sexual desire, inhibitedLack of sexual
desire or of the ability to become physi-
cally aroused during sexual activity.
sexual deviationSee deviation, sexual.
sexual dysfunctionSee psychosexual
dysfunction.
sexual intercourseA term sometimes
used to describe a variety of sexual activ-
ities, but which specifically refers to the
insertion of the penis into the vagina.
sexualityA term describing the capacity
for sexual feelings and behaviour, or an
individual’s sexual orientation or prefer-
ence. Heterosexualityis sexuality directed
towards the anatomically opposite sex;
homosexualityis attraction to the same
sex; and bisexualityis attraction to both
sexes. (See also gender identity.)
sexually transmitted infections(STIs)
Infections transmitted primarily, but not
exclusively, by sexual intercourse. Com-
mon STIs include chlamydialinfections,
genital herpes, pubic lice, genital warts,
trichomoniasis, syphilis, gonorrhoea, and
HIVinfection. Antibioticscan be used to
treat most bacterial STIs. Confidential
tracing and treatment of an affected per-
son’s partners is an essential part of the
management of STIs (see contact tracing).
Practising safer sexcan help prevent STIs.
sexual problemsAny difficulty associat-
ed with sexual performance or behaviour.
Sexual problems are often psychological
in origin (see psychosexual dysfunction).
Sex therapymay help such problems.
Some sexual problems are due to physi-
cal disease, such as a disorder affecting
blood flow or a hormonal dysfunction.
A disorder of the genitals may result in
pain during intercourse (see intercourse,
painful). Such problems are addressed
by treating the cause, where possible.
Sézary syndromeA rare condition in
which there is an abnormal overgrowth of
lymphocytesin the skin, liver, spleen, and
lymph nodes. It mainly affects middle-
aged and elderly people. The first
symptom is the appearance of red, scaly
patches on the skin that spread to form
an itchy, flaking rash. There may also be
accumulation of fluid under the skin,
baldness, and distorted nail growth.
Sézary syndrome is sometimes associ-
ated with leukaemia. Treatment includes
anticancer drugs and radiotherapy.
shellfish poisoningSee food poisoning.
shell shockSee post-traumatic stress
disorder.
shigellosisAn acute infection of the
intestine by bacteria of the genus SHI-
GELLA. The source of the infection is the
faeces of infected people; the bacteria
are spread by poor hygiene. Endemic
in some countries, shigellosis occurs in
isolated outbreaks in the UK.
The disease usually starts suddenly,
with diarrhoea, abdominal pain, nausea,
vomiting, generalized aches, and fever.
Persistent diarrhoea may cause dehydra-
tion, especially in babies and the elderly.
Occasionally, toxaemia develops.
Shigellosis usually subsides after a
week or so, but hospital treatment may
be needed for severe cases. Dehydra-
tion is treated by rehydration therapy.
Antibioticsmay be given.
shinglesSee herpes zoster.
shin splintsPain in the front and sides
of the lower leg that develops or wors-
ens during exercise. There may also be
tenderness and oedemain the affected
area. Shin splints is a common problem
in runners. It may be caused by various
disorders, such as compartment syn-
drome, tendinitis, myositis, or periostitis.
In most cases, the pain disappears
after 1 or 2 weeks of rest. However, if it
is severe or recurrent, a course of non-
steroidal anti-inflammatory drugs or
corticosteroidsmay be needed. Rarely,
surgery is performed to alleviate exces-
sive pressure in a muscle. Some people
benefit from physiotherapy.
shiveringInvoluntary trembling of the
entire body that is caused by rapid
contraction and relaxation of muscles.
Shivering is the body’s normal auto-
matic response to cold; contraction of
muscles generates heat. Shivering also
occurs in fever.
shockA dangerous reduction of blood
flow throughout the body tissues, which
may occur with severe injury or illness.
Shock in this sense is physiological shock,
as distinct from the mental distress that
may follow a traumatic experience.
In most cases, reduced blood pressure
is a major factor in causing shock and is
one of its main features. Shock may de-
velop in any situation in which bloodSEXUAL DESIRE, INHIBITED SHOCK
S