Empyema is pus in the space around the lung, usually after pneumonia. Around 40 new cases of pleural infection are diagnosed each day in the UK, and about one in five patients either dies within a year or needs surgery after initial treatment fails. The operation depends on the stage: keyhole (VATS) debridement for loculated infection, decortication for a lung trapped by a fibrous peel. Dr Okiror is first author of the 2014 European Journal of Cardio-Thoracic Surgery paper on decortication outcomes, a co-author of the MIST-3 trial (Am J Respir Crit Care Med 2023) and Guy’s and St Thomas’ co-site lead for the MIST-4 Phase III trial. Surgery at London Bridge Hospital and The Lister Hospital Chelsea; unwell patients are admitted directly.
Last reviewed: October 2026 · Dr Lawrence Okiror FRCS(CTh) FRCSEd(CTh) · GMC 6150382
Pleural infection is the broader term for the condition that becomes empyema. It usually starts as a complication of pneumonia. Bacteria cross from the lung into the pleural space, fluid collects around the lung and becomes infected, and without effective treatment the infection organises into loculated pockets of pus and then into a thick fibrous peel that encases the lung and stops it re-expanding. Patients present with a fever that does not settle after pneumonia, breathlessness and chest pain on breathing; night sweats and weight loss are common once the infection has become chronic.
Admissions for empyema in England rose from 4,447 in 2008 to 7,268 in 2017 (Arnold et al., European Respiratory Journal 2021). Across the UK around 40 new cases of pleural infection are diagnosed each day. Standard treatment with antibiotics and a chest drain means a hospital stay of about two weeks, and about one in five patients either dies within a year or needs surgery after initial treatment fails (MIST-4 trial summary, Health Research Authority). Mortality has changed little in 15 years despite better antibiotics, intrapleural enzyme therapy and keyhole surgery.
The burden falls most heavily on older and frail patients and on those with diabetes, immunosuppression or significant comorbidity. It also occurs in previously healthy adults.
New cases of pleural infection diagnosed in the UK
Die within a year or need surgery after initial treatment fails
Typical hospital stay on standard treatment
Empyema admissions in England, 2008 to 2017
Sources: MIST-4 trial summary, Health Research Authority; Arnold et al., European Respiratory Journal 2021.
Empyema is not a single bacterial disease. The organisms differ between community-acquired and hospital-acquired infection, and the difference affects antibiotic choice, surgical urgency and prognosis.
Community-Acquired Pleural Infection
Streptococci & AnaerobesThe dominant organisms are the Streptococcus milleri group, often the single most common isolate in UK community-acquired empyema, Streptococcus pneumoniae, and a substantial proportion of anaerobes including Fusobacterium and Bacteroides species. Mortality is lower than in hospital-acquired infection. Surgical results are good when intervention is timely.
Empirical antibiotic cover follows the British Thoracic Society guideline and local microbiology advice, with broad-spectrum agents that cover anaerobes pending culture.
Hospital-Acquired Pleural Infection
Gram-negatives, MRSA & PolymicrobialHospital-acquired pleural infection has a different microbiological profile. Gram-negative organisms (E. coli, Klebsiella, Pseudomonas), MRSA and polymicrobial infection are all more common. Mortality is substantially higher. Time to surgical intervention is more critical in this group, and antibiotic cover must reflect local resistance patterns.
The source of infection, community or hospital, is one of the five components of the RAPID risk score and one of the stratification factors in MIST-4.
The surgical decision: patients with hospital-acquired pleural infection, multi-resistant organisms or significant comorbidity cannot afford a prolonged trial of failing medical therapy. Earlier surgical involvement, which does not always mean earlier surgery, allows the surgical option to be planned alongside the medical treatment instead of as a salvage step after weeks of failure. The 2023 GIRFT Cardiothoracic Surgery report recommends that surgery for empyema be performed within 48 hours of surgical referral.
