PBL 6

Question 1

What type of drug is Amlodipine? What is its basic effect on the body? What is it prescribed for? (2)

Answer 1

Amlodipine is a long-acting calcium channel blocker. It acts primarily on vascular smooth muscle and dilates the arteries, this lowers blood pressure and makes it easier for the heart to pump blood. As a result, the heart needs less oxygen. It is prescribed for the treatment of hypertension and chronic stable angina

Question 2

What type of drug is bendroflumethazide, in basic terms? What do you prescribe it for? (3)

Answer 2

A thiazide diuretic. It is used in the treatment of hypertension, edema, and urinary tract disorders.

Question 3

At what stage of a heart attack might you use a calcium channel blocker?

Answer 3

After a heart attack, especially in patients who cannot tolerate beta blockers.

Question 4

What type of drug can be used to prevent migrane headaches?

Answer 4

Calcium channel blockers

Question 5

What is the effect of Amlodipine on heart rate?

Answer 5

Other CCBs will slow the heart rate: used for treating abnormally rapid heart rhythms: Amlodipine has little effect on heart rate and so is safer to use in individuals with heart failure or bradycardia.

Question 6

By what mechanism does Amlodipine cause vasodilation?

Answer 6

It stabilises voltage-gated L-type calcium channels in their inactive state.
By inhibiting the influx of calcium in smooth muscle cells, amlodipine prevents calcium-dependent myocyte contraction and vasoconstriction.

Question 7

What type of drug is losartan? What are its basic effects effects on the body?

Answer 7

Losartan is an angiotensin-receptor blocker (ARB). It lowers blood pressure by antagonizing the renin-angiotensin-aldosterone system (RAAS); it competes with angiotensin II for binding to the type-1 angiotensin II receptor (AT1) and prevents the blood pressure increasing effcts of angiotensin II.

Question 8

What common side effect may ACE inhibitors have, and what kind of drug is often prescribed instead?
What are the less common side effects of ACE inhibitors? (6)

Answer 8

ACE inhibitors can cause a dry cough in 1/3 patients so angiotensin-receptor blockers such as Losartan can be prescribed instead.

Other side effects:

• kidney failure. Kidney problems seen in 1/10 patients
• decrease in white blood cells
• swelling of tissues (angioedema)
• elevated blood potassium levels
• low blood pressure, dizziness in about 1/2 patients
• erection problems

Question 9

What conditions can Losartan be prescribed for? (8)

Answer 9

Losartan may be used to treat

• hypertension,
• isolated systolic hypertension,
• left ventricular hypertrophy (enlargement)
• diabetic nephropathy.

It may also be used as an alternative agent for the treatment of

• systolic dysfunction (impaired ventricular contraction)
• myocardial infarction,
• coronary artery disease
• heart failure.

Question 10

What is the Frank-Starling mechanism?

Answer 10

The Frank-Starling mechanism is the ability of the heart to change its force of contraction and therefore stroke volume in response to changes in venous return. So, the more venous return to the heart, the larger the stroke volume - this is becasue the ventricles respond to the higher pressure at the end of ventricular filling (a higher End Diastolic Pressiure EDP) by contracting with more force.

Question 11

What is preload? What tends to be used instead of preload when assessing the heart function?

Answer 11

Preload can be defined as the initial stretching of the cardiac myocytes prior to contraction. Preload, therefore, is related to the sarcomere length. Because sarcomere length cannot be determined in the intact heart, other indices of preload are used such as ventricular end-diastolic volume (EDV) or pressure (EDP). For example, when venous return is increased, the end-diastolic pressure and volume of the ventricle are increased, which stretches the sarcomeres (increases their preload).

Question 12

What is afterload?

Answer 12

Afterload can be thought of as the “load” that the heart must eject blood against. In simple terms, the afterload is closely related to the aortic pressure. More precisely, afterload is related to ventricular wall stress (σ)

Question 13

why are vasodilators/blood pressure reducing drugs given in heart failure?

Answer 13

vasodilation reduces the afterload (closely related to aortic pressure) that the left ventricle has to pump blood against. Lower arterial pressure therefore improves the stroke volume(SV) of the heart and improves cardiac output.

Question 14

What two major categories of high blood pressure are there? What is the definition of high blood pressure?

