Clinical, Histopathological and Immunohistochemistry Evaluation of Reactive Cutaneous Histiocytosis in Canine in Western Amazonia

Background: Canine reactive cutaneous histiocytosis (RCH) is an immuneproliferative disease of skin histiocytes and is uncommon in occurrence. Its description in the literature is scarce and clinical studies are limited by the insufficient characterization of the patients' pathological findings. The objective of this report is to describe the clinical, histological and immunohistochemical findings of a case of canine reactive cutaneous histiocytosis in the state of Acre, Amazonia, Brazil.Case: It was attended at the Federal University of Acre, a 7-year-old male American pit bull terrier dog with nodular, allopecic and ulcerated lesions in the dorsal region of the ear, with purulent discharge and exacerbated painful tenderness. The animal was domiciled on the bank of the river Acre, municipality of Rio Branco, state of Acre, and suffered frequent parasitism by sandflies, especially in the head region. In the histopathological evaluation, hyperplastic cells were found, a large ulcerated area with the presence of fibrin and neutrophilic infiltrate in the epidermis. In the dermal layer, an inflammatory reaction pattern was identified, with the presence of fibrous connective tissue, dilated blood vessels and edema, however little defined. There was an intense presence of histiocytes with anisocytosis, in addition to neutrophils, plasma cells and lymphocytes in the perivascular and perianexal region. In immunohistochemistry, lysozyme and cell markers CD1a and Thy1 were detected, but negative result for E-cadherin and CD11d. The immunosuppressive therapy indicated with prednisolone, plus cephalexin for secondary infections and topical treatment, with clinical remission within two years.  Discussion: Although the etiopathogenesis of RCH is poorly understood, it is believed that, in addition to the genetic factor, the disease is triggered by an antigenic trigger on the skin, such as dogs susceptible to ticks and sandflies. The accumulation of defense cells in the skin tissue, against the antigenic stimulus, generates primarily an inflammatory process too. Immune maladjustment of dendritic cells and leukocytes occurs in the walls of dermal vessels, as well as exacerbated recruitment of histiocytes, characteristics seen in cell morphology analyzes. In RCH, the proliferation of histiocytes between collagen fibers and the infiltration of round cells in the dermis are indicative of the disease, as evidenced in this report. The immunohistochemistry is the method of choice, which allows establishing the cellular origin that triggered the disease, although the characterization of a differentiation cluster is underused in veterinary medicine. In this context, we seek to identify histiocytes, which comprise the group of cells derived from CD34 +, macrophage precursors, dendritic and Langerhans cells of the epithelial tissue, which act as antigen presenters. It can be concluded that canine RCH is an uncommon disease resulting from an inflammatory process of the dermis with difficult to identify immune dysregulation. Differential diagnosis with systemic histiocytosis, cutaneous histiocytoma, histiocytic sarcoma, as well as leishmaniasis and mycobacteriosis, are fundamental through histopathological, serological and immunohistochemical evaluations, to establish the definitive diagnosis of the disease, as well as the prognosis, and to better direct the therapeutic approach of the case

Uso da Dexmedetomidina para a contenção química de uma Anta Brasileira (Tapirus terrestris) de cativeiro

Background:  The Brazilian tapir (Tapirus terrestris), considered the largest land mammal in South America, is a vulnerable species in terms of its degree of conservation. In captivity, its health is evaluated through behavioral and physical observation and laboratory exams, and in some cases, chemical restraint, to reduce stress. Dissociative anesthetics and sedatives are used for the sedation of these animals, and few studies have reported the use of dexmedetomidine and its effects when associated with other drugs in chemical containment protocols; therefore, this work reports its use, in conjunction with ketamine and midazolam, in a young Brazilian tapir. Case:  A male Brazilian tapir, male, weighing 89 kg, 1 and a half year old,  housed at CETAS in Rio