VOLUME 9 NUMBER 3 • SEPTEMBER 2012
135
SA JOURNAL OF DIABETES & VASCULAR DISEASE
CONFERENCE REPORT
entailed home blood pressure monitoring
with three successive measurements a day,
over a period of seven days. The greater the
variability in readings, the higher the risk.
Recent data published in the
Lancet
in
2010
confirmed that visit–visit variability in
systolic blood pressure is a strong predictor
of stroke, independent of mean systolic
blood pressure. Increased residual variability
in systolic blood pressure in patients with
treated hypertension is associated with a
high risk of vascular events.
To most effectively prevent stroke, blood
pressure-lowering drugs should reduce
mean blood pressure without increasing
variability. Ideally they should do both.
Summary from conference report,
Cardiovasc
J Afr
2012;
23
(4): 232–234.
DR NAOMI RAPPAPORT
Specialist physician, Milpark Hospital,
Johannesburg
DR SHIRLEY MIDDLEMOST
Cardiologist, Hermanus MediClinic,
Western Cape
H
ypertension is increasingly becoming
a health concern in the younger
population. Prof Rayner illustrated this point
by comparing data from the 1970s, when
hypertension in children was extremely rare
and almost always prompted investigation
to search for an underlying secondary cause,
with current statistics.
Recent American studies have shown that
the prevalence of childhood hypertension has
risen as high as 4.5%. The Harvard Alumni
study assessing coronary heart disease
mortality in normal subjects and those with
pre-, primary and secondary hypertension
found that 5–15% of adolescents displayed
secondary hypertension.
Factors contributing to childhood
hypertension
‘
The current epidemic of obesity is the key
issue in childhood hypertension’, said Prof
Southern African Hypertension Society congress report, March 2012
The young hypertensive
Prof Brian Rayner
Head of Division of
Nephrology, Groote
Schuur Hospital and
University of Cape
Town
Active research
interests are therapy
of hypertension,
mutations in the
ENaC, genetic
determinants of
salt sensitivity, HIVAN, vascular calcification and
chronic kidney disease, primary aldosteronism and
the genetics of severe hypertension in blacks.
Rayner. Obesity is defined as a body mass
index > 85th percentile, leading to a rise in
leptin levels and heart rate and also linked to
insulin resistance. He noted that a definite
relationship between blood pressure and
fasting insulin has been observed.
A number of other factors are also
strongly linked to the rise in childhood
hypertension, including lowbirthweight and
predisposing genetic factors (family history
of risk factors or hypertensive disease). Also
contributing are reduced nephron number
(
Barker-Brenner hypothesis) and elevated
uric acid.
There are multiple health concerns
around elevated blood pressure in child-
hood. Childhood blood pressure (especially
systolic) tracks bloodpressure intoadulthood.
Elevated blood pressure is associated with
subclinical cardiovascular disease and is
a significant driver of overall mortality,
cardiovascular mortality and coronary heart
disease.
Assessing hypertension in the child
Key pointers to primary hypertension in the
child include adolescence, obesity, and a
family history of hypertension, cardiovascular
disease and type2diabetes. Pre-hypertension
and hypertension were defined as a blood
pressure persistently above the 90th and
95
th percentiles, respectively. Adult norms
of blood pressure should be used from 18
years of age.
Prof Rayner advised that assessment
of blood pressure should be based on
frequent measures; full 24-hour ambulatory
monitoring is ideal to avoid misdiagnosis.
Clinical examination should evaluate for
potential secondary causes of hypertension,
particularly use of illicit drugs (cocaine, tik)
and oral contraceptives, and chronic kidney
disease.
Other investigations advised included a
dipstick for urine, and creatinine assessment,
as well as kidney ultrasound. Blood tests
(
electrolyte, uric acid and fasting glucose
levels, lipogram), an electrocardiogram and
an echocardiogram were also considered
important.
Treatment of childhood
hypertension
Lifestyle modification, Prof Rayner empha-
sised, forms the basis of treatment of the
pre-hypertensive or hypertensive child.
Weight loss and increased exercise are of
particular importance.
The use of therapeutic agents should be
considered in those children with sympto-
matic hypertension, secondary hypertension,
organ damage and type 1 and 2 diabetes.
Also consider those with persistent hyper-
tension despite lifestyle modification.
There are some concerns over the use
of diuretics in the young, but the use of
angiotensin converting enzyme (ACE)
inhibitors or angiotensin receptor blockers
(
ARB), calcium channel blockers and beta-
blockers has been safely established. Prof
Rayner did comment that weight gain and
poor exercise tolerance arising from beta-
blocker use predisposes the patient to type
2
diabetes.
G Hardy
