Cardiovascular and renal disease review Flashcards
Define hypertension
Chronically elevated blood pressure with SBP of 140mmHg or above or a diastolic bp of 90mmHg or above.
If other risk factors present than bp of 135/85 is HTN
What is transient HTN?
Elevations in systolic pressure are normal- eg fever, exercise, emotional upset etc. Will return to normal when cause is eliminated
What is persistent HTN?
Resulting from conditions such as obesity, cushing’s syndrome (excess cortisol), hyperthyroidism
What is blood pressure?
Pressure exerted by the blood on the walls of blood vessels.
What determines BP?
CO (hr x sv) Peripheral resistance (vessel diameter and length), blood volume, blood viscosity
What is MAP and how do you calculate it
Is the pressure that propels the blood through the tissue. MAP=DBP + 1/3 Pulse pressure
What factors cause an increase in MAP?
An increase in both cardiac output and peripheral resistance increase BP and MAP
What mechanisms regulate BP?
The renin angiotensin aldosterone system; natriuretic peptide release; aldosterone release, ADH
What are the five classes of anti-hypertensive drugs?
Diuretics, beta blockers, CCBs, ACE inhibitors, Angiotensin II receptor blockers
How to CCBs work?
Decrease heart rate and contractibility= lower CO
What causes secondary HTN?
Cause identifiable- renal failure/obstruction of renal arteries, pregnancy, hyperthyrodism
What does HTN cause?
1- Damage to the endothelium of the blood vessels.
2- Thickening of the arterial wall and decreased lumen- increased peripheral resistance
3. An increase in peripheral resistance will increase fat deposits, decreasing the lumen further
What is angina pectoris?
Blockage of the coronary artery may result in intermittent ischemia. Results in severe pain caused by a fleeting deficiency in blood delivery to the myocardium (lack of o2 and increased lactic acid stimulate nerve endings).
Myocardial cells are weakened by don’t die; most commonly occur when stressed or during physical activity when the oxygen requirements of the myocardium are not met.
What is an MI?
Myocardial infarct- heart attack. Death of heart muscle resulting from a blockage of coronary arteries. The blockage deprives the heart of oxygen (ischemia), which causes injury to the heart muscle, chest pain and may result in irreversible death of the heart muscle (infarct). Cannot be relieved by vasodilators and rest.
What is ischemic heart disease?
Caused by an imbalance between the myocardial blood flow and the metabolic demand of the myocardium. Reduction in coronary blood flow may be related to progressive atherosclerosis, with increasing occlusion of coronary arteries.
Blood flow can be further decreased by superimposed events such a vasospasm, thrombosis, or circulatory changes leading to hypoperfusion.
What are causes of atherosclerosis?
Response damage of the tunica intima. Damage may be caused by bloodborne chemicals, HTN, components of cigarette smoke, viral or bacterial infections.
Risk factors= increasing age, kidney disease, lack of exercise, high blood cholesterol, HTN, family hx, smoking, being male, obesity, diabetes, stress
What can be done for atherosclerosis?
If the plaque is still soft an angioplasty or stent may be inserted.
Coronary bypass- one end of the blood vessel is attached to the aorta, other end is attached to coronary artery at the point below the blockage.
What is ST segment depression indicate?
Ischemia
What are cardiac biomarkers?
Troponin T, Creatine Kinase
Is the L or R ventricle the first to suffer from diminished blood supply?
Left- thickest muscle of the heart. Causes back pressure on the lungs, which may result in pulmonary oedema.
What can left ventricular failure result in?
Causes back pressure of the lungs, which may result in pulmonary oedema
Right ventricular failure is?
Failure of the right heart, which outputs blood to pulmonary circulation, causes signs and symptoms in the systemic circulation. Results in back up of blood in venous system
What is the treatment for MI?
Prevention; surgery- angioplasty, stent placement, coronary artery bypass, pacemaker, heart transplant
Medication- streptokinase (acute); beta blockers, diuretics, ACI inhibitors, pain management
What should total cholesterol levels be under?
4mmol/L
What should LDL levels be?
Less than 2
What should HDL levels be?
Greater than 1
What should TC/HDL ration be?
Less than 4
What should triglyceride levels be?
Less than 1.7
What are the five major functions of the kidneys?
- Removal of water and wastes from the blood
- Maintains electrolyte balance.
- Maintains acid-base balance.
- Regulate bp by renin secretion
- Stimulates production of RBCs by EPO secretion
What factors influence GFR?
Total SA available for filtration (number of nephrons); filtration membrane permeability; net filtration pressure (glomerular blood hydrostatic pressure minus the combined pressure of the osmotic and capsular hydrostatic pressure).
What is renal failure?
Decrease or cessation of glomerular filtration. Acute injury refers to an abrupt decrease or cessation of glomerular filtration rate or kidneys stop working. It is reversible if the patient gets correct and prompt treatment.
What are causes of acute renal failure?
Complications of surgery, severe burns, trauma; renal ischaemia caused by blood clots, hypovolemia; drugs (aspirin, ibuprofen, antibiotics); toxins; heatstroke; MOF; sepsis; obstructed urine flow; acute pyelonephritis; kidney stones
What are causes of renal failure?
Lack of blood supply/low bp- shock, burns, severe vomiting/diarrhoea, CF, septic shock
What are the causes of post-renal failure?
Mostly due to back pressure due to obstructions-prostatic hypertrophy, bilateral ureteric obstruction, surgical accident, ruptured bladder, external tumours etc
What are causes of renal failure?
Renal affecting the nephrons directly- ischaemia, toxins, acute glomerulonephritis, transfusion reaction, toxaemia of pregnancy, transplant reaction etc
What are the phases of acute renal injury?
Oliguric- decreased urine output; diuretic- filtration is increased but absorption is impaired; recovery- gradual return to normal functioning.
What are the causes of chronic renal failure?
Diabetes, hypertension, obstructive nephropathy (caused by kidney stones, prostate tumour); kidney disease (chronic glomerulonephritis, pyelonephritis, polycystic kidney disease); renal artery stenosis; lead poisoning; fatty plague deposits (increased cholesterol in kidney artery).
What are the stages of chronic renal failure?
1- diminished renal flow- no signs and symptoms
2- renal insufficiency- waste products build up, inability to concentrate or dilute urine (75% or more nephrons are lost); end stage- oliguria present, wast products build up and treatment required (90% or more nephrons are lost).
What is creatinine clearance rate??
The volume of blood plasma that is cleared of creatinine per unit time
What is creatinine?
Break-down product of creatine phosphate in muscle, usually produced at a fairly constant rate by the body (depending on muscle mass). Produced naturally by the body and is freely filtered by the kidney
What is continuous ambulatory peritoneal dialysis?
A bag of dialysis fluid is drained into the peritoneal cavity though a tenckhoff catheter. The fluid is left in the body for 4-6 hours, while it absorbs the wast products from the blood, though the peritoneum. The fluid is then drained.
This procedure takes 20-30 mins up to 4 times a day.
What is haemodialysis?
Removes waste products from the body by passing it out of the body, through a filtering system (dialyser) and returning it, cleaned, to the body.
The blood flows through tubes made of a membrane that allows the waste products to pass out through it.
The waste products pass through the membrane into a dialysis solution then out of hte machine. The clean blood is carried on through and returned to the body.
What are the necessary diet interventions when on dialysis?
Decreased fluid intake- replace insensible loss only, decreased sodium and potassium, decreased protein, adequate carb/calorie intake
