Hypertension

Persistent rise of blood pressure above the normal range is called hypertension.^1,2

Or,

A practical definition of hypertension is ‘the level of BP at which the benefits of treatment outweigh the costs and hazards’.^1,3

* ¹Pre-exam preparation for medicine, HN Sarker;  ²Long Cases in Clinical Medicine, ABM Abdullah Page: 210; ³Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 607

Classification according to JNC VII (Joint National Committee)

Type	Systolic BP (mm Hg)		Diastolic BP (mm Hg)
Normal	< 120	and	<80
Pre-hypertension	120 to 139	Or,	80 to 89
Stage 1 hypertension	140 to 159	Or,	90 to 99
Stage 2 hypertension	≥ 160	Or,	≥ 100

* Long Cases in Clinical Medicine, ABM Abdullah; Pre-exam preparation for medicine, HN Sarker

The British Hypertension Society classification –

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 607

Note: There has been a little conflict with Davidson with the classification of blood pressure levels of the British Hypertension Society.

Source: British Hypertension Society guidelines for hypertension management 2004

Hypertensive crises are:

1. Hypertensive emergency and
2. Hypertensive urgency?

Hypertensive emergency or hypertensive crisis:

It means severe elevation of BP (>180/120 mm Hg) with evidence of impending or progressive target organ dysfunction (e.g. hypertensive encephalopathy, aortic dissection and MI, etc.) which should be lowered within 1 hour to reduce morbidity or death.

 

Hypertensive urgency

It means severe elevation in BP without life-threatening target organ dysfunction when BP should be lowered within few hours.

It is characterized by asymptomatic severe hypertension (systolic BP > 220 mm Hg or diastolic BP > 125 mm Hg), optic disk edema, progressive target organ complications and severe perioperative hypertension.

* Pre-exam preparation for medicine, HN Sarker; Long Cases in Clinical Medicine, ABM Abdullah Page: 211

Malignant hypertension is a syndrome associated with an abrupt increase of blood pressure in a patient with underlying hypertension or related to the sudden onset of hypertension in a previously normotensive individual. The absolute level of blood pressure is not as important as its rate of rise.

 

Clinically, the syndrome is recognized based on evidence of high BP and rapidly progressive end organ damage, such as

• progressive retinopathy – grade 3 or 4 (arteriolar spasm, hemorrhages, exudates, and papilledema),
• deteriorating renal function with proteinuria,
• microangiopathic hemolytic anemia, and/or
• hypertensive encephalopathy.

It is a rare complication of hypertension and may complicate hypertension of any aetiology.

There is accelerated microvascular damage with necrosis in the walls of small arteries and arterioles (‘fibrinoid necrosis’) and intravascular thrombosis. This may lead to left ventricular failure and if untreated, death occurs within months.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 212; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 609; Pre-exam preparation for medicine, HN Sarker

Elevated blood pressure during pregnancy or first 24 hour postpartum in the absence of previous chronic persistent hypertension or proteinuria.

* Pre-exam preparation for medicine, HN Sarker

Hypertensive encephalopathy is an acute and transient disturbance of cerebral function due to sudden rise of blood pressure.

* Pre-exam preparation for medicine, HN Sarker

When there is no response to antihypertensive drugs, it is called refractory hypertension.

 * Long Cases in Clinical Medicine, ABM Abdullah Page: 212

An unrepresentative surge/ transient rise in BP when measured in the clinic, particularly by a doctor has been termed ‘white coat’ hypertension.

 

As many as 20% of patients with apparent hypertension in the clinic may have a normal BP when it is recorded by automated devices used at home.

* Pre-exam preparation for medicine, HN Sarker; Long Cases in Clinical Medicine, ABM Abdullah Page: 211; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 608

DASH means dietary approaches to stop hypertension.

* Pre-exam preparation for medicine, HN Sarker

The causes of hypertension are:

1. Essential hypertension > 95%
2. Secondary hypertension <5%.

Note:

In more than 95% of cases, a specific underlying cause of hypertension cannot be found. Such patients are said to have essential hypertension. The pathogenesis is not clearly understood. Many factors may contribute to its development, including renal dysfunction, peripheral resistance vessel tone, endothelial dysfunction, autonomic tone, insulin resistance and neurohumoral factors.

