How Is LAM Diagnosed?
Methods for diagnosing LAM have improved. It's now
possible to diagnose the disease at an early stage. LAM is diagnosed based on
your signs and symptoms and the results from tests and procedures.
If you have LAM, you may need to see a
pulmonologist. This is a doctor who specializes in lung diseases and
conditions. These specialists usually are located at major medical centers.
Signs and Symptoms
Your doctor will ask about your
signs
and symptoms related to LAM. He or she may ask how long you’ve had
them, and whether they’ve become worse over time.
Many of LAM’s signs and symptoms are the same
as those of other diseases, such as
asthma,
emphysema, and bronchitis. It’s important for your doctor to rule out
those conditions before making a final diagnosis.
Diagnostic Tests and Procedures
To diagnose LAM, you usually will have tests to show
how well your lungs are working and what your lung tissue looks like.
These tests can show whether your lungs are getting
enough oxygen to your blood. You also may need tests to check for complications
of LAM.
Tests for Lung Function
Lung function tests. For
lung
function tests, you breathe through a mouthpiece into a machine called a
spirometer (spi-ROM-e-ter). The spirometer measures the amount of air you
breathe in and out.
Other lung function tests can show about how much
air your lungs can hold and how well your lungs deliver oxygen to your blood.
Blood tests. Your doctor may take a
blood sample from a vein in your arm to look at your blood cells and blood
chemistry.
Pulse oximetry. For this test, a
small sensor is attached to your fingertip. The sensor can give an estimate of
how much oxygen is in your blood while you’re sitting still and while
you’re walking.
Tests To Check for Complications or Detect LAM
Cells
Chest x ray. A
chest
x ray takes pictures of your heart and lungs. It can show a collapsed lung
or fluid in your chest. In the early stages of LAM, your chest x rays may look
normal. As the disease gets worse, the x rays may show cysts in your lungs.
High-resolution CT (HRCT) scan. The
most useful imaging test for diagnosing LAM is an HRCT scan. This test creates
a computer-generated picture of your lungs. The picture shows more detail than
the pictures from a chest x ray.
A HRCT scan can show cysts, shadows of cell
clusters, excess fluid, a collapsed lung, and enlarged lymph nodes. It also can
show how much normal lung tissue has been replaced by the LAM cysts.
HRCT scans of your abdomen and pelvis can show
whether you have growths in your kidneys, other abdominal organs, or lymph
nodes.
Procedures To Look for LAM Cells
The results from the above tests, along with
information about your signs, symptoms, and medical history, are sometimes
enough for your doctor to diagnose LAM.
However, if more information is needed, the most
useful method involves looking at samples of your lung tissue for LAM
cells.
You may want to see a doctor who specializes in LAM
for this test. Several procedures can be used to get a sample of lung
tissue.
Video-assisted thoracoscopy
(tho-rah-KOS-ko-pe). In this procedure, also called VAT, your doctor
inserts a small, lighted tube into little cuts made in your chest wall. This
lets him or her look inside your chest and snip out a few small pieces of lung
tissue.
This procedure is done in a hospital. The procedure
isnt major surgery, but it does require general anesthesia (that is,
youre temporarily put to sleep during the procedure).
Open lung biopsy. In this
procedure, your doctor removes a few small pieces of lung tissue through a cut
made in your chest wall between your ribs. An open lung biopsy is done in the
hospital, while youre temporarily put to sleep.
This procedure is rarely done anymore because the
recovery time is much longer than the recovery time from VAT.
Transbronchial biopsy. In this
procedure, your doctor inserts a long, narrow, flexible, lighted tube down your
windpipe and into your lungs. He or she then snips out bits of lung tissue with
a tiny device.
This procedure usually is done in a hospital. Your
mouth and throat are numbed to prevent pain. You usually can go home right
after the procedure.
The amount of tissue thats removed is very
small, so this test doesnt always provide enough information.
Other biopsies. LAM also can be
diagnosed using the results of other tissue biopsies, such as biopsies of lymph
nodes or lymphatic tumors called lymphangiomyomas.
Other Tests
If youre diagnosed with sporadic LAM, your
doctor may advise you to have a computed tomography (CT) scan or magnetic
resonance imaging (MRI) scan of your head. These tests can help screen for
underlying
tuberous sclerosis complex (TSC).
CT and MRI scans will reveal TSC in only a small
fraction of people who are diagnosed initially with sporadic LAM.
Researchers are exploring other tests that may help
diagnose LAM. These tests include blood tests for the LAM cells or a blood
vessel growth factor called VEGF-D. |