engleski

Difficulties in assessing early cardiac response in a child with infantile Pompé disease on enzyme replacement therapy

Pompé disease is a progressive lysosomal disease caused by alpha-glucosidase deficiency which recently became amenable to efficient treatment with the introduction of enzyme replacement therapy. However, some patients still do not respond sufficiently and die despite the therapy. Apart from the age at the beginning of therapy, there are no other early indices that could, at least partially predict the outcome. Early evaluation of cardiac response is very difficult as well. We report a patient with infantile form of Pompé disease, in whom NT-proBNP showed promise that it might be an early marker of cardiac recovery. The girl presented to us at the age of four months with feeding difficulties, failure to thrive, mild psychomotor delay and severe hypotonia. Clinical examination revealed floppy infant with poor spontaneous movements, weak cry, dyspnea, tachycardia, macroglossia and enlarged liver. Biochemical results (CK up to 1673, AST 319, ALT 212) and some diagnostic procedures (chest roentgenogram, electrocardiogram and heart ultrasound that revealed hypertrophic cardiomyopathy and electromyography that showed myopathy) pointed to Pompé disease. Diagnosis was confirmed by lymphocyte acid maltase activity measurement (3% of normal activity). In short subsequent period, while waiting for enzyme replacement therapy to become available, the child became respiratory insufficient with tachydyspnea and oxygen saturation of about 85%. Due to feeding difficulties she had to be fed by nasogastric tube. Before enzyme replacement therapy was started AST was 299, ALT 323, CK 385, NT-proBNP 5459 pg/mL (normal <150) and left ventricular wall thickness (LVT) 12 to 15 mm. Already few days after the treatment with alglucosidase alfa (Myozyme® ; ; ; ; ; ; ; , 25 mg/kg every other week) was started, the child’ s general condition significantly improved. She was less dyspnoic, sucked much better, her muscle tone and mobility improved. Together with clinical improvement oxygen saturation increased and some laboratory parameters improved (NT-proBNP was 3985 and 2881, two and four weeks, respectively following the initiation of treatment, and since then further decreased). In the follow-up period the child’ s condition continued to ameliorate slowly, although serum CK and aminotransferases increased (last findings - CK 1412, AST 657, ALT 356). First improvement as assessed heart ultrasound was observed after ten weeks of ERT (LVT 11 mm). Before that, concerning signs of improvement, heart ultrasound and ECG findings were equivocal. Since no specific cardiac therapy has been applied, we conclude that NT-proBNP may be an early indicator of favourable cardiac response in Pompé disease.

infantile Pompé disease; assessing therapy response

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