Hypertension Flashcards
What are the complications of HT?
HT itself doesn’t do any damage, it is the complications it causes:
- Haemorrhage, stroke, cognitive decline, retinopathy, PVD, LVH, CHD, CHF, MI, renal failure etc –> many complications.
Define HT.
That BP above which the benefits of treatment outweigh the risks in term of morbidity and mortality.
What is the difference between normotensive and hypertensive BP?
Normotensive BP is below 140 mmHg systolic. Hypertensive BP is above 140 mmHg systolic –> 140/90 is hypertension.
Define stage 1 HT.
Clinic BP of 140/90, ABPM of 135/85.
Define stage 2 HT.
Clinic BP 160/100, ABPM 150/95.
Define severe HT.
Clinic systolic BP 180 or over, and diastolic 110 or over –> 180/110.
What are the causes of secondary HT?
- Chronic renal disease: renal artery stenosis, polycystic kidneys
- Endocrine disease: Cushings, Conns etc
- Pregnancy: pre-eclampsia
- Drug-induced: NSAID’s, OCP, corticosteroids
- Vascular: coarctation of aorta
- Sleep apnoae
What are the factors that contribute to HT?
Smoking (adds 10-20 mmHg), DM, renal disease, male, hyperlipidaemia, previous MI/stroke or LVH.
How is BP controlled?
CO, SV, HR and peripheral vascular resistance (TPR).
How does the sympathetic system control BP?
Vasoconstruction, reflex tachycardia and increased CO. Sympathetic system increases BP.
What is the renin-angiotensin-aldosterone system stimulated by?
Fall in BP, fall in circulating BV or Na+ depletion. Renin released from juxtaglomerular apparatus.
What is the function of the RAAS?
Renin converts angiotensin to angiotensin 1. Angiotensin 1 is then converted to angiotensin 2 by ACE.
What are the functions of angiotensin 2?
Vasoconstriction, anti-natruiretic and stimulates aldosterone release from adrenal glands. Aldosterone is anti-diuretic and anti-natruiretic.
What are key targets for HT treatment?
RAAS and sympathetic system.
What are the 2 main causes of HT?
Increased reactivity of resistance vessels and resultant increase in TPR by hereditary causes; or due to kidneys being unable to excrete Na –> Na and fluid are retained, and BP increases.
What other factors contribute to HT?
Age
Genetics and FH: closest correlation between siblings
Environment: mental and physical stress
Na intake/diet: BP
Race: African-American popultions are genetically selected to be Na retainers and so have higher BP than Caucasian populations
Weight: obese patients have > BP, 30% of all HT cases are attributable to obesity alone
Birth weight: low birth weight is associated with development of HT in later life
What would you do before starting treatment for HT?
Assess risk: previous stroke/MI, smoking, DM etc
Assess end organ damage: ECG, echocardiogram, renal function
Screen for treatable causes: renal artery stenosis, Cushings, Conns, sleep apnoea
What does using a ‘stepped approach’ mean?
Adding medications to current therapy until a target BP is achieved - not continuously changing medication.
How should young and elderly people with HT be treated?
Young: high renin and ACE inhibitor
Elderly: low renin, Ca channel blocker and Thiazide-type diuretic
When should stage 1 HT patients be given treatment?
Patients
When should stage 2 HT patients be given treatment?
ABPM > 150/95 at any age.
What is the BP target for > 80 year olds?
Describe the 4 steps of anti-hypertensive drug treatment.
1) Offer with Ca blocker (over 55 or Afro-Caribbean), evidence of heart failure add a thiazide-like diuretic, under 55 do not give ACEI
2) Add thiazide-type diuretic
3) Add CBB, ACEI and diuretic together
4) Consider further diuretic therapy if K+ is 4.5 mmol/L. Over 55? CCB. Under 55? ACEI.
Should ACEI be given during pregnancy?
No, they can cause malformations and stillbirths if given in the first trimester.
Name 2 ACEI’s.
Ramipril and perindopril.
Contraindications: renel artery stenosis, renal failure, hyperkalaemia.
ADR’s: cough, first-dose HT, taste disturbance, renal impairment, angioneurotic oedema.
Drug-drug interactions: NSAID’s, K+ supplements.
What is the advantage of ARB’s over ACEI?
No cough.
Describe the actions of CCB’s.
Block L-type Ca channels. Anti-hypertensive of choice in women of child-bearing age and over 55’s.
Describe the actions of thiazide-like diuretics.
Block reabsorption of Na+ and enhance urinary Na+ loss.
Which drug is mainly used to treat HT in pregnancy?
Methyldopa
Describe treatment regimes for over and under 55’s.
Over 55: start on CCB, add thiazide-like diuretic, add ACEI, add beta-blocker. CTAB
Under 55: ACEI (child-bearing CCB), thiazide-type diuretic, CCB, B-blocker.
What is pre-eclampsia?
When BP rises severely from 20 weeks > 140/90 and patient has proteinuria.
How are patients wiith hypertensive emergency best treated?
Continuous infusion of a short-acting, titratable anti-HT agent.
