Cardiovascular pathology Flashcards
What is the most common cause of cardiac disease?
Atherosclerosis - 80%
Hypertensive heart disease - 9%
What are the key differences in the histology of a muscular and elastic artery?
Elastic -> closer to heart - concentric rings of elastic and muscular tissue
Muscular -> clear internal and external elastic lamina
What are the key histological layera of a muscular artery?
Tunical intima (endothelium)
Internal elastic lamina
Tunica media (smooth muscle)
External elastic lamina
Tunica adventitia
What are the features of smooth muscle fibres?
No striations
Spindle shaped
Single central nucleus
Found in blood vessels, GIT, hollow organs etc
What are some key risk factors for atherosclerosis?
Increasing age
High cholesterol and TG
High BP
Smoking
Diabetes
Obesity
Physical inactivity
High saturated fat diet
At what stage of occlusion is an atheroma classified as a symptomatic?
70% obstruction of the lumen
What is the key pathology shown in this vessel?
An atheroma
What histological features may be seen in an athermoa?
Brown spots -> calcification
Fibrous cap -> collagen and elastin
Cholesterol crystals/clefs and foam cells -> white spaces
What are the key complications of atherosclerosis?
Erosion, ulceration or rupture
Induces thrombosis -> ACS
Aneurysm formation
Atheroembolism
How do the layers of blood vessels relate to the layers of the heart?
Endocardium = tunica intima
Myocardium = tunica media
Epicardium = tunica adventitia
Outer pericardium -> parietal layer (fibrous and adipose), visceral layer
How does a subendocardial/transmural myocardial infarction relate to the anatomy of the coronary arteries?
Arteries in the epicardium
The innermost myocardium (just superficial to endocardium hence subendocardial) is the furthest away -> longer perfusion distance -> hence dies first in infarction.
On gross pathology what does an area of infarction look like?
Yellow/lightish tinge
What are the histological features of cardiac muscle?
Striated
Branching
Single circular nucleis
Intercalated disks
Rectangular shape
What are the histological features of MI from 6hrs to 24hrs?
Widened spaces between myocytes due to oedema
Loss of nuclei
May also see haemorrhage (lots of rbcs) - not shown in this image
What are the histological features of 1-3days post MI of myocardium?
Inflammatory cells - neutrophils
Large areas of oedema and muscle loss
What are the histological features 3d to 2w post MI of myocardium?
Majority is inflammatory cells including macrophages (clear necrotic myocytes)
Damages area replaced by vascularised granulation tissue in 1 -2 w.
When should PCI be offered to treat a STEMI?
If present within 120 mins of symptom onset
AND - can be given within 120mins of when fibrinolysis could have been given.
What are the histological features of well healed myocardial infarction (scar tissue) 2-6 weeks?
Dense collagenous fibrous tissue
Light pink sheets with no nuclei
May have some residual myocytes
What is the gold standard test for diagnosis of myocarditis?
Endomyocardial biopsy.
What is the most common viral cause of myocarditis?
Coxsackie virus
What are the key infectios disease causing myocarditis?
Viral - coxsackie, parvovirus B19, HHV 6
Bacterial - chlamydiae, borellia
Rickettsia
Plasmodium
Toxoplasma
What immune mediated causes of myocarditis?
Post infections/viral
Post streptococcal (Rheumatic fever
Systemic inflammatory disorders such as SLE
Drug hypersentivities - antibiotics, vaccines, anticonvulsants
What are the key histological findings of myocarditis?
Myocardium -> interstitial inflammatory infiltrate
Myocyte damage - nucleus loss
What are the key histological findings in the image of myocardium?
Multinucleated giant cells (from fusion of macrophages)
is a giant cell myocarditis
What is the key management of myocarditis?
Treat cause: if infective antivirals etc, if immune mediated corticosteroids
Supportive
Most patients recover spontaneously
What is a potential complication of myocarditis?
Dilated cardiomyopathy
What are some predisposing factors for infective endocarditis?
Rheumatic heart disease
Mitral valve prolaspe
Degenerative calcific valvular stenosis
Artificial (prosthetic) valves
What are the common sources of infection in infective endocarditis?
Dental or surgical procedure
IVDU
Ivasive vascular procedure (central lines)
What are the common causative organisms of infective endocarditis?
Streptococcus viridans (from oral cavity)
Staph aureus (skin - IVDU) or hospital acquired
Enterococci
HACEK
What is key for the diagnosis of infective endocarditis?
3 sets of blood cultures
Transthoracic or transesophageal echo
What is the key histological features of infective endocarditis?
Neutrophil
Bacterial colonies (Dark purple)
What are some potential complications of infective endocarditis?
Septic emboli - pyogenic brain abcess, stroke
Roth spots (retina)
Septic pulmonary emboli
Peripheral fingers infacts
Aortic valve perforation
Mitral valve regurg
Acute heart failure (from acute valve failure
What is nonbacterial thrombotic endocarditis?
Deposition of small sterile thrombi on leaflets of cardiac wall
Common in debilitated patients - cancer, sepsis
Thrombi loosely attach so can become embolic
What is endocarditis of SLE? (Libman-sacks)
Small sterile vegations on cardiac valves of patients with SLE
Vegetations = finely granular fibrinous and eosinophilic material.
What is the difference between systolic and diastolic heart failure?
Systolic failure – left ventricle (LV) loses ability to contract (pump) – measured using LV ejection fraction
Diastolic failure – left ventricle has reduced ability to fill (stiffness) and is unable to fill with blood between heart beats
What are the typical causes of systolic heart failure?
CAD
Arterial HTN
Valvular heart disease (volume load)
Arrhthmia
INflammatory
Idiopathic/toxic cardiomyopathy
What are the typical causes of diastolic heart failure?
Diabetes mellitus
Arterial HTN
Valvular heary disease (pressure load)
Hypertrophic cardiomyopathy
Restricted cardiomyopathy
Constrictive pericarditis
Amyloidosis
