Further information on LAM and  available treatments

In a CT scan of the lungs of a LAM patient, the area between the alveoli are much thicker than normal and cysts have formed. There are few other diseases that give this same appearance. A high-resolution CT scan of the lungs can allow the diagnosis of LAM with reasonable confidence. The cysts are responsible for a pneumothorax, a common symptom in LAM patients. Pneumothorax occurs when a cyst ruptures on the outside of the lung. When the thin walled cyst leaks, air comes out of the lung, spreads around the lung, and the lung collapses away from the chest wall. This can sometimes be painful and cause shortness of breath. In a small pneumothorax where the lung is still well inflated, there may not be pain or significant shortness of breath and it may heal on its own. A medium pneumothorax may sometimes be treated by sucking the air out with a needle. If it is a large pneumothorax, a chest tube is required to draw out the air which has leaked out of the lung. In an otherwise normal lung, the leak may seal up quickly. In LAM, the leak may continue for a longer period of time. If the leak does not seal on its own, surgery may be required where the chest cavity is opened and the hole repaired. In order to prevent another pneumothorax, the surface of the lung can be treated with an irritant (talc, tetracycline, or mechanical abrasion) which sets up an inflammatory reaction and causes the lung to stick to the chest wall (pleurodesis).

Recurrent pneumothoraces are much more common in LAM than in other lung diseases and are more difficult to treat. Therefore, it is probably more sensible to resort to pleurodesis after the first or second pneumothorax in a LAM patient. About half of LAM patients will have a lung collapse at the onset of symptoms and eventually about 75% will have a pneumothorax at some time during the course of the disease. A tension pneumothorax can be very serious. In this situation, air keeps escaping from the lung until there is more air in the pleural space than in the lung. The center of the chest (the mediastinum) and the blood vessels will get pushed across the chest and compressed because of the increasing pressure of the air. This can cause the other lung to collapse as well. A chest drain must be inserted immediately.

Chylous effusions are much less common - about 25% of LAM patients will have them. They happen because the LAM cells block the lymphatic channels and lymph (the fluid that flows through these channels) will build up in other places, most commonly the lungs, but also in the abdomen or rarely around the heart. In pleural effusions, the lymph build up compresses the lung causing shortness of breath. The fluid can be drained but will usually reoccur. A pleurodesis (or pleurectomy) may be done to prevent the fluid from building up around the lung. Uncommonly, the thoracic duct may be tied off. Alternative channels will form (usually in the chest cavity) and the lymph fluid (chyle) will get returned to the blood stream by a different route. If there is chyle in the urine, it usually means that LAM cells are blocking the lymphatic vessels around the bladder. One of the functions of lymph fluid is to transport fat out of the gut back to the bloodstream, therefore fat can be a significant component of chyle. Reducing the dietary fat to a very low level can significantly reduce the build up of chyle however, these diets are very difficult to maintain. In about 10% of LAM patients, there may be large swellings (lymphangioleiomyomas) in the abdominal lymphatics but in 66% of patients with these there are no symptoms. Occasionally, there may be bloating or swelling of the ankles. It is much more common to have small tumors of the lymph glands in these regions (about 50% of patients) but in most patients, it is not a clinical problem.

The most common abdominal manifestation of LAM is angiomyolipomas (AMLs). These occur in about 50% of LAM patients. Most are small – average size is 1.5 centimeters (cm). Many people do not know that they have them unless there is a CT scan of the kidneys. If they remain small they usually don’t cause problems. AMLs that are larger than4 cm are more likely to cause complications such as flank pain and bleeding. AMLs are tumors that contain LAM cells, fat, and blood cells. The blood vessels in AMLs are abnormal and can sometimes bleed. The normal treatments are to cut off the blood supply to the tumor with a catheter (embolization). This is probably the best treatment since it only affects the tumor and not the rest of the kidney, and allows the patient to maintain normal kidney function. This method is preferable to removing the section of the kidney that contains the tumor or the entire kidney. A follow up CT is then done in 6-12 months to make sure the tumor is not larger. Sometimes AMLs are mistaken for kidney cancer and the kidney is removed. AMLs usually grow relatively slowly rather than suddenly appearing. Unless the tumors are very large (6 cm or more) or are causing symptoms, Dr. Johnson does not recommend embolization. Someone could die as a result of the bleeding but this is extremely rare. The concern is that a patient may be admitted to a hospital where AMLs are not well understood and the kidney would be removed. Patients with AMLs should carry some documentation with them explaining AMLs and asking that the kidney not be removed. There are a few reports of AMLs in other sites (usually the liver) but they do not tend to cause problems.

Pleurodesis does not affect the flexibility of the lungs, but enables them to adhere to and move with the chest wall. There may be some effect on lung function, but it is minimal.

There is a very loose correlation between DLCO and ABG (arterial blood gas) values. Because blood gases vary much more than DLCO, they are not a very good indicator of the severity of the disease.

Even with “normal”, healthy people, after a bad cold it may take 6-12 weeks for the lung function test to go back to normal. If something like exposure to cigarette smoke has irritated your lungs, that could also have an effect. In these cases the use of a bronchodilator may show a measurable improvement during your PFTs. However you may not always see an improvement after bronchodilator use in every PFT.