cardiovascular pathology 3 Flashcards
What is meant by:
- Epidemiology
- Aetiology
- Pathogenesis
- Clinical features
?
- Epidemiology is who gets a disease
- Aetiology is what causes a disease
- Pathogenesis is how does the disease make you ill
- Clinical features are what the disease looks like
what is the definition of peripheral vascular disease?
Atherosclerosis of arteries supplying legs (or arms), leading to narrowing of the vessel lumen and restriction of blood flow
what is the epidemiology of peripheral vascular disease like?
- Smokers
- obese people
- age > 40
- family history
- men (or postmenopausal women)
- those with a past medical history including diabetes, hypercholesterolaemia and hypertension
what is the aetiology of peripheral vascular disease?
It is caused by atherosclerosis
- normal artery
- endothelial dysfunction
- fatty streak formation
- stable (fibrous) plaque formation
- unstable plaque formation
What causes endothelial dysfunction leading to atherosclerotic plaque formation?
Oxidative stress leads to endothelial dysfunction and reduced NO bioavailability
factors that cause oxidative stress include:
- diabetes
- smoking
- hypertension
- dyslipidaemia
- obesity
- aging
- oestrogen
What is the pathogenesis of peripheral vascular disease?
Chronic peripheral vascular disease is caused by gradual atherosclerosis
Acute peripheral vascular disease is caused by plaque rupture or thrombus formation
both of these narrow the lumen and reduce blood flow
this leads to ischaemia and tissue damage / death
what are the key clinical features of acute peripheral vascular disease?
The 6 Ps
- pale
- pulseless
- painful
- paralysed
- paraesthetic
- perishing cold
what are the key clinical features of chronic peripheral vascular disease?
If it is chronic, you do NOT get the Ps as collateral vessels form
as severity increases, it goes from being asymptomatic (i.e. reduced pulses)
to intermittent claudication, which presents as pain upon exertion
and then critical limb ischaemia, which presents with rest pain and tissue loss
what is the definition of giant cell arteritis (temporal arteritis)?
A type of vasculitis affecting the large arteries in the head
it is considered a medical emergency as it can lead to blindness
what is the aetiology of giant cell arteritis?
Exact cause is not known, but the end stage problems are immune mediated
What is the epidemiology of large cell arteritis like?
- Affects older individuals and is very rare in <50s
- US / Europe
- affects more females than males
- past medical history of polymyalgia rheumatica
it is the most common form of vasculitis
What is involved in the pathogenesis of large cell arteritis?
- Chronic granulomatous inflammation
- thickens wall of artery
- narrows lumen
- reduced blood flow
- ischaemia
- tissue damage / death
What are the key clinical features of large cell arteritis?
Flu-like symptoms:
- fatigue
- weight loss
- fever
pain:
- tender superficial temporal artery / scalp
- biopsy the temporal artery for diagnosis
- Jaw claudication (when eating)
vision problems:
- blurred vision
- blindness (can be permanent so need STEROIDS ASAP)
stroke
What is the definition of infective endocarditis?
Infection and inflammation of the endocardium (lining of the heart), mainly involving the valves
(rarer non-infective forms of endocarditis also exist)
What is the epidemiology of infective endocarditis like?
It affects patients with:
- structurally abnormal valves
- rheumatic heart disease, congenital heart disease, age-related valve calcification
- foreign material in the heart
- ICD, prosthetic valves
- immunosuppression
- bacteraemia
- IVDU
- long term IV catheter (dialysis patients)
- colorectal cancer
- dental procedures (“prophylaxis not recommended routinely)
it can occur in healthy patients with normal hearts with virulent organisms (e.g. S. aureus)
what is the aetiology of infective endocarditis like?
Bacteria (common):
- streptococcus
- viridans - associated with dental procedures
- bovis - associated with colorectal cancer
- staphylococcus
- aureus - associated with normal hearts of healthy patients
- epidermis - associated with prosthetic valves
fungi (rare):
- candida
- aspergillus
what is the pathogenesis of infective endocarditis like?
- Damage to the endothelium over the valve
- fibrin deposition
- circulating bacteria colonise the fibrin
- vegetations form
- the vegetations damage the valve, as does the immune response to the infection
What symptoms of infective endocarditis result from vegetations on the heart valves?
Vegetations damage the valve:
- heart failure
- murmurs
bacteria in vegetations form local abscess:
- AV block
Bits of vegetations break off:
- emboli cause distant infection or infarction
- janeway lesions
- splinter haemmorhages
- splenic infarct
- kidney infarct
How does the immune response to infection cause symptoms of infective endocarditis?
- The immune response causes fever and weight loss
- immune complex formation leads to Roth spots, glomerulonephritis and Osler nodes
what are the key clinical features of infective endocarditis?
- Splenic infarct
- splinter haemorrhage
- janeway lesions
- osler’s nodes
- roth spots
What is the definition of pericarditis?
What are the 2 categories?
Inflammation of the pericardial sac
acute (<6/12):
- serofibrinous, caseous, haemorrhagic & purulent
chronic (>6/12):
- constrictive
What is the pathogenesis of pericarditis?
Insult to the pericardium leads to acute inflammation
this progresses to chronic inflammation
How does acute inflammation in pericarditis cause damage?
- Leaky vessels cause fluid to accumulate in pericardial sac (serous)
if + fibrin, serofibrinous
if + neutrophils, purulent (bacterial infections)
if + RBCs, haemorrhagic (malignancy)
if + caseous necrosis, caseous pericarditis (TB)
How does chronic inflammation in pericarditis cause damage?
- Extracellular matrix and collagen deposition
- fibrosis and thickening of the pericardium
- fibrosis reduces filling of the heart
- this leads to heart failure
What is the definition of myocarditis?
Inflammation of the myocardium
what is the definition of rheumatic fever?
A rare complication of group A streptococcal pharyngitis that affects the heart (and other parts of the body)
What is the pathogenesis of rheumatic fever like?
- Group A strep infection
- Antibodies made against M protein on the surface of Strep pyogenes bacteria
- Antibodies also recognise proteins on surface of cells (self antigens) in the heart, joints, skin and CNS
What is the definition of cardiomyopathy?
what are the 4 types?
Cardiomyopathies are diseases of the heart muscle
- dialted
- hypertrophic
- restrictive
- arrythmogenic right ventricular cardiomyopathy
this term does NOT include heart disease from ischaemia, valve disease or CCF
What is the epidemiology, aetiology and pathogenesis of hypertrophic cardiomyopathy?
Epidemiology:
- all ages and genders
aetiology:
- genetic
pathogenesis:
- there is impaired ventricular filling
- +/- left ventricular outflow obstruction in 1/3 of cases
- relative ischaemia
What is the epidemiology and aetiology of dilated cardiomyopathy like?
Epidemiology:
- any age
- most commonly males aged 20-50
aetiology:
- often unknown
- AD genetic (up to 50% of cases)
- alcohol
- catecholamines (Takotsubo)
- pregnancy
- haemochromatosis
- infection (including coxsackie b)
- others
