What Are Pleural (Lung Membrane) Diseases? What Are the Symptoms? How Is It Diagnosed and Treated?

Pleural diseases are medical conditions affecting the two-layered membrane structure surrounding your lungs and adjacent to the chest wall. The most common pleural diseases include pleurisy, pleural effusion (fluid accumulation), pneumothorax (air leakage), and pleural tumors. Early diagnosis is of great importance because the involvement of pleural structures can directly impair your respiratory functions. In this article, we will explain what you need to know about pleural diseases, their symptoms, causes, diagnostic methods, and treatment options in plain language.

What Are Pleural Diseases?

The pleura consists of two thin membranes lining the outer surface of your lungs and the inner surface of your chest wall. There is a small amount of fluid in the space between these membranes, which allows your lungs to move comfortably during respiration. Pleural diseases encompass conditions such as inflammation of these membrane structures, abnormal fluid accumulation, or air leakage.

Pneumothorax (Collapsed Lung)

Pneumothorax occurs when air leaks into the pleural space between the lung and the chest wall. The accumulated air pushes against your lung and causes it to partially or completely collapse. It can develop spontaneously as a result of the rupture of air sacs called blebs or bullae.

This condition is particularly common in young, tall, and thin males between the ages of 20-40. Chest traumas, certain medical procedures, or lung diseases such as COPD also lay the groundwork for the development of pneumothorax.

Pleural Effusion (Fluid Accumulation in the Lung Lining)

Pleural effusion is the accumulation of more fluid than normal between the pleural membranes. In a healthy person, there is approximately 20 ml of fluid in this space. However, this amount increases if fluid secretion increases or reabsorption decreases due to various reasons.

The accumulated fluid exerts pressure on your lung, making it difficult for you to breathe. Heart failure, pneumonia, tuberculosis, lung cancer, kidney, and liver diseases can lead to pleural effusion. Depending on the characteristics of the fluid, it is divided into two groups as transudate (clear fluid) or exudate (exudative fluid).

Empyema (Inflammation of the Lung Lining)

Empyema means the accumulation of pus in the pleural space. It generally occurs due to bacterial infections as a result of untreated pneumonia or failed treatment.

Today, the incidence of empyema has decreased thanks to the early use of appropriate antibiotics. High fever, chest pain, shortness of breath, and sputum production are its most prominent symptoms. If left untreated, it can lead to life-threatening complications.

Mesothelioma (Lung Membrane Cancer)

Mesothelioma is a rare but aggressive type of cancer that develops in the pleural membrane. The vast majority of cases occur as a result of exposure to asbestos.

The interesting point is that it can take 10 to 50 years for symptoms to appear after asbestos exposure. The disease usually presents with fluid accumulation in the pleural membranes. Stabbing pain in the chest, shortness of breath, and unexplained weight loss are among common symptoms.

Chylothorax (Lymph Fluid Accumulation)

Chylothorax is the collection of lymph fluid in the pleural space. It develops as a result of an injury to the main vessel called the thoracic duct in the lymphatic system. Heart surgery, thoracic surgery, trauma, or certain types of cancer can cause chylothorax.

Up to 2.5 liters of lymph fluid can accumulate per day. The accumulated fluid has a milky white appearance and contains high triglycerides. If left untreated, it progresses with serious complications.

What Are the Symptoms of Pleural Diseases?

Pleural disease symptoms vary depending on which part of the membranes is affected and the severity of the disease. While some patients experience mild discomfort, others encounter severe symptoms that affect their daily lives.

Chest Pain

Chest pain is the most prominent and common symptom of pleural diseases. This pain is usually sharp and stabbing in nature. The pain worsens when you take a deep breath, cough, or sneeze.

Many patients describe this pain as being stabbed with a knife. The pain is particularly pronounced in cases of pleurisy and results from the friction of the pleural layers against each other. It can also be felt as side pain and create a feeling of tightness in the chest.

Shortness of Breath

Shortness of breath is a frequently encountered symptom in pleural diseases. It becomes especially prominent in cases of fluid or air accumulation in the pleural space. The accumulated fluid or air hinders the expansion of your lung, making respiration difficult.

