Cardiomyopathy, Myocarditis and Pericarditis Flashcards
What is cardiomyopathy?
Chronic disease of the heart muscle
What are the three main types of cardiomyopathy?
- Dilated
- Restrictive
- Hypertrophic
Describe dilated cardiomyopathy
The heart can be up to 2-3 times normal size
Contractile muscle fibres are not in optimal directions
Contractile force is often less than required
What are causes of dilated cardiomyopathy?
- Genetics - any gene involved in heart muscle protein
- Toxins including alcohol
- Chemotherapy agents - doxorubicin
- Complications in pregancy
How may dilated cardiomyopathy present clinically?
- Heart failure
- Breathlessness
- Poor exercise tolerance
- Low cardiac output
Describe hypertrophic cardiomyopathy
- The heart becomes big (thick walled) and solid
- A strong contractile force is mainatined
- Outflow obstruction and filling problems may occur due to the heart shape
What are the cause(s) of hypertrophic myopathy?
Genetics
The heart muscle is still relatively functional, just less efficient as heart muscle fibres are less ordered
Describe restrictive cardiomyopathy
There is a lack of compliancy
Filling of ventricles is restricted
Contractile strength and wall thickness is normal - just not relaxation and filling
What are the causes of restrictive cardiomyopathy?
Deposition
Metabolic by products such as:
- Amyloid
- Sarcoid - causes bilateral lymphadenopathy in lungs (granulomatous)
- Tumours (from elsewhere)
- Radiation fibrosis
What is arrhythmogenic right ventricular dysplasia?
- Genetic disease affecting desmosomes
- Right ventricle becomes replaced with large amounts of fat causing inefficiency
What are some symptoms of arrhythmogenic cardiac dysplasia?
- Syncope (funny turns due to low BP)
- Arrhythmia
- Sudden death
What is myocarditis?
Inflammation of the heart
What can cause myocarditis?
Infection due to:
- Viruses
- Bacteria
- Fungi
- Protozoa
- Helminths
Non infectious causes:
- Hypersensitivity reaction to drugs
- Poststreptococcal and rheumatic fever
- Microscopic - Aschoff bodies - granulomatous body in heart
- Systeic lupus erythematosus (SLE)
What is amyloid and why is it bad?
It is abnormal protein deposition which tend to form beta sheets.
Its deposition can obstruct the fucntion of tissues
What is senile cardiac amyloidosis?
A type of restrictive cardiomyopathy
- Passage of electrical impulses can be disrupted causeing ECG abnormalities
- Amyloid deposits can replace normal heart muscle
What is abnormal atrial natriuretic protein?
- Released by atrial cells (localised to atria)
- The protein is a potent vasodilator
- Can stimulate sodium loss and can reduce BP (opposite to aldosterone)
- Accumulation can lead to isolated atrial amyloidosis potentially leading to arrythmias
How can amyloid be identified?
It tests postive for congo red stain and when combined with plane polarised lihgt, it exhibits apple green birefringence (looks green)
What is pericarditis?
Inflammation of the pericardium as a result of infection or other factors
When may pericarditis be present?
- Post MI inflammation
- Uraemia - kidney failure
- Connective tissue diseases (rheumatoid, lupus)
- Friction rub (bread and butter pericarditis)
What is Dressler’s syndrome?
Occurs several weeks after MI
Immune mediated response due to unencountered material being released from damaged heart muscle
What is endocarditis?
Inflammation of endocardium
Infectious endocarditis vegetations. What are these and why are they bad?
Vegetations - aggregates of colonies on valves (composed of bacteria, occasionally fungi)
Can cause emboli by coming lose
Which gram negative bacteria may cause endocarditis?
HACEK
- Haemophilus
- Aggregatibacter
- Cardiobacterium
- Eikenella
- Kingella
Lupus (not gram negative bacteria) can also cause the condition
How does endocarditis usually present?
Right sides murmur
Typically IV drug user - infcetion reaches right side first due to venous injections
During a physical examination, which signs may be indicative of endocarditis?
- Osler’s nodes
- Janeway legions
- Roth spots
- Splinter haemorrhages
- Systemic emboli (brain, lungs and kidneys)
What is marantic endocarditis?
This is a non-bacterial thrombotic endocarditis
How does lupus cause endocarditis?
This condition is called Libman-sacks endocarditis
Small sterile emboli present on the under surfaces of valves or on heart chords.
This can cause lesions (immune complexes/mononuclear cells) to appear
What is carcinoid heart disease?
Involves neoplasms of neuroendocrine cells seen in mucosa (common in GI tract and lung)
Hormones can be released affecting the right heart valves and eventually causing right sided heart failure
Hormones include serotonin, histamine and bradykinin
What are the symptoms of carcinoid heart disease?
