Amyloidosis
Amyloidosis is the deposition of misfolded proteins in the extracellular matrix
AMYLOIDOSIS (short notes essay, asked twice)
- Definition: extracellular deposition of abnormal, insoluble misfolded protein fibrils (beta-pleated sheet structure)
- Types: AL (light chain — associated with plasma cell disorders/myeloma), AA (serum amyloid A — associated with chronic inflammation/infection), transthyretin-related (familial/senile)
- Diagnosis: Congo red stain — shows apple-green birefringence under polarised light
- Organs affected: kidney (nephrotic syndrome), heart (restrictive cardiomyopathy), liver, spleen, nerves
- Clinical relevance: chronic infections (TB, osteomyelitis) and inflammatory conditions (rheumatoid arthritis) predispose to AA amyloidosis
Read this in General Pathology Revision: Cell Injury, Inflammation & Adaptation (MBPA 3500 Pa
What our notes say
- Amyloidosis is the deposition of misfolded proteins in the extracellular matrix (Medical MCQs: Chemical Pathology & Haematology Exam Review)
- Congo red: amyloid — shows apple-green birefringence under polarized light (this is the gold-standard test for amyloidosis) (Bone & Soft Tissue Tumour Pathology: Must-Know Diagnoses)
- Recurrent infection, massive haemoptysis, empyema, lung abscess, pneumothorax, respiratory failure and cor pulmonale, amyloidosis, metastatic infection (brain abscess), sinusitis. (Bronchiectasis)
- Empyema and bronchopleural fistula, massive haemoptysis, spread (brain abscess, meningitis), sepsis, amyloidosis (chronic), chronic cavity that becomes colonised by *Aspergillus* (aspergilloma), recurrent infection. (Lung Abscess)
- Sinusoidal (3 marks): cirrhosis (alcohol, hepatitis B and C, NASH); fatty liver; metastatic malignant disease; partial nodular transformation of the liver; amyloidosis. (Internal Medicine 4th Year 1st Semester CAT: HIV and the gut, liver disease and )
- Complications: recurrent infections, haemoptysis, lung abscess, cor pulmonale, amyloidosis (secondary, AA type) (Pathology Practical Revision Guide)
Study material on Amyloidosis
- Medical MCQs: Chemical Pathology & Haematology Exam Review
- Immunopathology complete mcqs
- Immunopathology
- 🫀 MISSING TOPICS — ULTRA DEEP NOTES
- White Cell Disorders — Must-Know Notes
- general Pathology Q&A
- Chemical pathology and Endocrine pathology
- CARDIOVASCULAR PATHOLOGY
- Bone & Soft Tissue Pathology: Cases, Tumors, & Answers
- Year 3: Endocrine and Metabolic Pathology
Practice questions on Amyloidosis
A patient is suspected of having systemic amyloidosis. Which stain would demonstrate characteristic apple-green birefringence under polarised light?
- PAS
- Alcian blue
- Congo red
- Giemsa
- Van Gieson ✅ Answer: C
Answer: A. Congo red stain is specific for amyloid deposits, which exhibit characteristic apple-green birefringence under polarized light.
Primary (AL) amyloidosis is associated with
- Chronic TB and rheumatoid arthritis
- Familial transthyretin mutations
- Long-term hemodialysis
- Plasma cell dyscrasias (multiple myeloma)
Answer: D. AL = immunoglobulin light chains from clonal plasma cells. Affects heart (restrictive cardiomyopathy), kidneys (nephrotic syndrome), liver, tongue (macroglossia). ---
Secondary (AA) amyloidosis complicates
- Multiple myeloma
- Alzheimer's disease
- Long-term hemodialysis
- Chronic inflammatory diseases (TB, RA, osteomyelitis)
Answer: D. AA = serum amyloid A protein elevated in chronic inflammation. Kidneys and liver primarily affected. Also complicates familial Mediterranean fever. ---