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Hypertension, or high blood pressure, is a very common chronic condition, affecting 20-25% of adults. It is also very serious, being one of the leading causes of cardiovascular disease. It is estimated to be responsible for over 7 million deaths worldwide annually (Perkovic et al, 2009), or 13% of deaths worldwide (ref).
The lifetime risk for hypertension among middle-aged, normotensive adults is around 90% (Vasan et al, 2002). In Ontario, age- and sex-adjusted prevalence has increased 60% from 1995 to 2005, while incidence increased 26% (Tu et al, 2008).
Hypertension is diagnosed with blood pressure readings over 140 systolic or 90 diastolic on at least three occasions.
Normal blood pressure is less than 120 systolic and 80 diastolic, while prehypertension is between 120-139 systolic and 80-89 diastolic.
The JNC-V (Pogue et al, 1996) criteria ranks hypertension as:
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
A specific cause of hypertension is found in 10-15% of patients. The other 85-90% is termed essential, meaning no other medical reason is present. Contributing factors to essential hypertension are thought to include:
It is more likely if HT onset is <30 or >55, if there is a poor response to treatment, if increase is accelerated, or if there are further clinical signs (electrolyte abnormalities, renal bruits, etc).
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medications and illicit drugs
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White coat syndrome
pseudohypertension: calcified brachial arteries
Peripheral resistance is increased by the sympathetic nervous system, hormines such as aldosterone, thyroid hormone, and insulin, as well as paracrine signals including prostaglandins, endothelin, and nitric oxide.
A reduced baroreceptor response also occurs. There is increasing evidence that essential hypertension may be a primary defect in sodium excretion by the kidney, leading to increased intravascular volume (ref).
Hypertension induces structural changes to the vasculature through hypertrophy of resistance vessels. Endothelial dysfunction includes reduced nitric oxide and increased endothelin.
It is speculated that excess insulin, as occurs in insulin resistance, may play a role in sodium retention, blood volume expansion, excess norephinephrine production, and smooth muscle proliferation. Hyperglycemia itself also leads to endothelial cell dysfunction, adding to the doubled rates of hypertension in people with diabetes.
Systolic pressure rises with age, though the diastolic does not. The elderly often show isolated systolic hypoertension.
As over 40% of people with hypertension do not know it (Joffres et al, 1997), it is termed 'the silent killer'. However, people may have an occipital headache on awakening, or can complain of vision changes.
Sudden onset would suggest renovascular hypertension.
History should be focused on symptoms of organ damage caused by hypertension:
Vascular disease can also point towards renovascular causes for hypertension.
family history
medications
social history
head and neck
cardiovascular exam:
abdominal exam:
skin
Lab investigations for everyone with hypertension include:
Other tests should be done for specific patient subgroups, and include:
ECG for left ventricular dysfunction.
Renal ultrasound if creatinine elevated or other evidence of renal disease.
MRA if renal artery stenosis
or renal captopril scan
Intensive control of blood pressure, lipid levels, and hyperglycemia can save the health care system money while preventing death and disability GET STATS (CDC, 2002). There has been remarkable improvement in hypertension control in recent years, with rates ranging from 25-82% (Mohan and Campbell, 2008).
Lifestyle measures are incredibly important in preventing and reducing hypertension. These include:
All pharmacological approaches to lowering blood pressure interfere with normal mechanisms of blood pressure regulation.
Combination therapy is increasingly being shown to improve blood pressure. The most important step is to gain buy-in by patients.
Various classes of medication include
Specific situations
A simple algorithm appears very helpful (Feldman et al, 2009):
Medications can be costly, but unnecessarily so. A 25 mg dose of thiazide can be bought for 0.3 cents US (Perkovic et al, 2007). All people of Africa with a 10-year risk of a major cardiovascular event could be treated for ~$20M, making the estimated cost of preventing each major event approximately $200 (Perkovic et al, 2007).
Nonadherence to plan is important. Reasons can include:
Resistant hypertension is defined as...
It is more common in:
Assess for non-adherence to lifestyle and pharmacological strategies, as well as secondary causes.
Options for managing resistant hypertension include:
Hypertension is a key contributor to disease in society. Nearly 2/3 of strokes and 1/2 of ischemic heart disease is directly attributable to it (Lawes et al, 2006).
Even mild hypertension, slightly above 140/90, if sufficiently prolonged, increases the demands of the heart, which adapts with concentric hypertrophy. This can lead to myocardial dysfunction, ischemic heart disease, atrial fibrillation, heart failure, or sudden death.
Cerebral ischemia or hemorrhagic stroke is most commonly caused by hypertension.
Other vascular conditions can include aneurysm, aortic dissection, or peripheral artery disease.
Even a 2 mmgHg reduction can lead to substantial reductions in mortality (ref).
Hypertension is one of the most common causes of end stage renal disease.
Renal nephrosclerosis is chronic nephron scarring with glomerulosclerosis, interstitial fibrosis, arteriolar thickening, and hyaline arteriosclerosis.
This can lead to further hypertension, mild proteinuria, bland urinalyis, elevated uric acid, and small kidneys on ultrasound.
retinal complications
main article: hypertensive emergency
Marked elevation in BP, usually in patient with long-standing, poorly controlled hypertension
retinal hemorrhages and papilledema
acute renal failure, hematuria, proteinuria
hypertensive encephalopathy (cerebral edema) can lead to headache, nausea, vomiting, confusion, and seizures
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