Morphometry, Topography and Arterial Supply of the Thyroid Gland in Brazilian Shorthair Cats

 Background: Thyroid gland diseases are the most common endocrinopathies in feline practice. Diagnosis and surgical treatment must base on solid anatomical knowledge about the gland size, localization, and blood supply. However, some textbooks provide a general anatomical description of the thyroid gland of domestic carnivores. Thus, specific details of the feline gland are missing. The present study aimed to investigate the dimensions, topography, and arterial supply of the thyroid gland in Brazilian shorthair cats and, therefore, provide additional data to diagnose and treat feline thyroid diseases.Materials, Methods & Results: Thirty Brazilian shorthair cats formalin-fixed cadavers (15 male and 15 female) were injected with red-stained latex solution by a canula in the thoracic aorta. The necropsy unit of the Rural Federal University of Rio de Janeiro donated the specimens. The study included only adult animals with no history of thyroid disease. After the fixation period, the cadavers were dissected to investigate the measurements (length, width at cranial and caudal poles, and thickness), topography, and in situ arterial supply of the thyroid lobes. The mean measurements of the length, cranial pole width, caudal pole width, and thickness in the right lobe were 19.39 ± 3.10 mm, 5.36 ± 1.40 mm, 3.67 ± 0.93 mm, and 1.30 ± 0.29 mm, respectively; and 20.29 ± 3.35 mm, 4.85 ± 1.58 mm, 3.88 ± 0.91 mm, 1.64 ± 0.65 mm in the left lobe, respectively. There were no statistical differences (P > 0.05) in the comparison of the measures between sexes or antimers (sides). Pearson's linear correlation detected a positive, moderate (r = 0.55), and significant (P < 0.05) correlation between the right and left lobe lengths. In 70% of the cats, both left and right lobes had the cranial poles located at the same level. Typically, the lobes extended between the first to the eighth tracheal ring. However, the cranial pole of some lobes located as cranially as the cricoid cartilage level, and the caudal pole as caudally as the 12th tracheal ring. Fifty-six percent of the cats had a ventrally located isthmus. In all the sampling, one single thyroid artery emerged as a branch of the common carotid artery and provided branches directly to the thyroid lobe, isthmus and the adjacent muscles and esophagus.Discussion: Besides establishing average dimensions of normal thyroid lobes in Brazilian shorthair cats, this study detected no significant difference between the average measurements of right and left lobes. Also, a positive linear correlation between the length and width of the right and left lobes became evident. Therefore, the practitioner must consider suspicious any length asymmetry between right and left thyroid lobes until further endocrine test proves otherwise. Most of the cats had the right and left thyroid lobe positioned at the same transversal level; however, positional asymmetries are not uncommon. Unlike dogs, Brazilian shorthair cats have only a single artery to supply each lobe: the thyroid artery. In a feline thyroidectomy, the surgeon must avoid blindly ligating the thyroid artery since this vessel also provided numerous branches to adjacent muscles and esophagus. In a bilateral thyroidectomy, the ventral region between lobes should be thoroughly inspected for the common presence of an isthmus. Sometimes, the surgeon may need to extend the incision caudally beyond the 12th tracheal ring level to visualize the gland tissue entirely.Keywords: endocrinology, feline anatomy, morphometrics, thyroidectomy

Duplikacija stražnje šuplje vene i bubrežnih vena u brazilske kratkodlake mačke - prikaz slučaja

The caudal vena cava in carnivores is the blood drainage pathway, originating from the pelvis and pelvic limbs, and entering the right atrium. Caudal vena cava duplication has rarely been reported in small animals. This report aims to describe a case of duplicity of the caudal vena cava and renal vein variation in a female feline corpse of a Brazilian shorthaired cat approximately 3 years of age, with the focus on the possible clinical and surgical implications of this anatomical variation. It was subsequently preserved in 10% formalin, and its vascular system was injected with colored S-65 Petrolatex. During the dissection of the abdominal region, the presence of a double caudal vena cava and two renal veins in both kidneys was observed. While uncommon in cats, caudal vena cava duplication should be differentiated from other vascular anomalies when planning surgeries and to avoid misdiagnoses.U mesojeda stražnja šuplja vena odvodi krv iz zdjelice i stražnjih udova u lijevu pretklijetku. Duplikacija stražnje šuplje vene u malih je životinja rijetko opisivana. Cilj ovoga rada jest prikazati duplikaciju stražnje šuplje vene i varijacije bubrežne vene u brazilske kratkodlake mačke, ženke dobi oko tri godine, s naglaskom na njihove moguće kliničke i kirurške značajke. Lešina je pohranjena u 10 %-postotnom formalinu, a u krvožilni je sustav injektiran obojeni S-65 Petrolatex. Tijekom otvaranja trbušne šupljine uočene su dvostruke stražnje šuplje vene i dvije bubrežne vene u oba bubrega. Budući da se dvostruka stražnja šuplja vena rijetko nalazi u mačaka, u planiranju kirurških zahvata treba je razlikovati od drugih krvožilnih anomalija kako bi se izbjegla pogrešna dijagnoza

