Child Development and Exercise Centre, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
Scand J Rheumatol. 2010;39(5):387-92. doi: 10.3109/03009741003742714.
To study the aerobic capacity and muscle strength in children and adolescents with mixed connective tissue disease (MCTD). Frequently reported clinical symptoms include joint swelling, muscle weakness, fatigue, decreased stamina/exercise tolerance, and shortness of breath. The exercise capacity of patients with MCTD has not been studied systematically in this detail before.
Eleven children and adolescents diagnosed with MCTD (mean age 15.7 years, range 11.3–19.9 years) were studied. Maximal exercise testing on a cycle ergometer was used to determine the peak oxygen uptake (VO2peak) and a hand-held dynamometer was used to measure muscle strength. Cardiac and pulmonary function tests (ultrasonography, electrocardiography, spirometry) were used to measure cardiac function and obstructive or restrictive respiratory impairment. Complementary data (e.g. disease duration and concurrent symptoms) were collected from a medical chart review.
VO2peak was significantly lower in patients with MCTD compared to the VO2peak of healthy subjects (Z-score –1.9, p = 0.008). The strength of the proximal muscles (hip flexors, shoulder abductors, knee extensors) of the patients was significantly lower than in the controls, whereas the strength of the distal muscles (dorsal flexors of the foot and handgrip strength) showed no differences. In eight children, arthritis was observed. No clinically relevant impairment in cardiac or pulmonary function was observed.
Aerobic capacity and also proximal muscle strength were significantly impaired in our sample of children and adolescents with MCTD. Because respiratory problems were non-dominant in our patient group, the decreased aerobic capacity and muscle strength were probably caused by musculoskeletal impairments. Further studies in larger multicentre samples are warranted to confirm our findings.
研究混合性结缔组织病（MCTD）患儿和青少年的有氧能力和肌肉力量。常报告的临床症状包括关节肿胀、肌肉无力、疲劳、耐力下降和呼吸急促。之前尚未系统地研究过 MCTD 患者的运动能力。
研究了 11 名被诊断为 MCTD 的儿童和青少年（平均年龄 15.7 岁，范围 11.3-19.9 岁）。使用自行车测力计进行最大运动测试来确定峰值摄氧量（VO2peak），并使用手持式测力计测量肌肉力量。使用超声心动图、心电图和肺活量测定法进行心肺功能测试，以测量心脏功能和阻塞性或限制性呼吸障碍。从病历回顾中收集了补充数据（例如疾病持续时间和并发症状）。
与健康受试者相比，MCTD 患者的 VO2peak 明显降低（Z 分数-1.9，p = 0.008）。患者的近端肌肉（髋关节屈肌、肩外展肌、膝关节伸肌）的力量明显低于对照组，而远端肌肉（足部背屈肌和手握力）的力量没有差异。在 8 名儿童中观察到关节炎。未观察到心脏或肺部功能的临床相关损害。
我们的 MCTD 患儿和青少年样本中，有氧能力和近端肌肉力量均明显受损。由于我们患者组中呼吸系统问题并不突出，因此，降低的有氧能力和肌肉力量可能是由肌肉骨骼损伤引起的。需要进一步在更大的多中心样本中进行研究以证实我们的发现。
