Okoye Okechukwu C, Paudyal Sunita, Iriza Shannon E, Wilson Jon
Rheumatology, Prisma Health, University of South Carolina (USC) Rheumatology, Columbia, USA.
Pathology, Arkana Laboratories, Little Rock, USA.
Cureus. 2024 Jun 29;16(6):e63453. doi: 10.7759/cureus.63453. eCollection 2024 Jun.
Disease manifestations of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), a small vessel vasculitis with multisystemic effects, include respiratory, renal, nervous, gastrointestinal, and skin implications. Muscle weakness and inflammatory myopathy are rare manifestations of AAV. We report the case of a 77-year-old female with a medical history of hypothyroidism and osteoarthritis who presented with a two-month history of worsening muscle weakness (mainly proximal). She endorsed dysphagia, a 40-lb unintentional weight loss, and persistent sinusitis with middle ear effusions, requiring bilateral tympanostomy. The physical examination was notable for 2/5 muscle strength in her hip flexors and extensors, with 4/5 strength in other extremities. Lower extremity MRI showed diffuse intramuscular edema between fat planes and intramuscular septal regions. Erythrocyte sedimentation rate (70 mm/hr), C-reactive protein (141 mg/L), creatine kinase (690 U/L), and anti-myeloperoxidase (MPO) antibodies (>999 AU/mL) were elevated. A thigh biopsy revealed fibrinoid necrosis of small intramuscular arteries, confluent circumferential granulomatous vessel wall inflammation, and associated mild chronic inflammation, including occasional eosinophils and a few plasma cells. She was diagnosed with MPO-positive AAV. The patient was started on high-dose steroids (prednisone), with a taper on a disease-modifying agent, azathioprine, with significant improvement in symptoms over the next four months and complete resolution at 16-month follow-up. This patient's clinical presentation of predominant lower extremity weakness due to inflammatory myositis is an unusual manifestation of AAV. Clinicians should keep a broad differential diagnosis and consider the possibility of AAV, especially in cases of muscle weakness presenting as inflammatory myositis, in the absence of other clinical manifestations of systemic vasculitis or specific myositis serologies.
抗中性粒细胞胞浆抗体（ANCA）相关血管炎（AAV）是一种具有多系统影响的小血管血管炎，其疾病表现包括呼吸系统、肾脏、神经、胃肠道和皮肤方面的问题。肌肉无力和炎性肌病是AAV的罕见表现。我们报告了一例77岁女性病例，该患者有甲状腺功能减退和骨关节炎病史，出现了两个月来逐渐加重的肌肉无力（主要是近端肌肉）。她自述有吞咽困难、40磅的非故意体重减轻以及伴有中耳积液的持续性鼻窦炎，需要进行双侧鼓膜造孔术。体格检查发现她的髋部屈肌和伸肌肌力为2/5，其他肢体肌力为4/5。下肢MRI显示脂肪平面和肌间隔区域之间存在弥漫性肌内水肿。红细胞沉降率（70毫米/小时）、C反应蛋白（141毫克/升）、肌酸激酶（690单位/升）和抗髓过氧化物酶（MPO）抗体（>999 AU/毫升）升高。大腿活检显示肌内小动脉纤维素样坏死、融合性环状肉芽肿性血管壁炎症以及相关的轻度慢性炎症，包括偶尔的嗜酸性粒细胞和少量浆细胞。她被诊断为MPO阳性的AAV。患者开始接受大剂量类固醇（泼尼松）治疗，并逐渐减量使用疾病修正药物硫唑嘌呤，在接下来的四个月里症状有显著改善，在16个月的随访时完全缓解。该患者因炎性肌病导致主要下肢无力的临床表现是AAV的一种不寻常表现。临床医生应进行广泛的鉴别诊断，并考虑AAV的可能性，特别是在肌肉无力表现为炎性肌病且无系统性血管炎或特定肌炎血清学其他临床表现的情况下。
