What Is LAM?
LAM, or lymphangioleiomyomatosis
(lim-FAN-je-o-LI-o-MI-o-ma-TO-sis), is a rare lung disease that mostly affects
women in their mid-forties.
In LAM, an unusual type of cell begins to grow out
of control throughout your body, including in the lungs, lymph nodes and
vessels, and kidneys.
Over time, these LAM cells form cysts and clusters
of cells, which grow throughout the lungs and slowly block the airways. They
also destroy the normal lung tissue and replace it with cysts. As a result, air
cannot move freely in and out of the lungs, and the lungs cannot supply enough
oxygen to the bodys other organs.
More than 1 out of every 3 people with LAM also
develops growths called angiomyolipomas (AN-je-o-my-o-li-PO-mas), or AMLs, in
their kidneys. People with LAM also may develop:
- Growths in other organs, including the liver and
brain
- Large tumors on their lymph nodes
There currently is no cure for LAM.
The most common cause of death from LAM is
respiratory failure.
There are two forms of LAM:
- Sporadic LAM, which occurs for unknown
reasons
- An often milder form of LAM that occurs in people
with a rare inherited disease called
tuberous sclerosis complex
The term lymphangioleiomyomatosis comes
from the Greek. Lymph and angio refer to the lymph
vessels, and leiomyomas refers to the type of cells involved in
LAM.
Doctors have learned a lot about LAM in recent
years. They are now able to diagnose the condition earlier and provide support
services that improve patients quality of life. Not too long ago, doctors
thought that the life expectancy for women with LAM was less than 10 years
following diagnosis. We now know that some patients with LAM may survive for
more than 20 years.
What Causes LAM?
Researchers do not know what causes LAM, or why it
affects mostly women. They have recently discovered that LAM has some of the
same features as another rare disease called
tuberous sclerosis complex (TSC). This discovery has begun to
provide some valuable clues about what causes LAM.
The common features of LAM and TSC are:
- People with TSC develop growths in their kidneys
that are the same as the
angiomyolipomas that many people with LAM develop in their
kidneys.
- About 1 out of every 3 women who has TSC develops
cysts in her lungs that are the same as the ones women with LAM develop in
their lungs.
TSC is a genetic disease. It is caused by
abnormalities, or defects, in one of two genes. These genes are called TSC1 and
TSC2. Normally, they make proteins that control the growth of the cells in the
body. In people with TSC, the genes are abnormal, and the proteins that they
make cannot control cell growth and movement.
LAM patients also have abnormal versions of the TSC1
and TSC2 genes, and researchers have discovered that these genes play a role in
the development of LAM. More research on the TSC genes and the proteins that
they make should shed new light on the causes of LAM.
Since LAM mostly affects women in their mid-forties,
many doctors think that estrogen also plays a role in causing LAM.
Who Is At Risk for LAM?
LAM mostly affects women in their mid-forties. More
than 7 out of every 10 patients are between the ages of 20 and 40 when they
begin to have symptoms. But LAM may occur in women as old as 70 to 80. There
are also a few reports of LAM occurring in men.
Today, about 675 women in the United States have
been diagnosed with either LAM alone or LAM with
tuberous sclerosis complex. Scientists believe that many more
women have LAM, but they have been misdiagnosed with another more common lung
disease, such as emphysema,
asthma,
or bronchitis.
Since LAM affects about 3 out of every 10 women with
TSC, there may be as many as 10,000 women in the United States who have TSC and
undiagnosed LAM. Many of these women may have mild cases of LAM that are not
causing symptoms. Not all TSC patients who have LAM have lung problems.
What Are the Signs and Symptoms of LAM?
The signs and symptoms of LAM are caused by the
uncontrolled growth of the LAM cells.
The most common signs and symptoms are:
- Shortness of breath, especially following
exertion. At first, you may feel short of breath only during strenuous
activity. Over time, you may have trouble breathing even during rest.
- Chest pain, usually caused by a collapsed
lung.
