heart defects called the tetralogy of Fal-
lot. Rarely, the stenosis develops later
in life, after rheumatic fever, and may
cause symptoms of heart failure.
Diagnosis is made by a chest X-ray,
ECG, echocardiography, and Doppler
ultrasoundscanning. A balloon catheter
may relieve the narrowing. Otherwise,
heart-valve surgeryor other types of
open heart surgeryare often successful.
pulp, dentalThe soft tissue containing
blood vessels and nerves in the middle
of each tooth (see teeth).
pulpectomyThe removal of the tooth
pulp. It is part of root-canal treatment.
pulpotomyRemoval of the coronal part
of the pulp of a tooth after it has
become inflamed, usually by infection.
Infection is most often due to extensive
tooth decay (see caries, dental)or dental
fractures (see fracture, dental). Pulpoto-
my prevents further degeneration of the
pulp. If treatment is unsuccessful, root-
canal treatmentmay be required.
pulseThe rhythmic expansion and con-
traction of an artery as blood is forced
through it, pumped by the heart.
pump, infusionA machine that is used
for the administration of a continuous,
controlled amount of a drug or other
fluid. The fluid is delivered through a
needle that is inserted into a vein or
under the skin.
pump, insulinA type of infusion pump
(see pump, infusion) used to administer
a continuous dose of insulin to some
patients with diabetes mellitus. The rate
of flow is adjusted so that the level of
blood glucose (sugar) is constant.
punch-drunkA condition that is char-
acterized by slurred speech, impaired
concentration, and slowed thought pro-
cesses. It is caused by brain damage
from several episodes of brief loss of
consciousness due to head injury.
pupilThe circular opening in the centre
of the iris. In bright conditions, the
pupil constricts; in dim light, it dilates.
purgativeA term for a laxative drug.
purineAny of a group of nitrogen-
containing compounds synthesized in
the body or produced by the digestion of
certain proteins. Increased levels of
purine can cause hyperuricaemia, which
may lead to gout. Foods that have a high
purine content include sardines, liver,
kidneys, pulses, and poultry.
purpuraAny of a group of disorders
characterized by purplish or reddish-
brown areas or spots of discoloration,
caused by bleeding within skin or mu-
cous membranes. Purpura also refers to
the discoloured areas themselves.
There are many different types and
causes of purpura. Common (senile)
purpura mostly affects middle-aged or
elderly women. Large discoloured areas,
caused by thinning of the tissues sup-
porting blood vessels under the skin,
appear on the thighs or the back of the
hands and forearms. Henoch–Schönlein
purpurais caused by inflammation of
blood vessels beneath the skin. Purpura
can also occur as a result of thrombocy-
topenia. In addition, it can be
associated with septicaemiaand can be
seen with meningitis(see glass test).
purulentA term that means containing,
producing, or consisting of pus.
pusA pale yellow or green, creamy fluid
found at the site of bacterial infection.
Pus is composed of millions of dead
white blood cells, partly digested tissue,
dead and living bacteria, and other sub-
stances. A collection of pus within solid
tissue is called an abscess.
pustuleA small skinblisterthat con-
tains pus.
PUVAA type of phototherapyused to
treat certain skin conditions, especially
psoriasis. PUVA combines a psoralen
drugand a controlled dose of long-
wavelength ultraviolet light.
pyelitisSee pyelonephritis.
pyelographySee urography.
pyelolithotomyAn operation performed
to remove a kidney stone (see calculus,
urinary tract). Pyelolithotomy has been
largely replaced by other procedures,
such as lithotripsy, which uses ultrason-
ic waves to break up the stones.
pyelonephritisInflammation of the kid-
ney, usually as a result of a bacterial
infection. Pyelonephritis is more com-
mon in women and is more likely to
occur during pregnancy. Symptoms of
pyelonephritis include a high fever,
chills, and back pain. Septicaemiais a
possible complication. Pyelonephritis is
treated withantibiotic drugs.PULP, DENTAL PYELONEPHRITIS
P