Hypertension Nov 3, 2006

Hypertension • 20% of Canadians have this. • Only 16% of hypertensives take medication needed to control it. • Sometimes called the “silent killer”. • Hypertensive people lose about 16 years of life on average. • Death is from cardiovascular (e.g. strokes), cardiac and renal diseases.

Hypertension, objectives: 1. 2. 3. 4.

Primary causes Secondary causes Effects Treatment issues.

Hypertension • Systolic pressure – caused by heart’s contraction • Diastolic pressure – between contractions of heart due to resistance of capillaries. • WHO: systolic 160 mm Hg diastolic 95 mm Hg. • 25% of adults exceed this – an example that “normal” is not healthy.

Blood pressure systolic Normal <130 Mild 140-159 Moderate 160-179 Severe 180-209 Very severe >210

diastolic <85 mm Hg 90-99 100-109 110-119 >120

On 2 occasions, 6 hours part. [Note: white coat phenomenon]

Hypertension, clinical: • Blurred vision, • Heart disease – cardiomegaly, ischaemic heart disease (IHD) • Stroke • Renal failure • Nocturia • Epistaxis • Headaches (occiput, throbbing, early morning).

Bp

=cardiac out + peripheral vascular resistance

1. Left ventricular pressure increased. 2. Mineralocorticoids. 3. Fluid load increased.

1. Sympathetic nervous system 2. Hormones: angiotensin, catecholamines

Control of blood pressure: • Aldosterone • Renin-angiotensin • Sodium pump ATP K Na O

K

Na

volume

ADH

Renal blood flow thirst Hypothalamic osmolality

Renin release Angiotensin II

Plasma Na

Aldosterone

Of interest in hypertension: • • • • • • • • •

Alcohol, Stress, Polycythaemia, Oral contraceptives, pregnancy, Diabetes mellitus, Gout, Obesity, Family history, Coarctation of aorta.

Coarctation of aorta

Hypertension’s causes, theories: 1. Prolonged high stress – arterial walls thicken – arteriosclerosis. 2. Sodium intake too high – inability of kidney to eliminate sodium and water load. Note: Chimpanzees. Preliterate societies. Blood pressure and age.

Take blood pressure properly • 2. 3. 4. 5.

Clinical examination: Fundus Pulse Left ventricular hypertrophy Heart sounds.

Systolic hypertension only then • Thyrotoxicosis, • Aortic valve disease • Psychogenic • Anaemia • Polycythaemia. • Could lead to heart failure.

Systolic and diastolic hypertension • “Essential”, primary 96% • Renal – nephritis, diabetes mellitus, renovascular • Endocrine – Cushing’s, Conn’s 1%, Pheochromocytoma < 0.1%. • Central nervous system – raised intracranial pressure. • Coarctation of aorta • Toxaemia of pregnancy.

Hypertension, be wary of: • Obesity, • Alcohol May have role in development of “essential” hypertension • Oral contraceptives • Hypertension could be benign or malignant (accelerated)

Secondary hypertension 1. Renal 2. Drugs – oral contraceptives 3. Aldosterone – Conn’s, Cushing’s, congenital, liquorice 4. Pheochromocytoma 5. Acromegaly 6. Pregnancy - eclampsia

Renal hypertension • Football player hit in lower back. • Headaches • Plasma renin increased

Renal hypertension 10 year old girl with headaches, flank discomfort, puffiness of face, red urine, 2 weeks ago had sore throat, painful swallowing, 39.5oC, swollen tonsils, Cervical lymph nodes enlarged,

10 year old girl, now • 37 C, blood pressure 140/100, pulse 100bpm • Face puffy, ankle and sacral oedema • Urine: • tea coloured (clear yellow) • Protein 1 g/L (0) • Blood large (0) • Microscopy: erythrocytes, casts (0) • Volume 250 mL (1L)

10 year old girl, now • • • • •

CBC: Haemoglobin 120 g/L (115-150) Leukocytes 9.6 x 109/L (4.5-13.5 x 109/L) Platelets 380 x 103/L (150-400) Serum creatinine 285 umo/L (53-97) Serum albumin 35 g/L (32-45)

OC hypertension, 22 year old student • • • • • •

Occipital headache Fuzziness of vision for 5 days On oral contraceptives Pulse 68 bpm, regular Blood pressure 220/130 Fundoscopic exam bilateral hemorrhages and exudates • 4th heart sound • Peripheral pulses normal.

