The pleural space — the thin cavity between the lung and the chest wall — can be affected by fluid accumulation, infection, thickening, cancer, or endometriosis. Each condition has a distinct cause and requires a distinct approach. Specialist assessment and keyhole surgery at London Bridge Hospital within 2–3 days. Dr Okiror is Co-PI of MIST-4 (ISRCTN16328099), the NIHR’s largest trial in pleural infection.
Last reviewed: April 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
The thin cavity between the lung and chest wall can be affected by fluid (pleural effusion), infection (empyema), cancer (mesothelioma), or endometriosis — each requiring a different approach
Co-PI, MIST-4 (ISRCTN16328099) — NIHR Phase III RCT comparing VATS surgery versus enzyme therapy for pleural infection, 604 patients across 25 UK sites. Co-PI, PRO-SEAL (ISRCTN15099654)
Drainage and biopsy, VATS decortication for empyema, surgical assessment for mesothelioma, keyhole excision for endometrial deposits. All under one thoracic surgeon at London Bridge Hospital
A pleural effusion is a build-up of fluid in the pleural space — the thin cavity between the lung and the chest wall. Small effusions may cause no symptoms at all. Larger ones cause breathlessness, a feeling of chest heaviness, and reduced exercise tolerance as the expanding fluid compresses the lung.
The cause matters enormously. Pleural effusions can result from heart failure, infection, cancer, pulmonary embolism, inflammatory conditions, or other causes. Identifying the cause is the first step — it determines both the appropriate treatment and whether any further investigation of the underlying condition is needed. A pleural effusion drained without knowing why it formed will recur.
Not all pleural effusions require surgery. Many are managed by drainage alone. Surgery is considered when fluid has become infected and loculated (empyema), when a simple drain has failed, or when the effusion recurs repeatedly and a more permanent solution is needed. Breathlessness page →
Empyema is an infection of the pleural space — a collection of infected fluid or pus between the lung and the chest wall. It most commonly develops following pneumonia or a chest infection, or after a surgical or medical procedure involving the chest.
In early-stage empyema, antibiotics and a chest drain can be sufficient. As the condition progresses, the fluid becomes thicker and divides into pockets — a process called loculation — making simple drainage ineffective. The pleural lining also begins to thicken, trapping the lung and preventing it from re-expanding fully.
Keyhole (VATS) surgery at this stage involves washing out the pleural space, breaking down the pockets of infected fluid, and in established cases performing a decortication — removing the thickened pleural peel that is trapping the lung. This allows full lung expansion and dramatically speeds recovery compared to conservative management alone.
Dr Okiror is Co-PI and Lead Surgeon at GSTT for MIST-4 — the NIHR’s largest trial comparing early VATS drainage versus intrapleural enzyme therapy (tPA/DNase) for pleural infection. 604 patients across 25 UK sites. Building on MIST-3, of which Dr Okiror is also an author. Eligible patients at Guy’s Hospital may be offered participation.
Thin fluid, not yet loculated. Often manageable with antibiotics and chest drain. Prompt treatment prevents progression to established empyema.
Thick, loculated fluid. Simple drainage insufficient. VATS washout and decortication required to clear the infection and allow lung re-expansion.
Long-standing inflammation or infection can leave the pleural lining permanently thickened, trapping the lung. Surgical decortication can restore lung function where indicated.
Thoracic endometriosis occurs when endometrial tissue — the tissue that normally lines the uterus — is present in the chest cavity. It most commonly involves the diaphragm, but can also affect the pleural lining or the lung surface.
The condition is significantly underdiagnosed. Symptoms are often dismissed as musculoskeletal pain, anxiety, or recurrent chest infections — sometimes for many years. The hallmark is that symptoms occur cyclically, around the time of menstruation. A BJOG 2024 study found diagnostic delay exceeding 5 years is common.
The most common manifestation is catamenial pneumothorax — a collapsed lung occurring within 72 hours of the start of a period. Other presentations include cyclical chest pain, pleural effusion, and rarely coughing up blood (haemoptysis), all timed with menstruation.
Keyhole (VATS) surgery to identify and remove endometrial deposits from the chest cavity and diaphragm. Diaphragm defects are repaired. Pleurodesis is performed to prevent further pneumothorax. This addresses the underlying cause rather than managing acute episodes as they arise.
For a full explanation, including symptoms, the diagnostic pathway, and what surgery involves, see the dedicated thoracic endometriosis page → and the cyclical chest symptoms page →
Mesothelioma is a cancer of the pleural lining, most commonly associated with previous asbestos exposure, often many years earlier. There is typically a latency of 30–50 years between exposure and diagnosis. It typically presents with breathlessness and a pleural effusion alongside chest wall pain.
Diagnosis requires thoracoscopy — keyhole inspection of the pleural cavity — to take biopsies of the pleural lining under direct vision. This allows accurate diagnosis and staging, which is essential before any treatment decisions are made.
Treatment options for mesothelioma are discussed by a specialist multidisciplinary team. They range from palliation of symptoms — managing breathlessness through pleurodesis or an indwelling pleural catheter — to more radical surgical approaches in carefully selected patients. A second opinion from a specialist thoracic centre before any treatment is always worthwhile. Dr Okiror has published on mesothelioma staging and has chapters on surgery for pleural disease in two major textbooks.
Request a Second Opinion →Where the focus is on improving breathlessness and quality of life, options include pleurodesis to prevent fluid re-accumulation, or insertion of an indwelling pleural catheter to allow fluid to be drained at home without repeated hospital admissions.
Common questions from patients referred with a pleural condition. If your question is not answered here, please get in touch directly.
Book a Consultation →Or call Jo Mitchelson:
020 7952 2882
Appointments within 2–3 days. Self-referrals welcome. No GP letter required. London Bridge Hospital and Lister Hospital Chelsea.
Jo Mitchelson, Private PA · 020 7952 2882 · pa@lungsurgeon.co.uk
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