Pleuroperitoneal shunts are effective in patients with trapped lung or failed pleurodesis, in the absence of multiple loculations. Shunting of \202 uid may occur spontaneously, at high pressures, or may require manip- ulation of a percutaneous pump chamber, inserted at t horacoscopy or mini-thoracotomy. Main problem is shunt occlusion, which occurs in at least 10% of cases and necessitates shunt removal. Malignant spread may also occur Surgical parietal pleurectomy may be performed as VATS (video-assisted thoracoscopic surger y). The procedure is effective in the management of refractory malignant effusions. May be useful in a minority of patients with good performance status and prognosis. Not suitable f or patients with heavily diseased visceral pleura and trapped lung; consider in patients wh o have failed pleurodesis Palliative care team involvement should also be considered. CHAPTER 35 Pleural effusion 352 Parapneumonic effusion and empyema: de \201 nition and clinical features De \201 nition a nd pathophysiology Pleural effusions occur in up to 40% of patients with pneumonia. An init ial sterile exudate (simple parapneu- monic effusion) may in some cases progress to a compl icated parapneu- monic effusion and eventually empyema (Fig. 35.1). Exudative stage Simple parapneumonic effusion Clear sterile fluid with normal pH, glucose, LDH Frequently resolves with antibiotics alone Drainage not usually required Complicated parapneumonic effusion Fibrinopurulent stage Fibrin deposited and septations occur Fluid infected but not yet purulent; appears clear or cloudy/turbid pH< 7.2, glucose < 2.2 mmol/L and LDH > 1000IU/L Gram stain/culture may be positive Drainage required Empyema Pus in pleural space May be free-flowing or multiloculated Gram stain/culture may be positive Drainage required Eventually, fibroblast growth may result in development of thick pleural peel (organizing s tage). Treatment at this stage is difficult and decortication may be required Fig. 35.1 Parapneumonic effusion and empyema: de \201 nition and clinical features. Pleural infection may also occur in the absence of a preceding pneumonic illness ( \200\230 primary empyema \200\231) Clinical features Common - Consider the diagnosis particularly in cases of \200\230slow to respond \200\231 pneumonia, pleural effusion with fever, or high-risk groups with non-spec i \201 c symptoms such as weight loss Similar to clinical presentation of pneumonia: fever, sputum production, chest pain, breathlessness Anaerobic empyema may present less acutely, often with weight loss and without fever. PARAPNEUMONIC EFFUSION AND EMPYEMA 353 Rare - Infected pleural \202 uid may spontaneously drain through the chest wall (empyema necessitatis) or into the lung, leading to a bronchopleural \201 stula and severe pneumonia History of atypical chest pain, vomiting, or oesophageal instrumentation suggests possible underlying oesophageal rupture (measure pleural \202 uid amylase) History of a recent sore throat may suggest Lemierre \200\231s syndrome (acute oropharyngea l infection with Fusobacterium species leads to septic thrombophlebitis of the internal jug ular vein and subsequent metastatic infection and abscess formation, commonly in the lungs and pleura; consider ultrasound of internal jugular vein if suspected); see p 446. Risk factors for developing empyema include diabetes, alcohol abuse, gastro-oesophageal re \202 ux, and intravenous drug abuse. Anaerobic infection is associated particularly with a spiration or poor dental hygiene. Empyema may rarely occur following bronchial obstruction from a tumor or foreign body. Many patients, however, have no apparent risk factors. Differ ential diagnosis includes malignancy, tuberculosis (when the pleural \202 uid is usually lymphocytic), and rheumatoid pleuritis. CHAPTER 35 Pleural effusion 354 Parapneumonic effusion and empyema: bacteriology and investigations Bacteriology - Communit y-acquired infection (% of cases): S. milleri (28%) \200 Anaerobes (19%) \200 S. pneumoniae (14%) \200 Staphylococci (12 %) \200 Other less common organisms include other streptococci, entero- bacteria, H. in \202 uenza, Pseudomonas, TB, and Nocardia. Legionella may very rarely caus e empyema Hospital-acquired infection (% of cases): MRSA (27%) \200 Staphylococci (22%) \200 Enterobacteria (20%) \200 Enterococci (12%) \200 Others include streptococci, Pseudomonas, and anaerobes. Gram-negative organisms may occur in mixed growths with other Gram-negatives or with anaero bes. Investigations - Diagnostic pleural tap is essential if pleural infection is suspected. Frankly purulent or turbid/cloudy pleural \202 uid, organisms on pleural \202 uid Gram stain or culture, or pleural \202 uid pH <7.2 are all indications for chest tube drainage . 