Reimers C D, Schlotter B, Eicke B M, Witt T N
Friedrich-Baur-Institute, Department of Internal Medicine and Neurology, Ludwig-Maximilians-University, Munich, Germany.
J Neurol Sci. 1996 Nov;143(1-2):46-56. doi: 10.1016/s0022-510x(96)00037-8.
Calf hypertrophy is a typical clinical feature in neuromuscular diseases such as X-linked muscular dystrophies of Duchenne and Becker type and can be seen as an atypical feature in numerous other diseases. The diagnosis of calf hypertrophy usually is based on subjective visual assessment. The aim of this prospective study was to examine the prevalence of calf hypertrophy in a large number of patients with various neuromuscular diseases based on quantitative ultrasound measurement of calf muscle thickness. Additionally, true and pseudohypertrophy should be distinguished according to the absence or presence of abnormal muscle echointensities caused by infiltration of fat tissue. Fifty adult normal controls and 350 patients with various neuromuscular diseases were investigated. Absolute calf hypertrophy was diagnosed if the combined thickness of the gastrocnemius and soleus muscles exceeded the mean value of the control persons by at least 3.0 standard deviations (SD). Relative calf hypertrophy was diagnosed when the ratio of the combined thicknesses of the gastrocnemius and soleus muscles divided by the combined thicknesses of the rectus femoris and vastus intermedius muscles lay at least 3.0 SD below the mean value of the controls. Pseudohypertrophy was present if the echointensities of the gastrocnemius and soleus muscles reached or exceeded 3.0 SD above the mean value of the controls. An absolute hypertrophy of the calves was detected in 80 patients (= 22,9%; 64 true and 16 pseudohypertrophies), 16 patients exhibited a relative hypertrophy of the calves (= 4.6%; 12 true and 4 pseudohypertrophies). A significantly increased portion of both absolute calf hypertrophies and pseudohypertrophies as compared to the control group were found in juvenile proximal spinal muscular atrophy type 3, central core disease, centronuclear myopathy, benign X-linked muscular dystrophy of Becker type, autosomal recessive limb girdle muscular dystrophy, acid maltase deficiency, polymyositis, and granulomatous myositis. A significantly increased number of relative calf hypertrophies was present in juvenile proximal spinal muscular atrophy type 3, facioscapulohumeral muscular dystrophy, and inclusion body myositis. In the majority of the diseases included in the study, calf hypertrophy occurred in at least some patients. In conclusion, calf hypertrophy is a frequent and unspecific clinical feature in many neuromuscular diseases. Ultrasound is a convenient method for the exact definition of calf hypertrophy.
小腿肥大是杜氏和贝克型X连锁肌营养不良等神经肌肉疾病的典型临床特征，也可见于许多其他疾病的非典型特征。小腿肥大的诊断通常基于主观视觉评估。这项前瞻性研究的目的是通过定量超声测量小腿肌肉厚度，检查大量患有各种神经肌肉疾病的患者中小腿肥大的患病率。此外，应根据脂肪组织浸润导致的肌肉回声强度异常的有无来区分真性肥大和假性肥大。对50名成年正常对照者和350名患有各种神经肌肉疾病的患者进行了调查。如果腓肠肌和比目鱼肌的联合厚度超过对照者平均值至少3.0个标准差（SD），则诊断为绝对小腿肥大。当腓肠肌和比目鱼肌联合厚度与股直肌和股中间肌联合厚度的比值至少低于对照者平均值3.0个标准差时，诊断为相对小腿肥大。如果腓肠肌和比目鱼肌的回声强度达到或超过对照者平均值3.0个标准差以上，则存在假性肥大。在80例患者（=22.9%；64例真性肥大和16例假性肥大）中检测到小腿绝对肥大，16例患者表现为小腿相对肥大（=4.6%；12例真性肥大和4例假性肥大）。与对照组相比，在3型青少年近端脊髓性肌萎缩、中央轴空病、中央核性肌病、贝克型良性X连锁肌营养不良、常染色体隐性遗传性肢带型肌营养不良、酸性麦芽糖酶缺乏症、多发性肌炎和肉芽肿性肌炎中，绝对小腿肥大和假性肥大的比例均显著增加。在3型青少年近端脊髓性肌萎缩、面肩肱型肌营养不良和包涵体肌炎中，相对小腿肥大的数量显著增加。在该研究纳入的大多数疾病中，至少部分患者出现小腿肥大。总之，小腿肥大是许多神经肌肉疾病中常见且非特异性的临床特征。超声是准确界定小腿肥大的便捷方法。
