Myasthenia gravis in an exotic shorthair cat

Background: Myasthenia gravis is a neuromuscular transmission disorder resulting from the deficiency or functional disturbance of the acetylcholine receptors at the neuromuscular junction with consequent impairment of action potential transmission from nerve to muscle and it can be either congenital or acquired. Acquired myasthenia gravis has been described less frenquently in cats. The purpose of this paper is to describe a case of acquired myasthenia gravis in a 6-month-old male Exotic Shorthair cat. Case: A 6-month-old male Exotic Shorthair cat was referred to the Veterinary Clinic with a 2-day history of flaccid paralysis of the four limbs. The cat was feeding well and defecating normally. Physical examination was unremarkable. On neurological examination the patient was bright, alert and responsive. Flaccid paralysis of the four limbs was evident with loss of muscular tonus and presence of superficial and deep nociception. All spinal reflexes were absent. Hematologic analysis was within normal parameters. Thoracic radiographs were taken and showed no abnormalities. Creatine kinase activity was elevated. Myasthenia gravis was suspected and the cat was submitted to an neostigmine methylsulfate injection and further pyridostigmine bromide administration. Within 15 days there was clinical improvement with muscular tonus and spinal reflexes recovery. The treatment was continued...(AU)

Myasthenia gravis in an exotic shorthair cat

Background: Myasthenia gravis is a neuromuscular transmission disorder resulting from the deficiency or functional disturbance of the acetylcholine receptors at the neuromuscular junction with consequent impairment of action potential transmission from nerve to muscle and it can be either congenital or acquired. Acquired myasthenia gravis has been described less frenquently in cats. The purpose of this paper is to describe a case of acquired myasthenia gravis in a 6-month-old male Exotic Shorthair cat. Case: A 6-month-old male Exotic Shorthair cat was referred to the Veterinary Clinic with a 2-day history of flaccid paralysis of the four limbs. The cat was feeding well and defecating normally. Physical examination was unremarkable. On neurological examination the patient was bright, alert and responsive. Flaccid paralysis of the four limbs was evident with loss of muscular tonus and presence of superficial and deep nociception. All spinal reflexes were absent. Hematologic analysis was within normal parameters. Thoracic radiographs were taken and showed no abnormalities. Creatine kinase activity was elevated. Myasthenia gravis was suspected and the cat was submitted to an neostigmine methylsulfate injection and further pyridostigmine bromide administration. Within 15 days there was clinical improvement with muscular tonus and spinal reflexes recovery. The treatment was continued...

Aloenxerto ósseo cortical desvitalizado com nitrogênio líquido - estudo experimental em ovelhas / Allogeneic bone graft devitalized in liquid nitrogen - sheep experimental study

O objetivo do trabalho foi avaliar a taxa e a forma de incorporação do aloenxerto ósseo cortical, submetido ao congelamento em nitrogênio líquido e inserido em tíbias de ovelhas. Foram utilizadas seis ovelhas clinicamente sadias que, aos pares, foram simultaneamente submetidas à ostectomia da diáfise tibial para a retirada de um segmento de 7cm que, após a desvitalização em nitrogênio líquido, foi implantado imediatamente no outro paciente e fixado com placa de compressão dinâmica (PCD) e parafusos corticais. Realizaram-se avaliações clínicas e radiográficas, imediatamente e a cada 30 dias, até o 180º dia de pós-operatório. Aos 180 dias, foi realizada eutanásia e coletou-se a tíbia direita para avaliação histopatológica. Aos 60 dias de pós-operatório, foi observado o uso funcional do membro operado, sendo a união radiográfica das interfaces proximal e distal verificadas, em média, aos 95 dias. Com isso, pôde-se concluir que o nitrogênio líquido é um método adequado de desvitalização de aloimplantes ósseos corticais de ovelhas, proporcionando altas taxas de incorporação óssea, em média, aos 95 dias de pós-operatório.(AU)

