Hypertrophic osteodystrophy in dogs: diagnosis and treatment

Osteoarthritis, adipokines and the translational research potential in small animal patients

Osteoartritis (OA) is a debilitating disease affecting both humans and animals. In the early stages, OA is characterized by damage to the extracellular matrix (ECM) and apoptosis and depletion of chondrocytes. OA progression is characterized by hyaline cartilage loss, chondrophyte and osteophyte formation, thickening of the joint capsule and function loss in the later stages. As the regenerative potential of cartilage is very limited and osteoarthritic changes are irreversible, prevention of OA, modulation of existing osteoarthritic joint inflammation, reducing joint pain and supporting joint function are the only options. Progression of OA and pain may necessitate surgical intervention with joint replacement or arthrodesis as end-stage procedures. In human medicine, the role of adipokines in the development and progression of OA has received increasing interest. At present, the known adipokines include leptin, adiponectin, visfatin, resistin, progranulin, chemerin, lipocalin-2, vaspin, omentin-1 and nesfatin. Adipokines have been demonstrated to play a pivotal role in joint homeostasis by modulating anabolic and catabolic balance, autophagy, apoptosis and inflammatory responses. In small animals, in terms of dogs and cats, naturally occurring OA has been clearly demonstrated as a clinical problem. Similar to humans, the etiology of OA is multifactorial and has not been fully elucidated. Humans, dogs and cats share many joint related degenerative diseases leading to OA. In this review, joint homeostasis, OA, adipokines and the most common joint diseases in small animals leading to naturally occurring OA and their relation with adipokines are discussed. The purpose of this review is highlighting the translational potential of OA and adipokines research in small animal patients.

Presenting signs and clinical outcome in dogs with metaphyseal osteopathy: 39 cases (2009-2018)

OBJECTIVE

To describe the presenting signs, concurrent conditions, treatment and outcome of dogs with metaphyseal osteopathy.

MATERIALS AND METHODS

Multi-centre retrospective review of medical records from January 2009 to September 2018 at four referral centres to identify dogs with a radiographic diagnosis of metaphyseal osteopathy.

RESULTS

Thirty-nine dogs were identified. The median age at onset was 14 weeks old (range, 8 to 32 weeks old). There was a higher proportion of male dogs (29 of 39 male entire, nine of 39 female entire, one of 39 female neutered and no male neutered dogs). Where information was available, median time from the most recent vaccination was 20 days (range, 2 to 144 days). The most commonly recorded clinical signs were pyrexia (34 of 39), lethargy (32 of 39), pain (30 of 39), and being non-ambulatory (17 of 39). Thirty-five dogs required hospitalisation for analgesia and supportive care, 19 of 39 were discharged on prednisolone (median dose 2.0 mg/kg/day; range, 0.9 to 2.6 mg/kg/day), 18 of 39 were discharged on non-steroidal anti-inflammatories, two of 39 did not receive NSAIDs or prednisolone at any time point. The median duration of hospitalisation for those admitted was 5 days (range, 1 to 21 days). Where follow-up was available, relapse occurred in eight of 25 cases before reaching skeletal maturity. At the time of metaphyseal osteopathy diagnosis, five of 39 cases had concurrent conditions. Where follow-up was available, four of 25 developed future immune-mediated conditions.

CLINICAL SIGNIFICANCE

Metaphyseal osteopathy should be considered in non-ambulatory painful young dogs. Some dogs developed future immune-mediated conditions, which may support the hypothesis that metaphyseal osteopathy is an autoinflammatory bone disorder. Further studies with a larger cohort are required to determine the clinical significance of this.

Radiographic evidence of metaphyseal sclerosis secondary to canine distemper virus: 4 cases in juvenile dogs

Background

Metaphyseal sclerosis secondary to canine distemper virus has been described histopathologically, but its radiographic appearance has not been described.

Objectives

Describe the radiographic appearance of metaphyseal sclerosis secondary to canine distemper virus in juvenile dogs as distinct from metaphyseal osteopathy (formerly called hypertrophic osteodystrophy).

Animals

Four dogs (2 intact females and 2 intact males) between 2.5 and 4 months of age presented to 2 different veterinary teaching hospitals.

Methods

Retrospective case series in which definitive diagnosis of canine distemper virus based on antemortem positive reverse transcription‐polymerase chain reaction (RT‐PCR) result or necropsy was required.

Results

All 4 dogs were presented for evaluation of neurologic abnormalities, respiratory signs, and lethargy; 2 dogs had gastrointestinal signs and ocular abnormalities. Radiographs on all patients featured multifocal, symmetric, metaphyseal sclerosis, with no evidence of lysis or changes to the adjacent growth plate. The metaphyseal sclerosis was most apparent at the proximal humeral diaphyses and other included long bones. Diagnosis of distemper was confirmed by necropsy (2 of 4 dogs) or positive RT‐PCR results (2 of 4 dogs). Three dogs were euthanized because of progressive illness, and 1 dog was lost to follow‐up.

Conclusion and Clinical Importance

Identification of metaphyseal sclerosis on radiographs during diagnostic evaluation of young dogs should lead to a clinical suspicion of canine distemper virus infection. Sclerosis identified secondary to canine distemper virus is distinct from the necrosis and inflammation of metaphyseal osteopathy.