Diagnostic approaches | Confirmatory findings |
---|---|
CPK | Elevated (not more than 1500–2000 IU/L) |
Blood tests, such as ALT, AST, LDH, and urine tests, such as HEX4 | Elevated |
Chest X-ray | Reduction in lung volume, cardiomegaly, and/or areas of atelectasis |
Electrocardiogram | Short PR interval, inverted T-wave, wide/broad QRS complex |
Echocardiogram | Hypertrophic cardiomyopathy with or without ventricular outflow tract obstruction; the late stages of the disease are often characterized by dilated cardiomyopathy |
MRI (not routinely indicated) | Greater axial muscle involvement; complete involvement of lumbar paravertebral muscles and psoas; T1-weighted images are sufficient for an adequate assessment |
Muscle biopsy (histopathology) | Severe glycogen storage and vacuolar myopathy, positive acid phosphatase, positive PAS staining, and reduced myofibrils |