F222 - Non-infectious disease

When the smooth endothelium becomes damaged phagocytic cells migrate to the damaged area and start to accumulate lipids.

Fatty deposits build up under the damaged endothelium. Smooth muscle cells divide to repair the damaged and form fibrous connective tissue.

Tissue and fatty deposits build up over a very long period of time. This growing plaque narrows the lumen of the artery. Eventually it will break through the endothelium. 

A blood clot or thrombus starts to form narrowing the lumen further. It can continue to grow and can block the artery.

Or the the clot or a piece of it may break off - an embolus - . The embolus travels with the blood until it reaches a part where it can't pass through as the artery is too narrow.  (Often where an atheroma is). 

If a coronary artery is blocked it can lead to a MI (myocardial infraction). This can lead to oxygen starvation to some heart muscle cells and these can die.

Once coronary arteries have become narrowed by an atheroma, less blood can pass through and therefore less oxygen is supplied to the heart  muscle.

During exercise the heart muscle requires more glucose and oxygen and the narrowed arteries cannot supply this. This can lead to a pain called angina pectoris.

The pain is in the front of the chest and can spread down the left arm and up to the jaw.

Symptoms of a heart attack are; severe chest pain, breathlessness, faint, sweating, sense of doom, irregular pulse.

What to do; make the causality comfortable, sit them in a supported position, dial 999, help the causality take their medicine if they have any and then monitor the casualties heart and breathing rate and level of consciousness. 

Be prepared to preform CPR if needed.

Cardiac arrest - occurs when the heart doesn't beat efficiently enough to supply the body with blood. 

Can be caused by - myocardial infraction, overdose and drowning.

Cardio Pulmonary Resuscitation 

Should be applied when there is no pulse and no respiration.

Check the person to see if they are breathing and if they have a pulse. 

If the patient has a pulse but is not breathing then check the airways for a blockage and then carry out rescue breathing.

If not then lay the person on their back, raise legs to help more blood flow to the heart.

Place your hand at the centre of the chest, place the other one on top and interlock your fingers. Keeping arms straight apply pressure about 4-5 cm down then relieve it. 

Repeat it 30 times at a rate of 100 per minute then give 2 rescue breaths, carry on this pattern checking for signs of breathing and a pulse. If a pulse is felt continue with rescue breaths.

Angina is often treated by angioplasty.

A tube (catheter) is inserted into an artery in the groin or the arm.

There is  an inflatable balloon in the end of the catheter.

Once the catheter reaches the narrowed artery the balloon is inflated. It squashes the atheroma and widens the lumen.

Sometimes there is a metal mesh (stent) that is left behind keeping the lumen open.

The catheter and balloon are removed and the stent will be left behind

Coronary bypass surgery is used to treat blocked coronary arteries. 

A piece of vein is taken else where like the leg.

It is then attached to the aorta and to the coronary artery beyond the blockage, therefore bypassing the blocked artery.

Multipul arteries can be bypassed if needed.

The heart is normally stopped during the operation and the patient is put on a machine to pump the blood around the body during the operation.

Heart transplants are used as a last resort as the patient will have to take immunosuppresnt drugs for the rest of their life to prevent their immune system attacking the 'foreign' cells in the heart.

Donor's and patient's must be tissue matches which are hard to find.

A person may be on the transplant list for several months and can die waiting for a match as their is a shortage of organs donated.

It is only used when the heart is very badly damaged and cannot be repaired using other methods.

Diet - HIgh salt and high cholesterol can increase the risk. High amounts of antioxidants and vitamin C decrease the risk.

Blood pressure - High blood pressure can damaged the endothelium in the arteries and result in an atheroma.

Exercise - Lowers blood pressure, cholesterol which lowers risk of coronary heart disease. It can also reduce the chance of developing obesity which is another risk factor for developing coronary heart disease.

Smoking - Raises blood pressure, increases risk of atheroma and blood clot forming and therefore the risk of coronary heart disease increases.

Genetic - Men are more at risk than woman up to the age of menopause, after this it is the same. Also race and certain genes can give people a higher risk of developing coronary heart disease.

Effects of smoking on the lungs

Carbon monoxide from cigarette smoke diffuses through the walls of the alveoli and into the blood. There it combines with haemoglobin and forms carboxyhaemoglobin 

This stays combined with the carbon monoxide preventing it from being able to combine with oxygen and carry it around the body.

Only a small amount of carbon monoxide will reduce the amount of oxygen carried around the body a lot.

The person's heart rate will increase to compensate for the reduced amount of oxygen being carried in the blood.

Chronic - Disease starts slowly but they last for a very long time, they rarely cured.

Acute - Disease happens for a short time and then the person gets better.

Tar from smoke is deposited in the bronchi, bronchioles and alveoli, causing inflammation and the cila hairs to become paralysed. It also stimulates mucus production by goblet cells.

This results in mucus containing dirt and mirco-organisms building up in the lungs. Often resulting in infections. A smoker may develop a persisant cough to try and remove the mucus from the lungs. 

-Mucus reduces the diameter of the bronchi and bronchioles reducing the rate at which air can reach the alveoli.

-Infections can lead to emphysema, reducing surface area for diffusion.

-Mucus build up reduces volume of air alveoli can hold.

-Coughing can damage B,B,A and result in scar tissue narrowing diameter.

-Allergens in the mucus can cause inflammation in the bronchi and bronchioles and reduce the volume of air reaching the alveoli.

Build up of mucus in the lungs and effects caused by smoking can lead to chronic bronchitis. The condition develops over many years.

In a smoker there is often inflammation of the lungs, large numbers of phagocytic cells are attracted to the alveoli. The enzyme elastase is secreted by the cell and it breaks down the elastin in the walls of the alveoli.

As a result the alveoli become damaged and enlarged reducing surface area for diffusion. This causes breathlessness in smokers. Therefore they breathe in more deeply, stretching the elastin in the alveoli - permanently stretching the elastin. This means smokers cannot exhale fully and some air remains in the lungs. Making gaseous exchange less efficient.

As it worsens then a person becomes more disabled. There is no way to reverse the damage. Normally death by respiratory arrest.

People with chronic bronchitis and emphysema are said to have Chronic Obstructive Lung Disease.

Asthma - Membranes lining the airways release mucus and become inflamed, this inflammation causes the muscles of the airways to contract narrowing the airways - called bronchoconstriction. The mucus also blocks the airways. 

Types of asthma 

Allergic - Asthma triggered by allergens When the immune system over reacts eg, fur or pollen. Can be caused by smoking during pregnancy, or children inhaling second hand smoke. (Occurs more in children than adults).

Intrinsic - Triggered by respiratory irritants eg, perfume or cleaning agent. This is harder to treat than allergic asthma. (Occurs more in adults than children).

Exercise-induced - Can affect anyone. Caused by the loss of heat and moisture from the lungs during strenuous exercise. Worsened by cold, dry weather.

Nocturnal - Can be triggered by allergens in the bedding or bedroom.

Occupational - Triggered by inhaling irritants over a long period of time.

Treatment 

Steroids (corticosteroids) are used to reduce inflammation in the lungs. They work slowly but last a long time.

Beta-agonists - They act as bronchodilators, relaxing the muscles in that constrict the airways.

In serve attacks a person is admitted to hospital and steroids will be injected into the bloodstream. Beta-agonists will also be given to stop the muscles in the airways narrowing it. 

The patient may also be given oxygen to help their breathing.