What are the most common symptoms associated with mesothelioma?
Mesothelioma is a difficult cancer to diagnose. While the main risk factor in developing mesothelioma is exposure to asbestos, the time between initial exposure and conclusive diagnosis can range anywhere from 20 to 50 years. Mesothelioma takes a long time to develop, and the symptoms of the disease do not typically present themselves until the disease has progressed to later stages. Early signs of mesothelioma can be easily mistaken for common, everyday ailments. As a result, early symptoms such as fatigue, cough, muscle weakness, fever and night sweats are often ignored, dismissed, or misdiagnosed. While symptomatic patients can go undiagnosed for as many as six months, it is common for patients to be diagnosed after two to three months of symptom onset.
Pleural Mesothelioma Symptoms
The symptoms of pleural mesothelioma, a type of mesothelioma that originates in the two layers that make up the lining of the lungs and chest wall (known as the pleura), are most often caused by the tumors that form within these layers. These tumors form, over time, after asbestos inhalation has occurred. When asbestos fibers are inhaled, they make their way through the trachea or bronchi and eventually penetrate the pleural lining. These asbestos fibers may then damage the DNA of mesothelial cells, causing uncontrolled cell growth and the development of mesothelioma, which leads to the symptoms below.
Roughly 60% of patients diagnosed with pleural mesothelioma report lower back or side chest pain. There are also frequent instances of shortness of breath. Some people may experience difficulty swallowing, a persistent cough, fever, weight loss, or fatigue. Additional symptoms include muscle weakness, loss of sensory capability, hemoptysis or coughing up blood, facial and arm swelling, and hoarseness.
Pleural mesothelioma is also the only type of mesothelioma that is formally classified into stages. The symptoms that accompany these stages depend largely on the size and location of tumors and if any form of fluid buildup is present.
Stage I Symptoms
During stage I, which also includes sub-stages Ia and Ib, the tumors are so small and localized that symptoms are rarely present. In stage Ia, the tumors form in a scattered pattern, known as diffuse mesothelioma, within the outer layer of the pleura that lines the chest wall, or the parietal pleura. In stage Ib, this diffuse mesothelioma takes place within the inner layer, or the visceral pleura. The presence of pleural effusion during these stages — the collection of fluid between the layers of the pleura — may cause some early warning signs such as fever, body aches, chest pain, and coughing. To control the effusion and these associated symptoms, the fluid may need to be drained in a relatively limited surgical procedure.
Stage II Symptoms
In stage II, the small tumors remain localized within the chest, but may begin to spread from the pleura to other lung tissues as well as the diaphragm. In addition to pleural effusion and associated symptoms from stage I, pleural thickening may occur in this stage due to scarring from asbestos inhalation and tumor growth. This causes further respiratory distress such as difficulty breathing, or dyspnea. Some patients also report symptomatic weight loss.
Stage III Symptoms
In addition to an increase in severity of the symptoms associated with the previous stages, stage III symptoms are specific to pleural mesothelioma. This is also the stage at which the majority of patients are diagnosed; at the same time, many stage III symptoms mirror those seen in lung infections such as pneumonia and bronchitis. Tumors have spread throughout the pleura and chest cavity on one side of the body as well as the lymph nodes, affecting the lining of the heart and diaphragm, the chest wall, and neighboring tissues. Depending on how the tumors spread, patients may continue or begin experiencing chest pain or tightness and difficulty breathing or shortness of breath. Symptoms presented at this stage can also include fever, fatigue, and weight loss.
Stage IV Symptoms
By stage IV, the most advanced stage, the cancer has metastasized and tumors have spread throughout the chest cavity, and often to organs and tissues on both sides of the body. Patients experience a range of symptoms present in the previous stages such as fever, night sweats, chest pain and tightness, shortness of breath, fatigue, and weight loss. Additionally, symptoms may include fluid buildup and pain in the abdomen, anemia, hemoptysis, and dysphagia, or difficulty swallowing.
Stage IV treatments generally focus on symptom alleviation and management. Doctors may continue to drain fluid effusions to ease the discomfort of the associated symptoms. Pain medication and various respiratory therapies may also be included for pain and symptom management.
Peritoneal Mesothelioma Symptoms
Peritoneal mesothelioma, the most common form beside pleural mesothelioma, originates in the abdomen and is difficult to diagnose due to a lack of distinct symptoms. Similar to the role asbestos plays in the development of pleural mesothelioma when inhaled, asbestos fibers can also be coughed up, swallowed, and settle in the stomach, leading to peritoneal mesothelioma and the symptoms specific to the abdominal area. Reported symptoms include localized abdominal pain related to a tumor, abdominal distension without pain, weight loss, nausea, and vomiting. Fluid buildup in the abdomen, or peritoneal effusion, may also occur, as well as painful bowel obstructions. As with pleural effusions, doctors may also drain abdominal fluid buildup to lessen discomfort.
Pericardial Mesothelioma Symptoms
The symptoms of pericardial mesothelioma, a rare type of mesothelioma originating in the lining of the heart, often present themselves insidiously and may present as medical conditions such as constrictive pericarditis, or inflammation of the sac-like covering of the heart, and fluid around the heart known as pericardial effusion. Both of these conditions can lead to pressure around the heart. As the tumor grows and places strain on the heart, chest pain may also occur. Other symptoms may include cough, dyspnea, paradoxical pulse, fever, night sweats, weight loss, and generalized weakness.
Testicular Mesothelioma Symptoms
Testicular mesothelioma, the rarest type of mesothelioma, comprises less than 5% of all mesothelioma cases, and the symptoms are nonspecific. A consistent sign, however, is a mass or tumor located in the testes, which is most often discovered during a surgical procedure.
Metastatic Mesothelioma Symptoms
In some cases where the cancer has progressed to later stages, the cancerous cells may spread to other parts of the body through the blood or lymph nodes. The symptoms of metastasis depend on the origin of the cancer and where it then spreads. While mesothelioma typically metastasizes locally, it can spread to the brain, bones, and adrenal glands, though malignant cases are extremely rare. Some common symptoms of mesothelioma metastasis outside of those that are stage-related include hemoptysis, nerve issues, and bone pain.
Latency Period and Misdiagnosis
Identifying the warning signs of mesothelioma early on is extremely difficult due to the characteristically long latency period between onset and symptoms, which may not present themselves until the cancer has progressed to its later stages. This, again, is due partly to the length of time it takes mesothelioma to develop after initial exposure to asbestos. When symptoms do arise, they are often nonspecific and thus misattributed to other ailments. In its early stages, pleural mesothelioma is typically misdiagnosed as influenza or pneumonia. Peritoneal mesothelioma is commonly misdiagnosed as a hernia or Irritable Bowel Syndrome (IBS).
Mesothelioma Risk Factors
Exposure to asbestos is considered the primary risk factor in developing mesothelioma. Anyone displaying any of the above symptoms who may have been exposed to asbestos should seek immediate medical attention from their primary care physician. Upon receiving a positive diagnosis, he or she should then be referred to a doctor specializing in the treatment of mesothelioma and thoracic oncology.
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