Causes - LAM
Researchers do not know the exact cause of LAM or why it mainly affects women, but they believe genes and the female hormone estrogen play a role.
People with LAM or TSC-LAM have abnormal TSC1 or TSC2 genes. These genes are known to cause another rare genetic disease called tuberous sclerosis complex (TSC).
Abnormal TSC genes make proteins that cannot control cell growth and cell movement in the body. As a result, abnormal muscle-like cells begin to grow out of control in certain organs or tissues, such as the lungs, kidney, and lymph nodes. These abnormal cell growths cause the signs, symptoms, and complications of LAM.
Estrogen is thought to play a role in LAM because the condition:
- Primarily affects women.
- Worsens in a pattern that matches up with a women’s menstrual cycle, during pregnancy, and after using medicines such as birth control that contain estrogen.
- Has been known to stop worsening in some women who have entered menopause.
Visit Treatment to read the latest clinical recommendations about not using hormone therapy to treat LAM.
Risk Factors - LAM
LAM is a rare disease that mostly affects women of childbearing age. LAM can occur in older women as well, although this is less common. Women with tuberous sclerosis complex (TSC) have an increased risk of developing TSC-LAM.
In rare cases, LAM has been reported in men.
Signs, Symptoms, and Complications - LAM
The uncontrolled growth of LAM cells and their effect on nearby body tissues causes the signs, symptoms, and complications of LAM. Symptoms tend to start when women are between the ages of 20 and 40.
Usually, TSC-LAM is milder than sporadic LAM and may not cause symptoms affecting the lungs. However, the severity of the disease varies from patient to patient and it is still possible for some women with sporadic LAM to also have mild disease without symptoms and some women with TSC-LAM to have more severe disease with worse symptoms and complications.
Signs of LAM are:
- Lung cysts detected by chest imaging tests
- Increased VEGF-D levels in the blood. VEGF-D is a vascular growth factor involved in tumor spread.
- Reduced lung function
- Reduced oxygen levels in the blood
The most common symptoms are:
- Chest pain or aches that may worsen when you breathe in.
- Fatigue that may affect your overall quality of life.
- Frequent cough that may occur with bloody phlegm.
- Shortness of breath that at first may occur only during high-energy activities but over time may happen after simple activities such as dressing and showering.
- Wheezing or a whistling sound when you breathe.
Possible complications of LAM include any of the following:
- Angiomyolipomas and other tumors. Many women who have LAM get tumors in their kidneys, called angiomyolipomas. Women who have LAM also may develop large tumors in the lymph node or growths in other organs such as the liver.
- Blood in the urine. This may occur in women who have kidney tumors.
- 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.
- 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 chylothorax. The excess fluid in the chest may cause shortness of breath because the lung has less room to expand.
- Pneumothorax or collapsed lung. This potentially life-threatening condition occurs when air leaks out of the lung and into the space between the lung and chest wall, an area called the pleural space. In LAM, a pneumothorax 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. A collapsed lung can cause pain and shortness of breath. Sometimes one lung will collapse repeatedly. Pneumothorax usually requires urgent medical care and treatment.
- Swelling or the build-up of fluid. This can happen in the abdomen, pelvic area, legs, ankles or feet. Pain may also occur with the swelling.
What causes the signs, symptoms and complications of LAM?
When a person has 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 destroy the normal lung tissue. As a result, air no longer moves freely in and out of the lungs. In some cases, this means the lungs can’t supply enough oxygen to the body’s other organs.
Diagnosis - LAM
Methods for diagnosing LAM have improved, making it possible to diagnose the disease at an early stage. LAM is diagnosed based on your medical history and the results from diagnostic lung function tests, imaging tests such as high-resolution CT scans, VEGF-D blood tests, or other procedures. To help diagnose your condition, you may want to see a pulmonologist, a doctor who specializes in lung diseases and conditions, who has experience providing care to patients with LAM.
Your doctor will ask you about your medical history to see if you have signs and symptoms related to LAM. Your doctor may ask how long you’ve had symptoms and whether they’ve become worse over time.
Many women may not know they have it because many of LAM’s signs and symptoms are the same as those of other diseases, such as asthma, emphysema, and bronchitis. But, your doctor will want to rule out those other conditions before making a final diagnosis.
