Hypertension & Hypotension Flashcards
Name the 5 main types of hypertensives
Angiotensin converting enzyme inhibitor (ACEi) Angiotensin II Receptor Blocker (ARB) Beta adrenoreceptor blockers (B Blocker) Ca channel blocker (CCB) Thiazides
What’s the treatment for hypertension in patients <55?
- ACEi/ARB/B Blocker
- Add CCB/thiazides
- CCB + thiazide
- High dose thiazide/spironolactone or alpha Blocker
What’s the treatment for patients >55 or of afro-Caribbean descent?
- CCB/ Thiazides
2. ACE/ARB
What are the effects of ACEi
Vasodilation
Reduce afterload
Reduced BP
Reduces aldosterone (increased Na+, H20 secretion)
Side effects of ACEi
Persistent dry cough
Hypotension
Hyperkalaemia
NSAIDs used in conjunction with ACEi increase RF risk
Stop medication if patient is in renal failure, has an AKI or renal artery stenosis
Examples of ACEi
Ramipril. Max 10mg, initial 2.5mg OD
Lisinopril: Max 80mg, initial 2.5
Perindopril:
Mechanism of action for B blockers
Blocks B1 adrenergic receptors:
In SAN has negative chronotrophic effect
In myocardium has negative ionotrophic effects (decreases force of contraction)
Side effects of B Blocker
Bronchospasm Fatigue Cold extremities Headaches GI disturbance Sleep disturbance
Contraindication: Asthmatic
Examples of B Blockers
Atenolol: 25-50mg daily
Propanolol: 40mg OD to TD
Metoprolol: IVI max 15mg oral 50-200 mg
Bisoprolol: 10mg daily max. Long term
Mechanism of ARB
Blocks binding of angiotensin II to angiotensin I receptors
Examples of ARB
Losartan (Cozaar)
Candesartan (Atacand)
Valsartan (Diovan)
Olmesartan (Olmetec)
Examples of Calcium channel blockers
Dihydropyridines (Nifedipine and Amlodipine)
Nondihydropyridines (Verapamil and diltiazem)
CCBs mechanisms of action
Prevent calcium entering the heart and blood vessels walls. Thereby preventing contraction and relaxing the heart and blood vessels to relieve BP
Uses of CCB
HTN, Angina, Raynaud’s, AF (nondihydropyridines)
Isolated systolic HTN
Elevated systolic reading (>160 mmHg, 140mmHg-159 bordeline,) with a normal diastolic reading (<90mmHg)
Common causes of secondary hypertension
Vascular
Renal artery stenosis
Coarctation of aorta
Pre-eclampsia
Renal CKD Glomerulonephritis Nephrotic syndrome Obstructive uropathy Polycystic kidney disease
Endocrine Phaeochromocytoma Hyperaldosteronism Cushings Hyper/Hypothyroidism Hyperparathyroidism
Orthostatic/postural hypotension
Systolic BP drop off at least 20mmHg or diastolic BP drop of at least 10mmHg within 3 minutes of standing
Pathophysiology of orthostatic hypotension
When an otherwise healthy person stands, about 700 mL of blood pools in the leg veins and the lower abdominal veins. Venous return to the heart decreases, resulting in a transient decline in cardiac output. This leads to baroreflex-mediated sympathetic activation with an increase in cardiac stroke volume and peripheral vasoconstriction, as well as parasympathetic withdrawal with an increase in heart rate. These rapid haemodynamic changes prevent blood pressure from falling.
Failure of these mechanisms causes orthostatic hypotension.
Typical presentation of orthostatic patient
Light headed, dizzy, weak, faintness, dimming of vision usually doesn’t occur supine.
Parkinsonian features
Cerebellar ataxia from multisystem atrophy (MSA or Shy-Drager syndrome). Ataxia of gait and speech is the most common for MSA
Resting tachycardia-sign of diabetic loss of parasympathetic
Abnormal GI, erectile dysfunction-Autonomic neuropathy
What may elicit orthostatic hypotension
Early in the morning (because of relative volume depletion after overnight fast and pressure diuresis)
In hot environments (because of cutaneous vasodilation)
After meals (because of splanchnic blood pooling)
After standing motionless (because of decreased venous return caused by loss of muscle pump action)
After exercise (because of metabolic vasodilation).
Common causes of orthostatic hypotension
In elderly: Anti-hypertensives Alpha-blockers Diuretics TCA Prolonged bed rest resulting in physical deconditioning
Diabetes and amyloidosis cause autonomic neuropathy
Parkinson’s disease with lewy body dementia
Multiple system atrophy (MSA) commonly have cerebellar ataxia resulting in ataxia of speech and gait
Management of orthostatic hypotension
Lifestyle
Fludrocortisone and NaCl (volume expansion)
Midodrine (presser)
Droxidopa (noradrenaline)
Causes of shock
Cardiogenic: after myocardial infarction, due to cardiomyopathy, valvular abnormalities, or arrhythmias. (pump dysfunction)
Hypovolemic: haemorrhages, burns, GI loss, heat stroke
Distributive (failure of vasoregulation)
Obstructive: PE, cardiac tamponade, tension pneumothorax