Intraperitoneal (IP) use of antimicrobial agents may lead to therapeutic effects with better clinical results than intravenous (IV) administration. The aim of this study was to compare plasma and peritoneal fluid concentrations of ceftriaxone after IP and IV administration in horses, and to evaluate possible adverse effects. One group of five horses received 25mg/kg ceftriaxone diluted in 1L saline solution by IP catheter once daily for 5 days, while a second group of five horses received 25mg/kg ceftriaxone diluted in 250mL saline solution by IV injection once daily for 5days and 1L saline solution by IP catheter once daily for 5 days. Peritoneal fluid and plasma were collected to determine ceftriaxone concentrations after the first and fifth administration. IP administration of ceftriaxone resulted in concentrations above a minimum inhibitory concentration (MIC) of 1μg/mL for 24h in peritoneal fluid and for 12h in plasma, while IV administration of ceftriaxone resulted in lower peritoneal fluid concentrations, which remained above a MIC of 1μg/mL for 12h in peritoneal fluid and 10h in plasma. No adverse effects were observed. Comparisons of ceftriaxone concentrations, time of occurrence of the maximum (T) and minimum (T) concentrations, and the mean residence time (MRT), between the two groups showed that IP administration provided greater availability of cephalosporin in peritoneal fluid. The IP use of ceftriaxone (25mg/kg diluted in 1L saline solution once daily) may be useful for the prophylaxis and/or treatment of peritonitis in horses.

Peritonitis in horses persists with high incidence and mortality, requiring more innovative and effective therapeutic strategies. The aim of this study was to evaluate Tenckhoff catheters and intraperitoneal use of ceftriaxone in horses. Ten healthy, male horses, with an average age of 5 years, were used and divided into two groups of five animals each. A Tenckhoff catheter was implanted in both groups. The intraperitoneal group received 25 mg/kg of ceftriaxone diluted in 1 L of 0.9% saline solution (SS) intraperitoneally via the Tenckhoff catheter, and the intravenous group received 25 mg/kg of ceftriaxone intravenously and 1 L of SS intraperitoneally. In both groups, the dosing interval was every 24 hours for 5 days. The animals were evaluated clinically and with laboratory tests through a blood count and plasma fibrinogen assay. A macroscopic, physical-chemical, and cytological evaluation of the peritoneal fluid and an abdominal sonographic evaluation were conducted before the catheter implantation and at 1, 3, 5, 7, and 10 days after the implantation and ceftriaxone administration. Seven days after the catheter insertion and the beginning of the intraperitoneal treatment, a laparoscopic evaluation was performed. The Tenckhoff catheter proved to be an appropriate route for intraperitoneal solution administration; however, it promoted a moderate inflammatory response in the abdomen. No differences in inflammatory reaction was observed between groups, suggesting that the intraperitoneal administration of the drug did not trigger a local or systemic inflammatory process, amplifying the possibilities of intraperitoneal route utilization in the treatment of peritonitis.

RESUMO Oito equinos foram distribuídos em delineamento randomizado cruzado, sendo um grupo sem suplementação (GC) e outro grupo suplementado com óleo de avocado (GOAv) por um período de sete semanas. Ao fim da sexta semana, os animais foram submetidos a teste padrão de exercício progressivo (TPEP) e, após sete dias, a teste de baixa intensidade e longa duração (BILD). Após o primeiro ciclo, houve período de descanso “washout” de 30 dias para troca de grupos para o segundo ciclo, que seguiu o protocolo do primeiro. A termorregulação foi avaliada com base na temperatura retal e na temperatura superficial corpórea, obtidas por termografia, de 15 regiões de interesse. A temperatura retal e as imagens termográficas foram obtidas antes, um minuto e 15 minutos após o exercício. Não houve diferença entre os grupos GC e GOAv em nenhum momento. Os resultados obtidos neste estudo revelaram que a suplementação de 5% da matéria seca (MS) com óleo de avocado por seis e sete semanas não influenciou na termorregulação com base na temperatura superficial corpórea dos equinos submetidos ao teste padrão de exercício progressivo (TPEP) e ao exercício de baixa intensidade e longa duração (BILD), respectivamente.

Background: Sinus neoplasms are reported as low frequency in horses. Its clinical characteristics are often nonspecific, depend on complementary methods for diagnosis, and when diagnosed, generally they are already advanced, limiting therapeutic possibilities. The objective of this case series was to detail clinical aspects and complementary exams for sinus neoplasms for early diagnosis, comparing them with the literature.Cases: Four horses were treated at the College of Veterinary Medicine and Animal Science of the University of São Paulo, with different clinical signs and previous diagnoses, which when evaluated by respiratory endoscopy, radiography, oral cavity evaluation and histopathological exams, revealed the diagnosis of anaplastic carcinoma, poorly differentiated carcinoma, ossifying fibroma and lymphoma. Previous diagnosis, based mainly on clinical signs, were sinusitis secondary to apical infection, ethmoidal hematoma, sinus cyst and sinusitis secondary to periapical disease. The cases of anaplastic carcinoma (case 1) and lymphoma (case 4) presented with an advanced degree of the disease with involvement and destruction of paranasal structures and adjacent tissues, in addition to a poor general condition, which made surgical treatment impossible and led to euthanasia. In these cases, previous treatment was made to apical infection and periodontal disease with secondary sinusitis, but negative evolution led to suspicion of neoplasia, confirmed by histopathological exam of incisional biopsy of the mass in oral cavity. Benign ossifying fibroma (case 3) presented with progressive respiratory difficulty due to occlusion of the lumen of some nasal meatus and radiographic signs of invasion and deformation of the adjacent bones, it was submitted for surgical excision and there was no recurrence until hospital discharge. The poorly differentiated carcinoma (case 2) was a multilobulate neoformation in the ethmoidal region, similar to ethmoid hematoma in endoscopic and radiographic evaluation, it was submitted for excision and two sessions of electrochemotherapy with bleomycin, associated with administration of piroxicam, which obtained a good result until the period of 1 year after discharge.Discussion: It was found that many characteristics are common with these types of neoplasms, and the clinical signs, such as nasal secretions, airway obstruction, increased facial volume, severe alterations in oral cavity, although unspecific, suggest the differential diagnosis for neoplasms. It is important to differentiate from other diseases noting the evolution and growth of these tumors, like in cases 1 and 4, especially the growth to internal tissues, using complementary methods described here, like endoscopic and radiographic examination. Late identification or even manipulation of neoplasms, without proper diagnosis, leads to a few prognoses regarding life. When it is possible to perform surgical excision, complementary methods are important to guide the procedure, and definitive diagnosis is made through histopathologic exam and some need immunohistochemistry analysis. Cases 2 and 3 had surgical access, were submitted to excision and treatment with good results, both with close monitoring in first months and prolonged quality of life. These results highlight the importance of complementary methods for early diagnosis, correct intervention and monitoring of evolution.Keywords: sinus neoplasia, paranasal sinus, tumor, head, horses.