Diagnostic tests and procedures
Your doctor may recommend tests to show how well your lungs are working and what your lung tissue looks like. These tests can show whether your lungs are delivering enough oxygen to your blood. You also may have tests to check for complications of LAM.
Lung function tests
- Lung function tests. For lung function tests, you breathe through a mouthpiece into a machine called a spirometer. The spirometer measures the amount of air you breathe in and out. Other lung function tests can show how much air your lungs can hold and how well your lungs deliver oxygen to your blood.
- Arterial blood gas tests. Your doctor may take a blood sample from an artery in your wrist to measure your blood oxygen levels and to determine if you need oxygen therapy.
- Pulse oximetry. For this test, a small sensor is attached to your finger or ear. The sensor uses light to estimate how much oxygen is in your blood.
- Six-minute walk test. This test measures the distance you can walk in six minutes. It can help determine if you need oxygen therapy while exercising.
- Chest x ray. A chest x ray creates a picture of the structures in your chest, such as your heart and lungs. The test 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 detect cysts in your lungs and assess how cysts change over time.
- High-resolution CT (HRCT) scan. The most useful imaging test for diagnosing LAM is a high-resolution CT scan of the chest. This test creates a computer-generated picture of your lungs. The picture shows more detail than the pictures from a chest x ray. An HRCT scan can show cysts, excess fluid, a collapsed lung, and enlarged lymph nodes. The test 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.
Blood tests for VEGF-D
Your doctor may take a blood sample from a vein in your arm to measure VEGF-D levels. The VEGF-D blood tests test may help confirm the diagnosis of LAM in patients whose HRCT scans show lung cysts that suggest a patient has LAM.
VEGF-D levels of 800 pg/mL (picograms per milliliter) or more can help your doctor confirm that you have LAM. Because you may still have LAM if your levels are less than 800 pg/mL, your doctor may have you undergo other diagnostic procedures that look for LAM cells.
If lung function, imaging, or blood VEGF-D tests cannot diagnose LAM, your doctor may recommend one of the following procedures to collect tissue samples that can be used to detect LAM cells.
- Video-assisted thoracoscopic surgery (VATS). In this procedure, 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. VATS is done in a hospital. The procedure isn’t major surgery, but it does require general anesthesia to make you 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 a hospital. You’ll be given medicine to make you sleep during the procedure. Open lung biopsies are rarely done anymore because the recovery time is much longer than the recovery time from VATS.
- 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 using a tiny device. This procedure usually is done in a hospital. Your mouth and throat are numbed to prevent pain. Because only a small amount of tissue is collected, it is possible that this test will not provide enough information.
- Other biopsies. Your doctor also can diagnose LAM using the results from other tissue biopsies, such as biopsies of lymph nodes or abdominal or pelvic lesions.
If your chest imaging tests show that you have pleural effusions, your doctor may order a pleural fluid analysis. For this test, a fluid sample is taken from the pleural space, which is a thin space between two layers of tissue that line the lungs and chest cavity. Doctors use a procedure called thoracentesis to collect the fluid sample. The fluid is studied for the milky substance called chylothorax.
If you’re 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), a condition that can also cause kidney growths and lung cysts. If a woman who has cysts in her lungs is found to have TSC, the doctor will diagnose TSC-associated LAM or TSC–LAM.
Treatment - LAM
While there is no cure for LAM, doctors treat LAM with sirolimus (rapamycin), a medicine that stabilizes lung function, treats an abnormal fluid buildup in the lung called chylothorax, and improves overall quality of life. They may also prescribe other medicines or therapies to control other symptoms or complications.
You may want to see a pulmonologist doctor who specializes in lung diseases and conditions, especially LAM, to help treat your condition. You may also want to ask your doctor about the latest American Thoracic Society clinical guidelines for diagnosis and management of LAM which include new treatment recommendations.
Your doctor may prescribe sirolimus (rapamycin) to treat your condition, or bronchodilators or oxygen therapy to help you breathe better. Lung function tests can sometimes show whether these medicines are likely to help you.