Branco, Acre, was chemically restrained with dexmedetomidine (7 µg/kg), ketamine (1.5 mg/kg), and midazolam (0.2 mg/kg) for venous blood collection, oral and rectal mucosal swabs, and microchipping. The protocol was administered intramuscularly to the right triceps brachii, after physical restraint. After 5 min of application, the animal assumed sternal recumbency and presented reflux. After 15 min, the patient was placed in the right lateral decubitus position. During collection, heart rate (48 ± 10 bpm), respiratory frequency (29 ± 1 mpm), rectal temperature (38.1 ± 0.18 °C), oxyhemoglobin saturation (97 ± 1%), and electrocardiographic tracing were recorded. The tapir showed deep sedation, immobility, good muscle relaxation, discreet medial palpebral reflex, and bilateral rotation of the eyeball. After 40 min of protocol administration, sedative reversal was performed intramuscularly with 14 µg/kg atipamezole. Five min after administration, the tapir showed signs of mild sedation. After 10 min, he assumed the quadrupedal position, remained in this position for 8 min, and gently resumed the sternal decubitus. After only 20 min, he resumed the quadrupedal position, with mild ataxia and good muscular and conscious tone. After 50 min, the patient was discharged from anesthesia. Discussion: Domestic horses are phylogenetically close to tapirs, so the choice of drugs and doses of the protocol used was based on their use in horses, and on studies carried out with tapirs as well. Despite being docile and passive, the tapir was not conditioned and did not allow the manipulation and collection of samples collaboratively; therefore, it was chemically contained. The physical restraint performed did not generate satisfactory immobilization of the tapir, resulting in agitation and stress and causing the needle to break. The reflux presented by the tapir minutes after sedation and at recovery was induced by dexmedetomidine, and only the undigested banana pieces were offered to the animal. Reflux plus stress from extensive fasting and suboptimal physical restraint was responsible for the change in the tapir's eating behavior, with possible stress gastritis 24 h after chemical restraint. Only one study reported the use of dexmedetomidine in tapirs, associated with continuous infusions of ketamine, midazolam and guaiacol glyceryl ether for moderate to long-term field procedures. Sedative reversal of dexmedetomidine by atipamezole reduced the recovery time and the risk of death from cardiorespiratory depression. The anesthetic combination used was effective, promoting immobility, muscle relaxation, and stability of the physical parameters evaluated, with rapid and gentle induction and an adequate level of sedation for the objective, good sedative reversal, and anesthetic recovery. Keywords: anesthesia, anesthetic management, wild animals, mammals, sedative.Antecedentes: Considerado o maior mamífero terrestre da América do Sul, a Anta brasileira (Tapirus terrestris), é uma espécie vulnerável quanto ao seu grau de conservação. Em cativeiro, sua saúde é avaliada por meio da observação comportamental, física e por exames, sendo necessária, e alguns casos, a contenção química, reduzindo o estresse. Anestésicos dissociativos e sedativos são utilizados para a sedação destes animais, e poucos estudos relatam o uso da dexmedetomidina e seus efeitos quando associadas a outros fármacos em protocolos de contenção química, por isso, este trabalho relata o seu emprego, com cetamina e midazolam, em uma anta brasileira jovem. Caso:  Uma anta brasileira, macho, 89 kg, um ano e meio de idade, lotada no CETAS de Rio Branco, Acre, foi contida quimicamente com dexmedetomidina (7µg/kg), cetamina (1,5mg/kg) e midazolam (0,2 mg/kg), para a coleta de sangue venoso, swab da mucosa oral e retal, e microchipagem. O protocolo foi administrado por via intramuscular, no tríceps braquial direito, após contenção física. Após cinco minutos da aplicação, o animal assumiu decúbito esternal, e apresentou refluxo. Passados 15 minutos, este foi posicionado em decúbito lateral direito. Durante a coleta, foram monitoradas, a frequência cardíaca (48 ± 10 bpm), frequência respiratória (29 ± 1 mpm), temperatura retal (38,1 ± 0,18 °C), saturação da oxihemoglobina (97 ± 1%) e o traçado eletrocardiográfico pelo monitor multiparamétrico. A anta apresentou grau de sedação profundo, imobilidade, bom relaxamento muscular, reflexo