Pulmonary fluid or pleural effusion – causes, diagnosis and treatment explained clearly

Causes and frequency of pleural effusions

A pleural effusion can be caused by benign or malignant processes. Common causes include heart failure (cardiac insufficiency), pneumonia, pulmonary embolism or liver cirrhosis – these usually lead to transudative effusions (fluid due to pressure or protein changes). Exudative effusions are caused by inflammation or tumors. Malignant pleural effusions occur particularly in advanced cancers, most frequently in lung cancer, breast cancer or tumors of the pleura (pleura). It is estimated that up to 150,000 malignant pleural effusions per year are diagnosed in the USA alone. In total, around Every sixth cancer patient of patients had a pleural effusion during the course of their disease, which underlines the high relevance of this symptom. Malignant effusions are a sign of advanced tumor disease and are associated with a limited prognosis.

Symptoms and diagnostics

The main symptom of a pleural effusion is shortness of breath – the lungs can no longer expand freely due to the fluid. Many sufferers also notice a dry, irritating cough and a feeling of pressure or pain in the chest. The symptoms of malignant effusions can increase within a short period of time, as fluid often forms again quickly.

For diagnostics a physical examination is performed first. The chest X-ray typically shows a shadowing in the lower lung fields with a large effusion. Even more sensitive is the Ultrasound examination of the thoraxwith which even small amounts of fluid can be detected. Ultrasound also helps to perform a safe puncture. Thorax CT (computed tomography) and in special cases PET-CT can provide further indications of tumor infestation of the pleura.

The most important diagnostic measure is the pleural puncture (thoracentesis): Under local anesthesia, a needle is inserted into the pleural cavity to remove fluid. This is analyzed in the laboratory for signs of inflammation, protein content and Tumor cells (cytology) examined. In around 60-75% of malignant effusions, puncture alone is sufficient to detect cancer cells in the effusion. If the puncture alone is not sufficient (e.g. if the cytology does not provide clear findings), a Pleural biopsy may be necessary – either with a special needle through the chest wall or by means of thoracoscopy.

Importance of thoracoscopy (pleuroscopy) for confirming the diagnosis

The thoracoscopy is an endoscopy of the chest cavity: a thin endoscopic instrument (video thoracoscope) is inserted into the pleural cavity through a small incision. This procedure allows the pleura to be viewed directly and targeted tissue samples can be taken. Thoracoscopy has a very high diagnostic yield, particularly in the case of malignant pleural effusion. Studies show that the diagnostic Accuracy of a thoracoscopic pleural biopsy can be well over 90 %. By comparison, a “blind” pleural biopsy or puncture alone is more likely to produce no result. For this reason, medical guidelines recommend unclear cause of a unilateral pleural effusion Thoracoscopy, provided there are no contraindications.

A further advantage of thoracoscopy is that if it is already apparent during the procedure that a malignant effusion is present, it is possible to therapeutic can be undertaken directly – for example, a complete drainage of the drainage of the fluid and, if necessary pleurodesis (adhesion, see below). Modern thoracoscopy procedures can even be performed with a single access (” uniportals” thoracoscopy). These can increasingly also be performed under local anesthesia and sedation, i.e. without general anesthesia and without intubationbe carried out. Initial studies show that these “awake VATS”-technique (video-assisted thoracoscopy on an awake, spontaneously breathing patient) is similarly successful and safe for experienced surgeons as conventional thoracoscopy under general anesthesia. This is a gentle alternative for patients with a high risk of anesthesia.

Molecular diagnostics and predictive markers in pleural oncology

In modern oncology, tumor tissue is increasingly tested for molecular changes in order to be able to use targeted therapies. In lung cancer patients with pleural effusion, it is often possible to use the tumor material contained in the pleural fluid for this purpose. Genetic markers such as EGFR mutations or ALK translocations in lung cancer can now be reliably determined from tumor cells contained in the effusion or even from cell-free DNA in the effusion fluid. This means that a therapy tailored to the individual tumor can often be planned without always requiring an invasive tissue biopsy of the lung. Even with Pleural mesothelioma (pleural cancer) and other tumors are searched for characteristic biomarkers – such as mesothelin or fibulin-3 in the blood or pleural effusion, which can be elevated in mesothelioma. Such markers can support the diagnosis and provide partial indications of the progression, but do not replace histological confirmation by biopsy.

Also for the forecast assessment In the case of malignant pleural effusion, there are scoring systems that combine clinical and laboratory markers. One example is the LENT scorethe LDH value, ECOG status (general condition), Neutrophil content and Tumor type in order to estimate the life expectancy of MPE. Overall, molecular and clinical markers are increasingly being incorporated into decision-making, such as whether local effusion therapy should be the primary treatment or whether systemic cancer treatment should be prioritized.