- Sirolimus (rapamycin). Studies have shown that sirolimus helps regulate the abnormal growth and movement of LAM cells. Sirolimus stabilizes lung function and improves quality of life, shrinks abnormal kidney and lymph node growths, and reduces abnormal fluid in the lung called chylothorax. The latest clinical guidelines recommend sirolimus for people with LAM if they have abnormal or declining lung function or in some patients with LAM who have pleural effusions containing chylothorax. Sirolimus may also reduce the size of angiomyolipomas and therefore may be a treatment option before procedures that remove or shrink kidney tumors. Sirolimus does have side effects, some of which can be serious. If you have LAM, talk with your doctor about the benefits and risks of this medicine, and whether it’s an option for you.
- Bronchodilators. If you’re having trouble breathing or are wheezing, your doctor may prescribe bronchodilators. These medicines relax the muscles around the airways. This helps the airways open up, making it easier for you to breathe.
- 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 need oxygen only while exercising. It also may help to use it while sleeping. Over time, you may need full-time oxygen therapy.
The latest clinical guidelines, which are based on currently available clinical data, do not recommend the following medicines to treat LAM:
- Doxycycline, an antibiotic that did not show a clinical benefit when used to treat LAM.
- Hormone therapies including certain medicines—progestins, gonadotrophin-releasing hormone (GnRH) agonists, selective estrogen receptor modulators (SERMs) such as tamoxifen—or surgical procedures such as . While these therapies had previously been used to treat LAM, newer analyses suggest they do not produce clinical benefit in all patients with LAM. If you are taking any of these hormone medicines, talk to your doctor to see if you need to discontinue their use.
Living With will discuss medicines your doctor may prescribe to help prevent complications such as osteoporosis.
Procedures that remove air or fluid from the chest or abdomen
Several procedures can remove excess air or fluid from your chest or abdomen. Removing fluid from your chest by thoracentesis or from your abdomen by paracentesis may help relieve discomfort and shortness of breath.
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 pneumothorax, or 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 repeatedly collapse, you may need surgery.
If fluid or air often leak into your chest, your doctor may recommend a procedure called pleurodesis to prevent repeat episodes. Your doctor may inject a chemical at the site of the leakage. The chemical fuses your lung and chest wall together, which 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 can be done in an operating room using video-assisted thoracoscopy. In this case, you will be given medicine to make you sleep during the procedure.
Procedures that remove or shrink kidney tumors
Kidney tumors, or angiomyolipomas, often don't cause symptoms, but sometimes they can cause ongoing pain or bleeding. If this happens, you may need surgery to remove some of them. If bleeding isn't too severe, a radiologist often can block the blood vessels feeding the kidney tumors. This may cause them to shrink.
Some patients who have severe lung damage due to advanced LAM may be eligible for lung transplants. While lung transplants can improve lung function and quality of life for eligible patients, they have a high risk of complications, including 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. However, the LAM cells generally don't stop the transplanted lung from working.
Living With - LAM
Not long ago, doctors thought women who had LAM wouldn't live more than 10 years after diagnosis. With earlier diagnosis and newer treatment, patients with LAM are living longer, with some living more than 20 years after diagnosis.
For your follow-up care, you may want to see a pulmonologist, a doctor who specializes in lung diseases and conditions, and who has experience providing care to patients with LAM. Your doctor will monitor your condition to see if it is stable or getting worse and causing serious complications. Also, your doctor may recommend other medical care, including vaccines, lifestyle changes, and pregnancy and birth control planning.
Monitor your condition
If you have LAM, it is important for you to have routine follow-up care so your doctor can monitor your condition to see if it is stable or worsening. LAM has no cure, and the disease tends to worsen over time. How quickly the disease worsens varies between patients.
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, you may find it harder to be active and you may need oxygen therapy.
Serious and possibly life-threatening complications can occur if you have LAM. More than half of women who have LAM develop pneumothorax, or collapsed lung. LAM may cause death from respiratory failure. Read more about possible signs, symptoms and complications of LAM.
Receive other medical care
In addition to monitoring your condition, your doctor may recommend emotional support to improve your quality of life, vaccines to prevent lung infections, lifestyle changes to improve your overall health and avoid some complications, tests or medicines to care for your bones, and pregnancy and birth control options.