The evidence base for pleural infection has been built over twenty years by the MIST series of UK trials, run by the Oxford Respiratory Trials Unit. Each trial answered one question. The remaining question, whether surgery or intrapleural enzyme therapy should come first when medical management fails, is what MIST-4 is testing in a Phase III randomised trial across UK sites including Guy’s and St Thomas’.
MIST 1 · 2005
Maskell et al. · New England Journal of Medicine · 2005 · 454 patients
The First Multicentre Intrapleural Sepsis Trial randomised patients with pleural infection to intrapleural streptokinase or placebo. There was no difference in mortality, the need for surgery or hospital stay, and streptokinase alone was abandoned.
MIST 2 went on to test a different combination of drugs.
MIST 2 · 2011
Rahman et al. · New England Journal of Medicine · 2011 · 210 patients
A 2×2 factorial trial of intrapleural tPA plus DNase against either drug alone or placebo. The combination improved drainage on imaging, reduced surgical referral at three months from 16% to 4%, and shortened hospital stay by 6.7 days. Either drug alone was no better than placebo. This established intrapleural enzyme therapy, alteplase plus DNase, as the medical step before surgery.
Intrapleural enzyme therapy is now in the British Thoracic Society pleural disease guideline (2023).
MIST-3 · 2023
Bedawi et al. · Am J Respir Crit Care Med · 2023 · 60 patients · 8 UK centres · ISRCTN18192121
The Third Multicentre Intrapleural Sepsis Trial tested whether patients with pleural infection could be randomised to early VATS surgery, early enzyme therapy or standard care. It met its feasibility criteria, suggested a shorter hospital stay with early surgery and earlier symptom resolution with enzyme therapy, and confirmed that a Phase III trial was feasible. Dr Okiror is a co-author of MIST-3, contributing the Guy’s and St Thomas’ surgical data.
MIST-3 provided the feasibility evidence on which MIST-4 was designed.
MIST-4 · Phase III · Recruiting
Phase III multicentre RCT · 604 patients · Oxford Respiratory Trials Unit · ISRCTN16328099
The Fourth Multicentre Intrapleural Sepsis Trial compares early VATS debridement with early intrapleural enzyme therapy in adults whose pleural infection has not responded to initial medical management. It is stratified by RAPID score and by whether surgery is available on site. Recruiting at Guy’s and St Thomas’ since April 2026.
Dr Okiror is Guy’s and St Thomas’ co-site lead for MIST-4.
Summary
MIST 1 ruled out streptokinase. MIST 2 established intrapleural enzyme therapy as the medical step before surgery. MIST-3 showed that randomising patients to early VATS or early enzyme therapy was feasible. MIST-4 is the definitive comparison. Dr Okiror is a co-author of MIST-3 and Guy’s and St Thomas’ co-site lead for MIST-4.
The surgical decision rests on three questions: what stage the disease has reached, what has already failed, and which operation will reliably re-expand the lung.
First-line treatment under the British Thoracic Society guideline: empirical antibiotics appropriate to community-acquired or hospital-acquired infection, and an image-guided chest drain. Most Stage I effusions and many early Stage II cases respond. Persistent fever, a CRP that has not fallen by half within five days, or a persistent collection on imaging signal failure and the need to escalate.
For fibrinopurulent Stage II disease with established loculations, or when intrapleural enzyme therapy has failed or is not appropriate. Single-port or multi-port VATS, with all loculi broken down and the cavity washed until clear. Hospital stay is usually 4 to 7 days. GIRFT (2023) recommends surgery within 48 hours of surgical referral; the MIST-4 protocol requires VATS by day 4 from randomisation.
For organised Stage III empyema, where a fibrous peel has formed and the lung will not re-expand until the peel is removed. VATS alone is not adequate at this stage. Thoracotomy gives the access needed to free the visceral pleura without injuring the lung beneath it. This is the operation studied in Dr Okiror’s 2014 EJCTS paper on decortication for culture-positive empyema.
