Hypertension: Causes, Complications and Treatment

Hypertension: Causes, Complications and Treatment

Hypertension (HTN) is a common health problem that is strongly associated with cardiovascular events, stroke, and chronic kidney disease. A blood pressure (BP) of 115/75 mmHg has the lowest risk of cardiovascular disease. For every 20 mmHg increase in systolic BP or 10 mmHg increase in diastolic BP, the risk of cardiovascular disease and stroke doubles.

Common symptoms of HTN:

• Due to high BP: Headache in the occipital region in the morning, palpitations, fatigue, shortness of breath, blurred vision.

• Due to target organ damage in HTN: Nosebleeds, dizziness due to cerebral ischemia, stroke, heart failure, chest pain, blurred vision, hematuria.

Factors to be explored in patients with HTN (7 characteristics):

• Duration of hypertension.

• Previous treatment (medications, dosage, side effects).

• Use of drugs or substances that increase BP (corticosteroids, oral contraceptives, NSAIDs, salt intake, alcohol, etc.).

• Family history of hypertension.

• History of target organ damage.

• Diet and lifestyle (salt intake, high fat diet, smoking, alcohol, physical activity).

• Family history (cardiovascular disease, genetic conditions like gout, diabetes, kidney disease, etc.).

Indications for home BP monitoring or continuous BP monitoring:

• Suspicion of white coat hypertension.

• Suspicion of masked hypertension.

• Significant variation in clinic BP readings at different visits.

• BP lowering due to autonomic nervous system, posture, after meals, sleep, medications.

General examination of patients with HTN may reveal:

• Obesity, round face in Cushing’s syndrome.

• Upper limbs more developed than lower limbs in coarctation of the aorta.

• Xanthelasma, xanthomas, corneal arcus in cutaneous atherosclerosis.

Cardiovascular examination of patients with HTN may reveal:

• Evidence of left ventricular hypertrophy, signs of left heart failure.

• Intercostal artery pulsation in coarctation of the aorta.

• Palpation and auscultation of arteries to detect carotid artery occlusion in abdominal aortic aneurysm.

Abdominal examination of patients with HTN may reveal:

• Systolic murmur in both flanks in renal artery stenosis.

• Aortic aneurysm.

• Enlarged kidneys, polycystic kidneys.

Neurological examination of patients with HTN may reveal:

• New or old cerebrovascular accidents.

Pseudo-hypertension may occur in:

• Elderly people, patients with diabetes.

• Renal insufficiency due to arterial wall sclerosis leading to hypertension.

How to rule out pseudo-hypertension:

• Osler maneuver (direct BP measurement).

How to rule out white coat effect:

• Continuous BP monitoring.

Basic tests to be performed in all patients with HTN:

• Blood tests (complete blood count, serum creatinine => glomerular filtration rate, fasting blood sugar, electrolyte panel, lipids, ALT, AST, TSH, uric acid).

• Urine tests (urinalysis).

• Imaging tests (ECG, chest X-ray).

Recommended tests to be performed in patients with HTN:

• Echocardiography, carotid ultrasound.

• Fundoscopy.

• Ankle-brachial index.

• Urine protein, urinary albumin quantification.

• CRP.

Urine protein quantification to be done when:

• Protein is positive in urinalysis.

Diagnostic tests for complications in patients with HTN:

• CT scan, MRI brain.

• Coronary angiography.

Tests to find the cause of renal vascular disease in patients with HTN:

• Renal artery ultrasound, renal angiography.

Tests to find the cause of pheochromocytoma in patients with HTN:

• Quantification of urinary catecholamines in 24 hours.

Tests to find the cause of Cushing’s syndrome in patients with HTN:

• Quantification of urinary cortisol in 24 hours, dexamethasone suppression test.

Factors to be considered when diagnosing HTN (4 factors):

• BP values.

• Comorbidities.

• Target organ damage.

• Assessment of cardiovascular risk.

Definitive diagnosis of HTN:

• One of the two:

• BP values:

• At the clinic: >= 140, >= 90.

• At home, 24-hour average daytime BP: >= 135, >= 85.

• 24-hour average nighttime BP: >= 120, >= 70.

• 24-hour average total BP: >= 130, >= 80.

• Currently undergoing treatment for hypertension.

Classification of HTN according to JNC7:

• Normal.

• Prehypertension.

• Stage 1 hypertension.

• Stage 2 hypertension.

