Radiographic Features of Golden Retriever Muscular Dystrophy

Abstract

Golden Retriever muscular dystrophy is an inherited, degenerative myopathy due to the absence of dystrophin and is used as a model of Duchenne muscular dystrophy of young boys. This report describes the radiographic abnormalities of Golden Retriever muscular dystrophy in 26 dogs. The thoracic abnormalities included diaphragmatic asymmetry (18/26), diaphragmatic undulation (18/26), and gastro-esophageal hiatal hernia (6/26). Pelvic abnormalities included narrowing of the body of the ilia (14/19), ventral deviation and curvature of the tuber ischii (14/19), elongation of the obturator foramen with a decrease in opacity of the surrounding bone (12/19), and lateral flaring of the wings of the ilia (12/19). Abdominal abnormalities consisted of hepatomegaly (14/22) and poor serosal detail (12/22). The unique thoracic abnormalities were a consistent finding in affected Golden Retriever muscular dystrophy dogs. The diagnosis of muscular dystrophy should be included in the differential list if the combination of diaphragm undulation and asymmetry, and gastro-esophageal hiatal hernia are identified. These diaphragmatic abnormalities are related to hypertrophy and hyperplasia of the diaphragm. Additionally, the skeletal changes of pelvic tilt, elongation of the pelvis, widening of the obturator foramina and thinning of the ischiatic tables appear to be specific to Golden Retriever muscular dystrophy in dogs. These pelvic abnormalities are most likely secondary to bone remodeling associated with the progressive skeletal myopathy and subsequent contracture/fibrosis.

Canine models of Duchenne muscular dystrophy and their use in therapeutic strategies

“…To objectively characterize the cranioventral shift of the pelvis typically seen in GRMD dogs, we also measure the angle formed by two lines extending cranially from the tuber ischium, one drawn parallel to the lumbar spine and the other extending to the midpoint of the tuber coxae. Consistent with a previous report in which the pelvis was shown to shift into essentially a vertical position in some severely-affected dogs (Brumitt et al 2006), this angle has been larger in GRMD (~50°) versus normal (~ 35°) dogs at 6 months of age. While these pelvic limb joint angle data are preliminary and correlations have not yet been completed, we believe proximal joint and postural changes may contribute to the characteristic plantigrade tarsal stance in GRMD, just as relative sparing of proximal flexor muscles plays a role in distal limb flexor contractures in DMD (Vignos and Archibald 1960; Siegel et al 1968).…”

Ultra-sonografia abdominal e pélvica em cães da raça golden retriever sadios, portadores e afetados pela distrofia muscular progressiva

“…De igual modo, neste trabalho foram observadas alterações marcantes da ecotextura e padrões de tamanho, dimensões e volume das estruturas abdominais e pélvicas. Recentemente, BRUMITT et al (2006) descreveram para cães da mesma raça apenas uma hepatomegalia associada a discretas modificações da serosa abdominal, ao contrário das modificações detalhadas das estruturas abdominais aqui mostradas e enfatizadas (Tabela 1).…”

“…Além disso, a hepatomegalia também foi observada em outros seis cães filhotes (sadios e portadores) e em três adultos. Desde modo, confirmamos esses achados em cães GRMD adultos, tal qual descreveu BRUMITT et al (2006). Somam-se ainda os achados microscópicos descritos por SANTOS et al (2007), que descreveram a perda de organização trabecular e cordonal dos hepatócitos, a presença de células mononucleares em sinusoides e vasos, a hiperplasia dos espaços-porta e o tecido fibroso evidente, bem como áreas de congestão e isquemia em cães acometidos pela distrofia muscular.…”

Respiratory dysfunction in unsedated dogs with golden retriever muscular dystrophy

“…Hyperinflation is a common radiographic finding in GRMD dogs. [29,30] Purposeful hyperinflation in healthy people causes increased forced peak expiratory flows,[43] and is a technique used by people with DMD to improve effectiveness of cough through increased cough peak flows. [44] With hyperinflation due to lower airway obstruction, chest wall recoil may be inwards, adding to lung recoil in driving tidal expiratory flow.…”

“…Radiographic abnormalities include diaphragmatic flattening and undulations, hyperinflation of the lung, and hiatal hernia. [29,30]…”