Características ultrassonográficas das glândulas salivares maiores de pacientes com mucopolissacaridoses: um estudo descritivo

Abstract

Mucopolysaccharidoses (MPS) are a heterogeneous group of rare genetic diseases caused by the deficiency of enzymes responsible for the degradation of glycosaminoglycans (GAGs), which results in the pathological intra- and extracellular deposition of these macromolecules. GAGs structurally compose several tissues and organs, as well as influence the embryonic morphogenesis of teeth, condyles and salivary glands. Dental and temporomandibular joints alterations have been described clinically and radiographically in MPS, resulting from GAG accumulation. There are no data in the literature reporting whether the salivary glands exhibit GAG accumulation, as well as whether these may be affected in MPS. Recently, a reduction in salivary flow has been reported in MPS individuals. The reduction in salivary flow may be due to different causes, including alterations in the glandular parenchyma. Ultrasonography (US) is a safe, widely available and effective examination for the analysis of salivary glands. The aim of this study was to evaluate the major salivary glands of patients with MPS. A cross-sectional study was conducted based on ultrasound examination of the major salivary glands of individuals with MPS. The study was approved by the Research Ethics Committee of the Federal University of Minas Gerais. The data were collected in the Radiology sector and in the dentistry clinic for children and adolescents with disabilities at the UFMG School of Dentistry, in Belo Horizonte, southeastern Brazil. The appearance of the glandular parenchyma, their vascularization, identification of lymph nodes and the characteristics of the muscle tissues surrounding the glands were evaluated bilaterally. The findings were correlated with clinical and demographic information of these individuals. Fifteen individuals with MPS types I (n=5), II (n=5), IV (n=1) and VI (n=4), aged 6 to 37 years, with attenuated (n=4), intermediate (n=4) or severe (n=7) phenotypes, treated enzymatically (n=14) or by transplantation (n=1) were examined. Twelve individuals presented heterogeneous parenchyma with hypoechoic and hyperechoic areas, some of which were suggestive of high-density deposits. Glandular hypervascularization was observed in 6 individuals. Prominent lymph nodes and anatomical alterations of the muscles adjacent to the salivary glands were also observed. The alterations were observed regardless of age, type of MPS, phenotypic variation or treatment. Significant alterations were observed in the ultrasound images of the major salivary glands of individuals with MPS, notably regarding the heterogeneous appearance of their parenchyma and the constant visualization of lymph nodes. This is the first study, to our knowledge, that has evaluated the major salivary glands in individuals with MPS. Further studies may contribute to a better understanding of the ultrasound findings as well as the possible clinical implications of these findings.