RADIOGRAPHIC AND ULTRASONOGRAPHIC FEATURES OF HYPERTROPHIC FELINE MUSCULAR-DYSTROPHY IN 2 CATS

Hypertrophic feline muscular dystrophy has been reported as an X-linked inherited deficiency of a cytoskeletal myofiber protein called dystrophin. This report describes the radiographic and ultrasonographic abnormalities of two male littermate domestic short-hair cats and reviews the previous reported findings associated with hypertrophic feline muscular dystrophy. The thoracic radiographic abnormalities included: progressive cardiomegaly, large convex, scalloped irregularities associated with the ventral aspect of the diaphragm, and variable degrees of esophageal dilation (megaesophagus) with associated cranioventral aspiration pneumonia. Echocardiographic features included: concentric left ventricular wall thickening, increased left ventricular and diastolic and systolic dimensions, and an increase in endocardial echogenicity. Abdominal radiographic abnormalities included: hepatosplenomegaly, peritoneal effusion, renomegaly, adrenal gland mineralization, and paralumbar and diaphragmatic musculature enlargement. Abdominal ultrasonographic abnormalities included: irregularly thickened muscular portion of the diaphragm; hypoechogenicity of the liver; peritoneal effusion; hepatosplenomegaly; renomegaly with hyperechoic cortex and medulla; and adrenal gland mineralization. The irregular scalloped appearance of the diaphragm (particularly along the ventral/sternal margin) was a consistent radiographic abnormality in the two cats with hypertrophic feline muscular dystrophy after the age of 7 months. This finding was confirmed by ultrasound as a thickened irregular, hyperechoic diaphragm. A diagnosis of hypertrophic feline muscular dystrophy should be strongly suspected if this abnormality is identified.