The RAPID risk score
The RAPID score, Renal function (urea), Age, Purulence of pleural fluid, Infection source (community or hospital) and Dietary status (serum albumin), predicts 90-day mortality in pleural infection and identifies the patients who may benefit from earlier escalation to surgery. It was derived from the MIST trial populations (Rahman et al., Chest 2014) and validated prospectively in the PILOT study (Corcoran et al., European Respiratory Journal 2020). It is one of the two stratification factors in MIST-4.
If your treating team has not used the RAPID score to guide escalation, that is a reasonable question to ask.
Pleural infection reaches a surgeon through the NHS first, by way of A&E, respiratory medicine or intensive care, and surgery is needed when escalation is required. A large part of Dr Okiror’s emergency work at Guy’s and St Thomas’ is pleural infection and pneumothorax. His published work and trial roles in this condition are set out below.
Okiror L, et al. Thoracotomy and decortication: impact of culture-positive empyema on the outcome of surgery. European Journal of Cardio-Thoracic Surgery 2014;46(5):901–906.
Cited in international guidance including the 2023 Japanese Association for Chest Surgery guideline on empyema and in systematic reviews of pleural infection.
Bedawi et al. Early VATS or Intrapleural Enzyme Therapy in Pleural Infection: The Third Multicenter Intrapleural Sepsis Trial — MIST-3. Am J Respir Crit Care Med 2023;208(12):1305–1315.
Trial registry: ISRCTN18192121. Feasibility trial across 8 UK centres including the Guy’s and St Thomas’ surgical site.
Guy’s and St Thomas’ co-site lead for the Phase III MIST-4 trial, with Dr Poppy Denniston and Dr Owais Kadwani: the UK randomised comparison of early VATS surgery and early intrapleural enzyme therapy in adult pleural infection.
Trial registry: ISRCTN16328099. Run by the Oxford Respiratory Trials Unit.
Teaching. Dr Okiror teaches pleural disease and the surgical management of empyema each year on the SCTS Education Revision and Viva Course for the FRCS (Cardiothoracic), the national examination preparation course for senior thoracic trainees. He has also delivered the chest wall and pleural disease module on national specialty examination preparation programmes alongside authors of the British Thoracic Society pleural guideline.
A first-author publication on decortication, a current role in the Phase III trial and a national teaching role in this condition are uncommon together in private thoracic practice in London.
VATS debridement and washout for pleural infection is performed at London Bridge Hospital and The Lister Hospital Chelsea. Both have full thoracic surgical capability and the perioperative support needed for patients who are systemically unwell at the time of surgery.
Chronic Stage III empyema requiring thoracotomy and decortication, and patients with significant comorbidity, persistent sepsis or multi-organ involvement, are operated on at London Bridge Hospital, where the intensive care and respiratory medicine support match the complexity of the operation and the underlying illness. London Bridge Hospital is ranked tenth in the UK in the Newsweek World’s Best Hospitals 2026 list, the highest-ranked private hospital.
Outpatient consultations, including second opinions on a chest drain that has not resolved or on a recommendation against surgery, are also held at HCA outpatients in Canary Wharf and the City of London. Same-day or next-day video consultations can be arranged for urgent cases.
Fees and insurance. Empyema surgery is quoted individually after consultation, because the operation and the length of stay vary with the stage of disease. The hospital issues a written fixed quote before admission, and hospital charges are the largest part of the cost. Guide prices for the related pleural operations and how fees work → Dr Okiror is recognised by AXA Health, Bupa, Aviva, Vitality, WPA and Cigna, and by most other UK and international insurers. If you have private medical insurance, Dr Okiror and the hospital bill your insurer directly, and insurers usually settle the hospital, surgeon and anaesthetist fees in full, less any excess written into your policy. Pre-authorisation should be obtained before the first appointment. Self-paying patients are equally welcome.