In unilateral fluid accumulation, pain may be in the foreground rather than shortness of breath. However, in bilateral fluid accumulation, both symptoms are observed. As the amount of fluid increases, your shortness of breath also increases. Due to inflammation, the expansion of your lungs becomes difficult, and you experience trouble especially when taking a deep breath.

Cough and Fever

Cough generally occurs in the form of a dry cough. In some cases, it may also lead to sputum production. Your chest pain may intensify even more during coughing.

Fever is seen in infection-related pleural diseases. Symptoms such as high fever, chills, and shivering are added to the clinical picture in empyema. If the disease is related to infection, a general deterioration in condition also accompanies it.

General Symptoms

Certain general symptoms are also observed in pleural diseases. Fatigue and weakness are among common symptoms. Since your body is fighting inflammation, you feel tired.

Weight loss and loss of appetite occur particularly in malignant pleural diseases. Coughing up blood can also be seen in mesothelioma. In malignant conditions, symptoms usually follow a more insidious course and can manifest themselves with systemic findings such as night sweats. In chylothorax, an immunodeficiency picture develops if left untreated.

What Are the Causes of Pleural Diseases?

The causes of pleural diseases cover a very broad spectrum. Even systemic diseases outside the lungs can affect your pleural membranes. Each cause leads to pleural diseases through different mechanisms.

Infections

Bacterial infections are among the most common causes of pleural diseases. Pneumonia can lead to fluid accumulation in the lungs. Untreated pneumonia spreads to the pleural space and forms empyema.

Tuberculosis is an important cause of pleural disease, especially in our country. Tuberculosis patients experience more fluid accumulation than normal in the pleural space. This fluid accumulation lays the groundwork for inflammation.

Viral infections, although rarer, can cause pleural inflammation. Fungal infections, on the other hand, are seen in individuals with a weakened immune system.

Trauma and Injuries

Blows to the chest region lead to pleural diseases. Rib fractures are an important risk factor for the development of hemothorax. The risk of death increases 2.5-fold in patients with five or more rib fractures.

Penetrating and blunt traumas are the most common causes of hemothoraces. While blunt trauma constitutes 73.3% of cases, iatrogenic injuries are seen at a rate of 25%. Spontaneous hemothoraces, on the other hand, are only at a rate of 1.7%.

Heart surgeries and thoracic surgeries can cause pleural effusion as a complication. Injuries occurring during medical procedures such as central venous catheter placement also trigger pleural diseases.

Cancer and Tumors

Pleural involvement is seen in 8-15% of lung cancer cases. The spread of cancer cells to the pleura increases fluid accumulation. Lung adenocarcinomas are the most common cancer type causing malignant pleural effusion.

The peripheral localization of adenocarcinoma facilitates its spread to the pleura via contiguity. Breast cancer similarly leads to fluid accumulation by metastasizing to the pleura.

Mesothelioma is pleural cancer developing due to asbestos exposure. Pleural metastases emerge as an important cause in spontaneous hemothoraces.

Heart and Kidney Diseases

Congestive heart failure most frequently leads to fluid accumulation of the transudate type. The inability of the heart to pump blood properly causes fluid to accumulate in the chest. Hydrostatic pressure increases, and fluid with a low protein content accumulates.

Kidney diseases create pleural fluid of both transudate and exudate types. Pleural fluid is detected in 20% of patients undergoing long-term hemodialysis. Two-thirds of these fluids have transudate characteristics, and one-third have exudate characteristics.

Liver diseases and cirrhosis cause fluid accumulation due to hypoalbuminemia. Nephrotic syndrome leads to transudate formation with the decrease of oncotic pressure. Peritoneal dialysis patients may experience fluid passage into the pleura via small defects in the diaphragm.

How Is the Diagnosis of Pleural Diseases Made?

Making an accurate diagnosis is the first step for the effective treatment of pleural diseases. Physicians first listen to the patient's complaints and perform a physical examination. Afterwards, they finalize the diagnosis with various imaging methods and laboratory tests.

Physical Examination

The physician starts the examination primarily by listening to your chest region. In the case of pleural effusion, your lung sounds may decrease or disappear completely. In the presence of pleurisy, a pleural friction rub is heard.