ANESTESIA TOTAL INTRAVENOSA (TIVA) ASSOCIADA AO BLOQUEIO DO PLEXO BRAQUIAL EM UM OVINO SUBMETIDO À OSTEOSSÍNTESE DE RÁDIO E ULNA - RELATO DE CASO

A anestesia total intravenosa (TIVA) é uma técnica que vem sendo utilizada na prática anestésica veterinária, principalmente em pequenos animais. Seu emprego se popularizou na última década, devido aos novos estudos utilizando fármacos mais adequados, com menores efeitos cumulativos e menor tempo de recuperação anestésica. Objetivou-se avaliar a infusão de propofol juntamente com o bloqueio do plexo braquial em um ovino submetido a osteossíntese de rádio e ulna. A pré-medicação anestésica foi realizada com cetamina 10% na dose de 2 mg/Kg, a indução com propofol 1% na dose de 5 mg/Kg e a manutenção anestésica com propofol na dose de 0,25mg/Kg/min. O bloqueio do plexo braquial foi realizado com a associação de lidocaína 2% e bupivacaína 0,5%, ambas na dose de 0,12ml/Kg, com um volume final de 20 ml. Foram avaliados durante todo o procedimento: frequência cardíaca (FC), frequência respiratória (ƒ), saturação periférica de oxigênio na hemoglobina (SpO2) pressão arterial sistólica (PAS), pressão arterial diastólica (PAD), pressão arterial média (PAM), temperatura retal (T), reflexo palpebral, reflexo corneal e a profundidade anestésica. Os parâmetros foram anotados antes da medicação pré-anestésica (T0), imediatamente após a indução anestésica (T10), e depois, a cada 10 minutos, até o final da infusão (T90). Todos os parâmetros cardiorrespiratórios avaliados limitaram-se ao fisiológico para a espécie. Conclui-se que o protocolo de TIVA utilizado no ovino promoveu anestesia para realização da osteossíntese, juntamente ao bloqueio do plexo braquial, que foi essencial para a analgesia e para manutenção anestésica adequada

Morphometry, Topography and Arterial Supply of the Thyroid Gland in Brazilian Shorthair Cats

 Background: Thyroid gland diseases are the most common endocrinopathies in feline practice. Diagnosis and surgical treatment must base on solid anatomical knowledge about the gland size, localization, and blood supply. However, some textbooks provide a general anatomical description of the thyroid gland of domestic carnivores. Thus, specific details of the feline gland are missing. The present study aimed to investigate the dimensions, topography, and arterial supply of the thyroid gland in Brazilian shorthair cats and, therefore, provide additional data to diagnose and treat feline thyroid diseases.Materials, Methods & Results: Thirty Brazilian shorthair cats formalin-fixed cadavers (15 male and 15 female) were injected with red-stained latex solution by a canula in the thoracic aorta. The necropsy unit of the Rural Federal University of Rio de Janeiro donated the specimens. The study included only adult animals with no history of thyroid disease. After the fixation period, the cadavers were dissected to investigate the measurements (length, width at cranial and caudal poles, and thickness), topography, and in situ arterial supply of the thyroid lobes. The mean measurements of the length, cranial pole width, caudal pole width, and thickness in the right lobe were 19.39 ± 3.10 mm, 5.36 ± 1.40 mm, 3.67 ± 0.93 mm, and 1.30 ± 0.29 mm, respectively; and 20.29 ± 3.35 mm, 4.85 ± 1.58 mm, 3.88 ± 0.91 mm, 1.64 ± 0.65 mm in the left lobe, respectively. There were no statistical differences (P > 0.05) in the comparison of the measures between sexes or antimers (sides). Pearson's linear correlation detected a positive, moderate (r = 0.55), and significant (P < 0.05) correlation between the right and left lobe lengths. In 70% of the cats, both left and right lobes had the cranial poles located at the same level. Typically, the lobes extended between the first to the eighth tracheal ring. However, the cranial pole of some lobes located as cranially as the cricoid cartilage level, and the caudal pole as caudally as the 12th tracheal ring. Fifty-six percent of the cats had a ventrally located isthmus. In all the sampling, one single thyroid artery emerged as a branch of the common carotid artery and provided branches directly to the thyroid lobe, isthmus and the adjacent muscles and esophagus.Discussion: Besides establishing average dimensions of normal thyroid lobes in Brazilian shorthair cats, this study detected no significant difference between the average measurements of right and left lobes. Also, a positive linear correlation between the length and width of the right and left lobes became evident. Therefore, the practitioner must consider suspicious any length asymmetry between right and left thyroid lobes until further endocrine test proves otherwise. Most of the cats had the right and left thyroid lobe positioned at the same transversal level; however, positional asymmetries are not uncommon. Unlike dogs, Brazilian shorthair cats have only a single artery to supply each lobe: the thyroid artery. In a feline thyroidectomy, the surgeon must avoid blindly ligating the thyroid artery since this vessel also provided numerous branches to adjacent muscles and esophagus. In a bilateral thyroidectomy, the ventral region between lobes should be thoroughly inspected for the common presence of an isthmus. Sometimes, the surgeon may need to extend the incision caudally beyond the 12th tracheal ring level to visualize the gland tissue entirely.Keywords: endocrinology, feline anatomy, morphometrics, thyroidectomy