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Lymphangioleiomyomatosis
(LAM)

Lymphangioleiomyomatosis (LAM) is caused by the excessive growth of smooth muscle cells, the type of muscle that makes up your organs. This growth primarily affects the lungs, but also affects the lymphatic system and the kidneys. It leads to difficulty breathing, a build-up of lymph fluid in the chest, and growth of benign tumours in the kidneys that can cause bleeding.

The abnormal growth of cells in the lungs leads to lung tissue being replaced with fluid build-up and even holes in lung tissue. Many women aren’t diagnosed with LAM until they experience the collapse of a lung. LAM affects mostly women, and usually women between 20 and 40. There are two types of LAM, tuberous sclerosis LAM (TSC-LAM) and sporadic LAM (S-LAM).

Symptoms

LAM presents with the following symptoms, which are often confused for other lung conditions at first:

  • Shortness of breath
  • A cough with mucus or blood in it
  • Abdominal pain
  • Blood in the urine (haematuria)
  • Wheezing
  • Chest pain

Causes & Risk Factors

TSC-LAM is caused by tuberous sclerosis complex (TSC). TSC is an inherited disease that causes non-cancerous tumours to grow throughout the body, including the brain, lungs, skin, kidneys, and heart. TSC is caused by a mutation in 2 genes named TSC1 and TSC2. These mutations are passed on to their children.

S-LAM is also caused by mutations in the TSC genes. However, in people with S-LAM, these mutations only occur in them. They didn’t inherit them from their parents, and they can’t be passed onto children. The occurrence of LAM in them is completely random.

Diagnosis & Complications

LAM often goes undiagnosed or misdiagnosed for many years. Symptoms can often seem like bronchitis or asthma. Additionally, not every doctor is familiar with LAM, even doctors that specialise in lung care. It’s important that patients find a doctor that is knowledgeable about LAM in order to receive proper treatment. If your doctor suspects LAM based on a medical history and physical exam, they may request testing. These tests could include:

  • High resolution computerised tomography (CT) scan for a detailed picture of the lungs and abdomen.
  • Lung function tests – These measure how much air you can breathe in and out.
  • Lab tests – a doctor that suspects LAM will want to look for a protein called VEGF-D. This protein is commonly associated with excessive cell growth. If you have very high levels of VEGF-D, a doctor can make a definitive diagnosis of LAM.
  • Biopsy of lung tissue – this may be done if a blood test did not confirm a diagnosis of LAM.

Complications of LAM include:

  • A collapsed lung (pneumothorax)
  • Build-up of fluid in the tissues that surround the lungs (pleural effusion)
 
 
 

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