Polymyositis associated with brainstem signs in a dog

Background: Polymyositis is a generalized inflammatory myopathy which can lead to rhabdomyolysis. This affection may have several origins, including degenerative, metabolic, autoimmune, infectious, inflammatory, ischemic, traumatic, by drug use, induced by toxins and also of idiopathic origin. Diagnosis is made with seric dosage, electrodiagnostic tests and muscle biopsy. Lesions in the rostral oblong medulla may affect the central vestibular system, and there may be signs such as opisthotonos, nystagmus, and strabismus. The aim of this report is to describe a case of a mixed breed dog with manifestation of polymyositis associated with brainstem signs of probable idiopathic origin. Case: A 5-year-old mixed breed male dog was attended with opisthotonos episodes for 2 days, and pelvic limbs extension and thoracic limbs flexion that lasted 10 to 20 min at intervals of approximately 1 h. The animal was anorexic and had also presented one episode of emesis. Upon neurological examination, ventromedial strabismus and Horner's syndrome was observed on the right side, besides vertical nystagmus, flaccid tetraparesis and absence of proprioception in the four limbs. Biochemical analyses revealed creatine kinase (CK) increased (2,433.9 UI/L - reference: 1.5-28.4 UI/L), and urinalysis showed dark color and presence of occult blood without, however, erythrocyturia. Electrocardiogram (ECG) showed QS wave and deviation of the electrical axis. Treatment with prednisolone (1 mg/kg, BID), phenobarbital (2 mg/kg, BID), maropitant citrate (1 mg/kg in 2 doses), and crystalloid fluid therapy (50 mL/kg/day) were prescribed. On the 4th day, the dog was more active and feeding without a tube, so it recommended keep the treatment at home. On the 10th day, the animal had proprioception present on the 4 limbs and normorexia. Biochemical analyses and urinalysis showed no alterations, but normochromic normochromic anemia with thrombocytopenia and leukocytosis by neutrophilia showed in blood count exam. PCR to Ehrlichia canis, Hepatozoon sp., and Babesia canis resulted negative. On the 15th day, blood count, biochemical analyses and urinalysis showed no alterations. Neurological examination revealed only positional vertical nystagmus. which remained as a sequel. Discussion: Polymyositis may be accompanied by rhabdomyolysis, characterized by acute muscle necrosis, increased CK and myoglobinuria. The animal had polymyositis of acute onset, with myoglobinuria and elevated CK values, whose presentation included myalgia and muscle weakness. In humans, polymyositis is accompanied by changes in electrocardiographic tracing without clinical alterations. In dogs, the first report that showed cardiac involvement was compatible with myocarditis. The changes in ECG in the present case was attributed to failure in myocardial electrical conduction. The patient also showed signs of brainstem and central vestibular system injuries. Stress myopathy, intoxication, snakebite, infectious, and metabolic diseases were discarded leading to a clinical suspicion as idiopathic origin. Similar to a published case, the patient of this report received symptomatic and supportive treatment, being discharged from the hospital 20 days after the onset of clinical signs. Thus, polymyositis may be accompanied by signs indicative of brainstem injury. Patients with rhabdomyolysis require intense monitoring due to the high risk of developing acute renal failure. Since no causative agent was identified, symptomatic treatment combined with the prevention of possible complications were fundamental for the maintenance of the animal's life.