40% of pleural infections are culture-negative. Identi \201 cation of anaerobes is impro ved following inoculation of blood culture bottles with pleural \202 uid Ultrasound typically shows echogenic effusion that may be septated, and is useful in guidin g pleural tap in patients with small or loculated effusions or following an unsuccessful \200\230blind \200\231 tap. Very small effusions (<10 mm maximal thickness on ultrasound) p robably do not require tapping and can be observed Contrast-enhanced CT may be useful both in supporting the diagnosis and visualizing the dis tribution of \202 uid. Empyema is associated with pleural enhancement and increased atten uation of extrapleural sub- costal fat. The displacement of adjacent lung by empyema may he lp to distinguish from a parenchymal lung abscess. Empyemas frequently appear lenticular an d may exhibit the \200\230split pleura \200\231 sign of enhancing separated visceral and p arietal pleura. Absence of pleural thickening on CT is unusual in empyema. CT may also some times identify a proximal endobronchial obstructing lesion Blood cultures positive in only 13% of cases, but in these cases they are often the only positive microbiology Bronchoscopy is only indicated if a bronchial obstructing lesion is suspected This page intentionally left blank CHAPTER 35 Pleural effusion 356 Parapneumonic effusion and empyema: management and outcome Management 1. Antibiotics All pa tients with pleural infection should be treated with antibiotics; refer to local hospital p rescribing guidelines. Typical choices: - Community-acquired empyema \200\224second-generat ion cephalosporin (e.g. cefuroxime) plus metronidazole as anaerobic cover. Cipro \202 oxac in and clindamycin together may be appropriate. Add macrolide if Legionella is suspected Hospital-acquired empyema \200\224cover Gram-positive and Gram-negative organisms and anaer obes. MRSA infection is common. Consult with microbiology team. One option is meropenem and vancomycin. Rationalize with culture and sensitivity results (although note that anaerobes are frequent ly dif \201 cult to culture and may coexist with other organisms). Avoid aminoglycosides, which penetrate the pleural space poorly. Switch to oral antibiotics when apyrexial and improving clinically. Co-amoxiclav is a usefu l single agent with anaerobic cover (not if penicillin allergic). Optimal duration of antib iotic treatment unclear, although likely to be at least 3 weeks. 2. Chest tube drainage Indications for chest tube drainage - Frankly purulent or turbid/cloudy pleural \202 uid - Organisms on pleural \202 uid Gram stain or culture - Pleural \202 uid pH <7.2 Consider earlier chest tube drainage in the elderly and patients with comorbidity, and locu lated effusions, as these are associated with a worse outcome. Drain insertion should ideally be carried out under ultrasound or CT guidance, as effusions are frequently loculated. Ideal chest tube size remains subject to debate. Small (10 \200 \22314 French) \202 exible tubes are more comfortable and have been demonstrated to be as effective as large drains in the management of empyema. Usually apply suction ( \200\22320 cm water) and \202 ush regularly (e.g. 30 ml normal saline every 6 h) to prevent occlu- sion. Consider drain removal when clinical improvement occurs. If there is no indication fo r drainage, give antibiotics and monitor closely. If slow to improve or deteriorate, re-sam ple the effusion and consider chest drain. 3. Intrapleural \201 brinolytics Current evidence suggests that intrapleural streptokinas e has no effect on mortality, need for surgery, or hospital stay, and the routine use of \201 brinolytics is therefore not recommended. PARAPNEUMONIC EFFUSION AND EMPYEMA 357 4. Nutritional support Dietician review, consider supplementary nasogas- tric feeding. Intr avenous feeding may be required. 5. Surgery Consult with thoracic surgeon if there are ongoing features of sepsis and residu al pleural collection after 7 days despite tube drainage and treatment with antibiotics. Su rgical techniques include: - Video-assisted thoracoscopic surgery (VATS) allows the breakdown of adhesions and drainage of residual collection, but it is frequently unsuccessf ul in chronic empyema with very thickened visceral pleura Thoracotomy and decortication Removal of \201 brinous and infected tissue from the pleural space: a major surgical procedure Open thoracic drainage Resection of segments of several ribs adjacent to the empyema and in sertion of large-bore drains into the cavity: a more minor procedure that can be performed under local anesthesia, but results in open chest wound for long period (typically around 5 months). Dif \201 culties in management Chest drainage ceases despite residual