TESTS, MEDICAL
Diagnosis is by physical examination.
Surgery is performed to untwist the
testis and anchor it in the scrotum with
small stitches to prevent recurrence. If
the damage is irreversible,
o rc h id e c t o m y
(removal of the testis) is performed. In
either case, the other testis is anchored
to the scrotum to prevent torsion on
that side. W ith prompt treatment, full
recovery is complete.
te s tis , u n d e s c e n d e d
A testis that has failed to descend from
the abdomen to the scrotum.The condi-
tion usually affects only one testis. An
undescended testis often descends with-
in months of birth but rarely descends
after this time. The condition is more
common in premature baby boys.
An undescended testis does not deve-
lop normally, cannot produce normal
sperm, and is at increased risk of testic-
ular cancer (see
te stis, c a n c e r o f
).
If both
testes are undescended,
in f e rt ilit y
results.
CAUSES
The final descent of the testis through
the inguinal canal in the groin is con-
trolled by hormones produced by the
mother and by the testis itself. If these
stimuli do not have an effect, the sper-
matic
cord
(which
carries
the
va s
d e fe re n s
and blood vessels to the testis)
fails to lengthen sufficiently to allow
full descent. Less commonly a normal
testis is prevented from reaching the
scrotum because of fibres blocking its
route, and remains in the groin.
DIAGNOSIS AND TREATMENT
A diagnosis is made during a physical
examination after birth or later in infancy.
Treatment is by
o rc h id o p e x y
,
an operation
to place the testis in the scrotum, w hich
usually reduces the risk of later infert-
ility or testicular cancer. A poorly de-
veloped
undescended
testis
may
be
removed if the other is normal.
te s t m e a l
A procedure to measure the output of
acid by the
s t o m a c h
.
A
n a s o g a s t r ic tu b e
is
passed into the stomach after an over-
night fast, and a sample of gastric fluid is
sucked up through the tube. An injection
of
h is ta m in e
or, more usually, pentagas-
trin
(a
synthetic
preparation
of the
hormone gastrin) is given; further sam-
ples
of stomach fluid
are
taken
at
intervals
for
up
to
two
hours and
analysed for hydrochloric acid content.
The test is used for people thought to
be suffering from
Z o llin g e r - E llis o n s y n -
d r o m e
,
and to confirm the absence of
stomach acid in people with pernicious
anaemia (see
a n a e m ia , p e r n ic io u s ) .
te s to s te ro n e
The main
a n d ro g e n h o rm o n e
(male sex
hormone). It stimulates bone and muscle
growth and sexual development. It is pro-
duced by the
testes
and, in small amounts,
the
o v a rie s
.
Synthetic or animal testoster-
one is used to stimulate delayed
p u b e r t y
or treat some forms of male
in fe rt ilit y
.
te s ts , m e d ic a l
Tests may be performed to investigate
the cause of symptoms and establish a
diagnosis, to monitor the course of
TYPES OF MEDICAL TESTS
The table below lists some commonly performed medical tests, classified according
to the body system they are used to study, although all of the tests are often done
as part of the investigation for any system. Each test listed in the table has its own
entry. Only some of the most important imaging techniques for each body organ
have been included; a complete list appears in the appropriate imaging article.
System
Test
Brain and
• EEG
• Myelography
nervous system
• Evoked responses
• Brain imaging
• Hearing test
• CT scanning
• Vision test
• MRI
• Lumbar puncture
• Intelligence tests
• PET scanning
Skin, bones, and
• EMG
• Bone imaging
muscles
• Biopsy
• X-rays
Endocrine system
• Thyroid-function test
• Blood tests
and metabolism
• Thyroid scanning
• Urinalysis
Blood and
• Blood test
• Skin tests
immune system
• Lymphangiography
• Bone marrow biopsy
Heart and
• Heart imaging
• ECG (plus exercise and
circulation
• ChestX-ray
24-hour ECG)
• Angiography
• Catheterization, cardiac
• Echocardiography
• Cardiac stress test
• Venography
• Thallium scan
Lungs
• Pulmonary function tests
• ChestX-ray
• Blood gases/oxygen saturation
• Bronchoscopy
• Peak-flow meter
• Spirometry
• Sputum analysis
Biliary system
• Liver-function test
• Cholecystography
• Liver imaging
• ERCP
• Ultrasound scanning
• Cholangiography
• Liver biopsy
Gastrointestinal
• Endoscopy
• Barium X-ray examinations
tract
• Colonoscopy
• Jejunal biopsy
• Gastroscopy
• Occult blood, faecal
• Sigmoidoscopy
• Microbiology/parasitology
Urinary tract
• Kidney imaging
• Urinalysis
• Urography (IVU)
• Kidney-function tests
• Ultrasound scanning
• Cystoscopy
Reproductive
• Pregnancy test
• Amniocentesis
system
• Hysterosalpingography
• Cervical smear test
• Mammography
• Chorionicvillus sampling
• Ultrasound scanning
• Chromosome analysis
• Laparoscopy
• Seminal fluid analysis
T
737
previous page 736 BMA A Z Family Medical Encyclopedia   2004 read online next page 738 BMA A Z Family Medical Encyclopedia   2004 read online Home Toggle text on/off