Gastric surgery interferes with the nor-
mal mechanism for emptying food from
the stomach (see digestion). If a meal
rich in carbohydrates is “dumped” too
quickly from the stomach, the upper
intestine may swell. This, together with
the excessive amounts of certain hor-
mones released into the bloodstream,
causes the symptoms of early dumping.
As sugars are absorbed from the intes-
tine, they rapidly increase the blood
glucose level, causing excess insulin
release. This may in turn later lower the
blood glucose level below normal,
causing the symptoms of late dumping.
A person who has had a gastrectomy
can avoid symptoms by eating frequent,
small dry meals that do not contain
refined carbohydrates. Symptoms may
also be prevented by lying down after a
large meal. Adding guar gumto food is
sometimes effective.
duodenal ulcerA raw area in the wall of
the duodenum, due to erosion of its inner
surface lining. Duodenal ulcers and gas-
tric ulcers (similar areas in the lining of
the stomach) are also called peptic ulcers.
duodenitisInflammation of the duode-
num(first part of the small intestine),
producing vague gastrointestinal symp-
toms. The condition is diagnosed by
oesophagogastroduodenoscopy (see gas-
troscopy) which is the examination of
the walls of the upper digestive tract
with a flexible viewing instrument. Treat-
ment is similar to that for a duodenal
ulcer (seepeptic ulcer).
duodenumThe first part of the small
intestine extending from the pylorus
(the muscular valve at the lower end of
the stomach) to the ligament of Treitz,
which marks the boundary between the
duodenum and the jejunum (the second
part of the small intestine). It is about
25 cm long and shaped like a C; it forms
a loop around the head of the pancreas.
Ducts from the pancreas, liver, and gall-
bladderfeed into the duodenum through
a small opening. Digestive enzymes in
the pancreatic secretions and chemicals
in the bile are released into the duode-
num through this opening.
Dupuytren’s contractureA disorder
of the hand in which one or more fingers
become fixed in a bent position. In about
half the cases, both hands are affected.
In most cases there is no apparent cause,
but the disease may in part be inherited.
Men over 40 are most often affected.
The tissues under the skin in the fingers
or palm become thickened and short-
ened, causing difficulty in straightening
the fingers. Surgery can correct deformity
of the fingers, but in some cases there is
a recurrence of the condition.dura materThe outer of the 3 mem-
branes (meninges) covering the brain.
dust diseasesLung disorders caused by
dust particles inhaled and absorbedinto
the lung tissues. There they may cause
fibrosis(formation of scar tissue) and
progressive lung damage. The main
symptoms are a cough and breathing
difficulty. It may take at least 10 years of
exposure to dusts containing coal, sil-
ica, talc, or asbestos before serious lung
damage develops (see pneumoconiosis).
Hypersensitivity to moulds on hay or
grain may lead to allergic alveolitis. Pre-
ventive measures, such as the installation
of dust extraction machinery, have redu-
ced the incidence of dust diseases.
DVTDeep vein thrombosis (see throm-
bosis, deep vein).
dwarfismSee short stature.
dydrogesteroneA drug derived from
the female sex hormone progesterone.
It is used to treat premenstrual syn-
drome and menstrual problems (see
menstruation, disorders of). It is also
given together with an oestrogen drug
as hormone replacement therapyfollow-
ing the menopause. Dydrogesterone is
sometimes prescribed for endometriosis
or to prevent miscarriage. Adverse effects
include swollen ankles, weight gain,
breast tenderness, and nausea.DUODENAL ULCER DYDROGESTERONE
D
Thickened
tissue under
the skinDUPUYTREN’S CONTRACTURE