U12C1 Hypertension Flashcards
What is the normal vs abnormal range for blood pressure?
- Normal is a range
• Systolic 90-120 mmHg
• Diastolic 60-80 mmHg
• mean = 70-93 mmHg - Abnormal is a range
• Stage 1: 140/90 < ABP 159/99
• Stage 2: 160/100 < ABP < 180/120
• Stage 3: SBP > 180 or DBP > 120
What are the variants of hypertension?
-
Isolated Systolic Hypertension
• SBP > 140; DBP < 90
• Pulse pressure high
• Most common
• ↓ elasticity of vessels -
Isolated Diastolic Hypertension
• SBP < 140; DBP > 90
• Least common -
Mixed Hypertension
• SBP > 140; DBP > 90
What are the aetiologies of hypertension?
- > 90%: Essential hypertension
• Essential = cause unknown (idiopathic)
• Primary = no clear causative factor - <10%: Secondary hypertension
• Renal disorders → (role of kidneys)
• Endocrine:
• 1° hyperaldosteronism → (fluid regulation)
• Phaeochromocytoma → (sympathetic NS)
• Cushing’s syndrome → (cortisol) -
Drug-induced
• Abuse: e.g., cocaine → (sympathetic NS)
• Iatrogenic: e.g., combined oral contraceptive, glucocorticoids - Pregnancy = pre-eclampsia
What physiologies cause hypertension?
- cardiac output
- peripheral resistance
- autonomic nervous system
- endothelium
- vasoactive peptides
- RAAS
What does EDRF cause?
(endothelium-derived relaxing factor) = nitric oxide (NO) → vasodilation
• ↑guanylyl cyclase → ↑cGMP → ↑PKG → sm. muscle relaxation
• Atheroma → ↓NO production
• Sodium nitroprusside (↑NO) used in hypertensive emergencies
• Sildenafil inhibits phosphodiesterase V (PDEV) → ↑cGMP
What is prostacyclin?
(PGI₂) (lipid)→ vasodilation
• Analogues (e.g., iloprost) used to treat pulmonary hypertension
What is endothelin?
(peptide) → vasoconstriction
• ET receptor antagonists (e.g., macitentan) used to treat pulmonary hypertension
Vasodilators
- Bradykinin → vasodilation
• ACE inhibitors block bradykinin inactivation (see later)
- Natriuretic peptides (A, B & C)
• ANP = Atrial: secreted by atrium
• BNP = Brain: secreted by ventricles (!)
• CNP = C-type
• → ↑Na⁺ & H₂O excretion
• Receptor: NPR1 is a transmembrane guanylyl cyclase
→ ↑cGMP → smooth muscle relaxation → vasodilation
• Dysfunction may → fluid retention & hypertension
Vasoconstrictors
Vasopressin = anti-diuretic hormone (ADH)
• Vasoconstrictor, ↑BP & ↑H₂O reabsorption
What is Liddle syndrome and EnaCs?
What are the non-modifiable risk factors for hypertension?
What are the modifiable risk factors for hypertension?
What is the pathophysiology of hypertension?
What is the short and long term regulations for low blood pressure?
What are baroreceptor reflexes?