In about 5% of cases, hypertension can be shown to be a consequence of a specific disease or abnormality leading to sodium retention and/or peripheral vasoconstriction.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 607; Pre-exam preparation for medicine, HN Sarker

1. Renal disease
   • Parenchymal renal disease, particularly glomerulonephritis
   • Renal vascular disease
   • Polycystic kidney disease
2. Endocrine disease
   • Phaeochromocytoma
   • Cushing’s syndrome
   • Primary hyperaldosteronism (Conn’s syndrome)
   • Glucocorticoid-suppressible hyperaldosteronism
   • Hyperparathyroidism
   • Acromegaly
   • Primary hypothyroidism
   • Thyrotoxicosis
   • Congenital adrenal hyperplasia due to 11-β-hydroxylase or 17-α-hydroxylase deficiency
   • Liddle’s syndrome
   • 11-β-hydroxysteroid dehydrogenase deficiency
3. Drugs
   • e.g. Oral contraceptives containing oestrogens, anabolic steroids, corticosteroids, NSAIDs, carbenoxolone, sympathomimetic agents
4. Coarctation of the aorta
5. Alcohol
6. Obesity
7. Pregnancy (pre-eclampsia)

 *Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 607; Pre-exam preparation for medicine, HN Sarker

* Netter’s Internal Medicine, 2nd Edition Page: 164

The most common cause of hypertension is ideopathic.

* Pre-exam preparation for medicine, HN Sarker

The second common cause of hypertension are renal diseases.

* Pre-exam preparation for medicine, HN Sarker

The causes are:

• Poor compliance to drug therapy (the most common cause)
• Inadequate therapy
• Failure to recognize an underlying cause like renal artery stenosis or pheochromocytoma.

JNC 7 has defined resistant hypertension as, “the failure to reach BP control in patients who are adherent to full doses of an appropriate three drug regimen including a diuretic”. The following things should be carefully excluded:

• Improper BP measurement.
• Volume overload which may be due to excess sodium intake, renal disease or inadequate diuretic
• Inadequate dose, inappropriate combination of drugs or nonadherence.
• Drug induced hypertension like NSAIDs, steroid, oral contraceptive pills, cyclosporine, tacrolimus, erythropoietin, etc.
• Other secondary causes of hypertension.
• Associated conditions like obesity, excess alcohol intake, etc.

 * Long Cases in Clinical Medicine, ABM Abdullah Page: 212, 213

The clinical features of hypertensive encephalopathy are:

• Abrupt onset
• Slurring of speech
• Blurring of vision
• Paresthesia
• Papilledema
• Disorientation
• Convulsion

* Pre-exam preparation for medicine, HN Sarker

As follows:

• Puffy face:
  • Renal failure.
• Central obesity with plethoric moon face, hirsutism, striae:
  • Cushing syndrome.
• Pulse:
  • Bradycardia suggests raised intracranial pressure,
  • Feeble pulse in lower limbs with radiofemoral delay found in coarctation of aorta.
• Blood pressure:
  • High BP in upper limbs, but low in lower limbs suggest coarctation of aorta.
• Anemia:
  • Suggests chronic renal failure.
• Edema:
  • May be present in renal failure.
• Cardiovascular system:
  • Apex may be heaving and shifted (left ventricular hypertrophy or enlargement),
  • Murmur may be present in coarctation of aorta.
• Abdomen:
  • Bilateral renal mass in polycystic kidney disease, renal bruit in renal artery stenosis.
• Fundoscopy:
  • To see retinal change.
• Bed side urine examination
  • For hematuria and proteinuria.
• Other finding according to suspicion of cause like intracranial space occupying lesion.

* Long Cases in Clinical Medicine, ABM Abdullah

How to measure blood pressure

• Use a machine that has been validated, well maintained and properly calibrated
• Measure sitting BP routinely, with additional standing BP in elderly and diabetic patients and those with possible postural hypotension
• Remove tight clothing from the arm
• Support the arm at the level of the heart
• Use a cuff of appropriate size (the bladder must encompass more than two-thirds of the arm)
• Lower the pressure slowly (2 mmHg per second)
• Read the BP to the nearest 2 mmHg
• Use phase V (disappearance of sounds) to measure diastolic BP
• Take two measurements at each visit