palpebral medial discreto e rotação bilateral do globo ocular. Após 40 minutos da administração do protocolo, foi realizada a reversão sedativa com 14 µg/kg atipamezole, por via intramuscular. Depois de cinco minutos dessa administração, a anta apresentou sinais de grau de sedação leve. Após dez minutos, assumiu a posição quadrupedal, permaneceu nesta por oito minutos, e retomou o decúbito esternal, de modo suave. Somente após 20 minutos, reassumiu a posição quadrupedal, com leve ataxia, bom tônus muscular e consciente. Depois de 50 minutos, recebeu alta anestésica. Discussão: Os cavalos domésticos são filogeneticamente próximos das antas, por isso a escolha das drogas e das doses do protocolo utilizado foi baseada em seu uso em cavalos, e também em estudos realizados com antas. Apesar de dócil e passiva, a anta não era condicionada e não permitia a manipulação e coleta de amostras de forma colaborativa; portanto, estava quimicamente contido. A contenção física realizada não gerou uma imobilização satisfatória da anta, resultando em agitação e estresse e causando a quebra da agulha. O refluxo apresentado pela anta minutos após a sedação e na recuperação foi induzido pela dexmedetomidina, e apenas os pedaços de banana não digeridos foram oferecidos ao animal. Refluxo mais estresse de jejum prolongado e contenção física abaixo do ideal foi responsável pela mudança no comportamento alimentar da anta, com possível gastrite de estresse 24 h após a contenção química. Apenas um estudo relatou o uso de dexmedetomidina em antas, associado a infusões contínuas de cetamina, midazolam e guaiacol gliceril éter para procedimentos de campo de moderada a longa duração. A reversão sedativa da dexmedetomidina pelo atipamezol reduziu o tempo de recuperação e o risco de morte por depressão cardiorrespiratória. A combinação anestésica utilizada foi eficaz, promovendo imobilidade, relaxamento muscular e estabilidade dos parâmetros físicos avaliados, com indução rápida e suave e nível adequado de sedação para o objetivo, boa reversão sedativa e recuperação anestésica

Uso da Dexmedetomidina para a contenção química de uma Anta Brasileira (Tapirus terrestris) de cativeiro

Background:  The Brazilian tapir (Tapirus terrestris), considered the largest land mammal in South America, is a vulnerable species in terms of its degree of conservation. In captivity, its health is evaluated through behavioral and physical observation and laboratory exams, and in some cases, chemical restraint, to reduce stress. Dissociative anesthetics and sedatives are used for the sedation of these animals, and few studies have reported the use of dexmedetomidine and its effects when associated with other drugs in chemical containment protocols; therefore, this work reports its use, in conjunction with ketamine and midazolam, in a young Brazilian tapir. Case:  A male Brazilian tapir, male, weighing 89 kg, 1 and a half year old,  housed at CETAS in Rio Branco, Acre, was chemically restrained with dexmedetomidine (7 µg/kg), ketamine (1.5 mg/kg), and midazolam (0.2 mg/kg) for venous blood collection, oral and rectal mucosal swabs, and microchipping. The protocol was administered intramuscularly to the right triceps brachii, after physical restraint. After 5 min of application, the animal assumed sternal recumbency and presented reflux. After 15 min, the patient was placed in the right lateral decubitus position. During collection, heart rate (48 ± 10 bpm), respiratory frequency (29 ± 1 mpm), rectal temperature (38.1 ± 0.18 °C), oxyhemoglobin saturation (97 ± 1%), and electrocardiographic tracing were recorded. The tapir showed deep sedation, immobility, good muscle relaxation, discreet medial palpebral reflex, and bilateral rotation of the eyeball. After 40 min of protocol administration, sedative reversal was performed intramuscularly with 14 µg/kg atipamezole. Five min after administration, the tapir showed signs of mild sedation. After 10 min, he assumed the quadrupedal position, remained in this position for 8 min, and gently resumed the sternal decubitus. After only 20 min, he resumed the quadrupedal position, with mild ataxia and good muscular and conscious tone. After 50 min, the patient was discharged from anesthesia. Discussion: Domestic horses are phylogenetically close to tapirs, so the choice of drugs and doses of the protocol used was based on their use in horses, and on studies carried