Causes of Hypertension

Study Notes

Causes of Hypertension

Renal causes: Diabetic nephropathy, Pyelonephritis, Polycystic kidney, Analgesic nephropathy
Renovascular causes: Renal artery stenosis, Endocrinal hypertension
Endocrinal causes: Pituitary (Acromegaly), Thyroid (Hypothyroidism, Hyperthyroidism), Parathyroid (Hyperparathyroidism), Suprarenal gland (Conn's syndrome, Cushing's syndrome, Pheochromocytoma)
CNS, Vascular, Iatrogenic causes: CNS (↑ intracranial tension, Medullary lesions), Vascular (Polyarteritis nodosa, Coarctation of aorta), Iatrogenic (Contraceptive pills, Cortisone, Catecholamines, Calcium, Cabenoxolone, Cyclosporine, NSAIDs, Erythropoeitin)
Pregnancy: Preeclampsia/ eclampsia
Blood: Polycythemia (hyperviscosity)
Obstructive Sleep Apnea: Loud snoring, Witnessed apnea, Excessive daytime somnolence

Symptoms of Hypertension

Asymptomatic in most cases (Silent Killer)
May be discovered accidentally
Headache (occipital), Chest pain, Nocturia, Nausea, vomiting, tinnitus, blurring of vision, epistaxis
Symptoms of cause
Symptoms of complications
Signs of hypertension: BP > 140/90 mm Hg, Signs of cause, Signs of LV hypertrophy, Pulsating aortic area with dilated aorta
Cardiac auscultation: ↑S1 (muscular component), ↑S2 (close or reversed splitting of S2), S3 gallop (LVF), S4 gallop (diastolic dysfunction), Ejection click, Soft ejection systolic murmur, Early diastolic murmur (dilated aortic root)

Definition and Staging of Hypertension

Definition: Persistent elevation of arterial BP > 140/90 mm Hg
Staging of office blood pressure: three stages

Types of Hypertension

Primary (essential, idiopathic) hypertension: About 95% of cases, no known causes, starts between 35-55 years, family history is usually positive, predisposing factors: Genetic, obesity, stress, salt sensitivity, smoking
Secondary (curable) hypertension: About 5% of cases, known underlying cause, starts before 25 and after 55 years, negative family history, rapidly progressive with early complications

Theories of Primary Hypertension

Sympathetic overactivity
Activation of renin-angiotensin aldosterone system
Increased adrenal gland activity → ↑ aldosterone activity
Hyperinsulinemia due to peripheral insulin resistance
↓ atrial natriuretic peptide (ANP)
Baroreceptor re-seting
Multifactorial theory: Strss → ↑ sympathetic → renal ischemia → ↑ renin → ↑ aldosterone → ↑ BP

Complications of Hypertension

Target organs affected: Kidney (renal failure), Heart (LVH, heart failure), Brain (stroke or TIA), Eye (hypertensive retinopathy), Arteries (atherosclerosis, aortic dissection)
Acute complications: Cerebral stroke, hypertensive encephalopathy, subarachnoid hemorrhage, acute pulmonary edema, dissecting aneurysm, acute coronary syndromes, acute renal failure, hypertensive crises

Investigations of Hypertension

For etiology: as secondary hypertension
For complications: Cardiac (ECG, CXR, ECHO), Cerebral (CT, MRI brain), Renal (urinalysis, renal function, renal imaging)

Measurement of BP

Variables that may affect BP: Eating, Emotion, Exercise, Exposure to cold, Empty or full bladder, Smoking, Sympathomimetics (cold remedies)
Blood Pressure Measurement: Sphygmomanometer, Systolic pressure = pressure when 1st sound is heard, Diastolic pressure = pressure when last sound is heard
Blood Pressure Cuff Size: Small – children and small adults, Average, Large – overweight and large adults
Types of sphygmomanometers: Mercury, Aneroid, Automatic (Electronic/Digital)

Description

This quiz covers the various causes of hypertension, including renal, renovascular, endocrinal, CNS, vascular, and iatrogenic causes. Learn about the different conditions that can contribute to high blood pressure.