- Frequent cough, sometimes with bloody
phlegm.
LAM also can lead to other serious conditions:
- About 6 of every 7 women with LAM develop a
collapsed lung (pneumothorax (noo-mo-THOR-aks)) at some point. Sometimes one
lung will collapse over and over again. Both lungs can collapse too. This is a
serious condition that can be life threatening. A lung that is only partly
collapsed may slowly re-expand without treatment, but treatment is often
required.
- In 1 out of every 3 women with LAM, a fluid
called lymph leaks into the chest cavity and builds up.
- Nearly half of the women with LAM develop growths
called
angiomyolipomas in their kidneys.
Many women with LAM also have:
- Blood or lymph in their sputum
- Blood in their urine
- Enlarged lymph nodes
- Abdominal swelling
Other diseases can cause many of these signs and
symptoms and complications, so it is important that you see a doctor.
How Is LAM Diagnosed?
Methods for diagnosing LAM have improved, and it is
now possible to diagnose it at an early stage.
Many of the signs and symptoms of LAM can be caused
by other diseases such as
asthma,
emphysema, and bronchitis. It is important for your doctor to rule out those
conditions before making a final diagnosis.
- Chest x ray. A chest x ray takes a picture of your heart and
lungs. It can show a collapsed lung or fluid in your chest cavity. In the early
stages of LAM, your chest x rays may look normal, but as the disease gets
worse, they may show cysts in your lungs.
- Lung function tests. For these tests, you breathe through a
mouthpiece into a machine called a spirometer (spi-ROM-e-ter). The spirometer
measures the amount of air you inhale and exhale and how fast your lungs move
it in and out. These tests also can provide an estimate of the amount of air
your lungs can hold, and how well your lungs can take oxygen into the
bloodstream.
- Exercise stress test. This test helps the doctor evaluate the
effect of exercise on your heart and lungs.
- Blood tests. The doctor takes a sample of your
blood from an artery in your arm and examines it to see whether your lungs are
providing enough oxygen to your blood. These tests may show low oxygen levels
in your blood even when you are resting. The doctor also may take a blood
sample from a vein in your arm to look at your blood cells and blood
chemistry.
- Pulse oximetry. A small sensor attached to your
fingertip also can give an estimate of the level of oxygen in your blood.
- High-resolution CT scan (HRCT). This test shows a
computer-generated picture of your lungs that has more detail than a chest x
ray. It is the most useful imaging test for diagnosing LAM. HRCT can show cysts
or shadows of cell clusters in your lungs, a collapsed lung, or 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 if you have growths
in your kidneys, other abdominal organs, or lymph nodes.
- Lung biopsy. Although the tests mentioned above sometimes
provide enough information for your doctor to diagnose LAM, the most useful
test involves removing samples of your lung tissue so they can be looked at
under a microscope. You should go to a doctor who specializes in LAM for this
test. Several procedures can be used to obtain lung tissue:
- Thoracoscopy (tho-rah-KOS-ko-pe). Your doctor
inserts a small, lighted tube (endoscope) into little incisions in your chest
wall. This lets him or her see the insides of your chest and snip out a few
small pieces of lung tissue. This procedure is done in a hospital, and you are
under general anesthesia. It is not major surgery, but it usually provides all
the tissue your doctor needs.
- Open lung biopsy. Your doctor removes a few small pieces of
lung tissue through an incision in your chest wall between your ribs. This
procedure also is done in the hospital, and you are under general anesthesia.
Recovery takes longer than recovery from thoracoscopy.
- Transbronchial biopsy. Your doctor inserts a
long, narrow, flexible, lighted tube (bronchoscope) down your windpipe, or trachea (TRA-ke-ah), into
your lungs. He or she then snips out bits of lung tissue with a tiny forceps.
This procedure is usually done in a hospital on an outpatient basis, and you
are under local anesthesia. Doctors usually are not able to remove enough
tissue to diagnose LAM with this procedure.