Patients who are unwell and attend the Urgent Care Centre at London Bridge Hospital are admitted directly to the ward, and surgery is usually within 48 hours. Patients already in an NHS hospital with pleural infection that is not resolving can be transferred, with the bed, ambulance and insurer authorisation arranged by the HCA Medical Concierge team. Patients who are stable are seen within 2–3 days, and surgery, where needed, is usually within a week of completing investigations. To discuss a transfer, call Jo Mitchelson, PA, on 020 7952 2882.
Patients with chronic empyema are sometimes told that surgery is too risky, or that long-term antibiotics or an indwelling drain are the only options left. Those answers are sometimes correct. Where a unit has limited experience of decortication they can also be wrong. Three questions help.
RAPID is the validated tool for stratifying risk in pleural infection. If it has not been calculated, the judgement that surgery is too risky has been made on clinical impression alone.
An assessment of operative risk by a chest physician and one by a thoracic surgeon who performs decortication regularly can differ. For complex cases a specialist surgical opinion is the right standard, and it is reasonable to ask for one.
Antibiotics and chest drain. Intrapleural enzyme therapy with alteplase and DNase. VATS debridement. Decortication. Each is a separate rung on the ladder. If only one or two have been tried, options remain. If all have been tried and failed, the conversation is different, and it should include a surgeon experienced in the disease.
A second opinion appointment with Dr Okiror is usually available within 2–3 days. For acutely unwell patients a video consultation can be arranged the same day. Dr Okiror requests the imaging and reviews it before the appointment; please also send the inflammatory marker trend, microbiology results and any treatment recommendation already made.
If your problem is pleural fluid rather than infection
Pleural effusion, pleural thickening or suspected mesothelioma?Non-infective pleural disease follows a different pathway. The pleural disease page covers the diagnostic work-up for malignant pleural disease; the pleural effusion and pleurodesis page covers VATS talc pleurodesis, pleural biopsy and indwelling catheters; and a milky, lymph-rich effusion is a chylothorax, which has its own page.
Questions from patients whose pleural infection has not resolved on antibiotics, from families of patients with chronic empyema seeking a second surgical opinion, and from referring physicians considering early surgical involvement.
Book a Consultation →Jo Mitchelson, PA
020 7952 2882
pa@lungsurgeon.co.uk
Appointments within 2–3 days. Same-day video consultations for urgent pleural infection. Unwell patients admitted directly to the ward at London Bridge Hospital. Surgery at London Bridge Hospital and The Lister Hospital Chelsea.
Jo Mitchelson, PA · 020 7952 2882 · pa@lungsurgeon.co.uk
St Thomas’ Hospital #1 UK · Guy’s Hospital #2 UK · London Bridge Hospital #10 UK · Newsweek World’s Best Hospitals 2026
Pleural effusion, pleural thickening and mesothelioma assessment: the non-infective pleural pathway
Pleural Effusion & PleurodesisVATS talc pleurodesis with biopsy, or an indwelling pleural catheter, for fluid that keeps returning
ChylothoraxA milky, lymph-rich effusion after chest or neck surgery or from lymphoma: diagnosis, thresholds and the surgical options
Lung Infection SurgerySurgery for localised bronchiectasis, aspergilloma, lung abscess, TB and hydatid disease, by specialist referral
Specialist Second OpinionIndependent review for patients told surgery is not possible, within 2–3 days, same-day by video for urgent cases
For Referring GPs & PhysiciansDirect surgical referral for chest physicians and ICU teams managing pleural infection that is not resolving
Thoracic Symptom ManagementSymptom-directed thoracic care: relieving breathlessness, pain, cough and recurrent chest fluid
BreathlessnessThe symptom page: when breathlessness needs a specialist chest assessment
Night Sweats & Weight LossThe symptom page: chronic infection, including empyema and tuberculosis, among the causes a thoracic surgeon looks for