From the Guidelines
Lymphangioleiomyomatosis (LAM) is a rare lung disease that primarily affects women of childbearing age, characterized by the abnormal growth of smooth muscle-like cells in the lungs, leading to cystic lung destruction and respiratory symptoms. The diagnosis of LAM is made by a combination of clinical features, high-resolution computed tomography (HRCT) scanning, and tissue biopsy, with vascular endothelial growth factor D (VEGF-D) testing used as a noninvasive diagnostic tool in some cases 1.
Key Features of LAM
- Rare lung disease primarily affecting women of childbearing age
- Characterized by abnormal growth of smooth muscle-like cells in the lungs
- Leads to cystic lung destruction and respiratory symptoms
- Associated with tuberous sclerosis complex (TSC) in some cases
Treatment and Management
Treatment with sirolimus (rapamycin) is recommended for patients with LAM and abnormal or declining lung function, as it has been shown to improve lung function, functional performance, and quality of life 1. The recommended dose of sirolimus is 1-3 mg daily, adjusted to maintain blood levels between 5-15 ng/mL. In addition to sirolimus, patients should:
- Avoid smoking and estrogen-containing medications
- Get annual flu shots and pneumococcal vaccinations
- Use supplemental oxygen if needed
- Consider bronchodilators for symptom relief
Monitoring and Follow-up
Regular lung function tests and chest imaging should be performed to monitor disease progression. Patients should be aware that sirolimus can have side effects, including mouth sores, increased risk of infection, and impaired wound healing. In severe cases, lung transplantation may be considered as a last resort. The American Thoracic Society/Japanese Respiratory Society clinical practice guidelines provide evidence-based recommendations for the diagnosis and treatment of patients with LAM, emphasizing the importance of frequent reassessment and updating of these guidelines 1.
From the Research
Definition and Characteristics of Lymphangioleiomyomatosis (LAM)
- LAM is an uncommon disease presented as diffuse thin-walled cystic changes in the lung 2.
- It is a rare lung disease that predominantly affects young women 3.
- LAM is a slow albeit progressive rare neoplastic disease featured with diffuse thin-walled cysts in lungs and angiomyolipomas in kidneys 4.
- It is a slowly progressive lung disease that is associated with mutations in tuberous sclerosis complex genes, infiltration of the pulmonary parenchyma and lymphatics with neoplastic smooth muscle cells 5.
Clinical Presentations and Diagnosis
- Dyspnea, pneumothorax, and hemoptysis are common presentations in LAM patients 2.
- Chylothorax, chylous ascites, and lymphangiomyomas are frequently seen in LAM patients 2.
- A combination of clinical, radiological, and pathological approaches as well as genetic testing will clarify the diagnosis in most cases 2.
- Vascular endothelial growth factor-D (VEGF-D) in serum is a noninvasive and reliable diagnostic biomarker 2.
- Trans-bronchial lung biopsy (TBLB) provides a convenient and safe way to obtain lung specimens for diagnostic purposes 2.
Treatment and Management
- An effective treatment for LAM is now available, namely using a mechanistic target of rapamycin (mTOR) inhibitor such as sirolimus 2, 4.
- Sirolimus has been approved for LAM treatment in the United States and many other countries 4.
- Therapies targeting female sex hormones have shown preclinical efficacy in animal and cell culture-based experiments, but have not been properly investigated clinically 4.
- Lung transplantation is a treatment option for LAM patients with advanced disease 3.