JC10 (Medicine) - Hypertension Flashcards
Etiologies of Hypertension
Essential hypertension (95%): → Environmental: high salt intake, heavy alcohol consumption, obesity, lack of exercise, IUGR → Genetics
Secondary hypertension (5%): distinct, identifiable cause
Pathogenesis of hypertension
Mechanism: complex interplay between neurohormonal mechanisms
- Young patients: predominantly ↑SN and ↑RAAS activities → ↑SVR ↑CO
- Elderly patients: predominantly arterial degeneration → ↑SVR
Chronic hypertension causes target organ damage (TOD) in heart, brain, kidneys, vessels
3 methods of BP monitoring/ diagnosis
Office BP: Average of three readings, risk of masked HTN and White-coat hypertension
Home BP monitoring (HBPM): better adherence and correlation with prognosis
Ambulatory BP monitoring (ABPM): better accuracy and correlation with prognosis
Diagnosis of white-coat hypertension, masked hypertension and true hypertension
High office BP but normal ABPM/HBPM - white coat hypertension
High office BP and high ABPM/HBPM - True hypertension
Normal office BP but high ABPM/HBPM - Masked Hypertension
Cut-off BP for hypertension stages
Diagnosis of true hypertension
□ Hypertensive crisis, i.e. >180/120
□ Evidence of Target organ damage (TOD) + High BP (≥160/100)
□ High office BP (≥130/80) confirmed by HBPM/ABPM
Presentation of hypertension
□ Asymptomatic (incidental finding)
□ ↑BP: headache, dizziness, palpitations, easy fatigability, impotence
□ HTN vascular disease: epistaxis, haematuria, blurring of vision, episodes of weakness/dizziness, angina, dyspnoea
□ S/S of 2o cause
Risk factors of cardiovascular disease
Previous history of CVD
DM
HTN
Low HDL-C <1 mmol/L
Smoking
Age: ≥45y (M) or ≥55y (F)
Premature CHD in first degree relatives
Outline history taking questions for hypertension
□ Age: consider 2oHTN <35y or >55y
□ Duration of HTN and previous BP levels
□ Family Hx of HTN: essential HTN
□ Other risk factors: smoking, DM, lipid disorders, FHx of early CVD deaths
□ Lifestyle: diet, physical activity, family status, work
Outline physical exams for hypertension
□ BP/P: bilateral arms, supine and standing
□ BMI and waist circumference
□ CVS: standard + palpation/auscultation of all peripheral arteries
□ Fundus
Target organ damage (see pic)
First-line investigations for hypertension
Blood:
→ RFT and electrolytes: baseline renal function test, r/o renal parenchymal disease,
→ Hormone: hyperAldosteronmism and hyperPTH
→ Lipid profile for dyslipidemia
→ Serum fasting glucose: r/o DM
→ ± serum urate: baseline and look for hyperuricaemia
Urinalysis: haematuria (r/o renal disease), UACR (albuminuria)
ECG: LVH, MI, cardiac failure, heart block
Echocardiogram: for LVH
Calculation of 10y CVD risk
Causes of secondary hypertension
Aetiology: DANCER □ Drugs □ Apnoea □ Neurological: ↑ICP, stress, others □ Coarctation of aorta
□ Endocrine:
→ Thyroid: hyperthyroidism, hypothyroidism
→ Adrenals: Cushing’s, Conn’s, phaeochromocytoma
→ Parathyroid: hyperparathyroidism
→ Others: pre-eclampsia, acromegaly
□ Renal:
→ Renal vascular: renal artery stenosis (RAS)
→ Renal parenchymal: GN, polycystic kidney, kidney failure
List drugs that can cause secondary hypertension
SN-related/ psychiatric: caffeine, amphetamines/ cocaine, levodopa, MAOI, antidepressants, decongestants
Fluid retention: OCP, anabolic steroids, mineralocorticoids, corticosteroids
Immunosuppressants (cyclosporine)
NSAIDs, COX-2 inhibitors
Alcohol, nicotine
Anti-cancer: chemotherapy, angiogenesis inhibitor, TKIs
Indicators of secondary hypertension
General:
→ Age of onset: <30y or diastolic HTN for ≥65y
→ Severity: accelerated or malignant HTN, disproportionate TOD for degree of HTN
→ Course: abrupt onset, drug-resistant or exacerbation of previously controlled HTN
Specific:
- Unprovoked or excessive hypoK (thiazide diuretics use)
- Renal HTN: palpable kidney, renal bruit, abnormal urinalysis
- Endocrine: S/S of phaeochromocytoma, unexplained hypoK, signs of Cushing’s sundrome
- Coarctation: radiofemoral delay
primary aldosteronism and secondary hypertension
- Clinical features
- Indications for screening
- Screening tests
Renal artery stenosis and secondary HTN
- Clinical features
- Indications for screening
- Screening tests
Renal parenchymal disease and secondary HTN
- Clinical features
- Indications for screening
- Screening tests
OSA and secondary hypertension