pleural collection - Attempt to \202 ush drain with normal saline - Ensure that drain is not kinked at skin i nsertion site or lying subcutaneously Consider CT to assess extent of residual collection and drain position - Remove drain if pe rsistently blocked - Consider further image-guided chest drain(s), surgery Failure to clini cally improve despite antibiotics and chest drain - Review microbiology results and ensure appropriate antibiotics - CT to assess extent of residual collection and drain position - S urgical referral - Options if un \201 t for surgery: Further image-guided small-bore drains into loculated effusions \200 Large-bore drain \200 Surgical rib resection and open drainage under local anesthesia Outcome About 15% of patients require surgery. Empyema 1-year mor- tality is about 15%. Increased age, renal imp airment, low serum albumin, hypotension, and hospital-acquired infection are associated wit h a poor outcome. CXR may remain abnormal despite successful treatment of empyema, with evi dence of calci \201 cation or pleural scarring or thickening. Further information Davies CWH et al. BTS Guidelines for the management of pleural infectio n. Thorax 2003; 58 (suppl. II): ii 18 \200\22328 Maskell NA et al. UK controlled trial of intrapleural streptokinase for pleural infection. NEJM 2005; 352: 865 \200\22374 CHAPTER 35 Pleural effusion 358 Tuberculous pleural effusion De \201 nition and epidemiology Tuberculous pleural effusion usually develops from a delayed hypersensitivity reaction to mycobacteria released into the pleural space. It is a common manifestation of primary tuberculosis in regions with a high prevalence, affecting children and young adults; it may also be associated with reactivati on of tuberculosis in older individuals. May occur more commonly in the setting of HIV co-i nfection. Rarely, tuberculosis may present as pseudochylothorax or tuberculous empyema. Clinical features - Clinical features are similar to those of pulmonary tuberculosis, i.e. fever, sweats, weight loss, and dyspnoea, although it may present acutely with pleuritic ch est pain and fever, mimicking pneumonia Effusions are typically small \200\223moderate in volume, although can be massive Investigations - Associated parenchymal in \201 ltrate on CXR in less than one-third of ca ses - Tuberculin skin tests positive in two-thirds of cases - Pleural \202 uid lymphocyto sis, exudative effusion, pH and glucose moderately depressed, mesothelial cells rare. Pleural \202 uid acid-fast bacilli (AFB) sm ears are positive in around 5 \200\22310% of cases; pleural \202 uid cultures are positiv e in 25% of cases and take 2 \200\2236 weeks Blind Abrams \200\231 pleural biopsy alone has a sensitivity of 75%, but this increases to nearly 90% when histology and culture of both the \202 uid and biopsy are an alyzed Thoracoscopic biopsies have a sensitivity of nearly 100% - Measurement of adenosine deamina se (an enzyme released by macro- phages after phagocytosis of mycobacterium) in pleural \202 uid may be of bene \201 t in regions where tuberculosis is highly prevalent; a raised value is very sensitive for pleural tuberculosis, but is non-speci \201 c and may also oc cur in empyema and malignancy PCR for mycobacterial DNA in the pleural \202 uid may be useful diagnos- tically, but is not widely available Induced sputum for acid-fast bacilli may have a diagnostic role in high-risk patients with lymphocytic effusions, even in the absence of parenchymal disease o n CXR Treatment and outcome - Tuberculous pleural effusions resolve spontaneously in the majority of cases, but two-thirds of untreated patients go on to develop pulmonary tuberculosis wit hin 5 years and so treatment is recommended - Treatment is the same as for pulmonary tuberc ulosis (p 494) - Pleural \202 uid volumes may increase during effective treatment and therapeutic thoracentesis is often required Steroids may reduce \202 uid volumes, but do not affect long-term outcome - Pleural thick ening and calci \201 cation are common long-term consequences of tuberculous pleural effusion. This page intentionally left blank CHAPTER 35 Pleural effusion 360 Other causes Pleural effusion due to pulmonary embolism - Fourth commonest cause of pleural effusion in the USA - Consider in all patients with undiagnosed pleural effusion, particul arly if there is a history of pleuritic chest pain or of breathlessness/hypoxia out of prop ortion to the size of the effusion Frequently complicates other disease processes, e.g. occurs in one- \201 fth of patients with cardiac failure and pleural effusions Effusions are usually small (<one-third of hemithorax) and unilateral, although may be bilateral Pleural \202 uid analysis is non-diagnostic; appearance varies from clear to bloody, 