pathology of hypertension Flashcards
What are the pathological complication for hypertension?
- cerebral haemorrhage
- atheroma
- renal failure
- sudden cardiac arrest
What percentage of the population are hypertensive?
25%
What is white coat hypertension?
increased BP due to hospital setting
What is hypertension?
a disorder in which the level of sustained arterial pressure is higher than expected for the age, sex, and race of the individual’
What are key epidemiological points to do with hypertension?
- Varies between countries
- Higher in black populations
- Lower in South Pacific
- Familial tendency
- Rises with age
How do you classify hypertension according to cause?
- primary hypertension (unknown cause)
- secondary hypertension (known cause)
How do you classify hypertension according to consequences?
- benign hypertension (often primary)
- Malignant hypertension (often secondary)
What is the equation for blood pressure?
CO x peripheral resistance
How does peripheral resistance occur?
Narrow arterioles cause decrease in blood flow due to resistance. This generates BP
What does further narrowing of arterioles cause?
increase BP
Describe RAAS
- Renal blood flow increases causes release of renin
- converts angiotensin to angiotensin 1
- which circulates the blood into lungs
- where meet angiotensin converting enzyme
- which transforms angiotensin 1 to angiotensin 2.
- This then causes vasoconstriction and releases aldosterone
- which causes salt and fluid to remain in body.
what effect has salt got on BP?
increases BP
What are key characters of primary hypertension?
- 90% of cases
- No obvious cause
- Genetic factors (twin studies)
- Salt intake -25% salt sensitive
- Protein intake
- Renin - Angiotensin system
- Sympathetic activity
What causes secondary hypertension?
- renal disease
- endocrine disease
- aortic disease
- renal artery stenosis
- drug therapies ( steroids)
What are the renal causes of hypertension?
Anything that destroys the kidney causes
- reduced renal blood flow
- excess renin release
- salt and water overload
What is Chronic pyelonephritis ?
Dysfunction of ureters, leading to disruption to renal blood flow and hypertension leading to stroke
What are endocrine causes of hypertension?
- Adrenal gland hyperfunction / tumours
- Conn’s syndrome - excess Aldosterone
- Cushing’s syndrome - excess corticosteroid
- Phaeochromocytoma - excess noradrenaline
What are other causes of hypertension?
- coarctation of the aorta
- drugs including corticosteroids
What is coarctation of the aorta?
congenital narrowing of segments of the aorta
Describe bening hypertension
- slow process
- cause of serious life threatning morbidity
- If left untrrated will affect heart kidneys and circulation
What conditions can benign hypertension cause?
- Left ventricular hypertrophy
- Congestive cardiac failure
- Increases atheroma
- Increases aneurysm rupture - aortic dissection, Berry aneurysms Renal disease
What does left ventricular hypertrophy cause?
- INCREASED LV LOAD
- POOR PERFUSION
- INTERSTITIAL FIBROSIS
- MICRO-INFARCTS
- DIASTOLIC DYSFUNCTION
What other things can left ventricular hypertrophy cause?
-SUDDEN CARDIAC DEATH
ARRHYTHMIA AND POOR PERFUSION
-CARDIAC FAILURE
What is the difference in aorta in normal patients and hypertensive patients?
- normal - smooth pink wall
- hypertension - rough yellow.
Hypertensions predisposes to and complicated atherosclerosis
What damage does hypertension cause to microvascular injury?
changes in blood vessel wall- small arteries and arterioles
- thickening an hardening of muscle walls
- hyaline arteriosclerosis
Where does most microvascular injury occur?
retina and kidney
What is hyaline arteriosclerosis?
plasma proteins forced into vessel wall (cf ageing)
What is the main damage hypertension does to the retina?
haemorrhage
Describe malignant hypertension
- serious
- immediate treatment
- Diastolic pressure >130-140
- can be caused by primary or secondary hypertension
What are the complications of malignant hypertension?
- Causes cerebral oedema - seen as papilloedema (swelling of optic disc)
- Acute renal failure
- Acute heart failure
- Headache and cerebral haemorrhage
- Blood vessels show fibrinoid necrosis and endarteritis proliferans of their walls
What dies the vessels look like under the microscope?
swirling mass of endothelial cells - no lumen , vessel haemorrhage
What happens in pregnancy associated hypertension?
- Common up to 10% pregnancies
- Increased maternal and fetal morbidity and mortality
- Pre-eclampsia – hypertension and proteinuria
- Resolves following birth
- Eclampsia – obstetric emergency
- Hypertension secondary to silent renal or systemic disease
