Effects of inhaled beclomethasone dipropionate on respiratory function in horses with chronic obstructive pulmonary disease (COPD).

The effects of beclomethasone dipropionate on pulmonary function and arterial blood gas values were investigated in horses with chronic obstructive pulmonary disease (COPD). Six mature mares, diagnosed as having COPD based on clinical signs, cytological examination of bronchoalveolar lavage and pulmonary function testing, were used. Beclomethasone dipropionate (3750 microg) was administered b.i.d. for a 2 week period with a metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starting before beclomethasone administration and for 4 weeks thereafter. Upper airway endoscopy and nasopharyngeal fungal cultures were performed before and after treatment. Maximal variations in transpulmonary pressure (deltaPL) were elevated in all horses at baseline. Beclomethasone administration resulted in a significant decrease in deltaPL in 5 horses, and deltaPL fell to within the normal range in 4 horses. Two weeks after the end of treatment, deltaPL was at or above baseline values in all horses. Total pulmonary resistance and elastance decreased significantly during treatment and returned to or above baseline values after the administration of beclomethasone was discontinued. At baseline, PaO2 range was 53-90 mmHg. In 4 horses with pronounced laboured breathing, PaO2 increased with treatment. One horse became reluctant to inhale the beclomethasone after one week, and only a transient improvement in respiratory function was noted in this animal. One horse developed a mild lower airway infection 24 h after the beginning of treatment, but no other possible side effects were noticed. Pharyngeal fungal cultures were negative before and after treatment. It can be concluded from the results of this study that inhaled beclomethasone dipropionate causes a marked improvement of respiratory function in horses with COPD.

Effects of triamcinolone acetonide on pulmonary function and bronchoalveolar lavage cytologic features in horses with chronic obstructive pulmonary disease.

Effects of triamcinolone acetonide (TA) on pulmonary function, bronchoalveolar lavage cytologic features and serum cortisol concentration, were studied in 5 control horses and 5 horses with chronic obstructive pulmonary disease (COPD). In experiment 1, horses were brought in from pasture 3 weeks before administration of 1 injection of TA (0.09 mg/kg of body weight, IM), and were stabled in dusty conditions throughout the experimental period. Measurements of respiratory rate (f), tidal volume, minute ventilation, expiratory-to-inspiratory time ratio, maximal change in transpulmonary pressure (delta PL), pulmonary resistance (RL), and dynamic compliance (Cdyn) were obtained during quiet breathing, immediately before (baseline) and 1, 2, 3, 5, and 9 weeks after administration of TA. Pulmonary airway cells were collected by bronchoalveolar lavage while horses were at pasture, at baseline, and 2, 5, and 9 weeks after TA administration. Serum cortisol concentration was measured before and after adrenocortical stimulation with 100 IU of adrenocorticotropic hormone, 1 week prior to TA administration, and 4 and 8 weeks thereafter. In experiment 2, 4 months after TA injection, pulmonary function measurements were repeated in all horses immediately before and 30 minutes after administration of atropine (0.015 mg/kg, IV), to evaluate the reversibility of airway obstruction. In experiment 1 at baseline, COPD-affected horses had significantly (P < 0.05) higher values than did controls for f, delta PL, RL, and percentage of neutrophils, and had lower values for Cdyn and percentage of lymphocytes and macrophages. There was significant reductions in delta PL and RL, and increase in macrophage percentage after TA administration in COPD-affected horses only.(ABSTRACT TRUNCATED AT 250 WORDS)

Histamine inhalation challenge in normal horses and in horses with small airway disease.

A histamine inhalation challenge (HIC) procedure was developed to assess hyperreactive states in horses. Following clinical evaluation, percutaneous lung biopsies were performed on nine light breed mares aged 6 to 15 years. Five horses, with normal small airways, were classified as group A and four subjects with small airway disease (SAD) lesions formed group B. Pulmonary mechanics parameters were monitored following an aerosol of 0.9% saline and every 5 min for up to 30 min after HIC with 0.5% w/v of histamine diphosphate, administered through a face mask for 2.5 min. Tidal volume (VT) and airflow (V) values were obtained with a pneumotachograph. Transpulmonary pressure (delta Ppl) was measured by the esophageal balloon catheter method. Dynamic compliance (Cdyn), total pulmonary resistance (RL), end expiratory work of breathing (EEW) and respiratory rate (f) were calculated by a pulmonary mechanics computer. Group A horses had increases in RL, and decreases in Cdyn whereas horses in group B were hyperreactive and showed greater changes in EEW, Cdyn, and delta Ppl but with a relatively lower variation of RL. One horse in clinical remission from SAD, but with a high biopsy score (group B), and one clinically normal horse belonging to group A showed marked hyperreactivity as shown by increases in EEW, maximum change in delta Ppl and RL and decreases in Cdyn. These results suggest that the HIC described can be used as a method to investigate airway hyperreactivity and SAD in horses.

Fatal acorn poisoning in a horse: pathologic findings and diagnostic considerations.

Acorn poisoning was diagnosed in an 11-year-old Quarter Horse with signs of severe colic, tachycardia, hyperpnea, abdominal borborygmus, rectal tenesmus, and hemorrhagic diarrhea. The diagnosis was based on history and predisposing factors, clinical signs, laboratory data, acorn husks in the feces, the urinary gallic acid equivalent concentration, and necropsy findings. The most striking pathologic changes were gastrointestinal and mesenteric edema, ulcerative enterocolitis, and nephrosis.