Síndrome hemorrágica pulmonar em cão associada à leptospirose
Authors: Silva Vinícius Bentivóglio Costa , Stedile Simone Tostes de Oliveira , De Sousa Renato Silva , Sousa Marlos Gonçalves 
Published: December 2021

Background: Leptospirosis is probably the most widespread and prevalent zoonosis in the world, being classified as an emerging infectious disease for humans and dogs. Sporadically, dogs may present with cough and dyspnea, indicative of pulmonary involvement, associated with interstitial pneumonia and pulmonary hemorrhage with alveolar consolidation. Such changes stem from pulmonary haemorrhagic syndrome, which has emerged as a fatal complication, being documented in some areas in Europe and little described in North America. In this sense, the present study aims to report pulmonary hemorrhagic syndrome in a dog with leptospirosis.Case: A dog with no defined breed, aged 45 days, weighing 2.2 kg, with a history of apathy, anorexia, jaundice, hematochezia and vocalisation with a two day evolution was seen. Physical examination revealed a rectal temperature of 37.2°C, icteric mucosa, capillary filling time of two seconds, respiratory rate of 80 movements per minute and heart rate of 140 beats per minute, dehydration rate estimated at 8%, prostration, adequate body score, normal cardiac sounds and clean lung fields, in addition to petechiae in the abdominal region, whose palpation evidenced the presence of fluid in intestinal loops. The blood sample sent to the macroscopic serum agglutination was reagent for the serovar Icterohaemorragiae, titration of 200. Blood count revealed leukocytosis due to neutrophilia, with left-sided deviation, eosinopenia, presence of rare hypersegmentated neutrophils, rare toxic neutrophils, mild cytoplasmic basophilia and rare reactive lymphocytes. Platelet estimation demonstrated thrombocytopenia. No haemoparasites were seen. Regarding the biochemical evaluation, there were changes in liver enzymes and markers of renal failure. Fluid therapy was used with 0.9% NaCl solution, 5 mg/ kg doxycycline intravenously every 12 h and nasogastric probe for administration of nutritional support. One day after the initial evaluation, hemoptysis and diffuse crackling occurred in pulmonary lobes on auscultation. In the radiograph of the chest, pulmonary fields were characterized by a diffuse interstitial bronchial pattern and a focal area, located in the left caudal lobe, with opacification tending to the alveolar pattern. Due to pulmonary alterations, the animal presented respiratory arrest and evolved to death. During necropsy, the macroscopic evaluation revealed a pinkish coloration pattern, with multifocal reddish areas with coalescent interspersed in the parenchyma and hypocrepitation. Regarding the morphology, multifocal hemorrhagic pneumonia was observed, focally extensive, moderate to severe.Discussion: Recently, pulmonary haemorrhagic syndrome has emerged as a severe form of leptospirosis in many species, including humans and dogs. Patients may develop fulminant pulmonary haemorrhage and result in a high mortality rate. Physiopathogenesis is poorly understood, however, it is believed that there is a multifactorial pathogenesis involving factors related to both pathogen and host, such as immunological mechanisms and coagulopathies. Studies in humans have shown a better evolution after the use of cyclophosphamide, but the benefits of this therapy have not yet been determined in dogs. Therefore, pulmonary haemorrhagic syndrome should be considered in patients with leptospirosis who show respiratory changes, due to the severity of the clinical signs and the high lethality associated with this clinical condition.