LAM: Diagnosis

Methods for diagnosing lymphangioleiomyomatosis, or 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.

Typical diagnosis begins with your doctor discussing any signs and symptoms you may have related to LAM. He or she may ask how long you've had them, and whether they've become worse over time. Because 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.

A series of test that measure how well your lungs are functioning is necessary for a diagnosis. 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.

Such tests may include:

• 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 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.

• 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.

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.

The following procedures may be used:

• Video-assisted thoracoscopy. 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.

• 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.

• 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.