80% are exudates and 20% transudates. Bloodstained pleural \202 uid is not a contraindication to anticoagulation Imaging investigations, such as CTPA of the chest, are required to make the diagnosis; thes e should be performed prior to thoracentesis if pulmonary embolism is strongly suspected. Rheumatoid arthritis-associated pleural effusion - Pulmonary changes may be the \201 rst manifestation of rheumatoid arthritis Rheumatoid pleurisy is more common in men (70% are in men) - Pleural \202 uid may be yell ow-green, serous, turbid, or bloody - May be unilateral or bilateral - Pleural \202 uid g lucose level is frequently low (<1.6 mmol/L), and progressively falls in chronic effusions Pleural \202 uid pH is commonly reduced (<7.3) - Low pleural \202 uid complement levels (C4 <0.04 g/L) may also favor the diagnosis Elevated pleural \202 uid rheumatoid factor titre is found, but it is not more diagnostically helpful than serum rheumatoid factor Typically persist for months to years, although duration may be several weeks Some cases may respond to treatment with steroids Haemothorax - Haemothorax is de \201 ned as a pleural effusion with a haematocrit >50% of peripheral blood haematocrit Causes include trauma, iatrogenic, malignancy, pulmonary infarction, benign asbestos-related pleural effusion, pneumonia, post-cardiac injury syndrome, pneumoth orax, thoracic endometriosis, and aortic rupture - Massive haemothorax de \201 ned as >150 0 cm3 of blood in hemithorax, and is most commonly due to trauma. Traumatic haemothorax is said to require a chest drain and sometimes thoracotomy; all cases should be discussed imme diately with the cardiothoracic surgical team Large volumes of residual blood in the pleural space will clot and may lead to pleural thic kening, empyema, or trapped lung. Tube drainage is dif \201 cult and thoracoscopy or thora cotomy with decortication are often needed. However, undrained cases can resolve without in tervention OTHER CAUSES 361 Pleural effusion after coronary artery bypass grafting - Small, typically left-sided pleura l effusions occur in the majority of patients post-CABG, and most resolve spontaneously - Larger (>25% of hemithorax) effusions can be subdivided: Pleural effusions occurring within 30 days of surgery. Classically bloody and eosinophilic exudate, with high LDH; probably related to post-operative bleeding into pleural space Pleural effusions more than 30 days after surgery. Typically clear and lymphocytic exudate; cause unknown, perhaps immunological or a form of post-cardiac injury syndrome Main symptom in each case is breathlessness; chest pain and fever are unusual Management consists of repeated therapeutic thoracentesis to alleviate breathlessness. Recu rrent effusions after 1 year are rare and may be dif \201 cult to treat; NSAIDs, prednisol one, or thoracoscopy and pleurod- esis may be considered Differential diagnosis of pleural effusion post-CABG includes pulmo- nary embolus, cardiac failure, pleural infection, post-cardiac injury syndrome, chylothorax. Pleural effusion following asbestos exposure The main differential diagnosis is between ben ign asbestos pleural effusion (p 110) and mesothelioma (p 114). Further information Light RW. Pleural effusions after coronary artery bypass graft surgery. Curr Opin Pulm Med 2002; 8: 308 \200\22311 This page intentionally left blank 363 Chapter 36 Pneumoconioses Overview and causative mineral dusts 364 Coal-worker s pneumoconiosis 366 Silicosis 368 Ber ylliosis 370 CHAPTER 36 Pneumoconioses 364 Overview and causative mineral dusts \200 Pneumoconioses are non-neoplastic pulmonary diseases caused by the reaction of the lung to the inhalation of mainly mineral, but also organic, dusts Inhaled particles of dust size <5 m reach the terminal airways and alveoli and settle on the epithelial lining. From here they are slowly cleared by macrophages or alveolar cells. They may pass into the lymphatic system, be cleared via the airway, or remain in the alveolus The dust particles can lead to an in \202 ammatory reaction within the lung, depending on their physical and chemical pr operties The in \202 ammation causes characteristic alterations in pulmonary structure and radiological abnormalities Of the diseases caused by inhalation of mineral dusts, many are becoming less common in the UK, due to improved protection of workers from dusts and decre asing levels of mining. Newer industrial nations may see increasing numbers of cases of pne umoconiosis Organic dusts causing hypersensitivity pneumonitis and extrinsic asthma are dis cussed on p 249 and 142. Asbestos-related diseases are discussed separately on p 107. Table 36.1 Causative mineral dusts Mineral dust Disease Examples of exposure Coal mining, especially hard coal Coal dust