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Today's Ve T erinary Prac T ice | s eptember/ o ctober 2016 | tvpjournal.com Ju V enile o r T ho P edic d isease in d ogs & c a T s Peer r eviewed 28 In patients in which an endocrinopathy is suspected, include measurement of: • Serum thyroxine • Thyroid-stimulating hormone • Growth hormone (stimulation test) • Insulin-like growth factor-1 serum concentrations. Radiographic evaluation should include the lumbar spine and radius/ulna, with assessment for abnormal growth plate morphology, delayed epiphyseal growth center development, and reduced length of the axial/ appendicular skeleton. 3 Biopsy of growth plates (eg, rib, postmortem) can confirm the diagnosis (Figure 3). 1,3 Treatment Treatment is generally aimed at ameliorating clinical signs. As in other conditions discussed in this article, the heritable nature of this condition warrants neutering the affected animals or known carriers. Prognosis Prognosis varies according to the type and severity of osteochondrodysplasia. Swimmer Syndrome Overview Swimmer syndrome—also known as flat-pup syndrome, turtle-pup, splay leg, myofibrillar hypoplasia, and twisted legs—is a developmental abnormality generally apparent within the first few weeks of life. 3,7,8 The syndrome is characterized by hindlimb paraparesis or tetraparesis, with paraparesis being the most common form of presentation. 3 Affected animals move with a "swimming" motion of the limbs, often in a sternal position due to their inability to adduct their limbs to rise. 3,7,8 Animals with thoracic limb involvement commonly have concurrent thoracic abnormalities, including pectus excavatum, sterna concave, or dorsoventral flattening of the chest. 3,7,8 These concurrent abnormalities can lead to respiratory compromise. The cause of this condition is unknown, although poor traction in the environment has been implicated. 3 It is thought to be a rare syndrome; the prevalence in a population of small-breed dogs in Thailand is around 2%. 7 Signalment This condition, which can occur in any dog or cat, becomes apparent around 1 to 3 weeks of age, when walking is normally initiated. Certain breeds appear to be predisposed, 7,8 including dachshunds, Yorkshire terriers, Pekingese, basset hounds, and French and English bulldogs. It has also been reported in a Devon rex cat. 8 Diagnosis Physical examination alone is the most common means of diagnosis. As mentioned earlier, affected animals often display signs within 1 to 3 weeks of birth and the condition is characterized by sternal recumbency with lateral splaying of the hindlimbs and, occasionally, the forelimbs. 3,7,8 Animals are unable to walk and instead move their affected limbs in a paddling motion. 3 After some time, chronic positioning in sternal recumbency results in dorsoventral compression of the chest with lateral widening, which, without intervention, may become permanent. 3,7 Other conditions, such as encephalomeningitis, canine distemper, toxoplasmosis, neosporosis, myopathy, and spina bifida, should be considered. 7 a general rule of thumb is that nutritional diseases and osteochondro- dysplasias most often result in disproportion- ate growth, whereas metabolic, endocrine, and polysystemic diseases result in proportionate growth. 3 Figure 3. An 8-month-old, male castrated pitbull presented for further evaluation of elbow abnormalities and diagnosed with congenital disproportionate dwarfism, osteochondral dysplasia, and bilateral type i congenital elbow luxations. Lateral ( A ) and craniocaudal ( B ) views of the left forelimb; marked malformation of the left elbow joint, with an elbow luxation, is present. The abnormal growth plate morphology present in osteochondrodysplasia is demonstrated by the open and irregular anconeal and olecranon physes, as well as the distal physis of the ulna, which is abnormally shaped with widening ( arrow) at its medial aspect and lipping at the lateral aspect. Courtesy Dr. Dan Bucy, University of California– Davis Veterinary Medical Teaching Hospital A B