Hypotension And Hypertension Flashcards
What is the most common general cause of hypotension?
Loss of blood volume
What are the common ways in which hypotension can occur?
Blood loss due to: Haemorrhage Severe burns / sweating GI tract problems e.g. diarrhoea Unusual kidney losses
What are the other circumstances, other than blood loss, which can result in hypotension?
Allergic reactions
Emotional responses (possibly leading to fainting)
Decrease in cardiac contractility (due to heart attack)
How is hypertension defined?
A chronically increased systemic arterial blood pressure.
Between what values of bp is grade one hypertension?
140/90 - 159/99 mmHg
Between what values of bp is grade two hypertension?
160/100 - 179/109 mmHg
Between what values of bp is grade three hypertension?
Greater than 180/110 mmHg
What is the difference between primary and secondary hypertension?
Primary hypertension - no known cause though may be linked to genetic and environmental factors
Secondary hypertension - caused by another condition such as kidney damage, endocrine disorders, medications
What are the common treatments of hypertension?
ACE inhibitors
Angiotensin II receptor blocker
Beta blocker
Calcium channel blocker
Describe how the myogenic response maintains rate fo blood flow.
A rise in pressure in a vessel causes it to distend slightly so that the smooth muscle of the vessel wall is stretched - the muscle responds by contracting (this is the myogenic response), which narrows the vessels, increasing their resistance and restoring blood floe to its original value
How does the myogenic response work?
5e myogenic response to stretching depends on the activation of specific mechnorcepctor channels which increase the permeability of the membrane to sodium and potassium ions which leads to depolarisation and contraction of the smooth muscle of blood vessel walls
What is functional hyperaemia?
The phenomenon where the metabolic products of a cdll cause vasodilation - these products can be ATP,carbon dioxide and lactic acid for example
80% of patients have primary hypertension rather than secondary hypertension. T/F?
False - it is 90%
What are the risk factors for primary hypertension?
Obesity Increasing age Low level of fitness Moderate or high alcohol intake Metabolic syndromes Diabetes mellitus Black ancestry Poor diet
What are the possible causes of secondary hypertension?
Endocrine disorders such as cushings syndrome, conns syndrome and pharochromocytoma
Renal disease
Vascular pathology
What is the effect of chronic hypertension on the heart muscle?
The left ventricular wall hypertrophies
What are the possible chronic complications of hypertension?
Atherosclerosis Stroke MI Heart failure Renal failure Retinopathy
How do beta adrenoceptor blockers act as antihypertensives?
The block beta one sympathetic tone on the heart and reduce renin release from the kidney
This leads to a decrease in heart rate and stroke volume which decreases cardiac output and thus blood pressure
Give an example of a non selective beta adrenoceptor blocker
Propranolol
Give an example of a beta one elective beta adrenoceptor blocker
Atenolol
What are the possible side effects of beta adrenoceptor blockers?
Intolerance to exercise
Hypoglycaemia
Vivid dreams
Non selective drugs can exacerbate asthma
How do alpha adenoceptor blocks work as antihypertensives?
They decrease sympathetic gone in the arterioles by blocking alpha one receptors which decreases total peripheral resistance to decrease blood pressure
Give an example of a non selective alpha adrenoceptor blocker
Phentolamine
Give an example of an alpha one selective adrenoceptor blocker
Doxazosin
Prazosin
