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Background: Exercise induced pulmonary haemorrhage (EIPH) is an important condition of horses performing high intensity exercise, with reported prevalence among racehorses of up to 95%, based on the detection of blood on tracheobronchoscopy. Previously identified risk factors include age, sex, season, race type, years spent in racing and lower airway inflammation. Objectives: To estimate the prevalence of EIPH in British National Hunt racehorses as indicated by two outcome measures: presence of tracheal blood on tracheobronchoscopy, and presence of moderate-large (significant) proportions of haemosiderophages in tracheal wash (TW) fluid; and to identify training-related risk factors for these indicators of EIPH. Study design: Prospective longitudinal study.Methods: Data from tracheobronchoscopy and TW cytology were analysed using univariable and multivariable mixed-effects logistic regression.Results: 1184 observations, from 177 horses, were analysed. The prevalence of tracheal blood was 7.2% (95%CI: 5.8, 8.8) and significant haemosiderophages in TW fluid was 36% (95%CI: 33.3, 38.8). Increased time in training was significantly associated with increased odds of EIPH. For each additional year spent in training the odds of tracheal blood and presence of significant proportions haemosiderophages increased approximately 1.5-fold (OR = 1.5; 95%CI: 1.1-2.0; P = .005; and OR = 1.5; 95%CI: 1.3, 1.8; P < .001, respectively). Current inflammation was associated with previous haemorrhage, but not current haemorrhage. Main limitations:There are no standardised measures for quantification of TW cytological parameters for EIPH diagnosis. Few horses were examined following jumping.Recent racing dates were not included in analysis. Conclusions:Increasing time in training was a risk factor for both indicators of EIPH.Current inflammation was associated with previous haemorrhage, but not current or future haemorrhage, suggesting that haemorrhage leads to inflammation but not that inflammation leads to haemorrhage. Overall, our findings are consistent with the The abstract is available in Portuguese in the Supporting Information section of the online version of this article.

Background:The chemiluminescence (CL) and immunofluorescence (IF) assays yield different results for basal adrenocorticotropin hormone concentrations [ACTH] in pony plasma. It is unclear whether this difference also occurs in basal samples from horses or samples from ponies following thyrotropin-releasing hormone (TRH) stimulation.Objectives: To compare the results of [ACTH] analysis by CL and IF methods in basal samples from horses and pony samples following TRH stimulation. Study design: Method comparison.Methods: Plasma [ACTH] was measured concurrently using CL and IF methods in 12 ponies (basal and post TRH stimulation) in November and basal samples from horses (n = 45; November and May).Results: CL and IF methods yielded different results (P<0.01). The median difference (CL -IF) (95%CI) for ponies was 5.9 (0.1-7.5)pg/ml at baseline and 227.9 (61-1001)pg/ml post TRH; and horses 1.9 (1.1-5.4)pg/ml in November and 9.4 (8.2-11.5)pg/ml in May, at baseline. Correlation was good in ponies at baseline (R=0.80, p=0.003) but not post TRH, and good in horses in November and May (R=0.68 and 0.71, p<0.001). Bland-Altman analysis demonstrated moderate bias and wide 95% limits of agreement (95%LOA) in ponies at baseline (bias 5.5pg/ml; 95%LOA -9.9-20.9pg/ml) and horses in May (bias 10.6pg/ml; 95%LOA -9-30.3pg/ml) and very large bias and wide 95%LOA in ponies post TRH (bias 477pg/ml; 95%LOA -633-1587pg/ml). Using CL cut-offs of >29pg/ml and >110pg/ml, agreement was moderate (ƙ=0.67) and very good (ƙ=0.82) for binary classification of PPID in ponies at baseline and post TRH; and good (ƙ=0.73) for horses in November, but poor (ƙ=0.40) in May. Main limitations:Limited numbers of horses with [ACTH] above threshold values. Conclusions:The assays yielded different absolute values, particularly in post TRH samples from ponies, suggesting TRH stimulates secretion of cross-reacting peptides other than ACTH. Agreement for binary classification for PPID was moderate to good, except in basal samples from horses in May.

SummaryA 22‐year‐old Irish Sport Horse presented following a period of bilateral blindness with subsequent spontaneous resolution. Brain magnetic resonance imaging (MRI) demonstrated features consistent with pachymeningitis. Cerebrospinal fluid (CSF) analysis revealed increased numbers of basophils, suggestive of an immunologic or neoplastic aetiology. It was suspected that the enlarged meninges led to compression of the optic nerves in the optic canals, causing bilateral blindness. Initial spontaneous remission, as seen in this case, has been reported in human patients with this condition. Pachymeningitis should be considered as a possible cause of cranial nerve deficits, including bilateral and unilateral blindness, in horses.

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