Day: April 23, 2024

Pulmonary Embolus This is an embolus in the pulmonary circulation, which can impair gas transfer. The most common source is from a deep vein thrombosis (DVT) in the leg. Small emboli are usually clinically silent as the lung has a dual blood supply. Large emboli can give rise to pulmonary infarction causing a myriad of symptoms   Risk factors Immobility – especially abdominal or hip/knee surgery, bed rest, long haul flights Thrombophilia – these include blood disorders, e.g., antiphospholipid syndrome, factor V Leiden (the most common inherited thrombophilia) and malignancy Oestrogen – from the contraceptive pill, hormone replacement therapy, pregnancy

Varicose Veins This is a condition where the superficial veins become tortuous and enlarged. Usually occurs due to valve insufficiency of the leg vein valves, resulting in venous hypertension and dilation   Risk factors Obesity Family history Pregnancy Oral contraceptive pill   Symptoms Most are asymptomatic and only give cosmetic deformity (e.g., twisted superficial dilated veins) Can occur with aching heavy legs with cramps and itching. However, can lead to oedema and eventual ulcer formation with associated symptoms   Management Only should be referred if pain, ulceration or a severe impact on quality of life (not cosmetic) Non-surgical management –

The heart is covered in two layers of pericardium: The outer fibrous pericardium is attached to the central tendon of the diaphragm. The serous pericardium is split into an inner visceral layer and outer pericardial layer. Between these layers, there is a space which contains 15–50 mL of pericardial fluid.    Acute pericarditis This refers to acute inflammation of the pericardium, which surrounds the cardiac muscle.   Causes Infections – TB is one of the most common causes worldwide. Viral infections (Coxsackie) Autoimmune – SLE, rheumatoid arthritis etc. Metabolic – anorexia, hypothyroidism, uraemia (causes “fibrinous” pericarditis) Cardiac – post-MI, Dressler’s

Rheumatic fever This is a complication after being infected with group A β-haemolytic streptococcus. Antibodies directed against the streptococcus pyogenes M-antigen cross react with myosin and smooth muscle. This leads to a systemic condition which occurs in acute attacks, taking about three months to recover. It can also cause chronic inflammation leading to permanent damage to heart valves. It typically causes stenosis of valves (usually mitral) with a “fish mouth” appearance. Symptoms History of previous streptococcal infection (e.g., pharyngitis) Infective signs – fever and arthralgia Cardiac symptoms (e.g., mitral stenosis) may occur after multiple attacks of RF   Key tests

Angina This is the term which is used to describe symptomatic chest pain which occurs due to myocardial ischaemia. In the heart, the coronary circulation fills during diastole. Due to atherosclerosis, over time, the coronary arteries become occluded impeding blood flow to the muscle. It means areas of myocardium become ischaemic, especially in times of greater oxygen demand, which leads to chest pain. To counteract this, the body increases sympathetic stimulation which aims to increase cardiac output. But this worsens the issue as it increases O2 demand further. Hence, when treating angina, the main goals are increasing coronary filling by vasodilation,

  Hypertension (HTN) This refers to raised arterial blood pressure, usually defined as BP > 140/90 mmHg. It is usually asymptomatic but can produce symptoms if the blood pressure becomes very high. Hypertension can be categorised according to the cause:   Primary This is the most common type which occurs due to an unknown aetiology. It is a chronic condition which often develop around middle age and is known as essential hypertension. Risk factors include male sex, age, race, obesity, salt diet.   Secondary This is HTN which occurs secondary to an identifiable aetiology. It is important to remember that

Acute myocarditis (Inflammatory cardiomyopathy) This describes acute inflammation of the myocardium. It is most commonly due to a viral infection. The most common virus is Coxsackie A and B (although usually the causal virus is not identified). The most common cause worldwide is Trypanosoma cruzi (Chagas disease). It can also be due to drugs including ethanol, clozapine and doxorubicin. Half of patients recover in a month whereas many go on to develop dilated cardiomyopathy and heart failure.   Symptoms Patients may have signs of a recent viral infection e.g. fever, joint pain, fatigue Disease mirrors acute coronary syndrome e.g. acute

This is a clinical syndrome consisting of symptoms (e.g., breathlessness, oedema, fatigue) that occurs due to abnormalities in cardiac structure or function, causing inadequate cardiac output or raised intracardiac pressures. Usually, it is due to myocardial dysfunction, but can be due to other causes like valvular disease, pericardial disease or arrhythmias.   Systolic failure This is an inability for the ventricle to contract properly, decreasing cardiac output. In this case, the ejection fraction (EF) is < 40%. It occurs due to conditions which weaken the heart muscle reducing contractility, e.g., ischaemic cardiomyopathy, dilated cardiomyopathy and myocarditis.   Diastolic failure Refers

Rheumatic fever This is a complication after being infected with group A β-haemolytic streptococcus. Antibodies directed against the streptococcus pyogenes M-antigen cross react with myosin and smooth muscle. This leads to a systemic condition which occurs in acute attacks, taking about three months to recover. It can also cause chronic inflammation leading to permanent damage to heart valves. It typically causes stenosis of valves (usually mitral) with a “fish mouth” appearance. Symptoms History of previous streptococcal infection (e.g., pharyngitis) Infective signs – fever and arthralgia Cardiac symptoms (e.g., mitral stenosis) may occur after multiple attacks of RF   Key tests