Simple pneumoconiosis Progressive massive \201 brosis Caplan \200\231s syndrome Silica Silicosis Caplan \200\231s syndrome Foundry work, sandblasting, stone cutting, hard rock mining Asbestos Asbestosis Benign asbestos-related pleural disease Mesothelioma Lung cancer Mining, milling, and fabrication Installation and removal of insulation Beryllium Acute berylliosis Beryllium granulomatosis Mining, fabrication of electrical and electronic equipment, workers in nuclear and aerospac e industry Iron oxide Siderosis Welding Barium sulfate Baritosis Mining Tin oxide Stannosis Mining Mining, \201 rework, painting, and armament manufacture Aluminum Like silicosis (bauxite worker \200\231s lung, Shaver \200\231s disease) OVERVIEW AND CAUSATIVE MINERAL DUSTS 365 Types of mineral dust exposure Non- \201 brous mineral dusts \200 \200 \200 Silica Coal dust Mixed mineral dusts containing quartz: slate, kaolin, talc, non- \201 bro us clays. Fibrous mineral dusts \200 \200 Asbestos Other mineral \201 bres. Metal dusts and fumes \200 Iron, aluminum, beryllium, cobalt. Chest disease in coal miners It was recognized many years ago that coal miners had higher l evels of respiratory disease than the general popu- lation. Coal miners can get any or all of: \200 \200 \200 Chronic bronchitis COPD Pneumoconiosis. They may be eligible for compensation for all of these. It has been dif \201 cult to estab lish the independent effects of coal dust due to high smoking rates amongst miners. However , it is now thought that coal dust contributes to the COPD and bronchitis caused by smoking , because: \200 Miners have an increased prevalence of cough, sputum, and decreased FEV1 when compared with non-miners. The risk of cough increases with increasing dust exposure FEV1 declines in pro portion to the amount of dust exposure In smokers the response to dust is probably differen t to that of non- smokers, with worse disease at a given level of exposure. \200 In the past, tuberculosis has also been a major problem amongst miners and their families, relating to their socio-economic conditions. SWORD is the Surveillance of Work-related and Occupational Respiratory Disease scheme run i n the UK to monitor the numbers of patients with occupational lung diseases. Patients with a clinical diagnosis of an occupational lung disease are con \201 dentially reported by re spira- tory or occupational health physicians. Further information www.dti.gov.uk/coalhealth CHAPTER 36 Pneumoconioses 366 Coal-worker \200\231s pneumoconiosis This is the condition caused by the deposition of coal dust within the lung and its associated in \202 ammatory reaction. There are two types: Simple pneumoconiosis, which can progress to Complicated pneumoconiosi s, also known as progressive massive \201 brosis (PMF). \200 These are common diseases amongst coal miners who work in poorly ventilated conditions. The risk of pneumoconiosis varies with different compositions of coal from different geographi cal areas, but the larger the amount of dust to which the miner is exposed, the greater the risk of developing pneumoconiosis. It is now rare for miners under the age of 50 to be dia gnosed with pneumoconiosis in the UK. Pathology Simple pneumoconiosis Coal dust is inhaled into the alveolus and is engulfed by m acrophages, forming a black stellate lesion, the coal macule. This causes cytokine release and subsequent in \202 ammatory cell recruit- ment, leading to \201 broblast activation. These coal macules are found throughout the lung, especially in the upper zones of the upp er and lower lobes, and often associated with surrounding bronchiolar dilatation. They are not palpable. Regional lymph nodes also become blackened. In time, larger nodules develop, containing reticulin and collagen between the macrophages, and associated bronchiolar dilat ation leading to focal emphysema is seen. Progressive massive \201 brosis occurs on this background, but with aggre- gation of the \201 brotic nodules to form larger lesions, 2 \200\22310 cm diameter. Macroscopically, th ese look like large black scars, extending from the lung parenchyma to the chest wall. The central area of these nodules may be necrotic and the outer rim is \201 rm and collagenou s. It is not understood what causes the progression of small nodules to PMF, although conti nued exposure to coal dust in the presence of simple pneumoconiosis makes this development more likely. Clinical features Simple pneumoconiosis is usually asymptomatic with no associated clinical signs. This is a relatively benign disease. Progressive massive \201 brosis is usually associated with cough, productive of mucoid or blackened sputum, and breathlessness, particularly on exertion, and may in time lead to th e development of cor pulmonale. Examination