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Station 39: AMYLOIDOSIS What is meant by amyloid? SpoilerAmyloid is an abnormal fibrillar protein that is deposited in the extracellular tissue. The proteins are deposited in a rigid, mesh-like, sheet structure. What is amyloidosis or amyloid degeneration? SpoilerAmyloidosis is a life-threatening condition in which there is deposition of abnormal fibrillar proteins known as amyloid in the extracellular tissue. Why do amyloid deposits in chronic infection not resolve? SpoilerHumans are susceptible to the complications of the amyloid protein because they have no enzyme that can break this structure down. What are the common sites of amyloid deposition? SpoilerBased on the clinical features of AL and AA amyloidosis common sites of amyloid deposition include: Kidneys (leading to proteinuria and nephrotic syndrome) Heart (leading to restrictive cardiac disease and arrhythmias) Liver (Hepatomegaly) Spleen (Splenomegaly) Nervous System (Peripheral neuropathy, carpal tunnel syndrome, autonomic neuropathy) Gastro-intestinal tract (Macroglossia, bleeding, poor absorption) What are the different types of amyloid protein? SpoilerAL protein (associated with Multiple Myeloma/Immunocyte dyscrasias, i.e., Primary amyloidosis) AA protein (associated with Chronic inflammatory conditions e.g., T.B., Rheumatoid arthritis, Secondary amyloidosis) β₂ or microglobulin (Aβ₂m) protein (associated with Chronic renal failure or dialysis, i.e., Hemodialysis-associated amyloidosis). Note: Familial amyloidosis is also mentioned, caused by a mutation in transthyretin. Which type of amyloidosis occurs in chronic inflammation? SpoilerAA amyloidosis (or Secondary amyloidosis) occurs in chronic inflammation. Examples of chronic inflammatory conditions include: -Rheumatoid arthritis (commonest cause of AA amyloid in the UK) -Inflammatory bowel disease -Tuberculosis (T.B.) -Bronchiectasis -Osteomyelitis -Renal cell carcinoma What are the main clinical findings in amyloidosis? SpoilerThe clinical features depend on the type (AL vs. AA) and organs involved. The patient description in your prompt suggests AL amyloidosis due to the presence of: -Progressive ankle swelling / Pitting pedal oedema (suggests kidney/cardiac involvement) -Frothy urine / 3+ Proteinuria (Kidney involvement: Proteinuria and nephrotic syndrome) -Fatigue -Numbness in his feet (Nervous system involvement: Peripheral neuropathy) -Large, firm tongue / Macroglossia (Gastro-intestinal tract involvement) -Hepatomegaly (Liver involvement) How is amyloidosis classified? SpoilerAmyloidosis is classified by the protein and the system involved. Classification by Protein Involved (Systemic/Generalized Amyloidosis) • AL amyloid (Immunocyte dyscrasias with monoclonal B-cell proliferations like Multiple myeloma) • AA amyloid (Chronic inflammatory conditions) • Familial amyloidosis (Autosomal dominant disorder, commonly caused by a mutation in transthyretin) Classification by Clinical Type • Primary Amyloidosis: Associated with Immunocyte dyscrasias (e.g., Multiple myeloma), involving the AL protein. • Secondary Amyloidosis: Associated with Chronic inflammatory conditions (e.g., T.B., bronchiectasis), involving the AA protein. • Haemodialysis-associated amyloidosis: Associated with Chronic renal failure or dialysis, involving the β₂-microglobulin (Aβ₂m) protein. How to test for amyloidosis? SpoilerBlood and urine tests may provide hints about the diagnosis, but the gold standard for detecting amyloid deposits is to perform Congo red staining on a tissue sample, which appears apple-green when viewed with a polarizing microscope. Laser microdissection followed by mass spectrometry can determine the type of amyloid in virtually 100% of cases.