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 608

Investigation of all patients

1. Urinalysis for blood, protein and glucose
2. Blood urea, electrolytes and creatinine
   • N.B. Hypokalaemic alkalosis may indicate primary hyperaldosteronism but is usually due to diuretic therapy
3. Blood glucose
4. Serum total and HDL cholesterol
5. Thyroid function tests
6. 12-lead ECG (left ventricular hypertrophy, coronary artery disease)

 

Investigation of selected patients

1. Chest X-ray:
   • to detect cardiomegaly, heart failure, coarctation of the aorta
2. Ambulatory BP recording:
   • to assess borderline or ‘white coat’ hypertension
3. Echocardiogram:
   • to detect or quantify left ventricular hypertrophy
4. Renal ultrasound:
   • to detect possible renal disease
5. Renal angiography:
   • to detect or confirm presence of renal artery stenosis
6. Urinary catecholamines:
   • to detect possible phaeochromocytoma
7. Urinary cortisol and dexamethasone suppression test:
   • to detect possible Cushing’s syndrome
8. Plasma renin activity and aldosterone:
   • to detect possible primary aldosteronism

* Davidson’s Principles and Practice of Medicine, 22nd Edition

Fasting lipid profile.

* Pre-exam preparation for medicine, HN Sarker

As follows:

1. Age:
   • If young, likely to be secondary cause. If elderly, likely to be primary.
2. Family history:
   • Family history of hypertension, hyperlipidemia, diabetes mellitus, obesity, etc. may be present in case of primary hypertension.
   • In some secondary hypertension, there may be positive family history, e.g. polycystic kidney disease.
3. Past medical history:
   • Previous history of renal disease (hematuria, UTI, renal trauma, pain, pyelonephritis), toxemia of pregnancy (in female).
4. Drug history:
   • Prolong use of NSAIDs, steroids, oral contraceptive pill, etc.
5. History of smoking.
6. Symptoms to find out the secondary cause:
   • Symptoms of renal disease like polyuria, frequency, hematuria, loin pain.
   • Paroxysmal attack of headache, palpitation, flushing and sweating (pheochromocytoma).
   • Polyuria, polydipsia, extreme muscular weakness, tingling (Conn’s syndrome).
   • Weight gain, hirsutism, striae, menstrual abnormality in female (Cushing syndrome).
   • Claudication and cramp in lower limbs in a young patient (coarctation of aorta).
   • Frequent attack of headache, vomiting, visual disturbance, neurological features (intracranial tumor).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 213

Note:

As age is an important factor, consider the secondary causes of hypertension if the the patient is young.

When systolic blood pressure is 140 or more or diastolic BP is 90 or more, the patient is diagnosed as hypertensive.

Note

• A single reading is not sufficient. At least 3 readings in different times should be taken to label as hypertensive.
• BP should be measured at least 5 minutes after the patient has taken rest comfortably in sitting or supine position.
• BP should be measured at least 30 minutes after smoking or coffee ingestion.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 210

Example:

This is most likely to be primary hypertension as the patient is 40 years old with family history of hypertension and there are no history or physical signs suggestive of a secondary cause.

* Short and Long Cases in Clinical Medicine, HN Sarker Page: 260; Long Cases in Clinical Medicine, ABM Abdullah Page: 209

The objectives are:

• To obtain accurate and representative measurements of BP.
• To identify contributory factors and any underlying cause (secondary hypertension).
• To assess other risk factors and quantify cardiovascular risk.
• To detect any complications (target organ damage) that are already present.
• To identify comorbidity that may influence the choice of antihypertensive therapy.

* Pre-exam preparation for medicine, HN Sarker

The following patients should be treated with drugs and lifestyle change:

• Malignant hypertension.
• All patients with a sustained (at least 2 visits) systolic BP ≥ 160 mm Hg and/or diastolic BP ≥ 100 mm Hg (grade 2 or 3 hypertension).
• Patients with systolic BP 140 to 159 mm Hg and/or diastolic BP 90 to 99 mm Hg (grade 1 hypertension) with 10 year cardiovascular (CVD) risk of at least 20% or existing CVD, target organ damage or diabetes mellitus.
• Isolated systolic hypertension (systolic BP >160 mm Hg).