is unremarkable, with no clubbing and no crepit ations audible (the presence of crepitations suggests a different diagnosis). COAL-WORKER \200\231S PNEUMOCONIOSIS 367 Investigations \200 CXR In simple pneumoconiosis there is nodular shadowing, with nodules of varying size, up t o 10 mm, particularly in the upper and middle zones. Pneumoconiosis can be graded according to the number of different sized nodules, p = <1.5 mm, q = 1.5 \200\2233 mm, and r = 3 \200\22310 mm. Nodule numbers increase with increasing dust inhalation and usually stop for ming when the miner has left the work environment. PMF is diagnosed when one or more opacit ies of >1 cm diameter are present, on the background of simple pneumoconiosis. These lesion s are often located in the upper lobes and enlarge, becoming increasingly radi- odense and clearly demarcated with time. They may distort the adja- cent lung and cause emphysema. The lesions continue to progress out of the work environment HRCT of simple pneumoconiosis sho ws parenchymal nodules 1 \200\22310 mm in size, with upper zone predominance. In PMF, nodul es of >1 cm are seen, with irregular borders and associated parenchymal distortion and emph ysema. Larger lesions may have cavitation and necrosis. They may also have areas of calci \201 cation PFTs Simple pneumoconiosis: FEV1 and FVC are normal, although TLCO may be sligh tly decreased. PMF: signs of airway obstruction due to emphysema, and restriction due to lo ss of lung volumes. TLCO is reduced. Management Minimization of dust exposure with improved mine ven- tilation, respirator provi sion, and monitoring of dust levels. Miners have CXR every 4 years and are moved to less du sty work if they show signs of pneumoconiosis, to prevent the development of PMF. Miners wi th signs of coal worker \200\231s pneumoconiosis are entitled to industrial injury bene \201 ts from British Coal. No increased risk of lung cancer with pneumoconiosis or PMF. Cap lan \200\231s syndrome Miners with seropositive rheumatoid arthritis or positive serum rheu matoid factor can develop large well-de \201 ned nodules. These occur on a background of s imple pneumoconiosis and in those with a relatively low coal dust exposure. They may be mul tiple and may cavitate. They cause no signi \201 cant functional impairment and have no ma lignant potential. CHAPTER 36 Pneumoconioses 368 Silicosis This is a chronic nodular densely \201 brosing pneumoconiosis, caused by the pr olonged inhalation of silica particles. \200 \200 \200 Long lag time of decades between exposure and clinical disease Insidious onset, progressive Larger radiological opacities than those seen in coal-worker \200\231s pneumo- coniosis an d more rapid progression The pattern of disease depends on the level and duration of the si licone dust exposure. Silica is present mostly as crystalline quartz, which is mined and quarried, and used in in dustries such as ceramics, brick-making, and stone masonry. It is becoming less prevalent i n Western societies, due to changes in silica working conditions. Pathology Quartz and cris tobalite forms of crystalline silica cause sili- cosis. When they accumulate within the air ways, lymphocytes and alveolar macrophages engulf the particles and are removed into the ly mphatic system. Any remaining silica dust causes focal aggregations of macro- phages, which are, in time, converted into \201 brosing nodules. Silica dust can cause surfactant secr etion from the alveolus due to local irritation. This leads to further macrophage recruitme nt. Large nodules are formed by the aggregation of smaller nodules. Different types of sili cosis There are four types, and the distinction is often not clear. \200 Acute silicosis is caused by intense exposure to \201 ne dusts, such as those produced by sand blasting. It may become apparent in workers within a few months to a year of starting work. Rapid deterioration over 1 \200\2232 years, with treatment being ineffective. Rare n ow, due to regulation of silica levels in the workplace \200 Clinically dry cough, shortness of breath, and a feeling of tightness on breathing deeply. Rapid deterioration over a few weeks. Fine crepitations are heard over the lower zones bila terally. Respiratory failure CXR Patchy bilateral lower air space consolidation, which may look like pulmonary oedema Pathology Irregular \201 brosis adjacent to alveolar spaces \201 lled with a lipoproteinaceous exudate, similar to that found in alveolar proteinosis. Subacute silicosis This is the classic picture of silicosis, which is now quite rare. Dry c ough, gradual onset of shortness of breath \200 CXR Upper and mid-zone nodules are present, measuring between 3 and 5 mm diameter. Initiall y indistinct, but become clearer with time. Nodules