BP is < 120, < 80 is considered normal according to JNC7.

BP is 120 – 139, 80 – 89 is considered prehypertension according to JNC7.

BP is 140 – 159, 90 – 99 is considered stage 1 hypertension according to JNC7.

BP is >= 160, >= 100 is considered stage 2 hypertension according to JNC7.

If systolic and diastolic BP are not at the same level, choose the higher level for classification.

Special forms of HTN:

• Isolated systolic hypertension.

• Isolated diastolic hypertension.

• White coat hypertension.

• Masked hypertension.

• Pseudohypertension.

White coat hypertension:

• This is HTN that only increases when measured at the hospital.

Masked hypertension:

• This is the opposite of white coat hypertension.

Causes of pseudohypertension:

• Due to arterial sclerosis.

Males are the main cardiovascular risk factor in patients with HTN.

Smoking is the main cardiovascular risk factor in patients with HTN.

Total cholesterol > 4.9 mmol/L is the main cardiovascular risk factor in patients with HTN.

LDL-c > 3 mmol/L is the main cardiovascular risk factor in patients with HTN.

HDL-c < 1 mmol/L in males, < 1.2 mmol/L in females is the main cardiovascular risk factor in patients with HTN.

Triglycerides > 1.7 mmol/L is the main cardiovascular risk factor in patients with HTN.

Fasting blood sugar 102 – 125 mg/dL is the main cardiovascular risk factor in patients with HTN.

Impaired glucose tolerance is the main cardiovascular risk factor in patients with HTN.

Obesity BMI >= 30 kg/m2 is the main cardiovascular risk factor in patients with HTN.

Abdominal obesity >= 102 cm in males, >= 88 cm in females is the main cardiovascular risk factor in patients with HTN.

Family history of premature coronary artery disease < 55 years in males, < 65 years in females is the main cardiovascular risk factor in patients with HTN.

Cardiac complications of HTN include:

• Left ventricular hypertrophy.

• Left heart failure.

• Coronary artery disease.

• Arrhythmias, sudden death.

Left ventricular hypertrophy is an early cardiac complication of HTN.

Diagnostic tests for left ventricular hypertrophy:

• ECG.

• Chest X-ray.

• Echocardiography.

• MRI, CT, 3D echocardiography.

Other causes of heart failure must be ruled out before diagnosing heart failure as a complication of HTN.

Stages of left heart failure:

• Left ventricular hypertrophy (diastolic dysfunction).

• Asymptomatic left ventricular systolic dysfunction with concentric hypertrophy.

• Asymptomatic left ventricular dilatation with eccentric hypertrophy.

• Heart failure with left ventricular dilatation and eccentric hypertrophy.

Diagnostic tests for coronary artery disease:

• ECG.

• Echocardiography.

• Percutaneous coronary angiography.

HTN causes arrhythmias including:

• Atrial fibrillation.

• Ventricular premature beats.

• Ventricular tachycardia.

Sudden death due to HTN is often due to ventricular arrhythmias.

Left ventricular hypertrophy is an independent risk factor for sudden death.

Cerebral complications of HTN include:

• Cerebral atherosclerosis.

• Cerebral infarction.

• Intracerebral hemorrhage, subarachnoid hemorrhage.

• Dementia.

Cerebral arteries commonly affected by atherosclerosis include:

• Carotid artery, vertebral artery, basilar artery, circle of Willis.

Relationship between HTN and kidney damage:

• HTN damages the kidneys, conversely, kidney disease can also increase BP.

Factors that help diagnose nephrosclerosis as a complication of HTN:

• No underlying kidney disease.

• Persistent stage 2, 3 HTN.

• Family history of HTN onset at 25-45 years of age.

• Retinopathy due to HTN.

• Left ventricular hypertrophy.

• Elevated uric acid.

• Onset of HTN before proteinuria.

• Kidney biopsy.

Vascular complications of HTN include:

• Atherosclerosis (carotid arteries, abdominal aorta, peripheral arteries).

The most important test to detect vascular complications is ultrasound.

The most important test to detect ocular complications is fundoscopy.

Secondary HTN occurs in some diseases including:

• Renal artery stenosis.

• Parenchymal kidney disease.

• Primary aldosteronism (Conn’s syndrome).

• Cushing’s syndrome.

• Pheochromocytoma.

Why does renal artery stenosis cause secondary HTN:

• Renal artery stenosis causes renal hypoperfusion => increased RAAS secretion => increased BP.

