Lymphangioleiomyomatosis (LAM)

What is Lymphangioleiomyomatosis?

a rare lung disease that results in a proliferation of disorderly smooth muscle growth throughout the lungs, in the bronchioles, alveolar septa, perivascular spaces, and lymphatics, resulting in the obstruction of small airways and lymphatics.

More on LAM

Recent studies

LAM and TSC researchers have identified a wealth of potential molecular targets and experimental therapies that may be appropriate for testing in clinical trials. Many of these drugs are FDA-approved or in development for other indications.



LAM Foundation funded scientists reported numerous breakthroughs, resulting in the first-ever LAM treatment trial to test a drug called sirolimus, or rapamycin, which proved to be an effective treatment for LAM (results published in the April 2011 issue of the New England Journal of Medicine (NEJM). Additional clinical trials are underway as LAM Foundation-funded researchers continue to work with urgency in search of more safe and effective treatments.

Symptoms of LAM

  • Shortness of breath on exertion
  • Cough
  • Hemopostysis, as a result of vascular congestion
  • recurrent pneumothorax
  • chylous pleural effusion and chylous ascrites, as a result of lymphatic obstruction.

Symptoms are more likely in women, with average age at onset 34 years. Symptoms may precede radiographic abnormalities.

Causes of LAM

The proliferating smooth muscle that occurs in the type of LAM seen in patients with tuberous sclerosis (TSC-LAM) has been shown to represent clones of the smooth muscle in those patients' renal Angiomyolipomas. Thus it is believed to represent metastases of this "benign" tumor. There is a female preponderance to TSC-LAM.

Prevention of LAM

None available

Living with LAM (treatment included)

LAM is a progressive disease, which means it gets worse over time. However, the rate of progression differs from one person to the next, for reasons unknown. There is currently no cure nor have any treatments been definitely proved to stop or slow the formation of cysts in the lungs or elsewhere in the body. Treatment aims to ease the symptoms and reduce the risk of complications.

Treatment options may include:
  • Medicines – such as bronchodilators to open the airways and improve airflow or water tablets (diuretics) to remove excess fluid.
  • Flu (influenza) vaccination – to reduce the risk of respiratory infection.
  • Supplemental oxygen – oxygen that is breathed through a tube or mask to increase the oxygen supply to the lungs.
  • Surgery – to reinflate a collapsed lung (repair a pneumothorax) or prevent recurrence of fluid. A biopsy may be used to make a diagnosis.
  • Lung transplantation – the diseased lungs are surgically removed and replaced with healthy lung tissue from a deceased donor. This is a major operation with serious risks. Doctors consider a lung transplant as the last resort in the treatment of a potentially life-threatening case of LAM.

Testing

Tests used to diagnose LAM may include:
  • Physical examination
  • Medical history
  • Lung function tests, to check the amount of air that the lungs can inhale and exhale
  • Blood tests
  • Pulse oximetry, a non-invasive test that checks the levels of oxygen in the blood
  • Chest x-ray
  • Computed tomography (CT) scans of the chest and abdomen
  • Ultrasound of the kidneys
  • Lung biopsy, performed under local or general anaesthesia.

where to get help

Because LAM is rare, it is difficult for doctors to find enough people to participate in trials to test the effectiveness of new treatments. Drugs currently under consideration for the treatment of LAM include:
  • Doxycycline – an antibiotic that it is thought may decrease the spread of LAM cells in lung tissue.
  • Rapamycin – an immunosuppressant drug that may decrease LAM cell growth.
  • Progesterone – a female hormone.
Other trials are being considered to test the effectiveness of a range of other treatments, including statins, metformin (an oral anti-diabetic drug), lymphangiogenesis inhibitors and autophagy inhibitors.

Body parts affected

LAM can cause problems in other areas of the body, such as:
  • Kidneys – benign (non-cancerous) growths. About one woman in three who has LAM has kidney tumours, which are called angiomyolipomas (AMLs).
  • Abdomen and pelvis – cysts or tissue masses called lymphangioleiomyomas that develop behind the lining of the abdomen (peritoneum).
  • Lymph nodes – enlargement, which is usually harmless.

LAM complication

LAM may cause serious complications including:
  • Collapsed lung (pneumothorax) – caused by changes in air pressure inside the chest. Typically, a cyst bursts and leaks air from the lungs into the chest cavity. In mild cases of partial collapse, the lung may reinflate by itself. In other cases, surgery is needed. Sometimes, the condition is chronic and the affected lung may collapse over and over again. Pneumothorax is relatively common in people with LAM.
  • Pleural effusion – build-up of fluid in the space between the lungs and the lung membrane (pleura). The fluid may be an unusual type called chyle, producing a chylothorax. About one woman in three affected by LAM has an abnormal leakage of lymphatic fluid into the chest cavity.
  • Bleeding tumours – the kidney tumours (angiomyolipomas, or AMLs) may bleed. Symptoms include back pain and blood in the urine.