Thromboembolism in a bitch - diagnosis by infrared thermography

Background: Thermography is a noninvasive, non-contact, painless, and non-ionizing imaging technique that records cutaneous thermal patterns generated by infrared emission of the surface. The surface heat is closely related to dermal microcirculation. Thromboembolism is responsible for important changes in the thermal pattern of the body surface due to physical obstruction of blood flow, being the main complication in immune-mediated hemolytic anemia. The aim of this paper is to report a dog with thrombus in his left forelimb secondary to idiopathic hemolytic anemia, whose diagnostic screening was performed through infrared thermography. Case: A 9-year-old mixed breed bitch was referred to a veterinary hospital with a history of emesis, diarrhea and dark-colored urine for 2 days. The complete blood count showed hypochromic macrocytic anemia (hematocrit [HTC] 28%, reference: 37 to 55%) with the presence of nucleated erythrocyte (14/100 leukocytes, reference: 0 to 5/100 leukocytes), polychromasia and spherocytes. Leukocytosis (28,300 mm³, reference: 6,000 to 17,000 mm³) by neutrophilia with left deviation and toxic granulations was also present, in addition to hemoglobinuria at urine exam. Therefore, treatment for immune-mediated hemolytic anemia (IMHA) was instituted. After 2 days, the animal returned with acute functional impairment of the left forelimb. Physical examination revealed that the limb was cold, without pulse, proprioception, reflexes, and deep pain. New blood analyses revealed decreased hematocrit (HTC 17%, reference: 37 to 55%), and increased total leukocyte number (57,000 mm3, reference: 6,000 to 17,000 mm³). Infrared thermography revealed an important temperature difference between the limbs, with the affected limb temperature considerably lower (31.3ºC) when compared to the contralateral limb (35.0ºC). Thermography showed the site of the thrombus in the medial portion of the limb (cephalic vein), where the catheter had been placed for fluid therapy. Due to the severity of the condition, the bitch was submitted to amputation surgery, which occurred without complications. The patient had a good response to treatment, with decreased signs of hemolysis and hypercoagulability. The medications were slowly withdrawn, and the clinical discharge occurred after 4 weeks. Discussion: In humans, thermography has been widely used in the assessment of thrombotic diseases, contributing to diagnosis, localization, and prognosis. In veterinary medicine, however, the use of this tool in the diagnosis of thromboembolism is still rare. The difference of 3.7°C between the affected and contralateral limb was objectively verified using thermography. A minimum difference of 2.4°C between limbs has high sensitivity and specificity for diagnosing thromboembolism and occurs due to the reduction in local blood flow. In the present case this tool was essential for the anatomical location of the thrombus, which was in the middle third of the forearm, and allowed an adequate surgical planning. It is known that the main complication of IMHA is thromboembolism. Its predisposing factors include venous stasis, endothelial damage, and hypercoagulability, being exacerbated by cage confinement, decubitus and presence of a peripheral venous catheter. The reported case corroborates at least one of these factors since it had a peripheral venous catheter in the left forelimb, which later showed absence of pulse, spinal reflexes, pain and proprioception. The thermography showed to be an objective, rapid and non-invasive tool to diagnose and precisely locate the thrombus, which allowed for adequate treatment and surgical planning for the case. To the best of our knowledge, this is the first report about use of thermography to diagnose thromboembolism secondary to immune-mediated hemolytic anemia in a dog.

Non-cardiogenic thromboembolism in a Persian cat with hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy is the most common acquired cardiovascular disease in the feline species. A frequent complication of this cardiomyopathy is the development of cardiac congestive failure, left atrial enlargement and subsequent development of arterial thromboembolism. In a significant percentage of affected animals there is progression to congestive heart failure, resulting in cyanosis and dyspnea, often the first clinical signs reported by owners. This is a report of a 10-year-old Persian cat with hypertrophic cardiomyopathy and venous and arterial thromboembolism of non-cardiogenic origin. Case: The patient was referred for cardiac evaluation, arterial thromboembolism was the suspected cause of tetraparesis. On clinical examination, a metacarpal pulse was present in all limbs; there was no cyanosis or peripheral hypothermia thus, ruling out a thromboembolic event in the limbs. Changes consistent with feline asthma and pulmonary edema were seen on radiographs, therefore hypertrophic cardiomyopathy was suspected. Treatment with enalapril (0.25 mg/kg every 12 h) for the heart condition and prednisolone (1 mg/kg every 24 h) for asthma was started. Nine days later, the patient developed mixed dyspnea (inspiratory and expiratory) and was hospitalized with signs consistent with arterial thromboembolism: paralysis and cold extremities in the right and left pelvic limbs. The patient was euthanized due to the poor prognosis. Postmortem and histopathological findings revealed left ventricular concentric hypertrophy, with no valvular changes; disseminated intravascular coagulation, with thrombi in the arterial (iliac arteries, pancreatic and renal vessels) and venous (pulmonary and renal veins) beds; as well as multiple neoplastic lung masses, identified as scirrhous pulmonary adenocarcinoma, responsible for increased interstitial radiopacity. Metastasis was also identified at the tracheal bifurcation, causing radiographic changes similar to the alveolar pattern of pulmonary edema

Non-cardiogenic thromboembolism in a Persian cat with hypertrophic cardiomyopathy

Background: Hypertrophic cardiomyopathy is the most common acquired cardiovascular disease in the feline species. A frequent complication of this cardiomyopathy is the development of cardiac congestive failure, left atrial enlargement and subsequent development of arterial thromboembolism. In a significant percentage of affected animals there is progression to congestive heart failure, resulting in cyanosis and dyspnea, often the first clinical signs reported by owners. This is a report of a 10-year-old Persian cat with hypertrophic cardiomyopathy and venous and arterial thromboembolism of non-cardiogenic origin. Case: The patient was referred for cardiac evaluation, arterial thromboembolism was the suspected cause of tetraparesis. On clinical examination, a metacarpal pulse was present in all limbs; there was no cyanosis or peripheral hypothermia thus, ruling out a thromboembolic event in the limbs. Changes consistent with feline asthma and pulmonary edema were seen on radiographs, therefore hypertrophic cardiomyopathy was suspected. Treatment with enalapril (0.25 mg/kg every 12 h) for the heart condition and prednisolone (1 mg/kg every 24 h) for asthma was started. Nine days later, the patient developed mixed dyspnea (inspiratory and expiratory) and was hospitalized with signs consistent with arterial thromboembolism: paralysis and cold extremities in the right and left pelvic limbs. The patient was euthanized due to the poor prognosis. Postmortem and histopathological findings revealed left ventricular concentric hypertrophy, with no valvular changes; disseminated intravascular coagulation, with thrombi in the arterial (iliac arteries, pancreatic and renal vessels) and venous (pulmonary and renal veins) beds; as well as multiple neoplastic lung masses, identified as scirrhous pulmonary adenocarcinoma, responsible for increased interstitial radiopacity. Metastasis was also identified at the tracheal bifurcation, causing radiographic changes similar to the alveolar pattern of pulmonary edema…(AU)