Two causes of renal artery stenosis include:

• Fibromuscular dysplasia.

• Atherosclerosis.

Clinical signs that suggest the diagnosis of secondary HTN due to renal artery stenosis:

• HTN < 30 years of age, > 55 years of age.

• Malignant HTN, rapid progression.

• Sudden uncontrolled HTN.

• Widespread atherosclerosis.

• Auscultation of abdominal bruit.

• Unexplained elevation in blood urea nitrogen.

• Acute pulmonary edema with HTN episodes but normal left ventricular function.

• One kidney < 1.5 cm compared to the other.

• Elevated blood urea nitrogen with ACE inhibitor treatment.

Tests to diagnose renal artery stenosis:

• Renal angiography (gold standard).

• Captopril renography.

• Duplex ultrasound of the blood.

• Magnetic resonance angiography.

• Spiral CT scan.

Parenchymal kidney disease is the most common cause of secondary HTN.

Parenchymal kidney disease includes:

• Cystic kidney disease (polycystic kidney disease, medullary cystic disease).

• Glomerulonephritis (acute glomerulonephritis, chronic glomerulonephritis).

• Interstitial nephritis.

• Renal fibrosis.

Why does parenchymal kidney disease cause secondary HTN:

• Due to intravascular volume overload.

• Increased renin secretion => activation of RAAS => HTN.

Clinical symptoms of parenchymal kidney disease:

• Renal insufficiency.

• Hematuria.

• Proteinuria.

Tests to diagnose parenchymal kidney disease:

• Blood urea nitrogen.

• Creatinine, creatinine clearance.

• Urinalysis.

• Renal ultrasound.

Why does primary aldosteronism cause secondary HTN:

• Increased blood Na+, increased circulatory volume, blood volume.

• Increased vascular resistance.

Clinical symptoms of primary aldosteronism:

• Fatigue, muscle weakness (decreased K+).

Tests to diagnose primary aldosteronism:

• Increased Na+, decreased K+.

• Aldosterone/renin ratio (ARR) > 64 pmol/mU.

• Urinary aldosterone level > 12 ug/24h.

• Ultrasound, CT, MRI to detect adrenal tumor.

Clinical symptoms of Cushing’s syndrome:

• Central obesity.

• Facial flushing, subcutaneous vascular dilatation, striae.

• Hirsutism.

• HTN.

Tests to diagnose Cushing’s syndrome:

• 24-hour urinary cortisol quantification, dexamethasone suppression test.

• 24-hour urinary free cortisol quantification, dexamethasone suppression test.

• Plasma cortisol level.

• Cortisol suppression test.

• CT scan of the adrenal glands.

• MRI scan of the adrenal glands.

Why does pheochromocytoma cause secondary HTN:

• Secretion of catecholamines (epinephrine, norepinephrine) => increased heart rate, increased vascular resistance, vasoconstriction, increased BP.

Clinical symptoms of pheochromocytoma:

• Episodic or persistent HTN.

• Headaches, palpitations, sweating, anxiety, tremor.

Tests to diagnose pheochromocytoma:

• 24-hour urinary catecholamines quantification.

• Plasma catecholamines quantification.

• CT scan of the adrenal glands.

• MRI scan of the adrenal glands.

Treatment of HTN:

• Lifestyle modifications:

• Weight loss.

• Dietary changes (DASH diet).

• Regular physical activity.

• Smoking cessation.

• Limiting alcohol intake.

• Stress management.

• Medications:

• Diuretics.

• Beta-blockers.

• ACE inhibitors.

• Angiotensin II receptor blockers (ARBs).

• Calcium channel blockers.

Goals of HTN treatment:

• Reduce BP to below 140/90 mmHg in most patients.

• Reduce BP to below 130/80 mmHg in patients with diabetes or chronic kidney disease.

• Prevent cardiovascular events.

Management of HTN:

• Regular monitoring of BP.

• Medication adherence.

• Lifestyle modifications.

• Follow-up with healthcare provider.

Important points to remember:

• HTN is a serious condition that can lead to life-threatening complications.

• Early detection and treatment are essential for preventing these complications.

• Lifestyle modifications and medications can effectively control HTN.

• It is crucial to follow your healthcare provider’s recommendations for monitoring and treatment.

Note: This is a general overview of hypertension and does not substitute for professional medical advice. It is essential to consult with your healthcare provider for diagnosis and treatment.