Symptoms and signs of disease Flashcards
What accumulates in ischaemic muscle? Why?
Lactic acid
Lack of oxygen
so anaerobic glycolysis occurs
produces lactic acid
What is the effect of lactic acid accumulation?
Drop in pH
What is the effect of drop in pH?
Substance P is released
What is substance P?
Neuropeptide
What is the effect of substance P?
Increases sensitivity of pain afferents in muscle
What does ischaemia mean?
Ischaemia mean insufficient blood supply to cell, tissue or organ
compared to its requirement
What is the damaging effect of ischaemia?
The lack of oxygen is damaging
Why might someone with uncontrolled thyrotoxicosis develop angina or MI?
Tachycardia
less time in diastole
reduced perfusion of coronary arteries
reduced perfusion of myocardium
Whilst the heart is contracting more often
so actually requires more oxygen
more vulnerable to ischaemia
How do patients often describe ischaemic muscle pain?
Tight, constriction, vice-like
Heavy, crushing, cramping, pressing, pressure
Tearing
Choking in throat
When might a patient describe tearing pain?
Dissection of blood vessels
What gestures do patients often make to describe anginaa?
Clenched fists, sometimes placed over chest
Hand over chest
Whest gestures do patients often make to describe itntermittent claudication?
Hand pressed over calf
What are the outcomes of cardiac muscle ischaemia?
Stable angina
Unstable angina
MI
What is referred pain?
Pain located away from actual organ that is causing pain
What are the sites of cardiac referred pain?
Left ear Jaw Neck Arms Central abdomen
Why does chest pain in stable angina increase with exercise and stress?
Increased sympathetic activity
Increased heart rate, force of contraction
Reduced time in diastole, reduced perfusion of coronary arteries, myocardium
But heart is working harder so actually demands more oxygen
More prone to ischaemia
Why does chest pain in stable angina increase with cold weather?
Peripheral vasoconstriction
Increases resistance, TPR
Increased afterload
Heart has to contract harder, generate higher pressures in order to pump blood into aorta
Why does chest pain in stable angina increase after a meal?
Blood is redirected to the gut
reduced blood supply to heart
Why is chest pain in stable angina relieved with rest?
Increased parasympathetic activity
Reduced heart rate, force of contraction
More time in diastole for perfusion of coronary arteries, myocardium
And heart has reduced demand for oxygen
Why is chest pain in stable angina relieved with GTN?
Generates nitric oxide
Vasodilates veins and collateral coronary arteries
Veins hold more blood, reduced preload
How is unstable angina different to angina?
Chest pain occurs at rest
More intense
May last longer
Does not respond to GTN
What are the ECG features of unstable angina?
ST segment depression
T wave inversion
What are the levels of cardiac markers in unstable angina?
Cardiac markers are normal
Because no cell death has occurred
What can unstable angina lead on to?
MI
How is MI different to angina?
More intense than angina pain
How does a patient with MI present?
Sweaty Nauseated Dyspnoeic Pale Clammy
Why is a patient with MI pale and sweaty/clammy?
Due to increased sympathetic activity
What is a palpitation?
Noticeable rapid, strong or irregular heartbeat
When might palpitations occur?
Exercise Stress Night - more aware of heartbeat Caffeine Smoking, alcohol, drugs
What can palpitations be associated with?
Dizzyness
Loss of consciousness
Why are palpitations associated with dizziness, loss of consciousness?
Reduced cardiac output
Reduced blood supply to brain, CNS
becomes hypoperfused
What causes palpitations?
Arrythmias
Which arrythmias can cause palpitations?
Sinus tachycardia
Atrial or ventricular ectopic beats
Atrial tachycardias
Ventricular tachycardia, fibrillation
What are the different types of atrial tachycardias?
Supraventricular rhythms
Atrial flutter
Atrial fibrillation
What is dyspnoea?
Breathlessness
What causes dyspnea in terms of cardiac ischaemia?
Pulmonary oedema
What causes pulmonary oedema?
Blood backing up in pulmonary veins Increases hydrostatic pressure More loss of fluid than intake Fluid builds up in alveoli Reduces gas exchange
What is orthopnea?
Breathlessness when lying flat
What is paroxysmal nocturnal dyspnoea?
Attacks of shortness of breath at night
Why do orthopnea and paroxsymal nocturnal dyspnoea occur?
Fluid in lungs spreads out in alveoli and lungs
rather than being pooled at the bottom
Equal effect of gravity over body
get increased venous return to right side of heart
more blood enters pulmonary circulation
increases hydrostatic pressure further in pulmonary vessels…
Why are orthopnea and paroxysmal nocturnal dyspnoea relieved by sitting up?
Fluid pools at bottom of alveoli and lungs again
Effect of gravity
reduced venous return to right side of heart
What is another cause of dyspnoea and it being worse at night?
Asthma
Which arrythmias in particular may lead to loss of consciousness?
Ventricular tachycardia
Ventricular fibrillation
What is postural hypotension?
Low blood pressure when standing
How can you tell that an arrythmia was the cause of loss of consciousness?
Had palpitations before, during or after the loss of consciousness
What is actually being felt when feeling a pulse?
The change in pressure that arrives before the blood itself
What should be assessed when taking a pulse?
Rate
Rhythm
Quality
What is the normal pulse rate?
60-100 per minute
What are the different types of pulse rhythms?
Regular
Regularly irregular
Irregularly irregular
Give an example of a regularly irregular arryhthmia. Why is it regularly irregular?
Second degree heart block
Not in sinus rhythm, so it’s irregular
but has a pattern, so it’s regularly irregular
Give some examples of irregularly irregular arrythmias. Why are they irregularly irregular?
Atrial fibrillation
Atrial ectopic beats
Ventricular ectopic beats
Because not in sinus rhythm, so are irregular
And they occur randomly, no pattern, so are irregularly irregular
What is the pulse pressure? - can be measured in aorta
Difference between diastolic and systolic pressure
ESP - EDP
How does atrial fibrillation affect pulse pressure?
Pulse pressure varies with AF
due to depolarisation and contraction of ventricles occurring irregularly
different heart rate, time in diastole
get different EDVs, EDPs
How do ventricular ecoptic beats affect pulse pressure?
Compensatory pause before normal heart beat
increased time in diastole, EDV, EDP
gives bounding heart beat and pulse
What causes a bounding pulse?
Lower EDP usually
- low TPR
- bradycardia
- aortic regurgitation
How does low TPR cause a bounding pulse?
Reduced pressure in arteries
more blood flows out of aorta into arteries
lower pressure in aorta
so get reduced end-diastolic pressure
What can cause low TPR?
Exercise
Pregnancy
How does bradycardia cause a bounding pulse?
More time in diastole
more time for more blood to leave aorta
lower pressure in aorta
lower end-diastolic pressure
How does aortic regurgitation cause a bounding pulse?
Aortic valve is incompetent Backflow of blood from aorta into LV during diastole less blood in aorta lower pressure in aorta lower end-diastolic pressure
What are the causes of a thready pulse?
Shock
Left ventricular failure