22 year old student, continued: Complete blood count normal serum, sodium 140 mmol/L (135-147) Serum potassium 2.8 mmol/L (3.5-5) Serum chloride 102 mmol/L (95-108) Serum bicarbonate 25 mmol/L (22-30) Serum creatinine 110 umol/L (<110) Urinalysis, abnormal result Protein 1 g/L (0)

Aldosterone, 60 year old man, a known hypertensive • • • • • •

Serum K 2.0 mmol/L (3.5-5) Check for potassium loss Drugs Serum Na Give K supplements to normalize Put on Na 100 mmol/L diet

60 year old, continued: 8 hours in bed then • Blood for • electrolytes, • aldosterone, • renin 30 minutes ambulatory then • Blood for • electrolytes, • aldosterone, • Renin.

Conn’s hyperaldosteronism

Cushing’s, 30 year man, obese, hypertensive • Serum cortisol, no diurnal variation • Insulin hypoglycaemia test – no change in cortisol • Dexamethasone suppression – no suppression • Plasma ACTH < 2 ng/L (7-51)

Cushing’s syndrome

Pheochromocytoma: • 50 year old man • Headaches, palpitations, sweating, irritable, nephritis, diabetes, angina in family. • Blood pressure 190/115 mm Hg • Diuretics – no effect • Beta-blocker – bad effect.

Pheochromocytoma, continued 2, serum tests: • • • • • • • • • •

Sodium 140 mmol/L (135 147) Potassium 3.5 mmol/L (3.5-5) Chloride 102 mmol/L (96-108) Bicarbonate 30 mmol/L (22-30) Urea 5 mmol/L (3-7) Creatinine 120 umol/L (<120) Creatinine clearance 1.5 mL/s/sq m (0.6-1.3) Protein 72 g/L (64-83) Albumin 42 g/L (34-48) Urate 510 umol/L (<450)

Pheochromocytoma, continued 3, serum tests: • • • • • • • •

Thyroxine 108 nmol/L (55-155) Cholesterol 8 mmol/L (<5.2) Triglyceride 4 mmol/L (<1.8) Urinalysis dipstick: glucose ++ (0), protein negative (0). Haemoglobin 156 g/L(135-175) ECG normal chest X ray normal IVP normal

Pheochromocytoma, continued 4, urine tests: • • • • • • • •

Creatinine 12.2 umol/d (7-17) Aldosterone 40 nmol/L (14-66) Vanillyl mandelic acid VMA 60 umol/d (<35) Epinephrine 800 nmol/d (<110) Norepinephrine 1200 nmol/d (<500) Dopamine 2500 nmol/d (<2600) Renin 1.3ng/L/s(slight increase) Cortisol 160 nmol/d (55-250)

Pheochromocytoma

Toxemia of pregnancy: • • • • •

21 year old woman 31 weeks pregnant at 12 weeks blood pressure was 110/70 now 180/110 swollen.

Preclampsia (toxemia) • • • • • • • •

Multisystem disease Spectrum of symptoms Severe systolic bp >160 mmHg diastolic bp >110 Proteinuria > 5g/d (0) Oliguria <400mL/d (>1.5) Central nervous system CNS irritability Pulmonary oedema, cyanosis, epigastric pain, thrombocytopenia, haemolysis, severe liver dysfunction.

Pre-eclampsia, risk factors: Family history First pregnancy Multiple pregnancy Molar pregnancy Hypertensive before Previous toxemia Diabetes mellitus Black, Filipino

Increase in risk 7-11 6-8 5 10 5 1.2-1.5 common increased

Preclampsia tests: • •

Urine protein Renal function tests Sometimes: • Serum urate • Serum calcium • Anticonvulsant used MgSO4 then monitor s-Mg. * {Rarer CBC, LFT, LD in HELLP syndrome}

HELLP, hemolysis, liver, low platelets Measure serum • bilirubin • Lactate dehydrogenase • Aspartate amino transferase • Blood platelets • BP could be normal • 50% are > 170/110.

Hypertension’s effects: 1. 2. 3. 4.

Cardiovascular disease Peripheral vascular disease Cardiac failure Renal failure

HT heart

Hypertension laboratory investigations: • Look for secondary causes • Renal damage • Monitor therapy: • Salt restriction • Exercise • Weight loss • Drugs – thiazides, beta blockers.

Antihypertensive drugs: • • • • • •

Thiazides Loop diuretics Potassium sparing Beta-blockers Calcium channel blockers Angiotensin converting enzyme (ACE) inhibitors.