Objective—To evaluate the cardiopulmonary and clinicopathologic
effects of rapid IV administration of
dimethyl sulfoxide (DMSO) in awake and halothaneanesthetized
Animals—6 adult horses.
Procedures—Horses received IV infusion of 5 L of a
balanced electrolyte solution with and without 1 g/kg
(0.45 g/lb) of 10% DMSO solution when they were
awake and anesthetized with halothane (4 treatments/
horse). Arterial and venous blood samples
were collected immediately before and at intervals
during or after fluid administration and analyzed for
blood gases and hematologic and serum biochemical
variables, respectively. Heart rate, respiratory rate,
and arterial blood pressure variables were recorded
prior to, during, and after fluid administration.
Results—After administration of fluid with or without
DMSO, changes in measured variables were detected
immediately, but most variables returned to baseline
values within 4 hours. One awake control horse
had signs of anxiety; agitation and tachycardia were
detected in 2 awake horses administered DMSO.
These clinical signs disappeared when the rate of
infusion was reduced. In anesthetized horses,
increased concentrations of WBCs and plasma fibrinogen
and serum creatine kinase activity persisted
for 24 hours, which was related to the stress of anesthesia
more than the effects of fluid administration.
Conclusions and Clinical Relevance—Infusion of
5 L of balanced electrolyte solution with or without
10% DMSO induced minimal changes in cardiopulmonary
function and clinicopathologic variables in
either awake or halothane-anesthetized horses.
Stress associated with anesthesia and recovery had a
greater influence on measured variables in anesthetized
horses than fluid administration. (J Am Vet Med Assoc 2004;225:560–566)
Case Description—A 7-year-old 509-kg (1,120-lb) Tennessee Walking Horse mare was evaluated because of bilateral mucosanguinous nasal discharge, intermittent right-sided epistaxis, and worsening dyspnea of 9 months' duration.
Clinical Findings—Multiple masses in the nasopharynx were detected via endoscopic and radiographic examinations. Cytologic and histologic examinations of biopsy specimens of 1 mass revealed round yeasts with thick nonstaining capsules and occasional narrow-based budding that resembled cryptococcal organisms.
Treatment and Outcome—Oral administration of fluconazole and organic ethylenediamine dihydriodide and intermittent intralesional injections with fluconazole, amphotericin B, and formalin resulted in resolution of lesions for a period of 2.5 years. The horse then developed exophthalmos, recurring clinical signs, and extensive nasopharyngeal masses. The masses were surgically debulked via a large frontonasal bone flap, and the horse was treated with IV injections of amphotericin B and long-term oral administration of fluconazole. Clinical signs did not recur in the following 2-year period. A presumptive diagnosis of cryptococcosis was made following cytologic and histologic evaluations of the masses; results of serologic analysis and fungal culture confirmed infection with Cryptococcus neoformans.
Clinical Relevance—Cryptococcal infection of the upper respiratory tract in horses has previously been described as a uniformly fatal disease. As this case report illustrates, medical and surgical treatment of sinonasal cryptococcal granulomas in horses may be successful, but the importance of long-term follow-up and the potential for disease recrudescence should be considered. As efficacious antifungal agents become less expensive, their increased use will likely decrease mortality rates in horses with fungal infections.