Background: Diagnosis of pituitary pars intermedia dysfunction (PPID) is problematic because of large variations in ACTH concentrations. Hypothesis/Objectives: Compare the test characteristics of baseline and post-thyrotropin-releasing hormone (TRH) stimulation plasma ACTH concentrations in horses using diagnostic cutoff values (DCOVs) and reference intervals (RIs) and determine the clinical consequences of using each method. Animals: One hundred six mature horses: 72 control cases and 34 PPID cases. Methods: Prospective case-controlled study. Horses underwent monthly TRH stimulation tests. Diagnostic cutoff values were determined monthly by receiver operating characteristic curves using the Youden index. Reference intervals were determined monthly by a robust method. For each case age, sex and body condition score (BCS) were recorded. Results: Baseline ACTH concentrations varied by month (P < .001) with significant "month × age" (P = .003), "month × sex" (P = .003), and "month × BCS" (P = .007) effects. Baseline ACTH concentrations were accurate to diagnose PPID (0.91 ± 0.06) with DCOVs increasing the test sensitivity (0.61 ± 0.21 to 0.87 ± 0.05, P = .002) and RI increasing test specificity (0.85 ± 0.12 to 0.98 ± 0.01, P = .01). Thyrotropinreleasing hormone stimulation improved test accuracy (0.91 ± 0.06 to 0.97 ± 0.03, P = .004). Conclusions and Clinical Importance: ACTH concentrations follow a circannual rhythm and vary with physiological factors. As using DCOVs increases the ability to detect mild cases and using RI decreases the risk of unnecessary treatments, ACTH concentrations should be interpreted within a specific clinical context. The TRH stimulation test improves the diagnosis of PPID.

Summary Background Pituitary pars intermedia dysfunction (PPID) is a commonly described endocrine disorder in higher latitudes of the Northern hemisphere but the description of the disease at lower latitudes and in the Southern hemisphere is limited. Objectives Document the clinical features of PPID at different Australian latitudes and climates, and investigate factors associated with survival, laminitis and insulin dysregulation (ID). Study design Retrospective study of 274 equids from eight institutions across Australia. Methods A diagnosis of PPID was based on endogenous ACTH, overnight dexamethasone suppression test, thyrotropin‐releasing hormone stimulation test or necropsy. Clinical and clinicopathologic characteristics of PPID and therapeutic responses were investigated. Laminitis was diagnosed by radiographic or histologic changes and ID was diagnosed based on endogenous insulin, an oral glucose test or a 2‐step insulin‐response test. Results Being a pony, having a higher body condition score and pergolide administration were associated with survival. The clinical presentation of PPID changed with latitude and climate, with anhidrosis and polyuria/polydipsia more commonly recognised at lower latitudes. Laminitis was diagnosed in 89.9% of cases and ID was present in 76.5% of cases in which they were investigated. Main limitations Despite the sample size, the lack of uniform testing at all locations (primary or referral cases) and the incompleteness of data sets limited the power of the statistical analyses. Conclusions PPID can present with variable signs at different latitudes and climates, and ID should be investigated in equids diagnosed with PPID. Adequate body condition and administration of pergolide are fundamental in PPID management.

Summary Venous air embolism was suspected in 3 hospitalised horses on the basis of an inadvertently open jugular venous line. Subsequently the 3 horses developed clinical signs including cardiovascular collapse, cardiac dysrhythmia, pulmonary oedema, behavioural abnormalities and neurological signs consistent with central nervous system injury. Treatment included intranasal oxygen therapy, i.v. fluid administration and anti‐inflammatory therapy. Specific therapy aimed at treating air embolism in man is reviewed, with pertinent therapy potentially applicable to horses emphasised.

Duration of analgesia after oral administration of tramadol might be < 3 hours in horses, with ODT and the parent compound contributing equally.

Medical records of 101 blood culture-confirmed bacteremic foals were reviewed to determine whether foals with Actinobacillus sp. bacteremia are affected at an earlier age, have more severe signs of disease, and have a worse prognosis than do foals with bacteremia of other causes. Thirty percent (30/101) of bacteremic foals had Actinobacillus sp. cultured, and these were 2 times more likely to die (crude odds ratio [OR CR ] 0.8, 4; P ϭ .14), with a survival rate of 43% (13/30) compared to the overall survival rate of 55% (56/101). When compared to other bacteremic foals, foals with actinobacillosis were 7 times more likely to have been sick from birth (adjusted odds ratio [OR ADJ ] 2, 26; P ϭ .003) and 6 times more likely to have diarrhea (OR ADJ 1, 22; P ϭ .009). By bivariate analysis, foals with Actinobacillus sp. bacteremia were 5 times more likely to have a sepsis score Ͼ11 (OR CR 1, 18; P ϭ .007), 6 times more likely to be obtunded (OR CR 2, 20; P ϭ .005), and 3 times more likely to have pneumonia (OR CR 1, 7; P ϭ .03). Furthermore, Actinobacillus sp. bacteremic foals were 27 times more likely to have a segmented neutrophil count Ͻ3.3 ϫ 10 9 cells/L (OR ADJ 4, 166; P Ͻ .0001) and were 4.5 times more likely to have a band neutrophil count Ͼ0.46 ϫ 10 9 cells/L (OR ADJ 1, 17; P ϭ .02) when compared to foals that had bacteremia caused by either gram-negative enteric or gram-positive organisms. Sepsis score was Յ11 in 49% (29/59) of bacteremia foals aged Ͻ13 days for which a discernible sepsis score was calculable. Results of this study should improve the diagnostic sensitivity of clinical examinations of neonatal foals, thereby facilitating treatment decisions.