Presentation of Case
A 52-year-old man with coronary artery disease (CAD), one-vessel disease, was admitted to the hospital because of intermittent episodes of dyspnea and chest tightness for 6 months. He had undergone angioplasty and stenting for CAD, but the symptoms worsened. He took an anti-platelet agent and beta-blocker for CAD regularly. He didn’t smoke and consume alcohol. The family history was not remarkable. His occupation involved moving house..
Initially, he presented with progressive exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. He also noted petechiae and purpura at the periorbital, neck, axilla, and inguinal regions. Massive bilateral pleural effusions were revealed by a chest radiograph, and thoracentesis showed findings consistent with transudate effusion.
On physical examination, the patient was afebrile and in the supine position had blood pressure of 96/73 mm Hg and a regular heart rate of 63 beats per minute. He was breathing at a rate of 24 breaths per minute. Oxygen saturation by oximetry was 99% while he was breathing oxygen via nasal cannula at a rate of 3L/min.
Cardiovascular exam revealed jugular vein engorgement and a grade 3/6 systolic ejection murmur at the apex without radiation. Auscultation revealed fine crackles at the bilateral lungs. The abdomen was flat and no tenderness was found. There was pitting edema of the bilateral lower extremities.
Electrocardiogram (Figure. 1) revealed a normal sinus rhythm at a rate of 64 beats per minute and left axis deviation. QS-pattern was noted in the inferior leads and poor R wave progression in the precordial leads. There was diffuse T wave inversion in lead I, AVL and V2 to V6.
A transthoracic echocardiogram revealed left ventricular (LV) hypertrophy (wall thickness of the interventricular septum and posterior wall 1.6 cm each) [Normal range, <1.3 cm] (Figure. 2), bi-atrial enlargement, small pericardial effusion (Figure. 3), moderate mitral regurgitation, and mild tricuspid, aortic, and pulmonic valve regurgitation. On 2-dimensional imaging, the myocardium had granular sparkling texture (Figure. 4). Left ventricular systolic function was severely reduced, with an ejection fraction of 30% [Normal range, >60 %]. Besides, LV diastolic function was markedly abnormal as was shown by severely the diminished peak early diastolic velocity (E’) of the medial mitral annulus by tissue Doppler imaging (Figure. 5). The blood velocity pattern at the mitral leaflet tips was consistent with restrictive pattern (Figure. 6).
Cardiac magnetic resonance imaging (MRI) disclosed delayed enhancement and perfusion defects in the endocardium (anterior basal subendocardium of LV and septal wall ). Delayed enhancement of the pericardium was also noted (Figure. 7).
Coronary angiography revealed patent left main, left anterior descending and left circumflex coronary artery. There was no ISRS [In-stent restenosis] in the right coronary artery. Endomyocardial biopsy was performed and pathology showed cardiac amyloidosis (Figure. 8). A bone marrow study revealed plasma-cell myeloma.
During the hospital stay, an episode of infection developed, which worsened heart failure. Mechanical support was instituted for cardiogenic shock and bortezomib was begun for plasma-cell myeloma. However, fatal arrhythmia developed. Despite all resuscitative efforts, he expired.
Figure legends:
Figure 1. Complete ECG.
Figure 2. Thickened left ventricular wall.
Figure 3. Thickened left ventricular wall (without chamber enlargement), interatrial septum and valve leaflets; bi-atrial enlargement; small amount pericardial effusion.
Figure 4. Granular sparkling texture.
Figure 5. Low mitral annular tissue Doppler E’ velocity.
Figure 6. Restrictive pattern of mitral inflow.
Figure 7. Cardiac MRI. delayed enhancement and perfusion defects in the endocardium.
Figure 8. Congo red-stained cardiac tissue.
病情解析:
類澱粉病變(amyloidosis)是由血清裡的蛋白質以特殊的排列(beta-pleated sheet configuration)成纖維(fibril)，沉積在全身特定的器官，心臟也是其中之一，一但侵犯了心臟，代表疾病已進展至後期，預後不佳。類澱粉蛋白有很多種類，是以蛋白質的前驅物命名，最常見侵犯心臟的種類是輕鏈(light-chain)型，這種類澱粉病變我們稱之為AL amyloidosis.
在成年人，如果出現無法解釋的心臟衰竭，而且在心臟超音波上有發現心臟壁有增厚 (但左心室腔室沒有增大)，就要把cardiac amyloidosis放在鑑別診斷之一 (尤其是此人沒有高血壓病史來解釋心臟壁的增厚)。其他有可能的發現還包括心電圖有低電壓(low voltage), 臨床症狀 - 暈厥, 胸痛, 心律不整, 中風, 周邊神經病變, 蛋白尿, 眼周圍紫斑, 肝脾腫大。
心臟超音波在診斷上相當重要，可以發現心室壁, 瓣膜, 心房中膈增厚 (有些甚至會出現granular sparkling texture). 左心室的收縮功能及舒張功能會下降，最嚴重的舒張功能下降會出現限制型型態. 心房的收縮功能也會下降而擴大，甚至產生血栓。
心臟的核磁造影可以幫忙診斷，會出現心內膜下的延遲顯影，但是最終的診斷還是需要組織學切片。(可以切心肌或是其他器官)。
治療上應針對兩方面，心臟衰竭以及類澱粉病變。心臟衰竭治療以環狀利尿劑(loops diuretics)及限鹽為主力，在其他原因造成的心臟衰竭常使用的乙型阻斷劑(beta-blocker) and 血管收縮素轉換酶抑制劑/血管收縮素轉換酶受器阻斷劑(ACEI/ARB) 在此類型的心臟衰竭病人身上可以使用，但病人常常會不堪負荷(如:低血壓)。鈣離子通道阻斷劑則不可使用。抗凝血藥物在有心房顫動, 心臟內血栓, 血管栓塞疾病或是心房擴大的病人身上建議使用。類澱粉病變的治療則是以化療為主，可以選高劑量melphalan再加上自體血液幹細胞移植, 也可以選擇以bortezomib為主的處方。 |
Case Discussion
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