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 It also can show how much normal lung tissue has been replaced by the LAM cysts.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 isn’t major surgery, but it does require general anesthesia (that is, you’re 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 you’re 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 that’s removed is very small, so this test doesn’t 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 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).

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.