LAM, or lymphangioleiomyomatosis, is a rare type of lung disease that affects mostly women of childbearing age (the years between puberty and menopause when it is possible to become pregnant).
In people who have LAM, abnormal muscle-like cells begin to grow out of control in the lungs and in the lymph nodes and kidneys. Over time, these LAM cells can destroy healthy lung tissue. As a result, fluid-filled pockets called cysts may develop, preventing air from moving freely in and out of the lungs. This can prevent oxygen from reaching the rest of the body.
There are two types of LAM.
- TSC-LAM occurs in some people who have a rare genetic disease called tuberous sclerosis complex (TSC).
- People who do not have TSC can develop sporadic LAM. Sporadic LAM is not hereditary, meaning you cannot pass it on to your children.
Symptoms of LAM may include shortness of breath, tiredness, and cough. LAM can be difficult to diagnose, as the symptoms often look like asthma, bronchitis, and other lung diseases.
Sometimes, LAM develops slowly. You may not discover you have LAM until you feel stabbing chest pain and have a hard time breathing. Both of these symptoms mean that air has leaked into the space between the chest wall and the lung, causing a collapsed lung (pneumothorax). This is a common complication of LAM that requires treatment right away.
If you are diagnosed with LAM, your doctor may prescribe medicine to help prevent more damage to your lungs and to treat other symptoms or health problems. Over time, LAM can cause permanent damage to the lungs or lead to respiratory failure, which happens when your blood doesn’t bring enough oxygen to your organs to keep them working well.
What causes LAM?
Most often LAM is caused by changes in the structure of one of two tuberous sclerosis complex (TSC) genes, called TSC1 and TSC2. These changes, or mutations, can also lead to a condition called tuberous sclerosis complex. Abnormal cells that behave like muscle cells appear and grow out of control in organs or tissues, such as the lungs, kidneys, and lymph nodes. The location and growth of these cells causes the symptoms of LAM.
Researchers believe that the hormone estrogen plays a role, because the condition affects mostly women after puberty and before menopause. The condition also gets worse during pregnancy and after using medicines with estrogen, such as birth control. After a woman goes through menopause, LAM sometimes stops getting worse.
People often begin to show symptoms of LAM between ages 20 and 40. Usually, TSC-LAM is not as serious as sporadic LAM and may not cause symptoms that affect the lungs. If left untreated, LAM can cause serious and life-threatening health problems.
If you have LAM, you may have one or more of these common symptoms:
- Chest pain or aches that get worse when you breathe in
- Shortness of breath, which may happen only during high-energy activities at first, but over time may start after simple activities, such as dressing and showering
- Severe chest pain and shortness of breath, which can be symptoms of a collapsed lung (pneumothorax)
- Extreme tiredness
- Frequent coughing, which can produce bloody phlegm, or mucus, that is made in your chest
- Wheezing or a whistling sound when you breathe
You may have other symptoms that are caused by LAM cells in other parts of the body.
- Lymph nodes that may be larger than normal: This can happen if LAM cells are in the lymph nodes. Usually these lymph nodes develop in the stomach area (abdomen) or the chest and cannot be felt. Rarely, larger-than-normal lymph nodes may develop in places where they can be felt, such as in the neck or under the arms.
- Abdominal pain: Many people who have LAM get benign (noncancerous) tumors in their kidneys. If these tumors grow large enough, they can lead to bleeding in the kidneys or fluid buildup, which can cause pain in the abdomen.
Your doctor may order tests to measure how your lung tissue is working and show whether your lungs are delivering enough oxygen to your blood.
A chest X-ray is a fast and painless imaging test to look at the structures in and around your chest.
A chest X-ray may look normal in the early stages of LAM. As the disease gets worse, the X-rays may be used to detect cysts in your lungs and monitor any changes over time. Your doctor may use a chest X-ray to look for complications of LAM, such as air in the chest that collapses your lung (a pneumothorax) or fluid in your chest.
The test may be done in the doctor’s office, clinic, or hospital. You will stand, sit, or lie still for the test. Chest X-rays have few risks. The amount of radiation used in a chest X-ray is very small. Talk to your provider if you are or could be pregnant.