Living with LAM may cause fear, anxiety, depression, and stress. Your doctor can evaluate how your condition is affecting your activity level and mental health. To improve your quality of life, your doctor may recommend medicines to treat pain, fatigue, or mental health concerns or serious depression that you may have.
Other steps you can take that may help include:
- Seeking support from family and friends to help relieve stress and anxiety. Let your loved ones know how you feel and what they can do to help you.
- Talking with your doctors or a professional counselor about how you feel.
- Joining a patient support group to help you adjust to living with LAM.
- Contacting the NHLBI Health Information Center for resources or help identifying patient support groups.
- Obtaining more information about your condition.
Vaccines for lung health
Take steps to care for your lungs. For example, talk with your doctor about getting a pneumococcal pneumonia vaccine and a yearly influenza or flu shot. Visit the Centers for Disease Control and Prevention (CDC) Web pages for more information about:
If you have LAM, taking good care of your health is important. Your doctor may recommend you adopt the following healthy lifestyle changes, many of which are also heart-healthy.
- Make healthy eating choices.
- Be physically active.
- Get plenty of rest.
- Quit smoking. Talk to your doctor about programs and products that can help you quit smoking. If you have trouble quitting smoking on your own, consider joining a support group. Many hospitals, workplaces, and community groups offer classes to help people quit smoking. Ask your family members and friends to support you in your efforts to quit.
Also, check with your doctor before traveling by air or traveling to areas where medical attention isn't readily available. Also, talk to your doctor before traveling to places where the amount of oxygen in the air is low.
Care for your bones
Some women who have LAM may be at risk forif they have undergone permanent hormonal therapy such as oophorectomy or are receiving certain hormone therapy medicines. This is in part because many hormone therapies affect estrogen, and estrogen is important for keeping bones strong. While newer clinical guidelines do not recommend hormone therapies for the treatment of LAM, your doctor may order tests to measure your bone density if you have previously had an oophorectomy or are still on hormone therapies for other conditions. If you have lost bone density, your doctor may prescribe medicines or calcium and vitamin D supplements to prevent more bone loss.
Pregnancy and birth control planning
Because hormone changes during pregnancy can worsen LAM, it is important to talk to your pulmonologist and obstetrician before you get pregnant.
Most doctors don't recommend birth control pills containing estrogen to women who have LAM because estrogen is thought to contribute to or worsen LAM. If you have LAM, talk to your doctors about birth control options.
Research for Your Health - LAM
The NHLBI is part of the U.S. Department of Health and Human Services’ National Institutes of Health (NIH)—the nation’s biomedical research agency that makes important scientific discovery to improve health and save lives. We are committed to advancing science and translating discoveries into clinical practice to promote the prevention and treatment of heart, lung, blood, and sleep disorders including LAM. Learn about the current and future NHLBI efforts to improve health throughand scientific discovery.
Improving health with current research
Learn about some of the ways we continue to translate current research into improved health for people with LAM.
- Building on past NIH-sponsored research on sirolimus (rapamycin) as a treatment for LAM. In 2011, the NIH funded Multicenter International LAM Efficacy of Sirolimus (MILES) trial published key findings. NHLBI researchers supported the MILES trial, which showed sirolimus to be a safe and effective treatment for LAM. Read about how NHLBI continues to perform and fund research on sirolimus as a treatment of LAM. Read the NIH Media Availability: Sirolimus Therapy Alleviates Symptoms of Lung Disease LAM or Lessons from the MILES trial to learn about the NIH-supported scientific discovery that led to the current use of sirolimus to treat LAM.
- Trans-NIH funding of the Rare Lung Diseases Consortium (RLDC). NHLBI co-funds some RLDC activities with NIH’s National Center for Advancing Translational Sciences (NCATS). Through funding the RLDC, NHLBI is supporting new clinical trials for LAM. Learn more about the RLDC, including its role with the Rare Lung Disease-Clinic Network and the annual international LAM research conferences it helps organize.
Learn about some of the research contributions we have made over the years to help improve clinical care and increased the life expectancy for people LAM.
- NHLBI Working Group on LAM. In 1995, the NHLBI organized a working group on LAM to determine what was needed to help find the cause and possible treatments for LAM. A critical recommendation from this group was to create a national LAM registry to store tissue and other biological specimens from LAM patients as a way to support basic and clinical research.