Fluid accumulation can be detected in the examination performed by lightly tapping your chest wall. Findings vary depending on the amount of fluid. If there is less than 300 ml of fluid in the pleural space, it is difficult to detect it with a physical examination. When the fluid reaches 500 ml, a change in percussion sound and a decrease in respiratory sounds are heard.

When the fluid amount reaches 1000 ml, a decrease in expansion on the ipsilateral chest wall and findings up to the scapula level are detected. When the effusion fills the entire hemothorax, swelling in the intercostal spaces and complete disappearance of respiratory sounds are observed.

Chest X-Ray and Imaging Methods

Chest X-ray is the most frequently used initial method in diagnosing pleural diseases. This imaging is the first step in evaluating the presence of fluid or air in the pleural space.

Fluid accumulation up to 300 ml may not be visible on a PA chest X-ray. Lateral radiography can show smaller amounts such as 50-75 cc. As the amount of fluid increases, a parabolic line looking upwards and inwards is observed.

Thoracic ultrasonography is a highly sensitive method in determining small amounts of fluid accumulation. It is a safe guide to determine the exact location of the fluid and intervene with a needle. When ultrasonography is used, the detection rate rises to 60%.

Detailed evaluation of pleural structures is performed with computed tomography. This method is particularly helpful in distinguishing situations such as tumors or complex pleural thickening. PET-CT is preferred to measure metabolic activity in cases suspected of cancer.

Thoracentesis and Fluid Analysis

With the thoracentesis procedure, it is aimed to obtain a fluid sample from the pleural space for both diagnosis and relieving symptoms. The procedure is performed by taking at least 50 cc of fluid with a 21 G needle. It is generally performed under ultrasound guidance.

The appearance of the collected fluid brings one step closer to the diagnosis. Most fluid has a straw-yellow consistency. If the fluid is cloudy or milky-looking, chylothorax, pseudochylothorax, and empyema are considered.

The fluid is analyzed biochemically, microbiologically, and cytologically. Protein, LDH, glucose, and pH levels are examined. Whether the fluid is a transudate or an exudate is determined using Light's Criteria. If the triglyceride level is above 110 mg/dl, a diagnosis of chylothorax is made.

Advanced Diagnostic Methods

In some cases, it is necessary to directly observe the pleural membrane and take a biopsy. Small samples are taken from the parietal pleura with a pleural biopsy. Biopsy positivity ranges between 40% and 60% in malignant pleural diseases.

Thoracoscopy is applied in cases where a diagnosis cannot be made after fluid analyses and biopsies. This method can be performed under local anesthesia and with sedation. Its contribution to the diagnosis is greater, especially in the evaluation of malignancies.

How Is the Treatment of Pleural Diseases Done?

Treatment options are determined according to the type and severity of the disease. While some conditions resolve with simple follow-up and drug therapy, others require surgical intervention. The physician evaluates your condition and creates the most appropriate treatment plan for you.

Pneumothorax Treatment

In small pneumothorax cases, your lung can be expected to heal spontaneously. Oxygen support is given during this process, and the acceleration of air absorption is ensured.

In more severe situations, a chest tube is inserted to evacuate the air in the pleural space. This tube placed between your ribs ensures the re-expansion of the lung. Air can be removed by needle aspiration method in some patients.

Surgical procedure is considered in recurrent pneumothorax cases. Pleural membranes are adhered to prevent air accumulation again. This procedure is called pleurodesis. The probability of the disease recurring can go up to 50 percent.

Pleural Effusion Treatment

Treatment of the underlying cause is the first step. Diuretic drugs are used in heart failure. Antibiotics are started in infections. Anti-inflammatory drugs are preferred in rheumatic diseases.

If the accumulated fluid causes shortness of breath, thoracentesis is performed. Your symptoms are relieved by draining the fluid with a thin needle. In recurrent cases, a pleural catheter is placed or a pleurodesis procedure is applied.

In pleurodesis, chemical substances such as talc are given into the pleural space to ensure the adhesion of the membranes. Thus, the re-accumulation of fluid is prevented. Surgical options include tube thoracostomy, pleurectomy, and decortication.