Some doctors recommend that once you are diagnosed
with LAM, you have
magnetic resonance imaging (MRI) of your head. This test can
show if you have signs of
tuberous sclerosis complex (TSC) or a growth in your brain
called a meningioma (me-NIN-je-O-mah). About 1 out of every 20 patients with
LAM has this kind of growth. It also appears in people with TSC.
The National Institutes of Health is studying
whether blood tests for the TSC1 and TSC2 genes may be helpful in diagnosing
LAM patients.
How Is LAM Treated?
There is no treatment available yet to slow or stop
the growth of the cell clusters and cysts that are the major feature of
LAM.
Most treatments for LAM are aimed at relieving
symptoms and preventing complications.
Since many women with LAM are now living so much
longer, doctors also focus on treating other health problems that happen with
menopause and aging.
The main treatments for LAM are:
- Medicines
- Oxygen therapy
- Procedures to remove fluid from the chest or
abdominal cavities and prevent it from building up again
- Procedures to remove
angiomyolipomas (AMLs)
- Lung transplantation
Medicines
Some medicines may help open your lungs so that you
can breathe more easily.
- Bronchodilators are drugs that relax the muscles
around the airways. As a result, the airways can open up, making it easier to
breathe. About 1 out of 5 women with LAM improves with the use of
bronchodilators.
- Octreotide and diuretics are sometimes used to
prevent the buildup of fluid in the chest cavity and abdomen. Octreotide may
reduce leakage of lymph into the abdominal or chest cavity.
Women with LAM have a greater chance of developing
osteoporosis (a condition that causes bones to become weak and brittle) than
other women. If you have LAM, your doctor should measure your bone density. If
you have lost bone density, your doctor may prescribe drugs that prevent bone
loss. He or she also may prescribe calcium and vitamin D supplements.
Physicians who think that estrogen may play a role
in the development of LAM usually treat their patients with hormone
therapy.
Oxygen Therapy
If the level of oxygen in your blood is low, you may
need oxygen therapy. Oxygen is usually given through nasal prongs or a mask. At
first, you may need oxygen only while exercising. It also may help to use it
while you are sleeping. Over time, you may need full-time oxygen therapy.
Your doctor may give you a standard
exercise stress test or a 6-minute walk test to find out
whether you need oxygen while exercising. A blood test will 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 abdominal cavities and prevent them from building up in your
chest cavity.
- Removing fluid from your chest or abdominal
cavities may help relieve abdominal discomfort and shortness of breath. Your
doctor can usually remove this fluid with a needle and syringe. If large
amounts of fluid build up in your chest cavity, your doctor may have to insert
a tube into your chest to remove it.
- Removing air from your chest cavity may relieve
shortness of breath and chest pain caused by a collapsed lung. Your doctor can
usually remove the air with a tube that is inserted into your chest cavity
between your side ribs. The tube is usually attached to a suction device. If
this procedure doesn't work, or if your lungs collapse frequently, you may need
surgery.
- If lymph and air leak into your chest cavity
often, your doctor may perform a procedure to fuse your lung and chest wall
together and remove space for leakage. This procedure is called pleurodesis
(ploo-ROD-e-sis). It involves injecting a chemical into the place where the
leakage is happening. Your doctor may do it at your bedside, while you are
under local anesthesia. It also can be done in the operating room by
video-assisted thoracoscopy surgery, while you are under general
anesthesia.
Procedures To Remove AMLs
If you have ongoing severe pain or bleeding caused
by AMLs, surgery to remove some of the abdominal growths may be helpful. If the
bleeding is not too severe, an experienced radiologist can often block the
blood vessels feeding the AMLs. This may cause them to shrink.
Lung Transplantation
Surgery to replace one or both of your lungs with
healthy lungs from a human donor may be helpful. Survival after a
lung transplant for LAM is probably better than survival after
a lung transplant for another condition, such as emphysema.
Lung transplantation has a high risk of
complications.