This study evaluated the allogeneic cortical bone graft incorporation after submission of the harvested fragment to a bout freezing in liquid nitrogen. Six adult sheep, clinically healthy, were submitted to a 7cm ostectomy of the tibial diaphysis. The fragment was submersed in a liquid nitrogen and implanted in another sheep missing a same-sized segment at the corresponding bone. Stabilization of the allograft in the host bone was accomplished by a dynamic compressive plate (DCP). Clinical and radiographic evaluations were performed in the immediate post-operatory period and in every 30 days for six months after surgery. The proximal and distal host-graft interfaces showed radiographic union at a mean postoperative time of 95 days in all the animals. The cortical bone allograft submitted to liquid nitrogen freezing provided adequate bone healing in the sheep model.(AU)

Aloenxerto ósseo cortical desvitalizado com nitrogênio líquido - estudo experimental em ovelhas / Allogeneic bone graft devitalized in liquid nitrogen - sheep experimental study

O objetivo do trabalho foi avaliar a taxa e a forma de incorporação do aloenxerto ósseo cortical, submetido ao congelamento em nitrogênio líquido e inserido em tíbias de ovelhas. Foram utilizadas seis ovelhas clinicamente sadias que, aos pares, foram simultaneamente submetidas à ostectomia da diáfise tibial para a retirada de um segmento de 7cm que, após a desvitalização em nitrogênio líquido, foi implantado imediatamente no outro paciente e fixado com placa de compressão dinâmica (PCD) e parafusos corticais. Realizaram-se avaliações clínicas e radiográficas, imediatamente e a cada 30 dias, até o 180º dia de pós-operatório. Aos 180 dias, foi realizada eutanásia e coletou-se a tíbia direita para avaliação histopatológica. Aos 60 dias de pós-operatório, foi observado o uso funcional do membro operado, sendo a união radiográfica das interfaces proximal e distal verificadas, em média, aos 95 dias. Com isso, pôde-se concluir que o nitrogênio líquido é um método adequado de desvitalização de aloimplantes ósseos corticais de ovelhas, proporcionando altas taxas de incorporação óssea, em média, aos 95 dias de pós-operatório.

This study evaluated the allogeneic cortical bone graft incorporation after submission of the harvested fragment to a bout freezing in liquid nitrogen. Six adult sheep, clinically healthy, were submitted to a 7cm ostectomy of the tibial diaphysis. The fragment was submersed in a liquid nitrogen and implanted in another sheep missing a same-sized segment at the corresponding bone. Stabilization of the allograft in the host bone was accomplished by a dynamic compressive plate (DCP). Clinical and radiographic evaluations were performed in the immediate post-operatory period and in every 30 days for six months after surgery. The proximal and distal host-graft interfaces showed radiographic union at a mean postoperative time of 95 days in all the animals. The cortical bone allograft submitted to liquid nitrogen freezing provided adequate bone healing in the sheep model.

Hemangiosarcoma in the radius of a dog treated by limb-sparing surgery

Background: Hemangiosarcoma is a malignant neoplasm particularly rare as a primary bone tumor. The standard treatment for dogs with this neoplasm usually takes limb amputation. The aim of this paper is to report a primary hemangiosarcoma on the distal radius, treated by limb-sparing surgery. Case: An 11-year-old mixed breed male intact dog with body weight of 30 kg was admitted to the Veterinary Teaching Hospital of the Federal University of Rio Grande do Sul (HCV-UFRGS) with previous history of progressive lameness on the right forelimb for a few months. Physical examination was unremarkable. The orthopedic examination revealed grade 4/5 lameness, swelling of the distal radioulnar joint with severe pain at palpation. Radiographs revealed intense osteolysis of the distal radial epiphysis with no involvement of the ulna and carpal bones. Biopsy revealed bone hemangiosarcoma. Chest radiographs and abdominal ultrasound showed no abnormalities or signs of metastases. The treatment of choice was limb-sparing surgery with the use of allogeneic cortical graft from bone bank preserved in glycerol 98% at room temperature. Arthrodesis was performed with a 4.5 mm dynamic compression plate with 10 holes and eight screws. Histological analysis of the bone fragment confirmed the diagnosis. The dog recovered satisfactory limb function and within 15 days postoperatively presented grade 2/5...(AU)

