1 - Serviço de Imagiologia, Hospital Dona Estefânia, CHLC
2 - Unidade de Doenças Metabólicas, Hospital Dona Estefânia, CHLC
3 - Serviço de Neuropediatria, Hospital Dona Estefânia, CHLC
- Poster no XI Simpósio Internacional da Sociedade Portuguesa de Doenças Metabólicas, Porto, 19 a 20 de Março de 2015
Background: Pompe’s disease (PD) is a disorder characterized by a deficiency in the lysosomal enzyme acid alpha-glucosidase. Several phenotypes are described, ranging from rapidly progressive infantile forms to slowly progressive late-onset forms. Recent studies have shown that magnetic resonance imaging (MRI) based principally on signal intensity changes resulting from fat infiltration into muscle and also from decreased muscle volume can contribute significantly to a specific diagnosis in patients with several inherited muscular disorders and contribute to an extensive evaluation of muscle alterations. MRI in PD usually shows a very suggestive myopathic pattern with fatty infiltration and atrophy of muscles more evident in the spine extensors and pelvic girdle muscles and consistent changes in the tongue and subscapularis.
Methods: A 9 year old child with PD presented before the age of four with high transaminases and moderately elevated phosphocreatinokinase in routine laboratory tests. A muscular biopsy performed when he was seven years old suggested Pompe/Danon disease. Enzymatic levels for alpha-glucosidase and molecular studies confirmed the diagnosis of PD. The patient is still usually asymptomatic relating muscular pain for a few days or hours about once every two months following more intensive playing or running. Evaluation of muscular strength, pulmonary function, cardiac evaluation and sleep test performed seem to be normal.
Results: Despite no treatment three successive MRI examinations performed about a year apart in a 3T MRI machine with a whole body muscular protocol consisting of T1 and STIR weighted sequences showed normal structural and volumetric muscle signal in all muscle groups without signs of fatty atrophy or edema, namely in the head and neck as well as in the axial muscles. Longitudinal semiquantitative analysis between examinations showed no significant changes in the inter- and intramuscle comparisons.
Conclusions: Although muscle MRI is pointed as a valuable diagnostic tool for the diagnosis of PD, normal MRI may be found in some patients. Some reports have found that muscle atrophy may not have the same appearance in MRI in children as in adults, lacking high signal on T1WI. On the other hand as our patient has successive normal muscular MRI patterns but is mostly asymptomatic we hypothesize that abnormal muscle MRI although characteristic of PD may correlate an advanced clinical disease.
Palavras Chave: Pompe’s disease, magnetic resonance imaging