out with tapirs as well. Despite being docile and passive, the tapir was not conditioned and did not allow the manipulation and collection of samples collaboratively; therefore, it was chemically contained. The physical restraint performed did not generate satisfactory immobilization of the tapir, resulting in agitation and stress and causing the needle to break. The reflux presented by the tapir minutes after sedation and at recovery was induced by dexmedetomidine, and only the undigested banana pieces were offered to the animal. Reflux plus stress from extensive fasting and suboptimal physical restraint was responsible for the change in the tapir's eating behavior, with possible stress gastritis 24 h after chemical restraint. Only one study reported the use of dexmedetomidine in tapirs, associated with continuous infusions of ketamine, midazolam and guaiacol glyceryl ether for moderate to long-term field procedures. Sedative reversal of dexmedetomidine by atipamezole reduced the recovery time and the risk of death from cardiorespiratory depression. The anesthetic combination used was effective, promoting immobility, muscle relaxation, and stability of the physical parameters evaluated, with rapid and gentle induction and an adequate level of sedation for the objective, good sedative reversal, and anesthetic recovery. Keywords: anesthesia, anesthetic management, wild animals, mammals, sedative.Antecedentes: Considerado o maior mamífero terrestre da América do Sul, a Anta brasileira (Tapirus terrestris), é uma espécie vulnerável quanto ao seu grau de conservação. Em cativeiro, sua saúde é avaliada por meio da observação comportamental, física e por exames, sendo necessária, e alguns casos, a contenção química, reduzindo o estresse. Anestésicos dissociativos e sedativos são utilizados para a sedação destes animais, e poucos estudos relatam o uso da dexmedetomidina e seus efeitos quando associadas a outros fármacos em protocolos de contenção química, por isso, este trabalho relata o seu emprego, com cetamina e midazolam, em uma anta brasileira jovem. Caso:  Uma anta brasileira, macho, 89 kg, um ano e meio de idade, lotada no CETAS de Rio Branco, Acre, foi contida quimicamente com dexmedetomidina (7µg/kg), cetamina (1,5mg/kg) e midazolam (0,2 mg/kg), para a coleta de sangue venoso, swab da mucosa oral e retal, e microchipagem. O protocolo foi administrado por via intramuscular, no tríceps braquial direito, após contenção física. Após cinco minutos da aplicação, o animal assumiu decúbito esternal, e apresentou refluxo. Passados 15 minutos, este foi posicionado em decúbito lateral direito. Durante a coleta, foram monitoradas, a frequência cardíaca (48 ± 10 bpm), frequência respiratória (29 ± 1 mpm), temperatura retal (38,1 ± 0,18 °C), saturação da oxihemoglobina (97 ± 1%) e o traçado eletrocardiográfico pelo monitor multiparamétrico. A anta apresentou grau de sedação profundo, imobilidade, bom relaxamento muscular, reflexo palpebral medial discreto e rotação bilateral do globo ocular. Após 40 minutos da administração do protocolo, foi realizada a reversão sedativa com 14 µg/kg atipamezole, por via intramuscular. Depois de cinco minutos dessa administração, a anta apresentou sinais de grau de sedação leve. Após dez minutos, assumiu a posição quadrupedal, permaneceu nesta por oito minutos, e retomou o decúbito esternal, de modo suave. Somente após 20 minutos, reassumiu a posição quadrupedal, com leve ataxia, bom tônus muscular e consciente. Depois de 50 minutos, recebeu alta anestésica. Discussão: Os cavalos domésticos são filogeneticamente próximos das antas, por isso a escolha das drogas e das doses do protocolo utilizado foi baseada em seu uso em cavalos, e também em estudos realizados com antas. Apesar de dócil e passiva, a anta não era condicionada e não permitia a manipulação e coleta de amostras de forma colaborativa; portanto, estava quimicamente contido. A contenção física realizada não gerou uma imobilização satisfatória da anta, resultando em agitação e estresse e causando a quebra da agulha. O refluxo apresentado pela anta minutos após a sedação e na recuperação foi induzido pela dexmedetomidina, e apenas os pedaços de banana não digeridos foram oferecidos ao animal. Refluxo mais estresse de jejum prolongado e contenção física abaixo do ideal foi responsável pela mudança no comportamento alimentar da anta, com possível gastrite de estresse 24 h após a contenção química. Apenas um estudo relatou o uso de dexmedetomidina em antas, associado a infusões contínuas de cetamina, midazolam e guaiacol gliceril éter para procedimentos de campo de moderada a longa duração. A reversão sedativa da dexmedetomidina pelo atipamezol reduziu o tempo de recuperação e o risco de morte por depressão cardiorrespiratória. A combinação anestésica utilizada foi eficaz, promovendo imobilidade, relaxamento muscular e estabilidade dos parâmetros físicos avaliados, com indução rápida e suave e nível adequado de sedação para o objetivo, boa reversão sedativa e recuperação anestésica

