背景:骨髓增生性疾病,包括意义不明的单克隆丙种球蛋白病(MGUS),通常与淀粉样蛋白轻链(AL)型心脏淀粉样变性(CA)有关,但偶尔与野生型甲状腺素运载蛋白(ATTR)CA有关。近年来,随着新的治疗方法的增加,ATTR淀粉样变性吸引了其可靠诊断的必要性。通常,野生型ATTRCA和AL型CA均存在明显的心脏肥大,但野生型ATTR淀粉样变性比AL型淀粉样变性轻.AL型淀粉样变性中度存在周围神经和自主神经症状,如麻木和感觉障碍,但在野生型ATTR淀粉样变性中较少。此外,ATTR型淀粉样变性的预后优于AL型淀粉样变性。
方法:一名72岁的男性,患有心脏肥大,表现为纽约心脏协会III级功能性呼吸困难和腿部水肿。他没有腕管综合征的病史。心电图显示心房颤动和低电压。N末端B型利钠肽前体水平为3310pg/mL,肌钙蛋白T升高至0.073ng/mL。然而,肾小球滤过率仅在69.0mL/min/1.73m2时略有下降.无血清轻链测定显示κ链显著增加,BenceJones蛋白和血清免疫电泳阳性.骨髓检查证实了意义不明的单克隆丙种球蛋白病(MGUS)的诊断。怀疑与骨髓增殖性疾病相关的AL型淀粉样变性,最初预测预后较差,归类为Mayo第四阶段.与这种预测相反,患者表现为心力衰竭进展缓慢.进一步的影像学模式和心脏组织检查结果证实了甲状腺素运载蛋白型淀粉样变性的诊断,并且使用tafamidis建立了良好的预后。
结论:MGUS偶尔与野生型ATTRCA共存。很少有自主神经症状,轻度肾功能不全,心力衰竭的缓慢进展可能是与骨髓增殖性疾病相关的CA是野生型ATTR淀粉样变性的线索。
BACKGROUND: Myeloproliferative disorders, including monoclonal gammopathy of undetermined significance (MGUS), are often associated with amyloid light-chain (AL)-type cardiac amyloidosis (CA) but occasionally with wild-type transthyretin (ATTR) CA. In recent years, ATTR amyloidosis has attracted necessity for its reliable diagnosis with the addition of new treatments. Usually, both wild-type ATTR CA and AL-type CA present with marked cardiac hypertrophy, but renal dysfunction is milder in wild-type ATTR amyloidosis than in AL-type amyloidosis. Peripheral neurologic and autonomic symptoms such as numbness and dysesthesia are moderately present in AL-type amyloidosis, but less so in wild-type ATTR amyloidosis. Furthermore, the prognosis of ATTR-type amyloidosis is better than that of AL-type amyloidosis.
METHODS: A 72-year-old man with cardiac hypertrophy presented with New York Heart Association functional class III dyspnea and leg edema. He had no history of carpal tunnel syndrome. An electrocardiogram showed atrial fibrillation and low voltage. The N-terminal pro-B-type natriuretic peptide level was 3310 pg/mL, and troponin T was elevated to 0.073 ng/mL. However, the glomerular filtration rate was only slightly decreased at 69.0 mL/min/1.73 m2. The serum free light-chain assay revealed a significant increase in the kappa chain, with positive results in Bence Jones proteins and serum immunoelectrophoresis. Bone marrow examination confirmed the diagnosis of monoclonal gammopathy of undetermined significance (MGUS). AL-type amyloidosis associated with a myeloproliferative disorder was suspected, and the prognosis was initially predicted to be poor, classified as Mayo stage IV. Contrary to this prognosis, the patient showed a slow progression of heart failure. Further imaging modalities and cardiac tissue findings confirmed the diagnosis as transthyretin type amyloidosis, and a favorable prognosis was established with the use of tafamidis.
CONCLUSIONS: MGUS occasionally coexists with wild-type ATTR CA. Scant autonomic symptoms, mild renal dysfunction, and slow progression of heart failure might be clues that the CA associated with the myeloproliferative disease is wild-type ATTR amyloidosis.