Management of Empyema Thoracis

466 Journal of the Royal Society of Medicine Volume 87 August 1994 Section Meetings Management of empyema thoracis John A Odell ChB FRCS(Ed) Department of Cardiothoracic Surgery, Mayo Clinic, Rochester, MN 55905, USA Keywords: empyema thoracis; drainage of empyema; decortication loculation, particularly posteriorly. The pleural fluid Paper read to pH and glucose level become progressively lower and Cardiothoracic Definitions the LDH level increases. In the third or organizational Section, An empyema thoracis is simply a collection of pus stage, fibroblasts grow into the exudate from both the 27 May 1993 in the pleural space. Some have tried to define it visceral and parietal pleural surfaces to produce an differently, but this is unnecessary; many term a inelastic membrane called the pleural peel or cortex. parapneumonic effusion associated with bacterial pneumonia, lung abscess, or bronchiectasis an Historical empyema whereas others state that only para- perspective pneumonic effusions with positive pleural fluid cultures can be called an Likewise, others Those cases of empyema or dropsy which are treated by empyema1. incision or the cautery, ifthe water or pus flows rapidly all use the term 'complicated parapneumonic effusion' at once, certainly prove fatal. to refer to those effusions that do not resolve without When empyema is treated either by the cautery or incision, tube thoracostomy'. Another term that is frequently if pure and white pus flow from the wound, the patients used, particularly in regions where tuberculosis is recover, but if mixed with blood, slimy and fetid they die. common, is the term 'tuberculous empyema'. However, Hippocrates2 we do not normally classify a straw-coloured effusion from which tubercle bacilli are isolated as an Cardiothoracic surgery probably began with the empyema, nor do we often find thick caseous management of empyema. Most empyemas were tuberculous pus within the pleura (this is invariably associated with pulmonary infection and sometimes a tuberculous lobar pneumonia which has been became obvious when pus discharged spontaneously intubated percutaneously because of difficulty in from the chest wall (an empyema necessitans or radiographic interpretation). What is frequently necessitatis or, in modem terms, a pointing empyema). meant by a 'tuberculous empyema' is a bacterial Those early physicians involved with medical empyema complicating active or previous tuberculosis. treatment determined the exact site for surgical An empyema may be associated with positive drainage by establishing the maximal site ofpain, or bacterial cultures or may even be sterile. The by smearing the chest with potters clay. The site that diagnosis does not require any complicated tests such dried first, the hottest and most inflamed, was chosen as glucose, LDH, pleural pH or leukocyte count (it is then as the site of drainage. Early chest drains used obvious to the naked eye!). If reliance on laboratory were hollow reeds. investigations influences management then patients Hippocrates described drainage of an empyema and with rheumatoid pleurisy, tuberculosis, malignancy he recognized the smell of anaerobic infection and or lupus pleuritis may be inadequately managed by its association with a poor prognosis2. The Greek intercostal drainage. The only investigations necessary physicians at that time had advanced the techniques are fluid and, if obtained, a pleural biopsy, sent of managing empyema to include early diagnosis, for bacteriological and histological examination. irrigation and placement of an indwelling tube. These Occasionally chylothorax, because ofits appearance, techniques became the standard of care for over two can be confused with empyema but this condition millennia. usually occurs in specific circumstances. Little therapeutic progress beyond open drainage The confusion in terminology probably is a result was made until the 19th century, when needles to of the stages in evolution of any empyema. The first locate and aspirate an empyema were developed3, stage is an exudative phase in which a focus of and drainage of the chest with an underwater infection adjacent to the visceral pleura leads to seal was introduced4. It was soon realized that increased permeability ofthe visceral pleura and the drainage was sometimes more effective after resection accumulation of a small usually sterile parapneumonic of a portion of rib. Thoracoplasty as a form of effusion. The pleural fluid is an exudate in which treatment for empyema was pioneered5; and the leukocytes may be found. For those who investigate, operation ofdecortication, which was discovered almost the glucose is normal as is the pH. Occasionally, the by accident6, was further developed7. Decortication septic lung focus adjacent to the pleura