hypertension

• prevalence of hypertension

  • 1.28 billion adults aged 30-79 worldwide have hypertension
  • approx 20 million in UK have hypertension (>1 in 4); 29% male and 32% female
  • 23-40% in least deprived vs most deprived
• what is hypertension is a major risk factor for in premature death and disability

  • stroke 2x
  • heart disease x3
  • vascular dementia
  • chronic kidney disease

  cardiovascular disease kills 160k people

  • 90% receiving treatment are not controlled to 140/90mmhg
  • costs NHS over 2 billion annually
• WHO diagnostic criteria

  • blood pressure of above 140/90 mmHf (either systolic or diastolic)
  • normotension - less than 140/90 (normal 120/80)

  systolic - contraction of the heart is above 140mmHg

  diastoic - relaxation of the heart is above 90mmHg

  accelerated hypertension - 180/20mmhg or higher and often over 220/120mmHg with signs of retinal haemorrhage and papilloedema - optic nerve swelling
• nice guidelines for diagnosis

  • clinical pressure of 140/90 or higher on average
  • >135/85 on a home ambulatory monitor during waking hours
  • if both met then diagnosis made
• measuring blood pressure

  • sphygmomanometery - cuff, pressure gage, pump, sensor to detect blood flow
  • inflatable cuff around arm above the elbow at same height as the heart, arm supported
  • relax 10-15 mins before
  • cuff inflated up to 180mmHg to extinguish blood flow, stethoscope listens for korotkoff sounds as pressure reduces
  • first heart corresponds to systolic pressure - take reading
  • no longer heard corresponds to diastolic pressure - take reading
  • reading recorded as systolic over diastolic
  • manual and electronic type
• measurement errors

  • incorrrect bladder and cuff size - average width is 12-14cm for adults
  • deflation rate - too rapid to under estimate systolic pressure and overestimate diastolic - too slow means an over estimate of BP
  • arm should be at resting heart heart level and unrestricted - BP increases as arm is lowered
  • take 2-3 readings at least one min apart
• readings and their meanings

  hyportension - 90/60 or lower

  normal - 91/61-139/89

  hypertension - 140/90 or higher

  severe hypertension - 180/20 urgent referral to A&E
• causes of hypertension

  • primary or essential hypertension
  • 90-95% - no identifiable cause
  • secondary hypertension in 5-10%
  • from renal disease - renal artery stenosis, chronic renal failure, renal tumours
  • from endocrine disease - diabetes, hyperthyroidism, cushing syndrome
  • from congential coarctation/ narrowing of the aorta (rare)
  • resistent hypertension where BP fails to be reduced through treatment
  • prevealent hypertension at diagnosis of diabetes with similar ocular conditions

  
• risk factors of hypertension

  behavioural risks

  • smoking
  • unhealthy diet
  • smoking
  • physical inactivity
  • alcohol

  metabolic risks

  • obesity
  • diabetes
  • raised blood lipids - serum cholesterol
  • age
  • ethnicity - afro caribbeans increased risk
  • family history of vascular diseases
• symptoms of hypertension - systemic

  • early = no symptoms
  • can get throbbing headaches, shortness of breath, palpitations, dizziness, fatigue, nose bleeds
• ocular hypertension

  • hypertensive retinopathy - changes to vasculature in retina
  • choroidopathy
  • disc oedema

  associated conditions

  • AION - non arteritis - often reduced VA and swollen disc
  • retinal arteriole and vein occlusions
  • retinal macro aneurysms and retinal emboli
  • ocular motor nerve palsy
  • glaucomatous optic neuropathy
• non pharmacological treatments

  • weight reduction
  • avoid excessive alcohol
  • reduce salt intake - less than 6g daily
  • take regular exercise
  • stop smoking
  • avoid high saturated fat intake
  • reduce caffeine intake
  • eat fruit and veggies
  • usually alongside medications
• common and uncommon medications

  common

  • angiotensin - converting enzyme inhibitors - captopril, ramipril
  • angiotensin receptor blockers - candesartan and losartan
  • calcium channel blockers - amlodpine, verapamil, felodipine
  • diuretuic water tablets - bendroflumethiazide

  less common

  • alpha adrenergic agonists - clonidine
  • beta blockers - atenolol, timolol, propanalol, nebivolol
  • alpha blockers - doxazosin, terazosin
  • direct renin inhibitors - aliskiren
• angiotensin converting enzyme inhibitors

  • prevent action of ACE which acts normally to constrict vessel walls which can raise BP so restricts this to lower it
  • side effects - reduced vision, hallucinations, lids and conjunctival redness, inflammation, brown discolouration, photosensitivity and subconj haemorrhage, paralysis of accommodation and retinal haem
  • ace inhibitors - captopril, lisionopril etc
• angiotensin receptor bockers

  • ARBS - candesartan, losartan, telmisartan
  • blocks action of hormone angiotensin 2 which restricts blood vessel diameter and retains fluids - by blocking can reduce vasoconstriction = vasodilation and reduce fluid levels so lowers BP
  • side effects - few but dizziness, headache and fatigue
• calcium channel blockers

  • CCBS - norvasc, diltiazem
  • act on calcium channels within smooth muscle of the blood vessels to inhibit vasodilation and reduce BP
  • side effects = avoid grapefruit juice, constipation, swollen ankles and foot pain, skin rashes, headaches, dizziness or tiredness
• diuretics - water tablets

  • thiazide like diuretics - chlorthalidone, indapamide
  • increases removal of sodium and water by kidneys to reduce blood volume
  • side effects - transient myopia, reduced tear sensation, colour vision problems; yellow tinge to objects
  • slight reduction in IOP
  • subconj or retinal haem due to drug induced anaemia
• beta adrenergic blockers

  • beta blockers - timolol, atenol
  • blocks beta receptors part of systemic nervous system - B receptors in heart increase cardiac output and in smooth muscles, not clear process but reduced CO reduces BP
  • side effects - reduced vision, hallucinations, decreased IOP, lids or conjunctival redness, inflammation, sub conj haem or dry eye
  • retinal haem
  • paresis of EOM
  • photophobia and ocular pain
• alpha adrenergic agonists

  • clonidine, methyldopa

  targets brain and alters the heart beat to inhibit signals causing vasoconstriction

  side effects - drowsiness, dry mouth, headaches and sleep disturbance

  • nausea, swollen legs and feet
  • lid or conj burning, oedema and dry eye
  • reduced IOP
  • abnormal EOG