What Is LAM?
LAM, or lymphangioleiomyomatosis
(lim-FAN-je-o-LI-o-MI-o-ma-TO-sis), is a rare lung disease. It mostly affects
women in their mid-thirties and forties.
In LAM, abnormal, muscle-like cells begin to grow
out of control in certain organs or tissues, especially the lungs, lymph nodes,
and kidneys.
Over time, these LAM cells can grow throughout the
lungs and destroy the normal lung tissue. As a result, air cant move
freely in and out of the lungs. In some cases, this means the lungs cant
supply the bodys other organs with enough oxygen.
Overview
There are two forms of LAM. Sporadic LAM occurs for
unknown reasons. LAM also can occur in women who have a rare disease called
tuberous sclerosis complex (TSC). Women who have TSC often
have a milder form of LAM.
About 6 out of 10 women who have LAM develop
pneumothorax
(noo-mo-THOR-aks), or collapsed lung. In this condition, air leaks out of a
lung and into the space between the lung and the chest wall (the pleural
space).
This condition can cause pain and shortness of
breath. Sometimes one lung will collapse over and over again. Pneumothorax is a
serious condition that usually requires treatment and can sometimes be life
threatening.
Normal Lungs and Lungs With LAM
Figure A shows the location of the
lungs and airways in the body. The inset image shows a cross-section of a
healthy lung. Figure B shows a view of the lungs with LAM and a collapsed lung
(pneumothorax). The inset image shows a cross-section of a lung with LAM.
Many women who have LAM get tumors called
angiomyolipomas (AN-je-o-my-o-li-PO-mas), or AMLs, in their kidneys. Women who
have LAM also may develop:
- Growths in other organs, including the liver and
brain
- Large tumors in their lymph nodes
- A buildup of fluid in their chests, abdomens, or
pelvic areas
Outlook
LAM has no cure. The disease tends to worsen over
time. How quickly the disease worsens varies from woman to woman. LAM may lead
to death from respiratory failure. Lung transplant is a treatment option for
women whose lungs have been damaged by LAM.
Not long ago, doctors thought women who had LAM
wouldn't live more than 10 years following diagnosis. They now know that some
women may survive for more than 20 years after diagnosis.
Doctors have learned a lot about LAM in recent
years. They're now able to diagnose the condition earlier. Support services
also are now available to help improve the quality of life for women who have
LAM.
Researchers continue to explore and test new
treatments for LAM.
What Causes LAM?
The cause of LAM and why it mainly affects women
isn’t known. Recent studies show that sporadic LAM has some of the same
traits as another rare disease called
tuberous sclerosis complex (TSC). This has begun to provide
some valuable clues about what causes LAM.
The common features of sporadic LAM and TSC are:
- Kidney growths. People who have TSC get growths
in their kidneys. These growths are the same as the angiomyolipomas that many
women who have LAM get in their kidneys.
- Lung cysts. About 1 out of every 3 women who has
TSC gets cysts in her lungs. These cysts are the same as the ones that women
who have sporadic LAM get in their lungs. When a woman who has TSC gets these
cysts in her lungs, the lung disease is called TSC-associated LAM or
TSCLAM.
TSC is a genetic disease. A defect in one of two
genes causes the disease. These genes are called TSC1 and TSC2. They normally
make proteins that control cell growth and movement in the body. In people who
have TSC, the genes are abnormal. The proteins that the genes make can’t
control cell growth and movement.
Women who have LAM also have abnormal TSC1 and TSC2
genes. Researchers have found that these genes play a role in causing LAM. This
finding is leading to new treatments for LAM.
Because LAM mostly affects women, the hormone
estrogen also may play a role in causing LAM.
Who Is At Risk for LAM?
Except for rare cases, LAM only affects women. More
than 70 percent of women who develop LAM are between the ages of 20 and 40 when
they begin to have symptoms. However, LAM can occur in women as old as 80.
