Madigan J E, Kortz G, Murphy C, Rodger L
Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis 95616-8737, USA.
Equine Vet J. 1995 Jul;27(4):306-11. doi: 10.1111/j.2042-3306.1995.tb03082.x.
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 putative mechanism for equine headshaking. Five of 7 horses had improvement with cyproheptadine treatment (0.3 mg/kg bwt b.i.d.). Headshaking developed within 2 calendar weeks of the same date for 3 consecutive years in one horse. Neuropharmacological alterations associated with photoperiod mechanisms leading to optic trigeminal summation are suggested as possible reasons for spring onset of headshaking.
本文描述了7匹患有晃头症的马。所有病例均未检测到身体异常。其中6匹马在春季出现临床症状。通过给马戴上眼罩或深灰色镜片、用面罩遮住眼睛并在户外完全黑暗的环境中观察马，来评估光线的作用。发现戴眼罩（5/5匹马）、户外夜间黑暗环境（4/4匹马）以及使用灰色镜片（2/3匹马）时晃头症状停止。户外行为表明4/4例存在避光行为。人类的光喷嚏反应被认为是马晃头症的一种可能机制。7匹马中有5匹经赛庚啶治疗（0.3mg/kg体重，每日两次）后症状改善。一匹马连续3年在同一日期的2个日历周内出现晃头症。与光周期机制相关的神经药理学改变导致视三叉神经总和，被认为是晃头症春季发病的可能原因。
