Department of Neurology and Neurophysiology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
Department of Radiology, Skåne University Hospital, Lund, Sweden.
Acta Neurol Scand. 2019 Feb;139(2):177-182. doi: 10.1111/ane.13040. Epub 2018 Nov 8.
Inclusion body myositis is characterized by inflammatory and degenerative changes, but the temporal relation of these events is unknown.
In nineteen patients with inclusion body myositis, muscle strength was correlated with inflammatory and degenerative findings on magnetic resonance imaging (MRI) and in muscle biopsies in three different muscles (tibialis anterior, vastus lateralis, and biceps brachii). Muscle strength, measured with a handheld dynamometer, was described as percentage of muscle strength in age- and sex-matched normal individuals. The muscles were categorized as the strongest, the intermediate, and the weakest muscle in each individual. T1-weighted sequences on MRI were used to evaluate the degree of fatty infiltration and muscle atrophy and STIR sequences to evaluate edematous changes.
The vastus lateralis, which in general was the weakest muscle, was significantly more atrophic compared to the other two muscles and also demonstrated most edema. The biceps brachii had in most cases an intermediate degree of weakness and atrophy but the most pronounced inflammatory cell infiltration on biopsy. Cytochrome c oxidase-negative muscle fibers were significantly more prevalent in the vastus lateralis and biceps brachii muscles than in the tibialis anterior and thus correlated with muscular atrophy, indicating that this is a secondary change. Inflammatory changes as assessed by MRI and muscle biopsy were seen in all muscles irrespective of atrophy and thus appear to be prevalent at all stages of the disease.
Our study could not provide an answer to the question which comes first, the inflammation or the degenerative changes.
包涵体肌炎的特征为炎症性和退行性改变，但这些事件的时间关系尚不清楚。
在 19 例包涵体肌炎患者中，我们将肌肉力量与磁共振成像（MRI）和 3 块不同肌肉（胫骨前肌、股外侧肌和肱二头肌）的肌肉活检中的炎症性和退行性发现进行了相关性分析。肌肉力量使用手持测力计进行测量，以年龄和性别匹配的正常个体的肌肉力量百分比来表示。将肌肉分为个体中最强、中等和最弱的肌肉。T1 加权序列 MRI 用于评估脂肪浸润和肌肉萎缩的程度，STIR 序列用于评估水肿变化。
股外侧肌通常是最弱的肌肉，与另外两块肌肉相比，其萎缩程度显著更大，并且还表现出更多的水肿。肱二头肌在大多数情况下肌肉力量和萎缩程度处于中等水平，但活检时炎症细胞浸润最明显。与胫骨前肌相比，股外侧肌和肱二头肌中细胞色素 c 氧化酶阴性肌纤维明显更为普遍，因此与肌肉萎缩相关，表明这是一种继发变化。MRI 和肌肉活检评估的炎症变化见于所有肌肉，无论有无萎缩，因此似乎在疾病的所有阶段都很常见。
我们的研究无法回答哪个先发生，是炎症还是退行性改变的问题。