More than 800 women in the United States have been
diagnosed with either sporadic LAM or TSCLAM.
Many more women may have LAM and not know it. They
may have been wrongly diagnosed with another, more common lung disease, such as
emphysema (em-fi-SE-ma),
asthma,
or bronchitis (brong-KI-tis).
LAM affects about 3 out of every 10 women who have
TSC. Thus, as many as 10,000 women in the United States who have TSC also may
have undiagnosed LAM. Many of these women may have mild cases of LAM that
don’t cause symptoms. Not everyone who has TSC and LAM has lung symptoms.
What Are the Signs and Symptoms of LAM?
The uncontrolled growth of LAM cells and their
effect on nearby body tissues causes the signs and symptoms of LAM. The most
common signs and symptoms are:
- Shortness of breath, especially during activity.
At first, shortness of breath may occur only during high-energy activities.
Over time, you may have trouble breathing even during simple activities, such
as dressing and showering.
- Chest pain or aches. This pain may be worse when
you breath in.
- Frequent cough. This may occur with bloody phlegm
(a sticky fluid).
- Wheezing (a whistling sound when you
breathe).
Other signs and symptoms of LAM include:
- Pneumothorax,
or collapsed lung. This condition can occur if lung cysts rupture through the
lining of a lung. Air that collects in the space between the lung and chest
wall must be removed to reinflate the lung.
- Pleural
effusions. This condition can occur if bodily fluids collect in the space
between the lung and the chest wall. Often the fluid contains a milky substance
called chyle. The excess fluid in the chest may cause shortness of breath
because the lung has less room to expand.
- Blood in the urine. This sign may occur in women
who have kidney tumors called angiomyolipomas.
- Enlarged lymph nodes. These usually occur in the
abdomen or the chest. Very rarely, enlarged lymph nodes may occur in locations
where they can be felt, such as the neck or under the arms.
- Abdominal swelling, sometimes with pain.
- Swelling in the legs, ankles, or feet.
Other diseases also can cause many of these signs
and symptoms. Its important to see your doctor and find out whats
causing these problems.
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.
How Is LAM Treated?
Currently, no treatment is available to stop the
growth of the cysts and cell clusters that occur in LAM.
An experimental medicine, rapamycin (sirolimus),
shows promise in shrinking tumors in the kidneys of women who have LAM. Studies
are under way to find out if this medicine improves lung function in women who
have LAM.
Most treatments for LAM are aimed at easing symptoms
and preventing complications. The main treatments are:
- Medicines to improve air flow in the lungs and
reduce wheezing
- Oxygen therapy
- Procedures to remove fluid from the chest or
abdomen and stop it from building up again
- Procedures to shrink angiomyolipomas (AMLs)
- Lung transplant
- Hormone therapy
Medicines
Medicines That Help You Breathe Better
Certain medicines can help open your lungs so that
you can breathe better.
Bronchodilators are medicines that relax the muscles
around the airways. This helps the airways open up, making it easier for you to
breathe. About 1 out of 4 women who has LAM breathes better with the use of
bronchodilators.
Lung
function tests can sometimes show whether these medicines are likely to
help you.
Medicines That Prevent Bone Loss
Women who have LAM are at risk for a bone-weakening
condition called osteoporosis (OS-te-o-po-RO-sis). This is in part because many
LAM therapies block the estrogen action needed to keep bones strong.
To prevent osteoporosis, your doctor may measure
your bone density. If you have lost bone density, your doctor may prescribe
medicines that prevent bone loss. He or she also may prescribe calcium and
vitamin D supplements.
Rapamycin
Rapamycin (sirolimus) is the first medicine to be
tested as a treatment for slowing or stopping the growth of LAM cell
clusters.
This medicine was originally developed to prevent
the immune system from rejecting kidney transplants. However, studies show that
rapamycin helps regulate the abnormal growth and movement of LAM cells.
