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74 Chapter 2: Cardiovascular system

Renal (80%): Most commonly glomerulonephritis, Table 2.9 Risk factors for cardiovascular disease

recurrent/chronic pyelonephritis, and polycystic kid-
Males >55 years; Females >65 years
neys. Hypertension is also a common cause of renal Smoking
disease. Total cholesterol >6.1 mmol/L or LDL-cholesterol >4.0
Endocrine causes: Acromegaly, Cushing’s syndrome,
mmol/L
Conn’s syndrome and phaechromocytoma. HDL-cholesterol: Males <1.0 mmol/L and Females <1.2
mmol/L
Cardiovascular (uncommon): Coarctation of the

History of cardiovascular disease in first-degree relatives
aorta, renal artery stenosis. before age 50
Pregnancy (pre-eclampsia). Obesity, physical inactivity

Drugs: Oral contraceptives, NSAIDs, steroids. Car-

benoxalone and liquorice mimic aldosterone.
Complications
Hypertension is a major risk factor for cerebrovascular
Pathophysiology
disease (strokes), heart disease (coronary artery disease,
Hypertension accelerates the age-related process of left ventricular hypertrophy and heart failure) (see Table

arteriosclerosis ‘hardening of the arteries’ and predis- 2.9) and renal failure. Other important complications
poses to atherosclerosis in larger arteries. Arterioscler- include peripheral vascular disease and dissecting aortic
osis, through smooth muscle hypertrophy and intimal aneurysms.
thickening, reduces luminal diameter in smaller arter- In patients with malignant hypertension there is risk
ies and so increases peripheral vascular resistance and of cerebral oedema, left ventricular failure, renal impair-
exacerbates hypertension. ment with proteinuria and microscopic haematuria. In
The chronic increased pressure load on the heart re- severehypertension,retinalhaemorrhages,exudatesand

sults in left ventricular hypertrophy and over time this papilloedema are features of malignant hypertension.
leads to heart failure.
Arteriosclerosis also reduces renal perfusion pressure,

Macroscopy/microscopy
whichactivatestherenin–angiotensinsystem.Saltand
Benign hypertension and small arteries: There is hy-
water retention occurs, which can itself worsen hyper-
pertrophy of the muscular media, thickening of the
tension.
elastic lamina, fibroelastic thickening of the intima
In some individuals the pressure rise is more rapid and
and reduction in the size of the lumen.
such patients are said to have malignant hypertension
Malignant hypertension and small arteries: Loose
(with rapidly worsening end-organ damage such as hy-
myxomatous intimal proliferation with reduced lu-
pertensive retinopathy and renal impairment). Without
men and normal media.
treatment these patients die within 1–2 years.
Arterioles:Thereishyalinewallthickening(hyalinear-
teriosclerosis), increased rigidity and reduced lumen
Clinical features size.
As blood pressure varies considerably (e.g. diurnal vari- Malignant hypertension and arterioles: Fibrinoid
ation, recent alcohol intake, stress and anxiety) the diag- necrosis is seen in the walls of arterioles.
nosis should be based on multiple measurements taken
on several different occasions. These should be taken Investigations
with the patient relaxed and at rest. In cases of doubt, Routine investigations must include fasting plasma
24-hour blood pressure recordings may be helpful such glucose, serum total cholesterol and lipid profile,
as when ‘white coat’ hypertension is suspected. U&Es, FBC, urinalysis (dipstick), ECG and serum uric
A full history and examination should be performed acid.
to assess the extent, to look for any underlying cause Other tests may include echocardiogram, carotid ul-
or contributing factors and to look for complications. trasound, microalbuminuria (essential test in diabet-
Often hypertension is asymptomatic and the history and ics), quantitative proteinuria (if dipstick test positive)
examination are unremarkable. and fundoscopy in severe hypertension.