HYDATID DISEASE
HYDROCEPHALUS
H
errors of
)
in which there is an abnormal
accumulation of substances known as
mucopolysaccharides in the tissues.
Affected children may appear normal
at birth but, at
6-12
months of age, they
develop cardiac abnormalities, umbil-
ical
hernia
, skeletal deformities, and
enlargement of the tongue,
liver
, and
spleen
.
Growth is limited and mental
development slows. If the condition is
diagnosed in early infancy, a
bone mar-
row transplant
may be curative.
hydatid disease
A rare infestation that
is caused by the larval stage of the
small tapeworm
echinococcus granu-
losus
(see
tapeworm infestation
).
Larvae
mostly settle in the liver, lungs, or mus-
cle, causing the development of cysts.
In rare cases, the brain is affected.
The infestation is generally confined
to dogs and sheep, but may be passed
on to humans through accidental inges-
tion
of worm
eggs
from
materials
contaminated with dog faeces.
The cysts grow slowly, and symptoms
may not appear for some years. In many
cases, there are no symptoms. Cysts in
the liver may cause a tender lump or
lead to
bile duct obstruction
and
jaun-
dice
.
Cysts in the lungs may press on an
airway and cause inflammation; rupture
of a lung cyst may cause chest pain, the
coughing up of blood, and wheezing.
Cysts in the brain may cause
seizures
.
Ruptured cysts may rarely cause
ana-
phylactic shock
,
which can be fatal.
Diagnosis of hydatid disease is by
CT
scanning
or
MRI
. The cysts are usually
drained or removed surgically.
hydatidiform mole
An uncommon non-
cancerous tumour that develops from
placental tissue early in a pregnancy in
which the embryo has failed to develop
normally. The mole, which resembles a
bunch of grapes, is caused by degenera-
tion of the chorionic villi. The cause of
the degeneration is unknown. In a small
number of affected pregnancies, the
mole develops into a
choriocarcinoma
.
Vaginal bleeding and severe morning
sickness
generally occur.
ultrasound
scanning
reveals the tumour. Urine and
blood tests detect excessive amounts of
human chorionic gonadotrophin (see
gonadotrophin, human chorionic
), which
is produced by the tumour. The tumour
can be removed by suction, a
D and C
,
or, less commonly, a
hysterectomy
.
hydralazine
An
antihypertensive drug
used principally as an emergency treat-
ment for
hypertension
.
Hydralazine may
cause nausea, headache, dizziness, ir-
regular heartbeat, loss of appetite, rash,
and joint pain. Taken long term in high
doses it may cause
lupus erythematosus
.
hydramnios
See
polyhydramnios
.
hydrocele
A soft, painless swelling in
the
scrotum
caused by the space around
a
testis
filling with fluid. A hydrocele
may be caused by inflammation, infec-
tion, or injury to the testis; occasionally,
the cause is a tumour. More often, there
is no apparent cause. Hydroceles com-
monly occur in middle-aged men, and
treatment is rarely necessary. If the
swelling is uncomfortable or painful,
however, the fluid may be withdrawn
through a needle. Recurrent swelling
may be treated by surgery.
HYDROCELE
hydrocephalus
An excessive amount
of
cerebrospinal fluid
,
usually under in-
creased pressure, within the skull. The
condition may be present at birth, when
it is often associated with other abnor-
malities, such as
spina bifida
,
or it may
develop as a result of major
head injury
,
brain
haemorrhage
,
infection (such as
meningitis
),
or a tumour.
With
congenital
hydrocephalus, the
main feature is an enlarged head that
continues to grow rapidly. Other features
include rigidity of the legs, vomiting,
288
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