eyes had hyperemic and edematous conjunctivas and lusterless corneas. For each eye, the Schirmer tear test value was only 7 mm/min. The horse's nasal mucosa was dry. Abnormal behaviors included mild repetitive vertical movement of the head, snorting, and flehmen response (classic signs of head shaking). Touching the horse's nostrils and face revealed paresthesia and dysesthesia with slight nasolabial muscle ...
Blythe LL.Otitis media/interna in the equine most commonly is a chronic, insidious infection with the unique sequella of temporohyoid osteoarthropathy in some horses. Head shaking may be the only clinical sign of the early stages of this disease. The arthritic condition often leads to fusion of the temporohyoid joint with resultant stress fractures of the petrous temporal bone. When this occurs, the horse presents as an acute neurologic case with clinical signs of vestibular and facial nerve dysfunction. Diagnosis, treatment, and prognosis are discussed. Recognition of this syndrome is important because...
Roberts VLH, Bailey M, Patel NK.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™. Objective: The aim of this study was to report long-term results from a larger number of cases and to investigate for predictors of outcome. Methods: Prospective case series using international, multi-centre data. Methods: Eligible cases were horses with a veterinary diagnosis of trigeminal-media...
Sheldon SA, Aleman M, Costa LRR, Santoyo AC, Howey Q, Madigan JE.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. Methods: Six geldings with trigeminal-mediated headshaking. Methods: Prospective randomized crossover study. Horses were controlled for diet and infused IV with 5% dextros...
Edwards RA, Hermans H, Veraa S.Headshaking is a common problem in horses. The etiology is unknown but thought to involve sensory input from branches of the trigeminal nerve, some of which are within the infraorbital canal. The objective of this retrospective cross-sectional study was to describe the CT anatomy and variations of the infraorbital canal in horses with local disease processes and normal horses, and to examine associations between those findings and headshaking. Computed tomography scans were reviewed and morphological changes of the infraorbital canal were described. Presence of changes was then tested for asso...
Sheldon SA, Aleman M, Costa LRR, Weich K, Howey Q, Madigan JE.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. Methods: 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 ...
Readford PK, Lester GD, Secombe CJ.Two cases of temporohyoid osteoarthropathy (THO) in young Australian horses are described. The pathogenesis of THO is yet to be fully elucidated, but current theories include extension of infection from otitis media or interna to the temporohyoid joint or a primary but non-infectious degenerative condition within the temporohyoid joint. The young age of the horses and the unilateral distribution suggested an infectious aetiology. Both horses partially responded to treatment with broad-spectrum antimicrobial and anti-inflammatory drugs with concurrent management of ulcerative keratitis. The man...
Kloock T, Hellige M, Kloock A, Feige K, Niebuhr T.Most horses affected by headshaking (HS) are diagnosed with idiopathic trigeminal-mediated headshaking (i-TMHS) when no underlying disease is found. Diagnosis is made by the exclusion of differentials considering history, clinical signs, and diagnostic investigations. Therefore, in horses presented with headshaking, many diagnostic procedures and therapies are conducted. Retrospectively, the digital patient records of 240 horses with HS were analysed regarding the impact of diagnostic procedures on diagnosis, therapy, and outcome. Horses were extensively examined using a standardised protocol ...