Hemangiosarcoma in the radius of a dog treated by limb-sparing surgery

Background: Hemangiosarcoma is a malignant neoplasm particularly rare as a primary bone tumor. The standard treatment for dogs with this neoplasm usually takes limb amputation. The aim of this paper is to report a primary hemangiosarcoma on the distal radius, treated by limb-sparing surgery. Case: An 11-year-old mixed breed male intact dog with body weight of 30 kg was admitted to the Veterinary Teaching Hospital of the Federal University of Rio Grande do Sul (HCV-UFRGS) with previous history of progressive lameness on the right forelimb for a few months. Physical examination was unremarkable. The orthopedic examination revealed grade 4/5 lameness, swelling of the distal radioulnar joint with severe pain at palpation. Radiographs revealed intense osteolysis of the distal radial epiphysis with no involvement of the ulna and carpal bones. Biopsy revealed bone hemangiosarcoma. Chest radiographs and abdominal ultrasound showed no abnormalities or signs of metastases. The treatment of choice was limb-sparing surgery with the use of allogeneic cortical graft from bone bank preserved in glycerol 98% at room temperature. Arthrodesis was performed with a 4.5 mm dynamic compression plate with 10 holes and eight screws. Histological analysis of the bone fragment confirmed the diagnosis. The dog recovered satisfactory limb function and within 15 days postoperatively presented grade 2/5...

Mielomalácia hemorrágica ascendente secundária à protrusão de disco intervertebral em cão / Ascending Hemorrhagic Myelomalacia Secondary to Intervertebral Disc Protrusion in a Dog

Background: Myelomalacia is a multifocal syndrome that causes hemorrhagic infarction of the spinal cord that can occur as a sequel to acute spinal cord injury. It occurs as a consequence of acute spinal cord trauma, usually by extrusion of intervertebral disc in the thoracolumbar spine, affecting up to 10% of dogs with acute paralysis and deep pain loss in the pelvic limbs due to disc disease. This disease may be focal or diffuse; the diffuse form is typically associated with cranial and caudal migration of neurologic signs and is often fatal. The mechanical lesion to the spinal cord triggers secondary injury mediated by the existence of oxygen free radicals, alterations in the concentrations of neurotransmitters ions and amino acids, and it results in the reduction of the spinal cord blood flow, ischemia and progressive cranial and caudal necrosis to the focus of the initial injury. Case: A 5-year-old Dachshund male intact dog weighting 8 kg was referred to the Veterinary Teaching Hospital of the Federal University of Rio Grande do Sul (HCV-UFRGS) with initial complaint of acute paralysis of the hind limbs for two days. On clinical examination there was paraplegia, absence of deep pain in the pelvic limbs, with decreased patellar, sciatic and tibial cranial reflexes. The anal sphincter was relaxed and the bladder was easily expressed. The panniculus reflex was intact up to the 10th thoracic vertebra (T10). The patient had exacerbated pain on palpation of the thoracic spine. The other physiological parameters were within normal limits. Based on clinical findings, ascending myelomalacia was the presumed diagnosis. Biochemical and haematological profiles were unremarkable. The myelographic examination did not reveal a site of spinal cord compression, as the column of contrast suffered no deviation or blockage in its path. Pain was medically managed. The following day, the animal had hypothermia, forelimbs paresis, dyspnea and abdominal breathing. The panniculus reflex had migrated cranially, to the height of the 6th thoracic vertebra (T6). The owner opted for euthanasia and the patient was referred to necropsy. At necropsy the L1-L2 intervertebral disc suffered disc protrusion and not extrusion. Along the spinal cord there was multifocal hemorrhage in the white and gray matter, with gliosis, malacia, fibrin deposition and axonal spheroids. In the lumbar spinal segments L1 and L2, there was neutrophilic infiltrate and calcification area in the meninges. Discussion: It is often cited in the literature that young dogs, especially the Dachshund breed, are prone to intervertebral disc disease, with acute paralysis and, in severe cases, myelomalacia ascending, as in this case. What is rare, though, is the occurrence of myelomalacia associated with disc protrusion only instead of disc extrusion. The multifocal character of the disease evidenced by changes and worsening of neurological signs in the course of the disease was reported in this case. The physical examination findings and its evolution are the same cited in the literature, such as atonic bladder, absence of patellar reflex, anal sphincter relaxation. Dyspnea is related to paralysis of the intercostal muscles and diaphragm and is irreversible and fatal. Early diagnosis of myelomalacia ascending hemorrhagic myelomalacia is crucial to prevent death from respiratory failure due to the progression of the disease. Effective treatment for preventing the progression of necrosis and hemorrhage resulting from spinal thoraco-lumbar disc disease, acute paraplegia and which leads to loss of deep pain has not been found yet.