In patients with grade 1 hypertension without 10 year CVD risk of at least 20% or target organ damage should get lifestyle modification and yearly reassessment. Those who have systolic BP < 140 and diastolic BP < 90 mm Hg should be reassessed in 5 years.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 214

Threshold for offering drug treatment –

• BP > 160/100 mm Hg
• Isolated systolic hypertension (systolic BP> 160 mmHg)
• BP > 140/90 mmHg and target organ damage or 10 years CVD 20%.

* Pre-exam preparation for medicine, HN Sarker

1. General measures –
   • Lifestyle modifications to manage hypertension.
2. Antihypertensive drugs.
3. Treatment of underlying cause in secondary hypertension.

Modification	Recommendation
Weight reduction	Maintain normal body weight (body mass index is 18.5–24.9 kg/m2).
Adopt DASH eating plan 1	Consume a diet rich in fruits, vegetables and low-fat dairy products with a reduced content of saturated and total fat
Dietary sodium reduction	Reduce dietary sodium intake to no more than 100 mmol per day (2.4 gm sodium or 6 gm sodium chloride)
Physical activity	Engage in regular aerobic physical activity such as brisk walking (at least 30 min per day, most days of the week)
Moderation of alcohol	Limit consumption to no more than consumption 2 drinks per day in most men and to no more than 1 drink per day in women

* Pre-exam preparation for medicine, HN Sarker

Figure: Antihypertensive drug combinations.

Note:

• Black patients are those of African or Caribbean descent, and not mixed-race, Asian or Chinese patients.
• ¹A = ACE inhibitor or consider angiotensin II receptor blocker (ARB); choose a low-cost ARB.
• ²C = calcium channel blocker (CCB); a CCB is preferred but consider a thiazide-like diuretic if a CCB is not tolerated or the person has oedema, evidence of heart failure or a high risk of heart failure.
• ³D = thiazide-type diuretic.
• ⁴Consider a low dose of spironolactone or higher doses of a thiazide-like diuretic.
• ⁵Consider an α- or β-blocker if further diuretic therapy is not tolerated, or is contraindicated or ineffective.

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 612

• The goal BP is <140/90 mmHg (≤ 140/90 mm Hg²) in otherwise normal individual¹
• In patients with diabetes or renal disease, the goal BP is <130/80 mmHg^1,2
• In case of proteinuria, the target is <125/75 mm Hg.²

According to Davidson –

The optimum BP for reduction of major cardiovascular events has been found to be 139/83 mmHg, and even lower in patients with diabetes mellitus.

The targets suggested by the British Hypertension Society –

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 610, 611; ¹Short and Long Cases in Clinical Medicine, HN Sarker Page: 261; ² Long Cases in Clinical Medicine, ABM Abdullah Page: 214

 

Treatment with Methyldopa or labetalol.

• Other drugs: Calcium channel blocker (nifedipin) may be used. Sometimes, b-blocker may be used but should be avoided in first trimester.
• More severe hypertension or eclampsia may be treated with intravenous hydralazine, even termination of pregnancy may be required.
• ACE inhibitor is contraindicated.
• Diuretic is also avoided (there is risk of uteroplacental blood flow reduction).

* Long Cases in Clinical Medicine, ABM Abdullah Page: 215, 216; Pre-exam preparation for medicine, HN Sarker

The risk of cardiovascular disease in these patients is less than that in patients with sustained hypertension but greater than that in normotensive subjects.

So these patients should be under regular follow-up.

* Pre-exam preparation for medicine, HN Sarker; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 608

• Thiazides or thiazide-like diuretics
  • Thiazide (bendroflumethiazide or cyclopenthiazide).
• ACE inhibitors
  • Enalapril, lisinopril, ramipril.
• Angiotensin II receptor blockers
  • Losartan, valsartan, irbesartan.
• Calcium channel blockers
  • Amlodipine, nifedipine, diltiazem, verapamil.
• β-blockers
  • Atenolol, metoprolol, bisoprolol.
• Others—α-blocker (prazosin, doxazosin), renin inhibitor (aliskiren) and centrally acting drugs, e.g. clonidine.

* Pre-exam preparation for medicine, HN Sarker; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 613; Long Cases in Clinical Medicine, ABM Abdullah Page: 214

Hypertensive emergency

• It needs substantial reduction of BP within 1 hour to avoid the risk of serious morbidity or death.
• Parenteral therapy is indicated in most hypertensive emergencies, especially if encephalopathy is present.
• At first BP should be reduced no more than 25% within minutes to 1 to 2 hours and then it should be gradually lowered to a target level of 160/100 mm Hg within 2 to 6 hours.
• Excessive reductions in pressure may precipitate coronary, cerebral or renal ischemia.