Stem : A male patient with a history of Aortic stenosis, going for TURP is found to have ejection systolic murmur in preoperative assessment. Pathophysiology of aortic stenosis? SpoilerLipid accumulation in the valve → fibrosis, calcification and stiffening → stenosis What are the symptoms of AS? SpoilerIn mild AS • Asymptomatic In moderate cases • Angina • Syncopal attacks • Dyspnoea In severe cases • Complications: pericarditis & MI • Sudden death Triad of aortic stenosis? Spoiler• Syncope • Anginal pain • Dyspnoea What are the complications you may expect? Spoiler• LVH • VF • Ventricular tachycardia (VT) • CHF • HTN • Angina • Intra operative sudden death Explain syncope in AS? SpoilerOccurs upon exertion when systemic vasodilatation in the presence of a fixed stroke volume and COP causes the arterial systolic blood pressure to decline. What intraoperative complications can lead to death? Spoiler• Myocardial infarction • Aortic dissection What are the anaesthetic considerations? SpoilerPatient will have fixed cardiac output cannot respond to decreased afterload. What preoperative investigation to do? Spoiler• Transthoracic echocardiography / Transoesophageal echo • Chest x ray • ECG What is the finding in ECG? [image: 1785435072943-75ee5eb6-890b-432b-8a3f-ecddb0b4c60c-image.jpeg] SpoilerLeft ventricular hypertrophy Why/Explain your finding in the previous answer? SpoilerS wave in V2 + R wave in V6 = more than 35 small squares. T wave inversion and altered ST segment in V2 to V6. ECG changes in Aortic stenosis? Left axis deviation LVH Heart block ST segment change How to calculate HR based on this ECG? Spoiler300 / number of large squares between two R‑R intervals What are the advantages and disadvantages of doing AS surgery first VS doing bladder cancer surgery first? SpoilerDoing AS first → reduces risk of complications but increases risk of cancer spread Doing cancer surgery first → prevents spread of cancer but increases risk of AS complications and death What to do first, AS or bladder cancer surgery? SpoilerDepends on severity of aortic stenosis Normal aortic valve surface area: 2.5–3.5 cm² If aortic valve surface area < 1 cm² → severe stenosis → do AS surgery first What is antibiotics prophylaxis? SpoilerNICE guidelines: No antibiotics except for major procedures or highly infected procedures (e.g., lower and upper GI surgeries) What are types of valve in valvular replacement surgery? SpoilerTissue valve Mechanical valve What are the differences between them? Mention 3 Spoiler-Mechanical Made of metal / ceramic Warfarin for life Higher thrombo‑embolism & bleeding risk Excellent durability (>95% at 10 years), can last lifetime Slight clicking noise -Tissue Valve Made of animal / human tissue No warfarin needed (only first 3 months) Lower thrombo‑embolism & bleeding risk Wear out after 10–20 years Noiseless What is the non‑surgical option for valvular replacement? SpoilerTranscatheter aortic valve replacement Right aortic balloon valvuloplasty Define aortic sclerosis? SpoilerValve disease with insignificant gradient across the valve that can progress to stenosis State a common complication from the use of thiazide diuretics that might result in postponing the surgery? SpoilerHypokalaemia and hyponatraemia --Note-- You may be asked about intrinsic and extrinsic pathways Intrinsic Pathway Trigger: Internal damage to the blood vessel wall (e.g., plaque rupture). Initiation: Exposure of negatively charged surfaces such as collagen activates factor XII (Hageman factor). Cascade: Sequential activation of factors XII, XI, IX, VIII, and X. Extrinsic Pathway Trigger: External trauma causing tissue injury. Initiation: Tissue factor (TF) released from damaged cells activates factor VII. Cascade: Activated factor VII (VIIa) activates factor X. Activated factor X (Xa) joins the common pathway Common Pathway Convergence: Both intrinsic and extrinsic pathways meet at factor X activation. Thrombin Formation: Factor Xa + factor V + calcium + phospholipids convert prothrombin → thrombin. Fibrin Formation: Thrombin converts fibrinogen → fibrin, forming a mesh that stabilises the clot.