Técnicas anatômicas como método complementar para aprendizado de nefrotomia / Anatomical techniques as a complementary method for learning nephrotomy

Background: The use of animals in attempt to understand biological processes began many years ago with Hippocrates (450 B.C.). Galeno (129-210 a.C.) studied the anatomy and physiology of the monkeys, believing in their similarity to humans. The use of animals in experiments has always been the target of too much criticism by several society segments, questioning animal suffering after manipulation. This is due to the fact that students and professors consider that such practices are against their moral and ethical principles, besides the psychological issues that they can promote. Because of this, alternative and complementary methods were developed for surgical training and motor development of surgeons, with the goal to reduce the number of animals in these practices and to increase qualification and surgical skills. The objective of this study is to offer a complementary method of learning in the area of surgery, specifically anatomical techniques as a complementary method for learning nephrotomy. Materials, Methods & Results: Four dog kidneys were used from the pathology sector of the Universidade Federal do Rio Grande do Sul. The kidneys were removed from the abdominal cavity with the perirenal fat, blood vessels and ureter. The renal artery, renal vein and ureter were cannulated and filled with red, blue and yellow colored latex, respectively. After this, the kidneys were immersed for one hour in running water for latex polymerization. Then, the nephrotomy technique was performed. At each step of the technique, renal structures were observed, incised in a clean and easy way, and each one identified perfectly by color. Discussion: The use of animals in practical classes is still a rule in the most of brazilian universities. Several studies have observed that the teaching of practices, based on alternative techniques instead of vivisection, enabled students to equal or more learning. Virtual reality techniques, handmade devices for training surgical nodes, models for anatomical and physiological study of the ocular and circulatory systems, objects for the practice of venous puncture, artifi cial limbs for surgical practice, models for the practice of microsurgery in small vessels, cylinder with several layers the simulates in every detail a surgical procedure, mannequins, simulators, videos and the use of cadavers and viscera chemically prepared for learning surgical techniques are some of the alternative methods found nowadays. Since it is expected that veterinary medicine students experience real patients, the combination of their acquired knowledge to the practice of complementary methods, helps the student to better understand the technique and facilitates the learning process. When using viscera to help in veterinary surgical technique classes, the students participate more effectively in the classroom, without the stress and fear they face when they first practice with live animals. Furthermore, this alternative allows them to train many times every technique, refining the accuracy, coordination and manual skills, so important for a surgeon. The use of colored latex injected kidneys to simulate nephrotomy proved to be an effective method to complement the training of future surgeons, without loosing teaching quality neither using animals for this purpose.

