PHOTOSENSITIVITY
PHYSOSTIGMINE
photosensitivity Abnormal reaction to
sunlight. Photosensitivity usually causes
a rash on skin exposed to sunlight. This
often occurs because a photosensitizer
(such as some drugs, dyes, chemicals in
perfumes and soaps, and plants such as
mustard) has been ingested or applied
to the skin. Photosensitivity is also a fea-
ture of disorders such as
systemic lupus
erythematosus.
People who are suscepti-
ble to photosensitivity reactions should
avoid exposure to sunlight and photo-
sensitizers, and use
sunscreens.
phototherapy Treatment with light, in-
cluding sunlight,
ultraviolet light,
blue
light, or
lasers.
Moderate exposure to
sunlight is the most basic form, and is
often helpful in treating
psoriasis.
PUVA
combines the use of long-wave
ultraviolet light with a
psoralen drug,
which sensitizes the skin to light. This is
used to treat psoriasis and other skin
diseases such as
vitiligo.
Psoriasis may
also be treated using short-wave ultravio-
let light, sometimes combined with the
application of coal tar.
Visible blue light is used to treat
neonatal jaundice
(see jaundice, neona-
tal),
which is due to high levels of the
pigment
bilirubin
in the blood. In pho-
totherapy, bilirubin is converted into a
harmless substance that can be excret-
ed. To maximize exposure, the baby is
undressed and placed under the lights
in an incubator to keep him warm.
phrenic nerve One of the pair of main
nerves supplying the
diaphragm.
Each
phrenic nerve carries motor impulses to
the diaphragm, and plays a part in con-
trolling breathing. Injury to, or surgical
cutting of, 1
of the nerves results in
para-
lysis
of 1
half of the diaphragm,
physical examination See
examina-
tion
,
physical.
physical medicine and rehabilitation
A branch of medicine concerned with
caring for patients who have become
disabled through injury or illness,
physiology The study of body func-
tions, including physical and chemical
processes of cells, tissues, organs, and
systems, and their various interactions,
physiotherapy Treatment with physi-
cal methods or agents. Physiotherapy is
used to prevent or reduce joint stiffness;
restore muscle strength; reduce pain;
inflammation, and muscle spasm; and
retrain joints and muscles after
stroke
or
nerve
injury.
Methods
include
heat
treatment,
exercises,
massage, ice-packs,
hydrotherapy,
and
TENS.
Physiotherapy
is also used to maintain breathing in
people with impaired lung function,
and to prevent and treat pulmonary
complications after surgery. Techniques
include
breathing exercises,
postural
drainage,
and administration of oxygen,
drugs, or moisture through a
nebulizer.
physostigmine A drug used in the form
of eye-drops to treat
glaucoma.
PHOTOTHERAPY
Lamp gives
off blue
fluorescent
light
Incubator
Newborn
baby
Eye
shield
PHOTOTHERAPY FOR NEONATAL JAUNDICE
448
previous page 446 BMA Illustrated Medical Dictionary read online next page 448 BMA Illustrated Medical Dictionary read online Home Toggle text on/off