Cellular Pathology - Amyloidosis | 아밀로이드증의 종류 | 제한성심근병증

I. 아밀로이드

- 세포 외 공간에 misfolded protein이 침착하여, 해당 조직에 손상을 일으키는 것

■ 아밀로이드증의 공통특징

left: H&E stain, right: Congo red stain

- beta-pleated sheet configuration
- H&E : amorphous eosinophilic extracelluar
- Congo red staining and apple-green briefringence when under polarized light
- Deposition은 국소적 또는 전식적으로 둘 다 가능함.

II. Systemic amyloidosis

■ Primary amyloidosis

- deposition of AL amyloid(Amyloid light chain)
- immunoglobulin light chian(Kappa, Lambda) 유래
- multiple myeloma , B cell lymphoma 에서 발생

■ Secondary amyloidosis

- deposition of AA amyloid(serum amyloid-associated protein)
- SAA is released by liver, sitmulated by marcophage(IL-1, IL-6)
- chromic inflammation or neoplasia 에서 주로 발생
- e.g. RA, SLE, TB, bronchiectasis, osteomyelitis, Crohn, cancer
- Rare : FMF(Familial Mediterranean fever)
→ Autosomal recessive, dysfunction of neutrophils, serosal inflammation

■ clinical features of systemic amyloidosis

▶kidney

- m/c involved organ

- nephrotic syndrome

- progressive renal failure

▶Heart

- restrictive cardiomyopathy

- low voltage EKG

- cardiac arrhythmias and CHF

▶Hepatosplenomegaly

▶GI tract

- tongue enlargment (AL type)

III. Localized amyloidosis 

■ Senile cardiac amyloidosis 

- deposition of ATTR amyloid(transthyretin)

- usually asymptomatic, 1/4 80세 이상 노인

- leading to restrictive cardiomyopathy

■ Non insulin dependant diabetes

- Amyline (derived from insulin) deposits in the islet of the pancreas

■ Alzheimer dz.

- deposition of Aβ 

- β-APP gene on chromosome 21 : Down syndrome developed Alzheimer disease by the age of 40

■ Dialysis associated amyloidosis

- β2-microglobulin deposit in joint

- joint disease or carpal tunner syndrome

■ Medullary carcinoma of the thyroid

- calcitonin deposition within the tumor 

IV. Clinical points of amyloidosis

■ Cardiac Amyloidosis

- Restrictive Cardiomyopathy = diastolic dysfunction

1) LV thick 

2) LV size : normal or decrease

3) LA enlargement

- jugular venous pressure with rapid 'y' descent and prominent S4

cardiac amyloidosis : 연한 분홍색 = amorphous eosinophilic material

▶ Restrictive Cardiomyopathy : https://medhamstern.tistory.com/114

▶ S4, S3 심음 : https://medhamstern.tistory.com/105