Chest CT scan
A chest computed tomography (CT) scan is a painless imaging test that takes many detailed pictures, called slices, of your lungs and the inside of your chest. Computers can combine these pictures to create three-dimensional (3D) models that show the size, shape, and position of your lungs and structures in your chest.
A chest CT scan can help figure out the cause of lung symptoms such as shortness of breath or chest pain. It can also tell your doctor if you have certain lung problems such as a tumor, excess fluid around the lungs that is known as pleural effusion, or pneumonia.
Your chest CT scan may be done in a medical imaging facility or hospital. You will lie still on a table and the table will slide into the scanner. You will hear soft buzzing or clicking sounds when you are inside the scanner and the scanner is taking pictures. You will be able to hear from and talk to the technician performing the test while you are inside the scanner. For some diagnoses, a contrast dye, often iodine-based, may be injected into a vein in your arm before the imaging test.
In rare instances, some people have an allergic reaction to contrast dye. There is also a slight risk of cancer, particularly in growing children, because the test uses radiation. Although the amount of radiation from one test is usually less than the amount of radiation you are naturally exposed to over three years, patients should not receive more CT scans than what is recommended by clinical guidelines recommend.
Lung function tests
Lung function tests can help your doctor see how well your lungs are working. They may help diagnose certain lung conditions or diseases.
Your doctor may order blood tests, such as a test for vascular endothelial growth factor D (VEGF-D) that looks for increased VEGF-D levels in your blood. Higher levels of VEGF-D can stimulate the growth of new blood vessels, which can cause tumors to spread.
Your doctor may also recommend other diagnostic tests, such as a lung biopsy, if other tests are inconclusive.
- A lung biopsy removes part of your lung to check for LAM cells. Your doctor may do an open lung biopsy, which involves making a cut in your chest wall between your ribs. With a transbronchial biopsy, your doctor inserts a long tube down your windpipe and into your lungs. Your doctor can also diagnose LAM using results from biopsies of other tissues such as the lymph nodes.
- Video-assisted thoracoscopic surgery (VATS) may be done if your doctor suspects LAM but is not able to diagnose you with a lung biopsy. In this procedure, your doctor makes several small cuts in your chest wall and inserts a small, lighted tube with tools and a camera on the end. The camera takes pictures of the lungs to guide your doctor as they do the biopsy.
Tests for other medical conditions
Your doctor may need to order other diagnostic tests to determine whether you have a related condition called tuberous sclerosis complex (TSC), which can lead to LAM, or to rule out another condition.
- CT scans or magnetic resonance imaging (MRI) scans of your head can help your doctor determine whether you have TSC. People with TSC often have tumors in the brain and other parts of the body.
- Genetic testing identifies mutations (changes) in your TSC1 and TSC2 genes to help your doctor confirm that you have LAM and not another lung disease.
- Thoracentesis uses a needle to collect fluid samples from the lining of your lungs. If your chest imaging tests show that you have fluid building up in the space between the lung and the chest wall (called pleural effusions), your doctor may order a pleural fluid analysis. For this test, a sample is taken from the pleural space.
Your doctor may prescribe medicines to open up your airways and make it easier for you to breathe.
- Sirolimus is a type of medicine called an mTOR inhibitor. Sirolimus may help control the abnormal growth and movement of LAM cells. The medicine may also help lung function, shrink kidney and lymph node growths, and reduce fluid in the lungs. Side effects can include diarrhea, nausea, acne, high blood cholesterol, swelling of your mouth and lips, and fluid buildup in your legs. Sirolimus may also affect your ovaries, liver, and kidneys and increase your risk of infections. Talk with your doctor about the benefits and risks of sirolimus, and whether it is an option for you.
- Bronchodilators are medicines that can help relax the muscles around the airways if you are having trouble breathing or are wheezing.
Your doctor may recommend oxygen therapy to increase the amount of oxygen your lungs receive and deliver to your blood. At first, you may need oxygen therapy only while exercising. It may also help to use it while sleeping. Eventually, you may need full-time oxygen therapy.
Some patients who have severe lung damage due to advanced LAM may be eligible for a lung transplant.