may rupture enjoyed a vogue after the First World War, only to directly into the pleural space; if it communicates fall into disuse until revived during the Second World with a bronchus a broncho-pleural fistula develops. War8'9. Only with the introduction ofbasic anaesthetic The second stage, the fibrinopurulent stage, is techniques, an understanding ofthe dangers of an open characterized by a much larger fluid collection which pleural cavity that had not been made rigid by fibrin is obviously pus (it contains many polymorphonuclear deposition and the use of antimicrobial therapy did leukocytes, bacteria and cellular debris). Ofimportance real progress in the management of empyema occur. is a tendency for fibrin to be deposited on both the One surgeon, Evarts Graham, stands as one of visceral and parietal pleura and a tendency for those, who advanced considerably our understanding Journal of the Royal Society of Medicine Volume 87 August 1994 467 of empyema' "'. In 1918 he was appointed to the US Management Army Empyema Commission which was charged to The patient with an empyema may have variable investigate the high mortality, averaging 30.2%, but symptoms difficult to distinguish from those of the ranging as high as 70% or more, in camps where open primary provocation, whether this be 'pneumonia', drainage was standard practice. He defined the mediastinitis, subphrenic abscess or posttraumatic difference between pneumococcal and streptococcal haemothorax. He may be virtually asymptomatic or empyema: pneumococcal empyema tended to occur may be frankly toxic, depending upon the causal late in the course of pneumococcal pneumonia organisms, the volume ofpus within the pleural space and be associated with thick and creamy pus and the host defence mechanisms. Other features whereas streptococcal empyema occurred earlier in result from occupation ofthe pleural space: dyspnoea; the phase ofthe disease when the pleural exudate was diminished movement of a hemithorax; dullness to serofibrinous. percussion; diminished breath sounds; and, if the Early open drainage as practised at that time empyema is large, displacement of the mediastinum frequently led to collapse of the lung from pneumo- to the opposite side. thorax which, superimposed upon pneumonia, was The patient with a bronchopleural fistula gives a often fatal. When the principles Dr Graham elucidated distinctive history - whenever he lies on the side were applied by the Empyema Commission, the opposite to the empyema he coughs excessively and mortality was reduced to 3.4%. The essential points the volume of pus produced is frequently large. The ofthese new principles were: (1) careful avoidance of patient with a pointing empyema characteristically an open pneumothorax in the acute stage: (2) the has a discharging sinus or a chest wall swelling that prevention of a chronic empyema by the rapid may be confused with an abscess. Most pointing sterilization and obliteration of the infected cavity; empyemata are associated with tuberculosis: if and (3) careful attention to the nutrition ofthe patient. associated with trauma or previous chest surgery this may occur at any site where the chest wall Aetiology of empyema was previously breached. The patient with an An empyema follows infection of the structures amoebic empyema usually has a painful tender surrounding the pleural space; an infection solely of liver. the pleural space probably does not occur. A relatively asymptomatic patient may be referred In the lung, empyema commonly follows pneumonia with an opacity on the chest radiograph that raises but may also be associated with lung abscess and the possibility of empyema, but the differential bronchiectasis. Lung abscess usually elicits an diagnosis may include pleural tumor, pulmonary inflammatory pleuritis over the adjacent pleura that tumor or even hydatid disease. Occasionally, pus obliterates the pleural space and lessens the may be loculated (encysted, fissural, mediastinal, likelihood of empyema, but, if the lung abscess subpulmonary). The appropriate first investigation in is particularly acute and the organisms virulent, this patient is ultrasound or computerized tomography the abscess may rupture into the pleural space (CT) examination to determine as far as possible the before obliteration has occurred, producing a pyo- nature of the opacity. Hydatid disease is obvious: it pneumothorax or empyema. In the vast majority of has a density approximating water: a tumour has a patients with bronchiectasis the pleural space is solid density; an empyema is ofvariable density and also obliterated but there are exceptions and in this a fluid component is usually present. Recently using situation empyema is possible. In both bronchiectasis CT examination

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