Microplacas de titânio em fraturas de tibiotarso em pombos domésticos / Titanium microplates for treatment of tibiotarsus fractures in pigeons

Entre os problemas cirúrgicos das aves, as fraturas são os de maior prevalência. Em virtude das variações no tamanho, peso, anatomia óssea peculiar, alta incidência de fraturas complicadas e das diferentes demandas funcionais entre espécies e indivíduos, não foi possível estabelecer ainda um método ideal de osteossíntese para os ossos longos das aves. Microplacas de titânio comumente utilizadas em cirurgias maxilofaciais de humanos foram empregadas recentemente na osteossíntese de aves, porém com poucos resultados disponíveis. O objetivo do presente estudo foi avaliar a utilização das microplacas de titânio no tratamento de fraturas experimentais de tibiotarso em pombos domésticos (Columba livia). Foram utilizadas 30 aves adultas, machos e fêmeas, com 7 meses de idade, pesando entre 400 a 500 gramas. Os animais foram separados em três grupos de dez, sendo que no grupo 1 foi utilizado uma microplaca de titânio com 6 furos e espaçador central; no grupo 2, com oito furos sem espaçador central; e, no grupo 3, com oito furos com espaçador central. Após avaliação clínica, as aves foram submetidas à osteotomia médio-diafisária no tibiotarso direito para colocação das diferentes configurações de microplaca de titânio, sendo fixadas com microparafusos de titânio com 7mm de comprimento. Os animais foram avaliados clínica e radiograficamente até os 90 dias de pós-operatório. Após esse período, foi realizada eutanásia em duas aves de cada grupo. Em todas elas, foi observada a consolidação óssea, sendo que, no grupo 1, o tempo médio e o desvio padrão foram 32,9±9,9; no grupo 2, 30,8±6,7 e, no grupo 3, 26,6±6,4 dias, não havendo diferença estatística entre os grupos. O envergamento do implante foi a complicação mais frequente. A configuração da microplaca resultou em diferença estatisticamente significativa em relação à deambulação e ao grau de envergamento nos diferentes grupos, sendo que, no grupo 3, houve maior precocidade no apoio do membro e menor grau de envergamento em relação aos outros grupos. Histologicamente, foi verificada a formação de calo ósseo em todos os animais e presença de tecido ósseo ao redor da microplaca e dos microparafusos. Apesar das complicações observadas, as microplacas de titânio são uma opção para osteossíntese de tibiotarso em aves de médio porte.

Among the surgical problems in birds, the fractures are the most prevalent. Due to variations in size, weight, peculiar bone anatomy, high incidence of complicated fractures and functional demands of different species and individuals, it is still not possible to establish an ideal method for osteosynthesis of long bones in birds. Titanium microplates commonly used in human maxillofacial surgery have been recently employed in osteosynthesis of birds, but with few results available. The aim of this study was to evaluate the use of titanium microplates in the treatment of tibiotarsus fractures in 30 pigeons (Columba livia) , adult males and females, with 7 months old, weighing from 400 to 500. The animals were divided into 3 groups with ten animals each. In group 1, a titanium microplate with 6 holes and a central spacer was used; in group 2, a titanium microplate with 8 holes without a spacer in the center was used; in group 3, a titanium microplate with 8 holes with central spacer was used. After clinical evaluation, the birds were submitted to mid-diaphyseal osteotomy in the right bone for placement of different configurations of the titanium plate, and fixed with titanium microscrews 7mm long. The animals were evaluated clinically and radiographically until 90 days postoperatively. After this period, euthanasia was performed in 2 animals from each group. In all animals was observed bone healing and in group 1 the mean and standard deviation were 32.9±9.9 days, in group 2, 30.8±6.7 days in group 3, 26.6±6.4 days. There was no statistical difference in healing time between groups. The bending of the implant was the most common complication. The configuration of the plate resulted in a statistically significant difference in relation to walking and to the degree of bending in the different groups. Moreover, in group 3 there was higher precocity in the member suppor and a lower degree of bending in relation to other groups. Histologically, it was verified formation of the callus in all animals and presence of bone tissue around the plate and microscrews. Despite the complications of titanium microplates, they are an option for tibiotarsus osteosynthesis in birds of medium size.