Lymphangioleiomyomatosis (LAM)
A rare cystic lung disease that mainly affects women
Quick Facts
- Type: Rare lung (pulmonary) disease
- Who it affects: Almost always women of childbearing age
- Key feature: Cysts throughout the lungs
- Common symptoms: Breathlessness, collapsed lung
Overview
Lymphangioleiomyomatosis, usually shortened to LAM, is a rare lung disease in which abnormal, muscle-like cells grow and multiply in the lungs and sometimes in the lymphatic system and kidneys. As these cells accumulate, they form numerous small, air-filled sacs called cysts throughout the lungs, which gradually interferes with breathing.
LAM occurs almost exclusively in women, typically during their childbearing years, which suggests that female hormones play a role in how the disease behaves. It can occur on its own (sporadic LAM) or in people with a genetic condition called tuberous sclerosis complex. LAM is a long-term, progressive disease, but treatments are available that can slow it and help preserve lung function.
Symptoms
Symptoms develop gradually and can be mistaken for more common lung conditions:
- Shortness of breath, at first with exertion and later with everyday activity
- A persistent cough, sometimes producing blood-tinged sputum
- Chest pain
- Fatigue and reduced exercise tolerance
- Collapsed lung (pneumothorax): Sudden chest pain and breathlessness when a cyst ruptures, which can be the first sign.
A sudden, sharp chest pain with breathlessness may indicate a collapsed lung and needs urgent care.
Causes
LAM is caused by changes in genes that normally help control cell growth. When these genes do not work properly, abnormal smooth-muscle-like cells grow uncontrollably in the lungs and other tissues.
- Sporadic LAM: Arises from gene changes that occur during a person's life and is not inherited.
- Tuberous sclerosis-associated LAM: Occurs in people with tuberous sclerosis complex, an inherited disorder caused by changes in the same family of genes.
The strong predominance in women and worsening that can occur with pregnancy suggest estrogen influences the disease, although the exact relationship is still being studied.
Risk Factors
- Being a woman of childbearing age
- Having tuberous sclerosis complex
- LAM is very rare overall and is not caused by smoking or lifestyle
Diagnosis
Because LAM is rare and resembles other lung diseases, diagnosis can take time:
- CT scan of the chest: Shows the characteristic pattern of many thin-walled cysts throughout the lungs.
- Blood test: A specific marker is often elevated in LAM and can support the diagnosis.
- Lung function tests: Measure how well the lungs are working.
- Biopsy: Occasionally needed to confirm the diagnosis when imaging and blood tests are not conclusive.
Treatment
There is no cure, but treatment can slow the disease and manage complications:
- Targeted medication: A drug that blocks the abnormal cell-growth signaling can slow the decline in lung function and is used for many people with LAM.
- Treating collapsed lungs: Procedures to re-expand the lung and prevent repeat collapses.
- Oxygen therapy: For people with low blood oxygen levels.
- Pulmonary rehabilitation to improve breathing efficiency and exercise capacity.
- Lung transplant: Considered for advanced disease that severely limits breathing.
Care is usually provided at centers experienced with rare lung diseases.
Prevention
LAM cannot be prevented because it arises from gene changes. However, people with LAM can take steps to protect their lungs:
- Avoid smoking and secondhand smoke
- Discuss the risks of pregnancy and certain estrogen-containing medicines with a specialist
- Stay current with recommended vaccinations to reduce respiratory infections
- Attend regular follow-up so treatment can be adjusted as needed
When to See a Doctor
See a doctor for unexplained, gradually worsening breathlessness, a persistent cough, or repeated collapsed lungs, especially as a younger woman. Seek emergency care for sudden, sharp chest pain with shortness of breath, which can indicate a collapsed lung, or for severe difficulty breathing.
Frequently Asked Questions
What is LAM?
Lymphangioleiomyomatosis (LAM) is a rare lung disease in which abnormal muscle-like cells grow in the lungs and form many small cysts that gradually impair breathing. It occurs almost entirely in women, usually during their childbearing years.
Why does LAM mostly affect women?
LAM occurs almost exclusively in women of childbearing age, and the disease can worsen during pregnancy, which suggests that the hormone estrogen influences how it behaves. The exact role of hormones is still being studied.
Is LAM inherited?
Most cases, called sporadic LAM, are not inherited and arise from gene changes that occur during a person's life. LAM can also occur in people with tuberous sclerosis complex, which is an inherited condition caused by changes in related genes.
Can LAM be treated?
There is no cure, but a targeted medication can slow the decline in lung function for many people. Other treatments manage complications such as collapsed lungs and low oxygen, and a lung transplant may be an option for advanced disease.
What is a collapsed lung and why is it linked to LAM?
A collapsed lung, or pneumothorax, happens when air leaks from a ruptured cyst into the space around the lung, causing sudden chest pain and breathlessness. Because LAM fills the lungs with cysts, collapsed lungs are common and can be the first sign. Sudden sharp chest pain with breathlessness needs urgent care.
References
- National Heart, Lung, and Blood Institute (NHLBI). Lymphangioleiomyomatosis (LAM).
- The LAM Foundation. About LAM.
- MedlinePlus, U.S. National Library of Medicine. Lymphangioleiomyomatosis.
- Genetic and Rare Diseases Information Center (GARD). Lymphangioleiomyomatosis.