coalesce and calcify and can progress t o progressive massive \201 brosis (PMF). Associated calci \201 ed hilar lymphadenopathy (egg shell calci \201 cation) and possible pleural thickening. Nodules continue to develop with continued exposure, but due to long lag time will also develop when patient stops bei ng exposed. In some cases with heavy exposure to silica, patients may develop progressive u pper zone \201 brosis with sparse nodularity SILICOSIS 369 PFTs Slow decline, including TLCO, with mild restrictive pattern, unless the silicosis has caused emphysema, when obstructive or mixed picture is seen Pathology Dust particles within the alveoli are phagocytosed by macrophages. They are removed to the lymphatics, where the y lodge and cause diffuse in \202 ammatory change. Layers of collagen are deposited around the dust particle. Nodules are found within the secondary pulmonary lobule, where they cau se \201 brosis Chronic silicosis occurs with lower dust concentrations than those seen in active silicosis \200 CXR A few upper and mid-zone nodules occur, which become calci \201 ed after 10 years or s o. There is no associated parenchymal distortion. There may be associated hilar lymphadenop athy. If there is further silica exposure, this disease may progress, with coales- cence of nodul es. \200 Silicotuberculosis Increased likelihood of active TB infection in people with silicosis, mo st likely due to the reactivation of quiescent lesions. Silica within the lung is thought t o affect the ef \201 cacy of the macrophage at clearing Mycobacterium tuberculosis. TB can be dif \201 cult to diagnose, due to multiple pre-existing CXR nodules. Cavitation may oc cur, which does not occur with silicosis alone. Haemoptysis, fever, and new soft CXR opacit ies should prompt sputum examination and BAL. Con \201 rmed TB should be treated with the usual 3 or 4 drug regime. Non-tuberculous mycobacterial infection is also more common. Management Prevention of silicosis by monitoring and minimizing dust levels with adequate v entilation. Masks can be useful for short-term use, if the high levels of dust are transien tly unavoidable. Disability bene \201 ts available from the Department for Work and Pensio ns. Small increased risk of lung cancer with silicosis and associated PMF. CHAPTER 36 Pneumoconioses 370 Berylliosis Beryllium is a light, strong industrial metal. It is mined and often used as an alloy in the manufacture of \202 uorescent tubes for lighting and televisions, radiologi cal equipment, in atomic reactors, and in heat-resistant ceramics. Cases of berylliosis are now rare, as beryllium levels have been tightly regulated to avoid sensitization. However, due to the long latent period between exposure and granuloma formation, as well as acciden tal beryl- lium exposure, cases are still occurring. There are two types of disease. \200 Acute beryllium disease is an acute alveolitis due to the direct effects of high-dose inhal ed beryllium fumes. There is subsequent widespread airway oedema and pulmonary oedema, whic h causes dyspnoea, cyanosis, and widespread inspiratory crepitations. CXR shows pulmo- nary oedema. It may be self-limiting if mild, but if severe is usually fatal. Corticosteroids m ay prevent progression, but the patient is often left with residual pulmonary impairment Su bacute and chronic berylliosis is a hypersensitivity-type skin or pulmonary disease that oc curs a long time after beryllium exposure in a minority of individuals. It can be clinicall y indistinguishable from sarcoidosis. It has also been seen in the wives of beryllium worke rs and those who live near beryllium re \201 neries. Inhalation of beryllium or the exposu re of beryllium to a skin abrasion causes initial sensitization in 2 \200\22319% of exposed individuals. Only low levels of exposure are required for this. There is a cell-mediated i mmune response, with the produc- tion of numerous in \202 ammatory cytokines, which cause granulomatous in \202 ammation. Following a long latent period, which may be months to 10 years plus after exposure, non-caseating granulomatous tissue reactions occur in the lungs or on the skin. Similar to sarcoidosis. There is a genetic predisposition to the response t o beryllium exposure and it is HLA-mediated (HLA-DPB1(Glu69)). HLA status could be used to identify workers at high risk of berylliosis (but is not routinely used at present). Clinical features of chronic berylliosis \200 Symptoms Cough, dyspnoea. Macular skin lesions, which do not spontaneously resolve Signs No clubbing or crepitations in early disease, but both occur with established \201 brosis. Hepato/splenomegaly and macular skin lesions. Do not get uveitis or erythema nodosum. Investigations \200 CXR Fine reticulonodular appearance