In a few cases, doctors have found LAM cells in the
new transplanted lungs and other parts of the body, but the LAM cells do not
seem to prevent the transplanted lung from working.
Possible New Treatments for LAM
Researchers are now studying several medicines as
possible treatments for LAM, including rapamycin.
Rapamycin (sirolimus) is the first drug to show
promise as a treatment that will slow or stop the development and growth of the
LAM cell clusters. Doctors now use it to prevent the immune system from
rejecting kidney transplants. Researchers are looking into whether this
medicine can reduce the size of kidney AMLs in LAM and
tuberous sclerosis complex (TSC) patients. They also are
planning a larger study of the effects of rapamycin, or another drug like it,
on TSC and LAM patients. This study will test whether the drug can prevent or
reverse the growth of the LAM cell clusters and cysts in other organs and slow
the decline of lung function.
Living With LAM
In the early stages of LAM, you usually can go about
your daily activities, including attending school, going to work, and
performing common physical activities such as walking up a hill. Later on, it
may be harder for you to be active. You also may require oxygen full time.
Ongoing medical care is important. Treatment by a
pulmonologist who specializes in LAM is recommended. These specialists are
usually located at major medical centers.
It is important for you to take good care of your
health. This means following the same healthy lifestyle that is recommended for
all Americans, including eating a healthy diet, being as physically active as
you can, and getting plenty of rest. You also should not smoke.
You should check with your doctor before traveling
by air or traveling to remote areas where medical attention is not readily
available. You also should ask about travel to places where the amount of
oxygen in the air is low.
If your lung function is normal, pregnancy may be an
option, but you should discuss it first with both a pulmonologist who
specializes in LAM and your obstetrician.
Most doctors do not recommend oral contraceptives
(birth control pills) containing estrogen. You also should avoid estrogen-rich
foods. Progesterone may be used as a contraceptive.
Joining a LAM support group can be helpful.
Information about patient support groups is available from the National
Institutes of Health/National Heart, Lung, and Blood Institute
Pulmonary-Critical Care Branch at 1877NIHLUNG
(18776445864), extension 3.
Key Points
- LAM is a rare lung disease that mostly affects
women in their mid-forties. It is sometimes seen in older women as well. It
almost never affects men.
- In LAM, clumps of cells and cysts grow throughout
the lungs. Over time, they destroy the normal lung tissue and block the flow of
air. They also reduce oxygen intake by the lungs.
- More than 1 out of every 3 women with LAM
develops growths called
angiomyolipomas (AMLs) in their kidneys.
- There are two forms of LAM: sporadic LAM, in
which the disease comes on for unknown reasons, and LAM that appears in people
with a rare inherited disease called
tuberous sclerosis complex (TSC).
- Doctors do not yet know what causes LAM. The
recent discovery of similarities between LAM and TSC has begun to provide some
valuable clues about the genes involved in both conditions.
- The symptoms of LAM include shortness of breath
(especially following periods of exertion), chest pain, and a frequent cough,
sometimes with bloody phlegm.
- LAM can lead to other serious conditions,
including a collapsed lung, blood in the urine, and abdominal swelling.
- To confirm or rule out LAM, doctors usually do a
chest x ray,
lung function tests, blood tests, pulse oximetry,
high resolution CT scans, and
lung biopsy.
- Doctors have not yet found any treatments to slow
or stop the growth of the cell clusters or cysts that are the main features of
LAM. As a result, most treatments are aimed at relieving symptoms and
preventing complications. These treatments include inhaled bronchodilators,
oxygen therapy, removal of air or fluid from your chest or abdominal cavities,
and lung transplantation.
- Several medicines are now being investigated as
possible treatments for LAM, including rapamycin.
- Most people with LAM can usually continue to be
active in the early stages of the disease. If the condition becomes worse, they
may not be able to be active, and they may need oxygen full time.
Links to Other Information About LAM
NHLBI Resources
Non-NHLBI Resources
Clinical Trials
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