Histopathology Part 1- (p135-148- Cardio and Resp) Flashcards
Which WBCs are responsible for acute inflammation?
Neutrophils and macrophages (late acute)
Which WBCs are responsible for chronic inflammation?
Macrophages (including granulomas like sarcoidosis), lymphocytes and plasma cells
Which WBC is involved in allergic reactions and parasitic infections?
Eosinophils
Two types of carcinoma?
Squamous cell carcinoma
Adenocarcinoma
Histological features of squamous cell carcinoma?
Keratin production
Intracellular bridges
Don’t form glands
Sites of squamous cell carcinomas?
Skin H+N Oesophagus Anus Cervix Vagina
Histological features of adenocarcinoma?
Form glands -> secrete glandular fluid
Mucin production
Sites of adenocarcinoma?
Lung Breast Stomach Colon Pancreas
What is the Congo Red stain used to detect?
Amyloidosis- +ve apple green birefringence
What does a positive result for the Prussian Blue stain show?
Iron (haemochromatosis)
What is the definition of atherosclerosis?
Chronic inflammation in intima of large arteries characterised by intimal thickening and lipid accumulation
What are the 7 steps of atherogenesis?
- Endothelial injury
- LDL enters intima and is trapped in subintimal space
- LDL converted into modified and oxidised LDL causing inflammation
- Macrophages take up oxLDL via scavenger receptors and become foam cells
- Apoptosis of foam cells causing inflammation and cholesterol core of plaque
- Increase in adhesion molecules on endothelium results in more macrophages and T cells entering the plaque
- VSMC form the fibrous cap
3 principal components of atherosclerotic plaques?
Cells- including SMC, macrophages and other leukocytes
ECM including collagen
Intracellular and extracellular lipid
Where is atherosclerosis more common?
Areas of turbulent blood flow where there is low shear stress which is atherogenic e.g. ostia of major branches
Risk factors for atherosclerosis (modifiable and non-modifiable)?
Modifiable- T2DM, HTN, Hypercholesterolaemia and Smoking
Non-modifiable- Gender (M>F), age, FHx
Complications of myocardial infarction?
Mechanical- Contractile dysfunction due to loss of muscle -> cardiogenic shock Congestive cardiac failure LV infarct Cardiac rupture Ventricular aneurysm
Arrhythmias-
VF usually occurs in first 24h, cause of sudden death
90% develop arrhythmia following MI
Pericardial- pericarditis, tamponade, Dressler’s syndrome (months after)
What are the histological findings <6h post-MI?
Normal by histology (CK-MB also normal
What are the histological findings 6-24h post-MI?
Loss of nuclei, homogenous cytoplasm, necrotic cell death
What are the histological findings 1-4d post-MI?
Infiltration of polymorphs then macrophages (clear up debris)
What are the histological findings 5-10d post-MI?
Removal of debris
What are the histological findings 1-2w post-MI?
Granulation tissue, new blood vessels, myofibroblasts, collagen synthesis
What are the histological findings wks-months post-MI?
Strengthening, decellularlising scar tissue
Common causes of HF?
IHD Valve disease Myocarditis HTN DCM Arrhythmias
Complications of HF?
Sudden death Emboli Arrhythmias DVT + PE Pulmonary oedema Hepatic cirrhosis- nutmeg liver
Pathophysiology of HF?
Damage -> reduced CO + SV
Compensatory mechanisms:
Low CO -> Activation of RAS -> Salt and water retention to maintain perfusion. Eventually -> fluid overload
Low SV -> Activation of SNS via baroreceptors -> maintains perfusion but increases TPR -> increased afterload -> LVH and increased EDV -> dilatation and poor contractility
Investigations in HF?
BNP
CXR
ECG
Echo
Causes of dilated cardiomyopathy?
Idiopathic Alcohol Peripartum Genetic Sarcoidosis Haemochromatosis Myocarditis
Causes of HCM?
Genetic
Storage diseases
Causes of restrictive cardiomyopathy?
Sarcoidoisis
Amyloidosis
Radiation-induced fibrosis
What is seen histologically in HCM?
Myocyte disarray
What is the inheritance pattern of HCM?
Autosomal dominant mutations in genes encoding sarcomeric proteins
Which mutations are most common for HCM?
betaMHC gene, MYBP-C + Trop-T
What is hypertrophic obstructive cardiomyopathy?
Septal hypertrophy resulting in outflow tract obstruction
What is arrhythmogenic right ventricular cardiomyopathy?
Myocyte loss with fibrofatty replacement typically affecting the RV