Multiple pathological bone fractures in a dog with adrenal-dependent Cushing's syndrome

Pathological bone fractures may occur secondarily to Cushing's syndrome in people. Although low bone mineral density due to cortisol excess has been described in dogs, there is no evidence that dogs with Cushing's disease can develop osteoporosis or secondary bone fractures. Here, we report a case of a dog with Cushing's disease and multiple pathological bone fractures. A 14-year-old female spayed mixed-breed dog was attended due to progressive lethargy, weakness, difficulty moving, trembling and clinical signs of Cushing's syndrome (polyuria, polydipsia, alopecia and abdominal distension). After confirmation of the diagnosis of Cushing's disease and 2 days after starting trilostane treatment (0.27 mg/kg every 12 hours), the dog presented to our hospital with reluctance to rise. In the computed tomography scan, decreased bone density in cervical and thoracic vertebrae, ribs scapular bones and multiple rib fractures were detected. Despite 8 days of hospitalisation, reluctance to rise and walk persisted. Given the unfavourable progression of the diseases, the owner opted for euthanasia. Post mortem evaluation confirmed a cortical carcinoma of the left adrenal gland and thin, irregular spicules and trabeculae of compact bone and reduced thickness of the cortex of the ribs.