Hypertensive urgency

• Here BP must be reduced within a few hours.
• Parenteral drug therapy is not usually required and slow reduction of BP with relief of symptoms is the goal.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 211

Treatment:

• Slow, controlled reduction of BP over a period of 24 to 48 hours is ideal (Rapid reduction is avoided, as it reduces tissue perfusion and can cause cerebral damage including occipital blindness, may even precipitate coronary or renal insufficiency).
• Complete rest.
• Oral antihypertensive is sufficient to control the blood pressure.
• Sometimes IV or IM labetalol, IV glycerin trinitrate, IM hydralazine, IV nitroprusside may be given with careful supervision.

* Long Cases in Clinical Medicine, ABM Abdullah Page: 212

The target organs of hypertension are:

• Central nervous system
• Eyes
• Heart
• Kidneys
• Blood vessels.

* Pre-exam preparation for medicine, HN Sarker

As follows:

1. Neurological:
   • CVD (intracerebral hemorrhage, sometimes infarction)
   • Carotid atheroma and TIAs
   • Subarachnoid hemorrhage
   • Hypertensive encephalopathy
     • transient disturbances of speech or vision,
     • paraesthesiae,
     • disorientation,
     • fits and
     • loss of consciousness.
   • Papilloedema
2. Ocular:
   • Hypertensive retinopathy
   • Central retinal vein thrombosis
3. Cardiovascular:
   • Ischemic heart disease
   • Left ventricular hypertrophy
   • Atrial fibrillation
   • Acute left ventricular failure
   • Aortic aneurysm and aortic dissection
4. Renal:
   • Renal failure

* Long Cases in Clinical Medicine, ABM Abdullah Page: 212; Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 608, 609

 

Eye complications of hypertension:

1. Hypertensive retinopathy
2. Central retinal vein thrombosis

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 609

Four grades (Keith-Wagener-Barker classification):

Grade 1	Arteriolar thickening, tortuosity and increased reflectiveness (‘silver wiring’)
Grade 2	Grade 1 plus constriction of veins at arterial crossings (‘arteriovenous nipping’)
Grade 3	Grade 2 plus evidence of retinal ischaemia (flame-shaped or blot haemorrhages and ‘cotton wool’ exudates)
Grade 4	Grade 3 plus papilloedema (Grade 3 and 4 indicate malignant hypertension).

* Davidson’s Principles and Practice of Medicine, 22nd Edition Page: 609; Long Cases in Clinical Medicine, ABM Abdullah Page: 213

Hypertension in bronchial asthma:

• Drugs like diuretics, calcium channel blocker, ARB, ACE inhibitor (it may cause cough).
• Avoid β-blockers.

 

 

Hypertension in chronic kidney disease: (Target BP is < 130/80 mm Hg).

• ACE inhibitors and ARB may delay progression of kidney disease (if creatinine is >2.5 mmol/l, these should be avoided).
• Calcium channel blocker may be used.
• Thiazide diuretic may be replaced with loop diuretics.

 

 

Hypertension in diabetes mellitus:

• ACE inhibitor, ARB, calcium channel blocker may be used.
• Avoid thiazide (it aggravates diabetes).
• Avoid β-blocker in patient who is on insulin (it masks symptoms of hypoglycemia).

 

 

Hypertention in peripheral vascular disease:

• Calcium channel blocker.
• Alpha blocker may be an alternative.
• Avoid β-blocker. ACE inhibitor should be used carefully (as the patient may have renal artery stenosis also).

 

 

Hypertension in dyslipidemia:

• Alpha blocker, ACE inhibitor, ARB, calcium channel blocker.
• Avoid β-blocker and diuretic (which worsen lipid profile).

 

 

Hypertension in psoriasis:

• Calcium channel blocker.
• Avoid β-blocker, ACE inhibitor (which aggravates).

 

 

Hypertension in angina:

• Beta blocker, calcium channel blocker, nitrate.

 

 

Hypertension in elderly:

• Thiazide (it is avoided if coexistent diabetes mellitus and gout).
• Calcium channel blocker.

Long Cases in Clinical Medicine, ABM Abdullah Page: 215, 216