Treatment options for pleural effusion

Treatment depends on the cause and symptoms of the pleural effusion. Smaller effusions without severe symptoms can often be observed initially and treated conservatively (e.g. treatment of the underlying disease, dehydrating medication for heart failure). Larger effusions or malignant effusions usually require invasive therapy to quickly alleviate the shortness of breath. The following procedures are available:

• Therapeutic pleural puncture: Similar to a diagnostic puncture, fluid is removed with a needle or cannula. This often provides immediate relief and reduces shortness of breath. However, in the case of malignant causes, the effusion often fills up again within days to a few weeks, so that a new puncture may be necessary.
• Thoracic drainage: A drain is often inserted if there is a large amount of effusion. The doctor inserts a thin tube into the pleural cavity through a small incision and connects it to a negative pressure system. This allows fluid to drain continuously. A drainage tube is often left in place for several days until the effusion subsides or further measures are taken.
• Pleurodesis (adhesion): In order to prevent the recurrence of an effusion, a pleurodesis is aimed at. This involves introducing an irritant substance into the pleural cavity, which causes an inflammatory reaction so that the lung and pleura adhere to each other and the cavity is closed. glued. Talcum pleurodesis is the most proven procedure – talcum powder is introduced via drainage or thoracoscopy and leads to permanent adhesion in over 80-90% of cases. Alternatively, drugs such as bleomycin or tetracycline have also been used, albeit with a somewhat lower success rate. It is important that the lung can be expanded (no “trapped lung”), as otherwise complete bonding is not possible.
• Video-assisted thoracoscopic surgery (VATS): The thoracoscopy described above can be used not only for diagnosis but also for treatment. During a VATS procedure, the effusion can be completely aspirated, adhesions can be loosened and – if necessary – visible tumor nodules on the pleura can be removed or reduced in size (so-called Pleurectomy or decortication). At the end of the procedure, a talc pleurodesis is often performed and a drain inserted. The VATS technique is minimally invasive and usually only requires 1-2 small incisions. New developments such as the uniportale VATS require only a single access and are now performed by some centers without general anesthesia (see above). In selected cases, this can make the procedure gentler and shorten the recovery time.
• Indwelling pleural catheter (permanent drainage): Another established option, especially for patients with shorter life expectancy or recurrent malignant effusionsis the insertion of a permanent pleural catheter. This is a thin tube that tunnels under the skin and can remain in place for weeks to months. It can be drained regularly by the patient or carer at home (ambulatory effusion drainage). Studies – like the large MIST and AMPLE studies – have shown that such a pleural catheter offers comparable symptom relief to talc pleurodesis. One advantage is that there is no need for inpatient readmissions for repeat punctures. Sometimes, if the catheter remains in place for a longer period of time, adhesions (pleurodesis) may even occur spontaneously due to the permanent drainage. The current British Guideline 2023 recommends such an IPC (intercostal pleural catheter) now as an equivalent first-line option in addition to the classic pleurodesis. Which method is chosen depends heavily on the individual circumstances, the expected prognosis and the patient’s wishes.

Outpatient and modern therapy approaches

In recent years, the treatment of malignant pleural effusion has increasingly shifted towards gentle, outpatient procedures developed. Where previously longer hospital stays were often necessary for repeated drainage or surgical procedures, pleural catheters and “awake” thoracoscopy techniques now allow care to be provided partly in the hospital. outpatient area. For selected patients, for example, a thoracoscopy under local anesthesia and the patient leaves the clinic on the same day after a short period of monitoring. Tunnel entrances for permanent drainage are placed under local anaesthetic and then continued at home as part of palliative care. Close consultation between lung specialists, thoracic surgeons and outpatient care services is important to ensure that symptoms are well controlled at all times.

Nevertheless, the crucial role of systemic cancer therapy exist: A malignant effusion is an expression of the tumor disease, which is why chemotherapy, immunotherapy or targeted therapy (such as against EGFR, ALK mutations) also aims to reduce effusion formation. In some tumor types, effusion can be absent or reduced for a longer period of time with effective systemic therapy. However, experience shows that Local measures on the effusion almost always necessary to provide rapid relief and improve quality of life. Modern pleural oncology therefore follows an individualized approach: depending on the patient’s prognosis and Expandability of the lung (radiologically assessable), a tailored plan is drawn up – be it initially a pleurodesis, a permanent drain, or primarily tumor therapy, accompanied by symptomatic effusion punctures.

Conclusion

Pleural effusions – especially malignant pleural effusions – pose challenges for patients and doctors. Thanks to advanced diagnostic procedures such as thoracoscopy and modern therapy concepts (talc pleurodesis, permanent drainage, minimally invasive VATS even without intubation) can usually be helped effectively today. The primary goal is to Relief of breathlessness and improvement in quality of life. At the same time, molecular diagnostics on the effusion allows the underlying tumor disease to be treated in an increasingly targeted manner. Close interdisciplinary cooperation between oncology, pulmonology and thoracic surgery is crucial in order to find the optimum combination of treatment for each patient. local effusion control and systemic therapy can be found.

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