- NHLBI support for the LAM Registry and National Disease Research Interchange. In 1997, the NHLBI co-funded this national registry to obtain clinical data and blood and tissue samples from LAM patients. In 2007, management of the data and materials form this registry were transferred to the National Disease Research Interchange (NDRI). NHLBI helps fund NDRI activities, which include the collection and distribution of fresh LAM tissue to qualified researchers.
Advancing research for improved health
In support of our mission, we are committed to advancing LAM research in part through the following ways.
- We perform research. Our Division of Intramural Research, specifically its Cardiovascular and Pulmonary Branch, has an active Translational Research Section and Lymphangioleiomyomatosis (LAM) Research Program that was the Nation’s first research program focused on LAM. Read Participate in NHLBI Clinical Trials to learn more about any open and enrolling LAM clinical trials that our researchers are leading, such as our Multicenter International Durability and Safety of Sirolimus in LAM trial called MIDAS.
- We fund research. The research we fund today will help improve our future health. Our Division of Lung Diseases (DLD) oversees the LAM research that we fund. Watch a video of how past NHLBI funding has supported genetic research in LAM. Search the NIH Research Portfolio Online Reporting Tools (RePORT) to learn about research NHLBI is funding on LAM, including RLDC Multicenter Interventional Lymphangiomyomatosis Early Disease (MILED) trials that are studying whether early sirolimus use can prevent LAM from worsening. Read Participate in NHLBI Clinical Trials to learn more about any open and enrolling LAM clinical trials that we fund.
- We stimulate high-impact research. The NHLBI Trans-Omics for Precision Medicine (TOPMed) Program has the potential to help advance LAM research by helping to define lung health across the lifespan so we can more precisely determine when disease begins. Through TOPMed and other collaborations, we hope to advance science so health professionals will be able to better predict who will develop lung diseases, identify subtypes of disease, and deliver personalized interventions to preempt, prevent, and treat disease. Our Strategic Research Priorities highlight ways we may support research over the next decade, including new efforts that may be relevant to LAM.
Learn about other exciting ways we are advancing research to help improve the lives of people with LAM, as well as their clinical care. This includes identifying better treatments and biomarkers for severe disease and to find out how well patients will respond to treatments.
- Exploring the molecular role of estrogen in LAM to find new treatments. Because LAM primarily affects women, estrogen is thought to play a role in this condition. NHLBI-funded research has discovered that known signaling pathways are activated by estrogen in LAM. These pathways may be possible targets for new therapies in LAM, and NHLBI is funding research in this area.
- Biomarkers to predict which LAM patients will respond to sirolimus (rapamycin) treatment. Researchers from the NHLBI-funded MILES trial are trying to see whether VEGF-D can be a biomarker for LAM severity and help doctors predict which patients will respond well to sirolimus treatment. Early findings suggest that patients who show decreased VEGF-D levels over the course of sirolimus treatment are more likely to have improved lung function than patients whose VEGF-D levels are unaffected by sirolimus treatment.
- Participate in NHLBI Clinical Trials will discuss some of our open and enrolling LAM clinical trials.
The National Heart, Lung, and Blood Institute (NHLBI) leads or sponsors many studies aimed at preventing, diagnosing, and treating heart, lung, blood, and sleep disorders.
Are you an adult woman with LAM who wants to support future studies of a new treatment or biomarker of disease severity?
Are you an adult woman with LAM who wants to try albuterol to improve lung function?
Are you an adult woman with LAM interested in sirolimus or everolimus treatment?
Are you an adult woman with LAM who wants to support future studies of a new treatment?
Are you 16 or older with LAM and interested in helping LAM research?
Are you an adult with advanced lung disease?
Related Health Topics
After reading our LAM Health Topic, you may be interested in additional information found in the following resources.
- Emphysema (National Library of Medicine [NLM] MedlinePlus)
- Lymphangioleiomyomatosis (NLM Genetics Home Reference)
- Pneumococcal Vaccination (CDC)
- Seasonal Influenza (Flu) Vaccination (CDC)
- Tuberous sclerosis (NLM MedlinePlus)
- Tuberous Sclerosis Fact Sheet (National Institute of Neurological Disorders and Stroke)