with asbestos in industry. Allergic alve-
olitis is caused by organic dusts (see
farmer’s lung).
Industrial chemicals can damage the
lungs if inhaled, or other major organs if
they enter the bloodstream via the lungs
or skin. Examples include fumes of cad-
mium, beryllium, lead, and benzene.
Carbon tetrachloride and vinyl chloride
are causes of liver disease. Many of these
compounds can cause kidney damage.
Work-related skin disorders include
contact dermatitisand squamous cell car-
cinoma. Rare infectious diseases that are
more common in certain jobs include
brucellosis and Q fever(from livestock),
psittacosis(from birds), and leptospirosis
(from sewage). People who work with
blood or blood products are at increased
risk of viral hepatitis (see hepatitis, viral)
and AIDS, as are healthcare profession-
als. The nuclear industry and some
healthcare professions use measures to
reduce the danger from radiation hazards.
Other occupational disorders include
writer’s cramp,carpal tunnel syndrome,
singer’s nodes, Raynaud’s phenomenon,
deafness, and cataracts.
occupational medicineA branch of
medicine dealing with the effects of var-
ious occupations on health, and with an
individual’s capacity for particular types
of work. It includes prevention of occu-
pational disease and injury and the
promotion of health in the working popu-
lation.Epidemiologyis used to analyse
patterns of sickness absence, injury, ill-
ness, and death. Clinical techniques are
used to monitor the health of a particular
workforce. Assessment of psychological
stress and hazards of new technology
are part of the remit. Occupational
health risks are reduced by dust control,
appropriate waste disposal, use of safe
work stations and practices, limiting
exposure to harmful substances, and
screening for early evidence of occupa-
tional disorders.
occupational mortalityDeath due to
work-related disease or injuries. Annual
death rates (deaths per million at risk)
vary widely between occupations, rang-
ing from 5 in UK clothing and footwear
manufacture to about 1,650 in offshore
oil and gas industries. More than 1,000per year are due to work-related diseases,
mainly pneumoconiosisand cancers.
occupational therapyTreatment com-
prising individually tailored programmes
of activities that help people who have
been disabled by illness or accident to
improve their function and ability to carry
out everyday tasks. Occupational ther-
apy also involves recommending aids
and changes to the home that help to
increase the person’s independence.
octreotide A somatostatin analogue, a
hormone that acts on the pituitary
gland. Given by injection, octreotide is
used mainly in the treatment of acro-
megalyand hormone-secreting intestinal
tumours. Octreotide is also used to pre-
vent complications following pancreatic
surgery. Side effects may include vari-
ous gastrointestinal disturbances such
as nausea, vomiting, abdominal pain
and bloating, flatulence, and diarrhoea.
ocularRelating to or affecting the eye
and its structures; also the eyepiece of
an optical device, such as a microscope.
oculogyric crisisA state of gaze in
which the eyes are fixed, usually up-
wards, for minutes or hours. The crisis
may be associated with muscle spasm
of the tongue, mouth, and neck, and is
often triggered by stress. It may also
occur following encephalitisand in par-
kinsonism, or may be induced by drugs,
such as phenothiazinederivatives.
oculomotor nerveThe 3rd cranial nerve,
controlling most of the muscles that
move the eye. The oculomotor nerve also
supplies the muscle that constricts the
pupil, that which raises the upper eyelid,
and the ciliary muscle, which focuses
the eye. The nerve may be damaged due
to a fracture to the base of the skull or a
tumour. Symptoms include ptosis, squint,
dilation of the pupil, inability to focus
the eye, double vision, and slight protru-
sion of the eyeball. (See also trochlear
nerve; abducent nerve.)
oedemaAbnormal fluid accumulation
in body tissues that may be localized
(as in swelling from an injury) or gener-
alized (as in heart failure). Symptoms of
generalized oedema, such as swelling
around the base of the spine and in the
ankles, occur when excess body fluid
increases by more than 15 per cent. InOCCUPATIONAL MEDICINE OEDEMAO