A study on a small number of women who have LAM
and/or TSC found that rapamycin shrank kidney tumors by 50 percent over 1 year.
The medicine also seemed to improve lung function in some women who have
LAM.
However, the study showed that the medicine had a
number of side effects. Thus, more research is needed to see how well this
medicine works in women who have LAM, and whether its risks outweigh its
benefits.
Oxygen Therapy
If the level of oxygen in your blood is low, your
doctor may suggest oxygen therapy. Oxygen usually is given through nasal prongs
or a mask. At first, you may only need oxygen while exercising. It also may
help to use it while sleeping. Over time, you may need full-time oxygen
therapy.
A standard
exercise
stress test or a 6-minute walk test can show whether you need oxygen while
exercising. A 6-minute walk test measures the distance you can walk in 6
minutes. An exercise stress test measures how well your lungs and heart work
while you walk on a treadmill or pedal a stationary bike.
You also may need a
blood
test to show what your oxygen level is and how much oxygen you need.
Procedures To Remove Air or Fluid From the Chest or
Abdomen
Several procedures help remove air or fluid from
your chest and abdomen. These procedures also help prevent air or fluid from
building up again.
Removing fluid from your chest or abdomen may help
relieve discomfort and shortness of breath. The procedure to remove fluid from
the chest is called
thoracentesis
(THOR-a-sen-TE-sis). The procedure to remove fluid from the abdomen is called
paracentesis (PAR-a-sen-TE-sis).
Your doctor often can remove the fluid with a needle
and syringe. If large amounts of fluid build up in your chest, your doctor may
have to insert a tube into your chest to remove the fluid.
Removing air from your chest may relieve shortness
of breath and chest pain caused by a collapsed lung. Your doctor usually can
remove the air with a tube. The tube is inserted into your chest between your
side ribs. Often, the tube is attached to a suction device. If this procedure
doesn't work, or if your lungs collapse often, you may need surgery.
If fluid and air often leak into your chest, your
doctor may inject a chemical at the site of the leakage. The chemical fuses
your lung and chest wall together. This removes the space for leakage.
Your doctor may do this procedure at your bedside in
the hospital. You will be given medicine to prevent pain. The procedure also
may be done in an operating room using video-assisted thoracoscopy. In this
case, you will temporarily be put to sleep for the procedure.
Procedures To Remove or Shrink Angiomyolipomas
AMLs often dont cause symptoms, but sometimes
they can cause ongoing pain or bleeding. If this happens, you may need surgery
to remove some of the tumors.
If bleeding isnt too severe, a radiologist can
often block the blood vessels feeding the AMLs. This may cause them to
shrink.
Lung Transplant
A lung transplant improves lung function and quality
of life in patients who have advanced LAM.
Lung transplants have a high risk of complications.
These include infections and rejection of the transplanted lung by the body.
Studies suggest that more than three-quarters of
women with LAM who receive a lung transplant survive for at least 3 years.
In a few cases, doctors have found LAM cells in the
newly transplanted lungs and other parts of the body. However, LAM cells
dont seem to stop the transplanted lung from working.
Hormone Therapy
Estrogen is thought to play a role in causing LAM.
Thus, your doctor may want to treat you with a hormone therapy that limits the
effects of estrogen on your body.
Hormone therapy can be taken as a pill or with
regular shots. Some doctors also suggest surgery to remove the ovaries. This
causes menopause and greatly reduces estrogen levels in the body.
Unfortunately, at this time, theres no clear
evidence that this type of treatment is effective for LAM.
Living With LAM
In the early stages of LAM, you usually can do your
normal daily activities. These may include attending school, going to work, and
doing common physical activities such as walking up stairs.
In the later stages of LAM, it may be harder for you
to be active. You also may need oxygen therapy full time.
Ongoing Care
Getting ongoing medical care is important. You may
need to see a pulmonologist. This is a doctor who specializes in treating lung
diseases and conditions. These specialists usually are located at major medical
centers.
