POTASSIUM CITRATE
PREGNANCY
P
in a similar way to
nitrates,
and widens
both arteries and veins. Possible side
effects include flushing, nausea, vomit-
ing, and dizziness.
potassium citrate A substance used to
relieve discomfort in mild
urinary tract
infections
by making the urine less acid.
potassium permanganate A drug that
has an
antiseptic
and
astringent
effect;
and is useful in the treatment of
derma-
titis.
It can occasionally cause irritation
and can stain skin and clothing.
potency The ability of a man to perform
sexual intercourse
; or the ability of a
drug to cause desired effects.
Pott's fracture A combined fracture and
dislocation of the ankle caused by exces-
sive or violent twisting. The
fibula
breaks
just above the ankle; in addition, the
tibia
breaks or the
ligaments
tear, result-
ing in dislocation.
poultice A warm pack consisting of a
soft, moist substance (such as
kaolin
)
spread between layers of soft fabric.
pox Any of various infectious diseases
characterized by blistery skin eruptions
(for example
chickenpox).
Pox is some-
times used as a slang word for
syphilis
.
pravastatin A
lipid-lowering drug.
praziquantel An
anthelmintic drug
used
to treat
tapeworm infestation
. Adverse
effects may include dizziness, drowsi-
ness, and abdominal pain.
prazosin A
vasodilator drug
used to treat
hypertension, heart failure,
and
Raynaud's
disease
. Prazosin is also used to treat uri-
nary symptoms resulting from an enlarged
prostate gland (see
prostate, enlarged
).
Side effects include dizziness and faint-
ing, nausea, headache, and dry mouth.
precancerous A term applied to any
condition in which there is a tendency for
cancer to develop. There are 3 types of
such conditions. In the 1st, there are no
tumours present but the condition car-
ries an increased risk of cancer. In the
2
nd, there are noncancerous tumours
that tend to become cancerous or are
associated with the development of can-
cerous tumours elsewhere. The 3rd type
comprises disorders which have irregu-
lar features from the beginning but do
not always become fully cancerous.
precocious pubertyThe development of
secondary
sexual characteristics
before
age
8
in girls and 9 in boys. It is uncom-
mon and may be caused by various
disorders that can result in production
of
sex hormones
at an abnormally early
age. Possible underlying causes include
a
brain tumour
or other brain abnormali-
ties; abnormality of the adrenal glands
(for example,
congenital adrenal hyper-
plasia); ovarian cysts,
and
tumours,
or a
tumour in the testes. In some cases, no
underlying cause can be identified.
The hormones may cause a premature
growth spurt followed by early fusion of
the bones. As a result, affected children
may initially be tall but, if untreated, final
height is often greatly reduced.
The child's pattern of pubertal devel-
opment is assessed by a doctor.
Blood
tests
are performed to measure hor-
mone levels.
Ultrasound scanning
of the
ovaries and testes, and
CT scanning
of
the adrenal glands or brain, may also be
carried out, depending on the underly-
ing cause suspected.
Treatment is of the underlying cause,
and hormone drugs may be given to
delay puberty and increase final height.
predisposing factors Factors that lead
to increased susceptibility to a disease.
prednisolone A
corticosteroid drug.
prednisone A
corticosteroid drug
.
pre-eclampsia A serious condition in
which
hypertension
,
oedema
, and
protein-
uria
develop in the last (3rd) trimester
of pregnancy. If severe, symptoms may
include headache, nausea and vomiting,
abdominal pain, and visual disturban-
ces. The condition, which is sometimes
called pre-eclamptic toxaemia or PET, is
more common in
1
st pregnancies and if
diabetes mellitus,
hypertension, or kid-
ney
disease
is
present.
Untreated
pre-eclampsia may lead to
eclampsia.
For some cases of pre-eclampsia, treat-
ment is bed-rest and
antihypertensive
drugs
. In late pregnancy, or if severe,
induction of labour
or
caesarean section
may be necessary.
pregnancy The period from
conception
to birth. Pregnancy begins with the
fer-
tilization
of an ovum
(egg) and its
implantation. The egg develops into the
placenta
and the
embryo
, which grows
to form the fetus. Most eggs implant
into the uterus. Very occasionally, an
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