  Hypertension (HTN) This refers to raised arterial blood pressure, usually defined as BP > 140/90 mmHg. It is usually asymptomatic but can produce symptoms if the blood pressure becomes very high. Hypertension can be categorised according to the cause:   Primary This is the most common type which occurs due to an unknown aetiology. It is a chronic condition which often develop around middle age and is known as essential hypertension. Risk factors include male sex, age, race, obesity, salt diet.   Secondary This is HTN which occurs secondary to an identifiable aetiology. It is important to remember that

Angina This is the term which is used to describe symptomatic chest pain which occurs due to myocardial ischaemia. In the heart, the coronary circulation fills during diastole. Due to atherosclerosis, over time, the coronary arteries become occluded impeding blood flow to the muscle. It means areas of myocardium become ischaemic, especially in times of greater oxygen demand, which leads to chest pain. To counteract this, the body increases sympathetic stimulation which aims to increase cardiac output. But this worsens the issue as it increases O2 demand further. Hence, when treating angina, the main goals are increasing coronary filling by vasodilation,

Regulation of Osmolality The body behaves as if its priorities are to maintain ECF osmolality first and then ECF volume. – Osmolality = the concentration of all solutes in a given weight of water  – Low osmolality means the plasma is more dilute than cells –> this will cause water to move into cells giving “water intoxication” causing brain to swell in the skull. – The major determinant of ECF osmolality is NaCl. However, changing NaCl does not affect the osmolality since water follows sodium – Instead ADH adjusts water excretion independently in order to maintain osmolality   The kidney

In addition to cardiac output, the arterial blood pressure is dependent on the resistance within the circulation. – This is mainly affected by the diameter of the arterioles, which contain smooth muscle in their walls. – The arterioles are capable of constricting and dilating but can be abnormally affected by the presence of atherosclerosis and also which narrow/occlude vessels.   Normal control The arterioles contain a lot of smooth muscle in the tunica media of their walls. – The contractile system of smooth muscle is more complicated as smooth muscle cells do not contain troponin. – An action potential generated

Heart Basics The cardiovascular system is mainly concerned with maintaining a sufficient arterial blood pressure, in order to ensure adequate supply of oxygen and glucose to vital organs like the brain.   There are many factors which affect arterial blood pressure:   The Heart The heart is the organ responsible for matching cardiac output to venous return. It is myogenic, generating its own beat, with external modulation from the autonomic system. Cardiac Action potential: Phase 0: This is the Na current. It is produced by voltage-gated Na+ channels which give a rapid phase of depolarisation   Phase 1: This transient

Varicose Veins This is a condition where the superficial veins become tortuous and enlarged. Usually occurs due to valve insufficiency of the leg vein valves, resulting in venous hypertension and dilation   Risk factors Obesity Family history Pregnancy Oral contraceptive pill   Symptoms Most are asymptomatic and only give cosmetic deformity (e.g., twisted superficial dilated veins) Can occur with aching heavy legs with cramps and itching. However, can lead to oedema and eventual ulcer formation with associated symptoms   Management Only should be referred if pain, ulceration or a severe impact on quality of life (not cosmetic) Non-surgical management –

Hypertension (HTN) This refers to raised arterial blood pressure, usually defined as BP > 140/90 mmHg. It is usually asymptomatic but can produce symptoms if the blood pressure becomes very high. Hypertension can be categorised according to the cause:   Primary This is the most common type which occurs due to an unknown aetiology. It is a chronic condition which often develop around middle age and is known as essential hypertension. Risk factors include male sex, age, race, obesity, salt diet.   Secondary This is HTN which occurs secondary to an identifiable aetiology. It is important to remember that these

The heart is covered in two layers of pericardium: The outer fibrous pericardium is attached to the central tendon of the diaphragm. The serous pericardium is split into an inner visceral layer and outer pericardial layer. Between these layers, there is a space which contains 15–50 mL of pericardial fluid.    Acute pericarditis This refers to acute inflammation of the pericardium, which surrounds the cardiac muscle.   Causes Infections – TB is one of the most common causes worldwide. Viral infections (Coxsackie) Autoimmune – SLE, rheumatoid arthritis etc. Metabolic – anorexia, hypothyroidism, uraemia (causes “fibrinous” pericarditis) Cardiac – post-MI, Dressler’s

The heart is covered in two layers of pericardium: The outer fibrous pericardium is attached to the central tendon of the diaphragm. The serous pericardium is split into an inner visceral layer and outer pericardial layer. Between these layers, there is a space which contains 15–50 mL of pericardial fluid.    Acute pericarditis This refers to acute inflammation of the pericardium, which surrounds the cardiac muscle. Causes Infections – TB is one of the most common causes worldwide. Viral infections (Coxsackie) Autoimmune – SLE, rheumatoid arthritis etc. Metabolic – anorexia, hypothyroidism, uraemia (causes “fibrinous” pericarditis) Cardiac – post-MI, Dressler’s syndrome

Acute myocarditis (Inflammatory cardiomyopathy) This describes acute inflammation of the myocardium. It is most commonly due to a viral infection. The most common virus is Coxsackie A and B (although usually the causal virus is not identified). The most common cause worldwide is Trypanosoma cruzi (Chagas disease). It can also be due to drugs including ethanol, clozapine and doxorubicin. Half of patients recover in a month whereas many go on to develop dilated cardiomyopathy and heart failure.   Symptoms Patients may have signs of a recent viral infection e.g. fever, joint pain, fatigue Disease mirrors acute coronary syndrome e.g. acute