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Q1. Which statement about amyloidosis is WRONG?

  • (A) The prognosis is determined by the extent of cardiac involvement
  • (B) Amyloidosis with heart involvement also cause cardiac hypertrophy and loss of systolic function
  • (C) Autologous stem cell transplant is still recommended as frontline consolidation therapy
  • (D) Amyloidosis can cause mixed axonal demyelinating peripheral sensory, motor or autonomic neuropathy
點此顯示正解

(B) Amyloidosis with heart involvement also cause cardiac hypertrophy and loss of systolic function

詳解

Why (B) is WRONG

Statement (B) is incorrect because cardiac amyloidosis characteristically causes restrictive physiology with preserved ejection fraction (HFpEF), not loss of systolic function. While cardiac amyloidosis does cause increased ventricular wall thickness (infiltrative thickening, not true hypertrophy), the hallmark dysfunction is diastolic with restriction to ventricular filling and reduced stroke volume despite normal systolic ejection fraction until late in the disease course4. As Gertz and Dispenzieri state in their JAMA systematic review: "Because dysfunction is diastolic, systolic ejection fraction is normal until late into the disease, which makes it a classic form of heart failure with preserved ejection fraction"4.

Reduced ejection fraction (<40%) can occur in advanced disease—reported in 30-50% of wild-type ATTR cases at diagnosis2—but this represents late-stage disease, not the typical presentation. The statement is misleading because it suggests systolic dysfunction is a characteristic feature when the cardinal feature is actually diastolic dysfunction with preserved EF45.

Why the Other Statements are CORRECT

(A) Prognosis is determined by extent of cardiac involvement — This is correct. Survival in AL amyloidosis is highly dependent on the severity of cardiac dysfunction at diagnosis[10][11]. The Mayo Clinic cardiac staging systems (2004 and 2012) use cardiac biomarkers (troponin and NT-proBNP) to stratify risk, with median survival ranging from approximately 94 months for Stage I to 5.8 months for Stage IV disease[^14]. Patients diagnosed late with advanced heart damage have median survival of only 3-6 months, whereas those without cardiac involvement can survive many years[10][11].

(C) Autologous stem cell transplant is recommended as frontline consolidation — This is correct for selected eligible AL amyloidosis patients. ASCT remains a standard treatment option for appropriately selected patients with AL amyloidosis who meet eligibility criteria[10][11].

(D) Amyloidosis can cause mixed axonal/demyelinating peripheral neuropathy — This is correct. Amyloidosis, particularly variant ATTR, commonly presents with peripheral neuropathy affecting sensory, motor, and autonomic nerves4[^11]. Wild-type ATTR can also present with neuropathic features including carpal tunnel syndrome and lumbar spinal stenosis4.

詳解 · 中文翻譯

為什麼 (B) 是錯誤的

敘述 (B) 是不正確的因為心臟澱粉樣變特徵性造成限制性生理與保留的射血分數（HFpEF），而不是收縮功能喪失。雖然心臟澱粉樣變確實造成增加的心室壁厚度（浸潤性增厚，不是真實肥厚），標誌性功能障礙是舒張性伴心室充盈限制和減少的搏出量儘管正常的收縮射血分數至疾病進程晚期4。正如 Gertz 和 Dispenzieri 在他們的 JAMA 系統評論中聲稱：「因為功能障礙是舒張性，收縮射血分數是正常的直到晚入疾病，使其成為保留射血分數心衰的經典形式」4。

減少的射血分數（<40%）可在高級病中發生—在診斷時報告於 30-50% 的野生型 ATTR 病例中2—但這代表晚期病，而不是典型表現。敘述是誤導性的因為它暗示收縮功能障礙是特徵特徵，當主要特徵實際上是舒張功能障礙與保留 EF45。

為什麼其他敘述是正確的

(A) 預後由心臟受累程度決定 — 這是正確的。AL 澱粉樣變的生存高度依賴於診斷時心臟功能障礙的嚴重程度[10][11]。Mayo 診所心臟分期系統（2004 和 2012）使用心臟生物標誌物（肌鈣蛋白和 NT-proBNP）分層風險，中位生存從約 94 個月用於 I 期到 5.8 個月用於 IV 期病[^14]。診斷晚期伴高級心臟損害的患者只有 3-6 個月的中位生存，而無心臟受累的患者可生存多年[10][11]。

(C) 自體幹細胞移植推薦作為一線強化 — 這對選定的合格 AL 澱粉樣變患者是正確的。ASCT 保留作為適當選定的符合合格標準的 AL 澱粉樣變患者的標準治療選項[10][11]。

(D) 澱粉樣變可造成混合軸突/脫髓鞘周邊神經病 — 這是正確的。澱粉樣變，特別是變體 ATTR，通常表現為影響感覺、運動和自主神經的周邊神經病4[^11]。野生型 ATTR 也可表現為包括腕管綜合症和腰椎脊柱狹窄的神經病特徵4。

參考文獻 (AMA)

  1. Gertz MA, Dispenzieri A. Systemic Amyloidosis Recognition, Prognosis, and Therapy: A Systematic Review. Jama. 2020;324(1):79-89. doi:10.1001/jama.2020.5493. PMID:32633805. ↩

  2. Ruberg FL, Grogan M, Hanna M, Kelly JW, Maurer MS. Transthyretin Amyloid Cardiomyopathy: JACC State-of-the-Art Review. Journal of the American College of Cardiology. 2019;73(22):2872-2891. doi:10.1016/j.jacc.2019.04.003. PMID:31171094. ↩↩

  3. Kotecha T, Martinez-Naharro A, Treibel TA, et al. Myocardial Edema and Prognosis In Amyloidosis. Journal of the American College of Cardiology. 2018;71(25):2919-2931. doi:10.1016/j.jacc.2018.03.536. PMID:29929616. ↩

  4. Sanchorawala V. Systemic Light Chain Amyloidosis. The New England Journal of Medicine. 2024;390(24):2295-2307. doi:10.1056/NEJMra2304088. PMID:38924733. ↩↩↩↩↩↩↩↩↩↩

  5. Kumar S, Dispenzieri A, Lacy MQ, et al. Revised Prognostic Staging System for Light Chain Amyloidosis Incorporating Cardiac Biomarkers and Serum Free Light Chain Measurements. Journal of Clinical Oncology : Official Journal of the American Society of Clinical Oncology. 2012;30(9):989-95. doi:10.1200/JCO.2011.38.5724. PMID:22331953. ↩↩

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