Answer 14

High blood pressure (hypertension) is designated as either essential (primary) hypertension or secondary hypertension and is defined as a consistently elevated blood pressure exceeding 140/90 mm Hg.

Question 15

What is primary hypertension,
how common is it compared to secondary hypertension?
which ethnic group is it more common in?

Answer 15

In essential hypertension (95% of people with hypertension), no specific cause is found for the hypertension. Essential hypertension may run in some families and occurs more often in the African American population, although the genes for essential hypertension have not yet been identified.

Question 16

What lifestyle factors should be avoided in a person with hypertension? (6)

Answer 16

High salt intake, obesity, lack of regular exercise, excessive alcohol or coffee intake, and smoking may all adversely affect the outlook for the health of an individual with hypertension.

Question 17

What bad outcomes can poorly controlled hypertension lead to? (6)

Answer 17

Poorly controlled hypertension ultimately can cause

• damage to blood vessels in the eye,
• thickening of the heart muscle (enlarged heart),
• heart attacks,
• atherosclerosis,
• kidney failure,
• stroke (becasue of clot or haemorrhage)

Question 18

What classes of drugs are prescribed for high blood pressure? (7)

Answer 18

Several classes of anti-hypertensive medications are available, including

• ACE inhibitors
• ARB drugs
• beta-blockers
• diuretics
• calcium channel blockers
• alpha-blockers
• peripheral vasodilators.

Question 19

Which individuals who have a bp lower than 140/90 would still benefit from lowering their blood pressure? (4)

Answer 19

• Pre-hypertension (bp between 120/80 and 139/89).
• Chronic kidney diseases spill protein into the urine, bp should be lower than 130/80 to slow kidney damage.
• Diabetes, keep bp lower than 130/80.
• African Americans have an increased risk for complications of hypertension, keep bp to less than 135/80.

Question 20

What does the risk of cardiovascular disease double with?

Answer 20

beginning at a blood pressure of 115/75 the risk of cardiovascular disease doubles with each increase in blood pressure of 20/10.

Question 21

What should you check with a patient before you take their blood pressure?

Answer 21

For at least one hour before blood pressure is taken, have they avoided eating, strenuous exercise (which can lower blood pressure), smoking, and caffeine intake.

Question 22

What are the risk factors for developing long term high blood pressure? (8)

Answer 22

• high salt intake (more than 5.8g daily)
• older age
• afro carribean background
• obesity
• lack of excercise
• genetic susceptibility
• kidney failure
• drinking alcohol - higher consumption is more strongly linked with hypertension.
• NOT SMOKING: smoking causes an immediate increase in blood pressure, but is not linked to hypertension: in fact smokers may have lower blood pressure than non-smokers

Question 23

What is creatinine? What fluids can be tested for creatinine and why?

Answer 23

• Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass).
• The creatinine blood test is used to assess kidney function.
• A combination of blood and urine creatinine levels may be used to calculate a creatinine clearance. This test measures how effectively your kidneys are filtering small molecules like creatinine out of your blood.
• Creatinine is chiefly filtered out of the blood by the kidneys (glomerular filtration and proximal tubular secretion). There is little-to-no tubular reabsorption of creatinine. If the filtering of the kidney is deficient, creatinine blood levels rise.

Question 24

What is Borderline high blood pressure? What do you do to check a patient with borderline high blood pressure? (2)

Answer 24

Borderline hypertension is defined as mildly elevated blood pressure higher than 140/90 mm Hg at some times, and lower than that at other times. As in the case of white coat hypertension, patients with borderline hypertension need to have their blood pressure taken on several occasions and their end-organ damage assessed in order to establish whether their hypertension is significant

Question 25

What is renal hypertension? What tends to cause it in the young, what is the cause in the old?

Answer 25

Diseases of the kidneys can cause secondary hypertension. One important cause of renal hypertension is narrowing (stenosis) of the artery that supplies blood to the kidneys (renal artery). In younger individuals, usually women, the narrowing is caused by a thickening of the muscular wall of the arteries going to the kidney (fibromuscular hyperplasia). In older individuals, the narrowing generally is due to hard, fat-containing (atherosclerotic) plaques that are blocking the renal artery.

