Pathology Flashcards
Cardiomyopathy
Any disease of the cardiac muscle. It often results in changes in the size of the heart and thickness of the heart
Classification of cardiomyopathy
Dilated, hypertrophic, restrictive, arrhythmogenic
What is dilated cardiomyopathy
Big heart - 2 or 3 times normal size. Heart is flabby and floppy
Causes of dilated cardiomyopathy
Genetics, toxins, alcohol, doxurubicin (chemotherapy agent), cardiac infection, pregnancy
Clinical features of dilated cardiomyopathy
General picture of heart failure, SOB, poor exercise tolerance, low ejection fraction
What is hypertrophic cardiomyopathy
Big solid hearts with thickened myocardium
What sort of dysfunction does hypertrophic cardiomyopathy result in?
Diastolic dysfunction - heart can’t relax, eventually resulting in outflow obstruction
Causes of hypertrophic cardiomyopathy
Most are genetic
Types of genes responsible for hypertrophic cardiomyopathy
Beta myosin heavy chain, myosin binding protein C, alpha tropomyosin
Interventricular septum and LV lumen in hypertrophic cardiomyopathy
Bulging interventricular septum and LV luminal reduction
Myocytes in interventricular septum
Swirling pattern
What is restrictive cardiomyopathy?
Stiff heart causing lack of compliance
What sort of dysfunction does restrictive cardiomyopathy result in?
Diastolic due to heart not filling well
What causes biatrial dilatation in restrictive cardiomyopathy?
Back pressure
Causes of restrictive cardiomyopathy
- Deposition of something in the myocardium
- Metabolic byproducts – iron
- Amyloid
- Sarcoid – multi system granulomatous disorder
- Tumours
- Fibrosis following radiation
What is amyloid?
Abnormal deposition of abnormal protein
Waxy pink material
Why can’t the body get rid of amyloid?
It is insoluble to any of the body’s enzymes
Classification of amyloid
- AA – relate to chronic diseases like rheumatoid
- AL – light chains, abnormal immunoglobulin
- Haemodynamically associated – beta 2 microglobulin
- Familial forms: transthyretin
- Diabetes
- Alzheimer’s
What colour does amyloid stain on a histological slide?
“congo-red” and exhibits apple green birefringence
Which type of cardiomyopathy is amyloid associated with?
Restrictive cardiomyopathy
Arrythmogenic right ventricular dysplasia - what is it?
Genetic disease - autosomal dominant with low penetrance - which causes the right ventricle to be largely replaced by fat and it appears big and floppy. There is near total replacement of the ventricular wall by fat
Symptoms of arrythmogenic right ventricular dysplasia
Syncope and ‘funny turns’, arrhythmias
What does myocarditis look like?
‘Beefy’ myocardium
Causes of infectious myocarditis
- Coxsackie A and B
- ECHO virus
- Many other viruses
- Chaga’s diesea (parasitic cause)
- Lyme’s disease (parasitic cause)
- HIV (very rare subcause)
Non-infectious myocarditis causes
- Immune mediated hypersensitivity reactions
- Hypersensitivity to infection – rheumatic fever after strep throat
- Hypersensitivity to drugs – eosinophilic myocarditis
- Systemic lupus erythematosus
Rheumatic fever:
- How does it affect valves?
- How does it affect chordae tendinae?
- Myocardium in rheumatic fever
- Histology
- Classic mitral stenosis with thickening and fusion of valve leaflets
- Short, thick chordae tendinae
- Myocardium patchily inflamed
- Aschoff bodies
Causes of pericarditis
- Infection
- Immune mediated (rheumatic fever)
- Idiopathic
- Uraemic (renal failure)
- Post MI (Dressler’s syndrome)
- Connective tissue disease
Causes of infectious pericarditis
Viruses - especially ECHO virus
Bacterial - extension from elsewhere, produce purulent effusions
Fungi - immunosuppressed patients, post-transplant, produce purulent effusions
TB - caseous material in sac producing constrictive pericarditis
Complications of pericarditis
Pericardial effusion, tamponade, constrictive pericarditis, cardiac failure, death
Causes of non-infectious endocarditis
Rheumatic fever, systemic lupus erythematosus
Carcinoid tumours
Neoplasms of neuroendocrine cells
Where can carcinoid tumours be seen?
Can see them in any mucosa, common in GI tract and lung
Most common tumour of the heart
Atrial myxoma
Atrial myxoma:
- Where does it mostly occur?
- What can it cause?
- What symptoms is it associated with?
- Right atrium
- Ball/valve obstruction, tumour emboli, endocarditis
- Systemic fever and malaise