- Skin flushing
- Nausea, diarrhoea
- Right side valve disease
- Tricuspid and pulmonary insufficiency
What are deep tumours of the myocardium called?
Rhabdomyomas
(benign)
What is the most common form of heart cancer?
Myxoma
Where are myomas normaly found and why do they cause problems?
Atria
Can cause ball/valve obstruction and also myxoid emboli
Similar presentation to endocarditis (systemic fever, malaise, IL-6 secretion)
What is Carney’s syndrome?
AD condition
Myxomas present in both heart and skin
Usually associated with left atrium
Spotty skin pigmentation may be present
What is the term given to a blood clot within a vessel?
Thrombosis
What is Virchow’s triad and what does it describe?
- Endothelial injury
- Hypercoaguable blood
- Turbuent blood flow (circulatory stasis)
It describes the areas, or conditions, required for thrombosis formation
What is produced at the end point of platelet activation?
Fibrin
GP IIb/IIIa on platelets will bind to what?
Collagen via von Willebrand factor
What are the two pathways for coagulation?
- Intrinsic
- Extrinsic
Describe the intrinsic pathway to coagulation
Begins with Hageman factor (XII) and kallikrein (a protease)
- XII → XIIa
- XI → XIa (also activated by thrombin)
- IX → IXa
- VIII → VIIIa (activated by thrombin, not IXa)
- X → Xa (by VIIIa and IXa)
- V → Va (by thrombin)
- II → IIa (by Va and Xa)
- Fibrin → fibrinogen (by thrombin (factor IIa)
Describe the steps in the extrinsic coagulation pathway
Begins with a tissue injury and the release of tissue factor
- VII → VIIa (by TF - tissue factor)
- X → Xa
- V → Va (activated by thrombin)
- II → IIa (activated by Xa and Va)
- Fibrinogen to fibrin
What is the time taken for the common pathway to occur termed?
Prothrombin time (PT time)
It is used to measure how long blood takes to clot
What is the activated partial thromboplastin time?
This measures how long blood taken to coagulate via the extrinsic pathway
It is used to monitor treatment effects such as heparin
Why is vitamin K essential for coagulation?
It is required to form factors:
- II
- VII
- IX
- X
Which factors may be affected if there is liver disease?
Vitamin K is stored in the liver and is used to make factors II, VII, IX and X
These factors will therefore be produced less
What effect does warfarin have on clotting factors?
It stops production of clotting factors II, VII, IX and X
What may cause endothelial injury in vessels?
- Hypertension
- Toxins (smoking)
- Infectious agents
- Autoimmune disease (primary vasculitis)
- Previous DVT
In which areas of the arterial system is turbulent blood flow more likey and what is the consequence?
Branching regions
This can cause endothelial damage
How is the normal laminar blood flow affected by circulatory stasis?
It is not maintained and blood components move to vessel walls
Why does circulatory stasis increase chances for clotting to occur?
Platelets have increased contact with vessel walls (loss of laminar blood flow)
This increases the likelihood of coagulation
Where does circulatory stasis most often occur?
Deep venous system
(Faulty valves can increase stasis)
Name three anti-clotting proteins and the clotting factors they degrade
- Protein C - degrade factors V and VIII
- Protein S - degrade factors V and VIII
- Antithrombin III - degrade factors II, IX and X
What can plasmin do?
It is an enzyme that can degrade fibrin clots
What may cause hypercoagubility?
- Protein C/S deficiency
- Factor V Leiden (name of specific gene mutation that results in thrombophilia - an increased tendency to form abnormal blood clots occulding vessels)
- Antithrombin III deficiency
What are some secondary causes for hypercoagubility?
- Atrial fibrillation
- MI
- Cancer - tumour can produce TF
- Marantic endocarditis
- Chemotherapeutic agents
- The birth control pill
- Cardiomyopathy
- Smoking
What can an embolism be?
- Air
- Septic
- Amniotic fluid
- Tumour
- Fat
- Thrombus
What is the difference between ischaemia and infarction?
Ischaemia - lack of blood flow and oxygen
Infarction - death of tssue as a result of ischaemia
Why can increased calcium levels in blood lead to tissue damage?
Calcium can stimulate:
- ATPase - aids calcium efflux from cells
- Phospholipase - membrane damage
- Proteases - membrane and cytoskeleton damage
- Endonuclease - DNA damage and breakdown
- Mitochondrial permeability - release of pro-death factors e.g. cytochrome C
Where is thrombosis most likely to occur?
- Sites of turbulence (branching vessels)
- Atherosclerotic areas
Give some sites of branching vessels in the body where thrombosis is likely to occur
- Carotid bifurcation
- Aortic bifuration
- Renal arteries
- Cornonary vessles
- Superior mesenteric artery