Take steps to care for your lungs. Get a flu shot
every year and a
pneumonia
shot every 5 years.
Lifestyle Changes
Take good care of your health. This means following
the same healthy lifestyle thats recommended for all Americans. Follow a
healthy eating plan, get as much physical activity as you can, and get plenty
of rest. If you smoke, try to quit. Talk to your doctor about programs and
products that can help you quit smoking.
You also should check with your doctor before
traveling by air or traveling to areas where medical attention isnt
readily available. Also, talk to your doctor before traveling to places where
the amount of oxygen in the air is low.
Pregnancy and Birth Control
If your lung function is normal, pregnancy may be an
option. However, hormones during pregnancy might worsen your LAM. Therefore,
you should discuss a possible pregnancy with both a pulmonologist who
specializes in LAM and your obstetrician.
Most doctors dont recommend birth control
pills containing estrogen to women who have LAM. Talk to your doctor about
birth control options.
Support Groups
You may find it helpful to join a LAM support group.
Information about patient support groups is available from the National Heart,
Lung, and Blood Institute (NHLBI) Health Information Center at
3015928573 or the National Institutes of Health/NHLBI
Pulmonary-Critical Care Branch at 1877NIHLUNG
(18776445864), extension 3.
Key Points
- LAM, or lymphangioleiomyomatosis, is a rare lung
disease. It mostly affects women in their mid-thirties and forties.
- In LAM, abnormal, muscle-like cells begin to grow
out of control in certain organs or tissues, especially the lungs, lymph nodes,
and kidneys.
- Over time, these LAM cells can grow throughout
the lungs and destroy the normal lung tissue. As a result, air cant move
freely in and out of the lungs. In some cases, this means the lungs cant
supply the bodys other organs with enough oxygen.
- LAM also can lead to
pneumothorax
(collapsed lung), angiomyolipomas (AMLs), growths in certain organs, large
tumors in the lymph nodes, and a buildup of fluid in the chest, abdomen, or
pelvic area.
- There are two forms of LAM. Sporadic LAM occurs
for unknown reasons. LAM also can occur in women who have a rare disease called
tuberous sclerosis complex (TSC). Women who have TSC often
have a milder form of LAM.
- The cause of LAM and why it mainly affects women
isnt known. Sporadic LAM has some of the same traits as TSC. The abnormal
genes that cause TSC also play a role in causing LAM.
- Except for rare cases, LAM only affects women.
More than 70 percent of women who develop LAM are between the ages of 20 and 40
when they begin to have symptoms. LAM affects about 3 out of every 10 women who
have TSC.
- The uncontrolled growth of LAM cells and their
effect on nearby body tissues causes the signs and symptoms of LAM. The most
common signs and symptoms are shortness of breath, especially during activity;
chest pain or aches; frequent cough; and wheezing.
- Methods for diagnosing LAM have improved.
Its 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.
- Currently, no treatment is available to stop the
growth of the cysts and cell clusters that LAM causes. Most treatments for LAM
are aimed at easing symptoms and preventing complications. Treatments include
medicines, oxygen therapy, procedures to remove fluid from the chest or
abdomen, procedures to remove AMLs, lung transplant, and hormone therapy.
- An experimental medicine, rapamycin (sirolimus),
shows promise in shrinking tumors in the kidneys of women who have LAM. Studies
are under way to find out whether this medicine improves lung function in women
who have LAM.
- In the early stages of LAM, you usually can do
your normal daily activities. In the later stages of LAM, it may be harder for
you to be active. You also may need oxygen therapy full time. If you have LAM,
you can take steps to care for yourself. Get ongoing medical care. Following a
healthy lifestyle, including a healthy eating plan.
- Researchers continue to look for the causes of
LAM and for better treatments.
Links to Other Information About LAM
Non-NHLBI Resources
Clinical Trials
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