Primeira ocorrência documentada de Dioctophyma renale em dois cães no Estado do Acre, Brasil

Background: Known as the “giant kidney worm,” Dioctophyma renale is the nematode that causes dioctophymosis in domestic and wild animals and in humans. Its biological cycle is indirect and dogs are definitive hosts. In this case, the adult parasite generally located in the right kidney; however, it can also be found in the left kidney, abdominal cavity, bladder, and testes. Dioctophymosis is diagnosed by visualizing parasite eggs in the urine or by visualizing the adult form using abdominal ultrasonography. This study aimed to report the occurrence of 2 cases of D. renale infection in dogs who underwent right unilateral nephrectomy, in the State of Acre, Brazil. Cases: Case 1. An adult, mixed breed bitch was treated at a private veterinary clinic in the city, having presented with a 1-month history of apathy and hematuria. During abdominal  ultrasonography, a right kidney with increased dimensions, total loss of parenchyma, and the presence of several tubular structures with anechoic content, suggestive of D. renale infestation was observed. After diagnosis, the animal was referred for nephrectomy of the right kidney, and after sectioning the capsule and renal parenchyma, the parasites were identified. Case 2. An approximately 3-year-old male, mixed breed dog, weighing 17 kg, rescued from the street by volunteers from an animal protection NGO in the city, was treated at the Teaching Veterinary Clinic of the Federal University of Acre. The animal exhibited lethargy and brown urine and had already been treated at another private veterinary clinic in the city, where an ultrasound examination had been performed that revealed the presence of the D. renale worm in the right kidney. Urinalysis of this animal revealed cloudy urine, dark yellow to greenish in color, and structures compatible with D. renale eggs (+++). The animal was referred for right unilateral nephrectomy. A total of 3 helminths measuring 25 - 40 cm in length were found inside the right kidney. D. renale was identified by considering the morphological characteristics of the worms, such as a simple mouth without lips and the presence of the copulatory bursa in males. The eggs found in the urine were elliptical in shape and brown in color, with thick walls, rough appearance, and transparent bipolar plugs. Discussion: The 2 animals described in this study were stray dogs. The change in urine color corroborates clinical findings in dogs with dioctophymosis. Dioctophyma renale is capable of generating direct renal lesions that lead to the destruction or atrophy of parenchyma of the organs and hematuria. In some cases, only the renal capsule is preserved, as in the animal reported in case 1. In both animals, the parasite was found only in the right kidney and was not present in the abdominal cavity, left kidney, testes, or bladder. Urinalysis is an excellent diagnostic tool for dioctophymosis; however, it should not be considered as the only diagnostic method, as it is not always possible to observe parasite eggs in the urine, as they are not constantly released even when adult female worms are present in the kidneys and not at all in their absence. Nephrectomy and surgical removal of parasites are the most effective methods for treating this disease in animals because there are no effective and safe antiparasitic drugs to combat the worm. The macroscopic characteristics of parts of the parasite’s body were sufficient for its identification and diagnosis of the first 2 cases of dioctophymosis in dogs in the state of Acre, Brazil. Keywords: endoparasite, parasitology, nephrectomy, nematode, kidney. Título: Dioctofimose renal em cães Descritores: endoparasita, parasitologia, nefrectomia, nematoide, rim.