Empyema Treatment

Antibiotic therapy is the fundamental approach. Medication is chosen according to the type of bacteria causing the infection. Treatment duration is generally between 2 and 6 weeks. Beta-lactam drugs are preferred in community-acquired cases.

The inflammation in the pleural space must definitely be drained. In the early stage, small or large diameter catheters are placed by tube thoracostomy method. Video-assisted thoracoscopic surgery is applied in advanced cases.

Open surgery may be required in patients in the organized stage. In the decortication procedure, the thick layer surrounding the lung is removed. Thus, the re-expansion of the lung is ensured.

Mesothelioma and Chylothorax Treatment

Treatment in mesothelioma depends on the type and stage of the disease. There are three different mesothelioma types, and surgical chance is found only in the epithelial type. In sarcomatoid and mixed types, the patient is directed to chemotherapy and radiotherapy.

Surgical treatment is applied in early-stage patients who are stage 1 or 2. Immunotherapy has begun to be used in recent years and gives effective results particularly in the sarcomatoid type. Chemotherapy and, if necessary, radiotherapy are given after surgery.

Palliative treatments are applied in advanced-stage patients. A chest tube is inserted to drain the fluid, and pleurodesis is performed to prevent re-accumulation. Attempts are made to increase the quality of life with low-dose chemoradiotherapy.

In chylothorax, oral feeding is stopped, and intravenous nutrition is applied. A low-fat diet or formulas containing medium-chain triglycerides are recommended. Lymph fluid is drained with tube thoracostomy. This treatment is sufficient in approximately 50 percent of patients. If no response is obtained, lymph duct ligation surgery is required.

Frequently Asked Questions

Patients ask many questions about lung lining disorders. These questions are generally related to the severity of the disease, the treatment process, and recovery expectations. Below you will find clear answers to the most curious subjects.

No, fluid accumulation does not occur in every pneumonia case. When pneumonia is diagnosed early and treated with drug therapy, you recover completely without fluid accumulation. Catching the problem early increases treatment success.

However, when diagnosed late and a large part of the lung is affected, the risk of fluid accumulation increases. In this case, thoracentesis procedure or more advanced treatments may be required. Fluid also appears in conditions such as tuberculosis, lung abscess, and cancer besides pneumonia.

Pleural effusion is a potentially dangerous condition. Complaints of chest pain or cough that seem simple can actually lead to serious health consequences. Therefore, it is important not to underestimate the symptoms.

The severity of fluid accumulation depends on the underlying cause. Fluid related to heart failure can be kept under control with treatment. On the other hand, fluid accumulations related to malignant tumors can progress more seriously. Therefore, you must definitely consult your physician.

A small pleural effusion generally heals on its own. Your body can correct a small amount of fluid by absorbing it over time. Consuming plenty of fluids and resting during this process helps.

However, it is essential for doctors to treat the condition causing pleural effusion. For example, if there is pneumonia or heart failure, medications directed at these diseases are used. When the primary disease heals, pleural effusion also disappears.

Pneumothorax is a disease that can recur. After experiencing it for the first time, there is a risk of it appearing again. This risk increases especially if there is an underlying lung disease.

The frequency of recurrence decreases significantly in patients who undergo surgery and have the adhesion procedure applied. The recurrence rate is low in individuals who have received surgical treatment. If you smoke, quitting reduces the risk of recurrence.

Mesothelioma is a malignant tumor of the lung lining and is difficult to treat. The disease is mostly diagnosed at an advanced stage. When diagnosed early, a chance of surgery exists.

If the patient's general condition is good, the combined application of surgical procedure and drug therapies has recently shown promising results. Immunotherapy and chemotherapy options are evaluated. Since each patient's condition is different, the treatment plan is personalized.

In Summary, Pleural Diseases

Pleural diseases can lead to serious complications, but they are treated successfully with early diagnosis. Do not underestimate symptoms such as chest pain, shortness of breath, or persistent cough. Your doctor will first perform a physical examination, then reach a definitive diagnosis with imaging methods and fluid analysis. Treatment options cover a broad spectrum ranging from simple medication use to surgical intervention. Specialist physician follow-up is essential in every case. Apply to a healthcare institution without wasting time when your symptoms begin. With the right treatment, most patients recover completely and return to their normal lives.

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