One of the most common and most frightening symptoms of pleural mesothelioma is what doctors call dyspnea or breathlessness. At first, the patient may only experience it when they are performing some kind of physical motion; however, as the disease progresses, they may also experience it while at rest.
The cause for breathlessness is what’s known as a malignant pleural effusion. What this means is that the disease causes a buildup of fluid between the membrane lining the outside of the lung called the pleura and the chest cavity wall. It interferes with normal lung function. The effusion starts out as only a small amount of fluid; but over time, it increases.
In most cases, doctors will recommend a treatment to relieve the problem. Since there are a number of methods that can be used, the decision to use a particular therapy will be based on certain criteria including: the level of breathlessness, how long the patient is expected to survive, characteristics of the primary tumor and the pH level of the pleural fluid.
The level of pH in the fluid indicates how acidic or alkaline it is. Fluids with a pH less than seven are considered acidic and fluids with a pH greater than seven are considered alkaline. A low pleural fluid pH level is associated with a lower chance of survival, and the doctor must weigh the risk factors before making a decision. However, a low pleural fluid pH level doesn’t necessarily mean that the doctor will not try to alleviate the problem.
The usual therapy for patients with continued, symptomatic, malignant pleural effusion is called chemical pleurodesis. This is a procedure in which the pleural space, the area between the outer surface of each lung and the membrane surrounding each lung, is eliminated so that fluid can no longer accumulate there. This is accomplished by introducing a chemical irritant into the pleural space, causing inflammation and the growth of scar tissue.
The chemical irritant that is most widely used is medicinal talc, which can contain different amounts of calcium, aluminum, and iron, as well as other minerals depending upon the manufacturer. However, medicinal talc is free from any contamination with asbestos. The talc preparations that have been found to be the most successful have a high proportion of particles less than five micron in diameter.
There have been recorded cases of acute respiratory failure associated with chemical pleurodesis using talc. However, the incidence rate is less than one percent, and in many instances the respiratory failure could not be definitively linked to the talc alone.
Once again, the doctor will consider the pH level of the fluid when deciding whether or not to perform a chemical pleurodesis because low pleural fluid pH may impact upon the success of the procedure. It is not the only factor that will be considered. Other factors that requiring consideration include: the patient’s general health, characteristics of the primary tumor and if the patient has a trapped lung, meaning a lung that cannot expand because the membrane surrounding it is restricting it.
In the event there is the presence of a trapped lung, the doctor may opt to use one of the following instead:
- Pleuroperitoneal shunt – This is a surgically implanted plastic tube called a catheter that is passed through the pleural space to the peritoneal cavity inside the abdomen to allow for continued drainage. The patient controls the flow by means of a manual pump. .
- Chronic indwelling catheter – This is a surgically implanted catheter that is meant to be permanent in most cases. It remains within the chest and passes out through the skin. The fluid must be periodically drained.