Clinical, Histopathological and Immunohistochemistry Evaluation of Reactive Cutaneous Histiocytosis in Canine in Western Amazonia

Background: Canine reactive cutaneous histiocytosis (RCH) is an immuneproliferative disease of skin histiocytes and is uncommon in occurrence. Its description in the literature is scarce and clinical studies are limited by the insufficient characterization of the patients' pathological findings. The objective of this report is to describe the clinical, histological and immunohistochemical findings of a case of canine reactive cutaneous histiocytosis in the state of Acre, Amazonia, Brazil.Case: It was attended at the Federal University of Acre, a 7-year-old male American pit bull terrier dog with nodular, allopecic and ulcerated lesions in the dorsal region of the ear, with purulent discharge and exacerbated painful tenderness. The animal was domiciled on the bank of the river Acre, municipality of Rio Branco, state of Acre, and suffered frequent parasitism by sandflies, especially in the head region. In the histopathological evaluation, hyperplastic cells were found, a large ulcerated area with the presence of fibrin and neutrophilic infiltrate in the epidermis. In the dermal layer, an inflammatory reaction pattern was identified, with the presence of fibrous connective tissue, dilated blood vessels and edema, however little defined. There was an intense presence of histiocytes with anisocytosis, in addition to neutrophils, plasma cells and lymphocytes in the perivascular and perianexal region. In immunohistochemistry, lysozyme and cell markers CD1a and Thy1 were detected, but negative result for E-cadherin and CD11d. The immunosuppressive therapy indicated with prednisolone, plus cephalexin for secondary infections and topical treatment, with clinical remission within two years.  Discussion: Although the etiopathogenesis of RCH is poorly understood, it is believed that, in addition to the genetic factor, the disease is triggered by an antigenic trigger on the skin, such as dogs susceptible to ticks and sandflies. The accumulation of defense cells in the skin tissue, against the antigenic stimulus, generates primarily an inflammatory process too. Immune maladjustment of dendritic cells and leukocytes occurs in the walls of dermal vessels, as well as exacerbated recruitment of histiocytes, characteristics seen in cell morphology analyzes. In RCH, the proliferation of histiocytes between collagen fibers and the infiltration of round cells in the dermis are indicative of the disease, as evidenced in this report. The immunohistochemistry is the method of choice, which allows establishing the cellular origin that triggered the disease, although the characterization of a differentiation cluster is underused in veterinary medicine. In this context, we seek to identify histiocytes, which comprise the group of cells derived from CD34 +, macrophage precursors, dendritic and Langerhans cells of the epithelial tissue, which act as antigen presenters. It can be concluded that canine RCH is an uncommon disease resulting from an inflammatory process of the dermis with difficult to identify immune dysregulation. Differential diagnosis with systemic histiocytosis, cutaneous histiocytoma, histiocytic sarcoma, as well as leishmaniasis and mycobacteriosis, are fundamental through histopathological, serological and immunohistochemical evaluations, to establish the definitive diagnosis of the disease, as well as the prognosis, and to better direct the therapeutic approach of the case