Hypertension

• Treat all patients with malignant hypertension or a sustained pressure >160/100mmHg
• For those with pressures >140/90 the decision depends upon the risk of coronary and stroke events, diabetes or end-organ damage
• Examples of end organ damage are; LVH, past MI or angina, past stroke or TIA, peripheral vascular disease or renal failure
• For diabetics aim for <130/90 and 125/75 if proteinuria
• Evidence from the Framingham and MrFIT studies indicates that systolic is more important that diastolic in determining risk in the over 50s
• Isolated systolic hypertension
  • Most common form in the UK (>50% of over 60)
  • Results from stiffening of the large arteries (arteriosclerosis)
  • Not benign – doubles risk of MI, triples risk of CVA
• Malignant hypertension
  • Systole >200, diastolic >130mmHg in conjunction with bilateral haemorrhages and exudates (papilloedeam may or may not be present)
  • Symptoms are headache and visual disturbance
  • May precipitate renal failure, heart failure and encephalopathy
  • Untreated 90% die within a year, if treated 70% survive 5 years
  • Pathological hallmark is fibrinoid necrosis

Causes of hypertension;

• Primary hypertension 95%, of unknown cause
• Secondary hypertension;
  • Renal disease
    • Intrinsic renal disease (75%);
      • Glomerulonephritis
      • Polyarteritis nodosa (PAN)
      • Systemic sclerosis
      • Chronic pyelonephritis
      • Polycystic kidneys
    • Renovascular disease (25%)
      • Artheromas
      • Fibromuscular dysplasia (young women)
  • Endocrine;
    • Cushing’s
    • Conn’s
    • Phaeochromocytoma
    • Acromegaly
    • Hyperparathyroidism
  • Others;
    • Coarctation
    • Pregnancy
    • Steroids
    • MAOI
    • ‘the pill’

Examination

• Always examine the CVS and check for retinopathy
• Look for signs of renal disease
• Radio-femoral delay or weak femoral pulses (coartation)
• Renal bruits
• Palpable kidneys
• Cushing’s syndrome
• Look for end organ damage – LVH, retinopathy, proteinuria

Hypertensive retinopathy

• I – tortuous arteries with thick shiny walls (silver or copper wiring)
• II – A-V nipping (narrowing where the arteries and veins cross)
• III – Flame haemorrhages and cotton wool spots
• IV – Papilloedema

Investigations;

• Basic – U&E’s, creatine, cholesterol. Glucose, ECG, urine analysis
• Specific – renal ultrasound, renal arteriography, 24hr urinary VMA, urinary free cortisol, rennin and aldosterone, ECHO

Management

• Look for and treat underlying causes
• Any adult over 50 would benefit from antihypertensives whatever their starting BP
• Reduce BP slowly, rapid reduction may be fatal
• Life style changes
• Drugs
  • If 55 or over and in Black patients 1^st choice is Ca2+ channel blocker or thiazide
  • If <55 1^st choice in an ACEI
  • If initial treatment with ACEI isn’t working add a thiazide or Ca2+ channel blocker, if treatment with those aren’t working add an ACEI
  • If treatment with 3 drugs is required try and ACEI, Ca2+ channel blocker and thiazide
  • If a 4^th drug is needed consider;
    • Increasing doses of thiazine
    • Spironolactone
    • ?-blocker
    • Selective ?-blocker
  • ?-blockers are not first line for hypertension but consider them in young people, if intolerant or contraindicated to ACEI or ARB, if it is a woman of child bearing age or there is increased sympathetic drive
  • If a ?-blocker is initiated and a 2^nd drug is needed add a Calcium channel blocker and not a thiazide to reduce the risk of diabetes

Malignant Hypertension

• Use oral therapy unless there is encephalopathy or CCF
• Aim for controlled reduction in BP in days not hours
• Avoid sudden drops in BP are cerebral autoregulation is poor so stroke risk is high
• Management;
  • Best rest – there is no ideal hypertensive by atenolol and log acting Ca2+ channel blockers may be used PO
  • Encephalopathy – aim to reduce the BP to around 100mmHg diastolic over 4hr
  • Insert intra-arterial line for pressure monitoring
  • Furosemide 40-80mg IV then either
  • IV labetolol or
  • Sodium nitrprusside infusion
  • Never use sublingual nifedipine to reduce BP – large drop in BP and high stroke risk