Chemodectoma in a bitch

Background: Chemodectomas, better known as tumors of the base of the heart, arise from aortic bodies, respiratory chemoreceptors located near or inside the aortic arch or originate from receptors located in the carotid arteries. Relatively rare, they affect dogs and, to a lesser extent, cats. They gain great importance when they influence the function of the cardiovascular system, with animals showing clinical signs related to congestive heart failure. Clinical diagnosis is based on symptomatology and complementary tests such as radiography, electrocardiography and echocardiography, while the definitive diagnosis is obtained by cytological and histopathological exams. This study aims to reports a case of malignant chemodectoma in a bitch, whose main symptomatology was neurological and not cardiovascular. Case: A 1-year-old Rottweiler bitch was attended with neurological alterations compatible with vestibular syndrome, hyporexia, dysphagia, apathy, melena, emesis, and purulent nasal discharge on the right nostril. On physical examination, the animal showed depressed level of consciousness, poor body condition, bilateral quemosis, paralysis of the right eye, inspiratory dyspnea and muffling of cardiac auscultation, besides a subcutaneous nodule between the scapulae. On neurological evaluation, horizontal nystagmus, head tilt to the right side, ventromedial strabismus and facial nerve paralysis on the right side were observed so that the localization of the lesion was set in peripheral vestibular system. During anesthesia for esophageal tube placement, a mass from the hard palate to the oropharynx was noted, making endotracheal intubation impossible to perform. Biopsy of this nodule was performed, and tracheostomy was indicated, but the owner opted for euthanasia before the procedure. Necropsy revealed white soft masses in the bilateral retromandibular region, on the subcutaneous tissue near the scapulae, in the right ear and since nasopharynx to the soft palate, in addition to sparse white nodules in the heart, lung, carotid artery, kidneys, right ovary, mesentery near to the spleen, and axillary lymph node. Histologically, the nodules were characterized by neoplastic cells population organized in short bundles or cords, arranged around small blood vessels surrounded by delicate connective tissue. Neoplastic cells infiltrated muscles and blood and lymphatic vessels were filled by multiple neoplastic emboli. The histological pattern of the cells allowed the diagnosis of chemodectoma. Discussion: The bitch from this case had 1-year-old when diagnosed with chemodectoma, differently from most cases from literature, that are between 7 to 15 years old. Furthermore, primarily cardiac tumors are considered rare, being chemodectoma the most common, often reported in Boxer and Boston Terrier dogs, but unusual in Rottweilers. Despites some articles mentioning seizure and Horner's Syndrome secondary to a carotid body chemodectoma, neurological signs are not commonly observed in these cases. The presence of the tumor in the middle ear region of the right side supports the occurrence of peripheral vestibular syndrome and facial nerve paralysis on the same side. Because it is a neoplasm that is usually detected late during the course of the disorder, most patients either cannot obtain diagnosis in vivo, as in this reported animal, which was in such a critical condition that underwent euthanasia, or there are no more possible therapeutic choices. In the patient described, there were numerous metastatic masses and nodules spread throughout the body. Although the typical clinical signs in animals with chemodectomas are often related to heart disease, neurological signs may also be present. This report emphasizes the importance of chemodectoma being included as a differential diagnosis in young dogs and even in breeds such as Rottweiler.

Acute erythroid leukemia in a cat infected with feline leukemia virus

Background: Erythroid leukemia is a myeloproliferative hematopoietic disorder considered acute when there is a predominance of blasts in the bone marrow. It is frequently reported in cats infected with feline leukemia virus, but it is unclear whether this virus is involved in the oncogenesis. The clinical signs in cats are anorexia, apathy, weight loss, with evolution from 2 weeks to 2 months, pale mucous membranes, hemorrhages, ascites, salivation, and dyspnea due to pleural effusion. This affection responds little to chemotherapy with an unfavorable prognosis. The aim of this study is to report a case of a feline leukemia virus infected cat with the onset of severe hemolytic anemia. Case: A 8-year-old male mixed breed cat was attended with a history of anorexia, oligodipsia, apathy, progressive weight loss, and yellowish color of urine for 7 days. Laboratorial exams showed anemia (with metarubricytes, acanthocytes and ghost cells), leukocytosis and FeLV reagent test. The cat underwent treatment with methylprednisolone acetate and supportive care. One day later, the animal returned with icteric mucous membranes, and emesis. A blood count was performed that found worsening anemia, increased leukocytosis, and lymphocytosis. Abdominal ultrasound showed cholangiohepatitis and lymphadenomegaly in mesenteric lymph nodes. Treatment was started with ondansetron, metronidazole, and amoxicilin with potassium clavulanate. The cat returned after 3 days and laboratorial exams revealed worsening of blood parameters, so blood transfusion was performed. After 2 days, the patient started with dyspnea and hypothermia, that evolved to cardiorespiratory arrest. The body was sent to necropsy and histopathology, where blast cells and rubricytes were found in blood vessels of various organs. The bone marrow was markedly cellular with complete disappearance of adipose tissue. Most of the cells were blasts with abundant and eosinophilic cytoplasm, central nucleus with finely dotted chromatin and a large nucleolus. There were rubricytes, which made possible to confirm acute erythroid leukemia as a morphological diagnosis. Discussion: The clinical signs observed in acute erythroid leukemia are lethargy, inappetence, fever, splenomegaly, mild lymphadenomegaly, associated with leukocytosis, severe anemia, and thrombocytopenia. The reported animal presented signs similar to those described in the literature except that there was no change in platelet counts. The diagnosis of leukemia was reached after histopathology, and it is made when is observed more than 30% of myeloblasts and monoblasts together or when the blast cells count including rubriblasts is greater than 30%. Although chemotherapy, the prognosis is usually poor. It is essential to perform the myelogram for the diagnosis of myeloid leukemias in vivo. In this report, we only achieve final diagnosis after the cat's death, due to the aggressive behavior of the disease. Clinicians must be aware of the likely development of acute erythroid leukemia whenever a feline leukemia virus infected cat presents hemolytic anemia to get an early diagnosis, since this is an extremely aggressive disease, to propose prompt chemotherapy and give the patient a longer survival period.