- Clinical features
- Indications for screening
- Screening tests
Coarctation of aorta and secondary HTN
- Clinical features
- Indications for screening
- Screening tests
Pheochromocytoma and secondary HTN
- Clinical features
- Indications for screening
- Screening tests
Cushing’s disease and secondary HTN
- Clinical features
- Indications for screening
- Screening tests
List all major target organs damaged by Hypertension
Vessels: Aorta, carotid arteries, peripheral arteries, coronary arteries… etc
Heart: Ventricles, Coronary arteries
Kidneys: renal vessels, tubules
Brain: Cerebral vessels, cerebral edema
Retina
List cardiovascular damage caused by hypertension
List renal and retinal damage caused by hypertension
Renal: Hypertensive nephrosclerosis, Hypertensive nephropathy
Retina: Hypertensive retinopathy, central retinal vein occlusion and blindness
List cerebral damages caused by hypertension
TIA due to carotid atherosclerosis
Stroke due to small vessel hyalinosis or intracerebral haemorrhage from microaneurysms
HT encephalopathy due to cerebral edema
Stages of hypertensive retinopathy
Treatment options for hypertension
Treatment options for hypertension ***
Lifestyle modifications:
- Weight reduction
- Diet: Low sodium, Low fat, High fruit/ vegetables, High K, DASH diet
- Exercise: 30min/day
- Alcohol: moderation ≤2 (M) or ≤1 (F) drinks/day
Medical therapy: Change dose/ combination therapy accordingly
- First line: ACEI/ARB, CCB, thiazide diuretic (+/- BB)
- Second line: Alpha blocker, Aldosterone antagonist or vasodilator
- Adjunctive drugs: Aspirin (lower CVD risk), Statins (hyperlipidemia)
- Substitute drugs: Methyldopa, hydralazine for pregnancy; Loop diuretics for CKD
Compelling indications: DM, CKD, CAD, LV dysfunction, Ischemic stroke
Resistant HTN
- Definition
- Diagnosis
Definition:
- Poor HTN control under 3 antihypertensive with 1 diuretic
- HTN only controlled by ≥4 drugs
Diagnosis: Exclude pseudoresistance: → Adherence → Timing of drugs → Home and ambulatory BP → Exclude secondary hypertension → Identify confounding factors: diet, obesity, drugs
Resistant HTN
- Treatment
Increase dosage of existing therapy
Use second-line drugs: Aldosterone blockers, Loop diuretics
Alter combination of therapy
Malignant hypertension
- Clinical features
ABCDEF:
- Azotemia
- BP ≥220/120
- Cardiac failure
- Distress
- Encephalopathy
- Fundus
Clinical presentation: ↑BP + rapidly progressive TOD
□ Retina: papilloedema, retinal haemorrhages and exudates
□ HTN encephalopathy: severe headache, vomiting, visual disturbances, transient paralyses, convulsions, stupor and coma
□ Heart: acute LV failure
□ Kidneys: acute RF with oliguria, proteinuria
Malignant hypertension
- Mechanism
Mechanism: accelerated microvascular damage including
□ Fibrinoid necrosis in small vessel wall
□ Intravascular thrombosis
Differentiate hypertensive emergency with hypertensive urgency
Hypertensive emergency (i.e. with TOD)
- BP >180/120 + worsening/new TOD
- Indication for acute BP control
- e.g. aortic dissection, pheochromocytoma, eclampsia
Hypertensive urgency (i.e. no TOD)
- Malignant HTN without TOD
- HT with grade III or IV retinal changes
- e.g. Hypertension with pre-op/ perioperative bleeding, Hypertension complicated by pregnancy, AMI, unstable angina
- e.g. Catecholamine excess or sympathomimetic overdose
First-line investigations for malignant hypertension
Ix:
- CBC,
- L/RFT,
- cardiac enzymes,
- aPTT/PT,
- CXR, ECG,
- urine RBC/albumin
Confirm BP twice, BP/P Q1H
Intra-arterial BP monitoring
Treatment of malignant hypertension
- HTN emergency and HTN urgency
HTN emergency:
- IV Labetalol
- Sodium nitroprusside
- Hydralazine
- Phentolamine
HTN urgency:
- Oral antihypertensive: ACBD
Specific treatment for malignant hypertension associated with following conditions
Acute Pulmonary edema
Angina/ AMI
Aortic dissection
Acute pulmonary edema: Nitroprusside/nitroglycerin + loop diuretic
Angina/AMI: Nitroglycerin, nitroprusside, labetalol, calcium channel blocker
Aortic dissection: Labetalol/propranolol IV + nitroprusside
Treatment of malignant hypertension during pregnancy
IV hydralazine, nicardipine, labetalol
Advantages and disadvantages of ABPM and HBPM
ABCDE acronym for cause of HTN
Investigations for target organ damage due to hypertension
Indications for emergency BP reduction with IV treatments
