pantothenic acidOne of the vitamins
in the vitamin B complex.
papainA naturally occurring mixture of
enzymes, including chymopapain, which
is found in pawpaws. Papain breaks
down proteins and has been used to
remove clotted blood and dead tissue
from wounds and ulcers.
papillaAny small, nipple-shaped pro-
jection from a tissue’s surface, such as
the mammary papilla (the breast nipple).
papilloedemaSwelling of the head of
the optic nerve, which is visible with an
ophthalmoscope. Also called optic disc
oedema, it usually indicates a danger-
ous rise in the pressure within the skull,
sometimes caused by a brain tumour.
papillomaA noncancerous growth of the
epitheliumthat resembles a wart and
most commonly affects the skin, tongue,
larynx, and urinary and digestive tracts.
pap smearSeecervical smear test.
papuleA small, solid, slightly raised
area of skin. Papules are usually less
than 5 mm in diameter, are raised or
flat, have a smooth or warty texture,
and are either pigmented or the colour
of the surrounding skin.
par-/para-Prefixes that may mean be-
side or beyond, closely resembling or
related to, or faulty or abnormal.
para-aminobenzoic acidThe active
ingredient of many sunscreenprepara-
tions. Its abbreviation is PABA.
paracentesisA procedure in which a
body cavity is punctured with a needle
from the outside to remove fluid for
analysis, to relieve pressure from excess
fluid, or to instil drugs.
paracetamolAn analgesic drug, used
to treat mild pain and to reduce fever.
Paracetamol may rarely cause nausea or
rash. An overdose may cause liver dam-
ageand can be fatal.
paraesthesiaAltered sensation in the
skin that occurs without a stimulus (see
pins-and-needles).
paraffinomaA tumour-like swelling
under the skin caused by prolonged
exposure to paraffin. Paraffinomas may
form in the lungs if paraffin is inhaled.
paraldehydeA sedative drugused to
stop prolonged epileptic seizures. Par-
aldehyde can be administered as an
enemaor by injection into a muscle.
paralysisComplete or partial loss of
controlled movement caused by the in-
ability to contract 1 or more muscles.
Paralysis may be temporary or perma-
nent. There may also be loss of feeling
in affected areas.
Paralysis of one half of the body is
called hemiplegia; paralysis of all 4 limbs
and the trunk is called quadriplegia. Para-
plegiais paralysis of both legs and
sometimes part of the trunk. Paralysis
may be flaccid, causing floppiness, or
spastic, causing rigidity.
Paralysis can be caused by brain disor-
ders such as stroke, brain tumour, brain
abscess, or brain haemorrhage. Some
types of paralysis are caused by damage
to parts of the nervous system (such as
the cerebellumandbasal ganglia) con-
cerned with fine control of movement.
Paralysis can also be caused by damage
to or pressure on the spinal cord as a
result of injury or disc prolapse. Disea-
ses affecting the spinal cord (such as
multiple sclerosisand poliomyelitis) and
muscle disorders (such as muscular dys-
trophy) may also cause paralysis. Nerve
disorders, called neuropathies, may cause
varying degrees of paralysis.
The underlying cause is treated, if
possible, and physiotherapyis used to
prevent joints from becoming locked
and to strengthen muscles and joints.
paralysis, periodicA rare, inherited
condition that affects young people.
Periodic paralysis is characterized by
episodes of muscle weakness, which
vary in frequency from daily to every few
years and last from a few minutes to a
few hours. In some cases, there is a drop
in the potassiumlevels in the blood; in
others, the levels rise. A carbohydrate-
rich meal may trigger an attack. The
condition often clears up without treat-
ment by age 40.
paramedicA term for any health-care
worker other than a doctor, nurse, or
dentist. The term usually refers to ambu-
lancestaff who attend accidents or
medical emergencies.
paranoiaA condition in which the cen-
tral feature is the delusionthat people
or events are especially connected to
oneself. The term paranoia may also be
used to describe feelings of persecution.PANTOTHENIC ACID PARANOIA
P