Question 26

How does narrowing of the renal artery cause hypertension?

Answer 26

First, the narrowed renal artery impairs the circulation of blood to the affected kidney. This deprivation of blood then stimulates the kidney to produce the hormones, renin and angiotensin. These hormones, along with aldosterone from the adrenal gland, cause a constriction and increased stiffness (resistance) in the peripheral arteries throughout the body, which results in high blood pressure

Question 27

When do you start to suspect that hypertension is renal in its origin? How do you go on to make a diagnosis? How might you treat renal hypertension?

Answer 27

Renal hypertension is usually first suspected when high blood pressure is found in a young individual or a new onset of high blood pressure is discovered in an older person. Screening for renal artery narrowing then may include renal isotope (radioactive) imaging, ultrasonographic (sound wave) imaging, or magnetic resonance imaging (MRI) of the renal arteries. The purpose of these tests is to determine whether there is a restricted blood flow to the kidney and whether angioplasty (removal of the restriction in the renal arteries) is likely to be beneficial

Question 28

Renal hypertension is caused by reduced blood flow to the kidneys - but why is the connection between the kidneys and blood pressure more complicated than that? (2)

Answer 28

Any of the other types of chronic kidney disease that reduces the function of the kidneys can also cause hypertension due to hormonal disturbances and/or retention of salt. It is important to remember that not only can kidney disease cause hypertension, but hypertension can also cause kidney disease. Therefore, all patients with high blood pressure should be evaluated for the presence of kidney disease so they can be treated appropriately

Question 29

What are the symptoms of a patient presenting with hypertension? (3 broad stages)

Answer 29

1) Uncomplicated hypertension may be present and remain unnoticed for many years, or even decades. This happens when there are no symptoms, and those affected fail to undergo periodic blood pressure screening. 2) Some people may experience symptoms such as * headache * dizziness * shortness of breath * blurred vision. The presence of symptoms can be a good thing in that they can prompt people to consult a doctor for treatment. 3) Often a person's first contact with a physician may be after significant damage to the end-organs has occurred: * heart attack * stroke * kidney failure * impaired vision (due to damage to the back part of the retina).

Question 30

What is malignant hypertension? How many people with hypertension have malignant hypertension? What are the symptoms?

Answer 30

About one out of every 100 (1%) people with hypertension is diagnosed with severe high blood pressure (accelerated or malignant hypertension) at their first visit to the doctor. In these patients, the diastolic blood pressure (the minimum pressure) exceeds 140 mm Hg! Affected persons often experience severe headache, nausea, visual symptoms, dizziness, and sometimes kidney failure. Malignant hypertension is a medical emergency and requires urgent treatment to prevent a stroke (brain damage).

Question 31

How do you assess the severity of end organ failure in patients with hypertension? (in each of the relevant organs)

Answer 31

* Eyes: may reveal damage; narrowing of the small arteries, small hemorrhages (leaking of blood) in the retina, and swelling of the eye nerve. From the amount of damage, the doctor can gauge the severity of the hypertension. * Heart: look for enlargement of the heart: X-ray, ECG, most accurately with echocardiography * Kidneys: serum creatinine. Look for protein in the urine * Brain: neurological check for stroke; muscle weakness, tingling, speech changes, balance problems

Question 32

What is the normal pattern of blood pressure throughout the day? How do you test whether the patient has a normal pattern?

Answer 32

Blood pressure is normally lower at night while you're sleeping. As soon as you get out of bed, your blood pressure starts to rise. Your blood pressure continues to rise during the day, usually peaking in the middle of the afternoon. Then in the late afternoon and evening, your blood pressure begins dropping again. Test this pattern by ordering a 24 hr blood pressure monitoring test.

Question 33

What are the risk factors for an abnormal blood pressure pattern over the course of the day? (5)

Answer 33

* Night-shift work * Caffeine use * Tobacco use * Too much stress * Taking blood pressure medications that don't last 24 hours

Question 34

Why would you ask a patient to do a 24 hr ambulatory blood pressure test? (7)

Answer 34

* "borderline" high blood pressure * Uncontrolled blood pressure * blood pressure problems caused by medicines * changed of medicine * pregnancy with high blood pressure * fainting spells * To find out if the patient has "white-coat hypertension."