snake bitesMost snake bites are by non-
venomous species. Venomous snakes are
found mainly in the tropics; the only
species native to the UK is the adder.
The effects of a venomous bite depend
on the species and size of the snake,
the amount of venom injected, and the
age and health of the victim. A bite from
an adder or other viper typically causes
immediate pain and swelling at the site,
followed by dizziness and nausea, a
drop in blood pressure, an increase in
heart-rate, and internal bleeding.
Antibiotic drugsand tetanusantitoxin
injections are given for all bites to pre-
vent infection and tetanus. An injection
of antivenomis also given for a ven-
omous bite. With prompt treatment,
most victims recover completely.
sneezingThe involuntary expulsion of air
through the nose and mouth as a result
of irritation of the upper respiratory tract.
This may be due to the common cold,
allergic rhinitis, the presence of mucus,
or inhaling an irritant substance.
Snellen chartA method of measuring
visual acuityused during vision tests.
snoringNoisy breathing through the
open mouth during sleep, produced by
vibrations of the soft palate. Snoring is
often caused by a condition that hinders
breathing through the nose, such as a
cold, allergic rhinitis, or enlarged ade-
noids. Snoring is more common when
sleeping on the back. If the underlying
cause can be treated, snoring may stop.
Snoring is also a feature of sleep apnoea.
snow-blindnessA common name for
actinic keratopathy.
snuffA preparation of powdered tob-
acco(often with other substances) for
inhalation. Snuff is addictive because it
contains nicotine; it also irritates the
nasal lining and increases the risk of
cancer of the nose and throat.
snufflesA general term for nasal obstruc-
tion,especially in infants suffering from
an upper respiratory tract infection.
social and communication disorders
A collective term for disorders such as
Asperger’s syndromeand autism, which
begin in childhood. Problems tend to
persist throughout life.
social skills trainingA form of behav-
iour modificationin which individualsare encouraged to improve their ability to
communicate. This is an important part
of rehabilitationfor people with mental
handicapor those with chronic psych-
ological disorders, such as schizophrenia.
Role-playingis a commonly used tech-
nique in which various social situations
are simulated in order to improve the
individual’s confidence and performance.
sociopathyAn outdated term for anti-
social personality disorder.
sodiumA mineralthat helps to regulate
the body’s water balance and maintain
normal heart rhythm and is involved in
conduction of nerve impulses and con-
traction of muscles. The level of sodium
in the blood is controlled by the kidneys,
which eliminate any excess in the urine.
Almost all foods contain sodium natu-
rally or as an ingredient added during
processing or cooking. Consequently,
deficiency is rare and is usually the
result of excessive loss of the mineral
through persistent diarrhoea or vomiting,
or profuse sweating. Symptoms include
weakness, dizziness, and muscle cramps.
In severe cases, there may be a drop in
blood pressure, leadingto confusion,
fainting, and palpitations. Treatment is
with supplements. In hot climates, sodium
supplements may help to prevent heat
disordersby compensating for sodium
lost through heavy sweating.
Excessive sodium intake is thought to
be a contributory factor in hypertension.
Another adverse effect is fluid reten-
tion, which, in severe cases, may cause
dizziness and swelling of the legs.
sodium aurothiomalateA preparation
of goldthat is given by injection.
sodium bicarbonate An over-the-
counter antacid drugused to relieve
indigestion, heartburn, and pain caused
by a peptic ulcer.It often causes belching
and abdominal discomfort. Long-term
use may cause swollen ankles, muscle
cramps, tiredness, and nausea.
sodium cromoglicateA drug given by
inhaler to control mild asthmain chil-
dren and allergic or exercise-induced
asthma in adults; as a nasal spray to
treat allergic rhinitis; in eye-drops for
allergic conjunctivitis; and orally for food
allergy. Side effects include coughing
and throat irritation on inhalation.SNAKE BITES SODIUM CROMOGLICATES