throughout both lungs. Finer nodules than those seen in sarcoidosis. Progression to irregular intersti- tial \201 brosis, with irregular linear opacities seen in the lung bases. Hilar lymphadenopathy can occur, but always in associatio n with interstitial lung disease HRCT Subpleural micronodular change, thickened interlobula r septae, traction bronchiectasis, and honeycombing. There may be ground-glass shadowing BA L High levels of T-lymphocytes PFTs Restrictive defect, with decreased KCO \200 BERYLLIOSIS 371 Pathology Non-caseating granuloma. May be indistinguishable from sarcoidosis. May develop i rregular \201 brosis with bulla and cyst formation No single test to distinguish berylliosis from sarcoidosis. Management Corticosteroids to t ry and prevent disease progression. Continue inde \201 nitely as few patients gain complet e resolution of symp- toms, CXR or PFTs. Annual screening of beryllium-exposed workers with CXR. If they develop breathlessness or skin rashes, this may be an indica- tion to start o ral steroids to delay progression to interstitial \201 brosis. Prognosis Progressive dise ase, although those with very low exposure who develop CXR changes may \201 nd they resol ve. Associated delayed skin sensitivity (anergy) to tuberculin. Granulomata do not spontane ously resolve, although can be excised if causing problems, such as troublesome lesions on the skin. Interstitial \201 brosis occurs in the lungs, which is pro- gressive and leads to cyanosis and death. Other complications include pneumothorax, hypercalcaemia, hypercalci uria, and nephrocalcinosis. Differential diagnosis \200 \200 Sarcoidosis Tuberculosis. In clinic \200 Ask patients with suspected sarcoidosis about possible exposure to beryllium Monitor PFTs a nd CXR to assess disease response or progression. This page intentionally left blank 373 Chapter 37 Pneumothorax Clinical features and investigations 374 Initial management 376 Further management 378 Trea tment algorithm for primary pneumothorax 380 Treatment algorithm for secondary pneumothorax 381 Speci \201 c situations 382 CHAPTER 37 Pneumothorax 374 Clinical features and investigations De \201 nition A pneumothorax is air in the pleural s pace. May occur with apparently normal lungs (primary pneumothorax) or in the presence of u nderlying lung disease (secondary pneumothorax). May occur spontane- ously or following tra uma. Epidemiology \200 \200 Annual incidence of primary pneumothorax is around 9 per 100 000 Primary pneumothoraces occ ur most commonly in tall thin men aged between 20 and 40. They are less common in women (ma le : female 5: 1) \200\224consider the possibility of underlying lung disease (e.g. lym- ph angioleiomyomatosis, catamenial pneumothorax) Cigarette smoking is a major risk factor for pneumothorax, increasing the risk by a factor of 22 in men and 9 in women. The mechanism is unclear; a smoking-induced in \202 ux of in \202 ammatory cells may both break down elas tic lung \201 bres (causing bulla formation) and cause small airways obstruction (increas ing alveolar pressure and the likelihood of interstitial air leak) May rarely be familial. Causes and pathophysiology Primary Pathogenesis is poorly understood; they are presumed to occur following an air leak from apical bullae, although small airway in \202 ammation is often also present and may contribute by increasing airways resistance. Secondary \200 Underlying diseases include: COPD (60% of cases), asthma, interstitial lung disease, necrot izing pneumonia, tuberculosis, PCP, cystic \201 brosis, Langerhans cell histiocytosis, ly mphangioleiomyomatosis, Marfan \200\231s syndrome, oesophageal rupture, lung cancer, catame nial pneumothorax, and pulmonary infarction Pneumothorax may be the \201 rst presentation of the underlying disease. Clinical features \200 Classically presents with acute onset of pleuritic chest pain and/or breathlessness. Breath lessness is often minimal in young patients and is more severe in secondary pneumothorax Si gns of pneumothorax include tachycardia, reduced expansion, hyper-resonant percussion note, and quiet breath sounds on the pneumothorax side. These are frequently absent in small pne umotho- races. Hamman \200\231s sign refers to a \200\230click \200\231 on auscultation in time with the heart sounds, due to movement of pleural surfaces with a left-sided pneumoth orax May feel \200\230bubbles \200\231 and \200\230crackles \200\231 under the skin of th e torso and neck if there is subcutaneous emphysema Presents in ventilated patients with ac ute clinical deterioration and hypoxia or increasing in \202 ation pressures. CLINICAL FEATURES AND INVESTIGATIONS 375 Investigations \200 CXR is the diagnostic test in most cases, revealing a visible lung edge and absent lung mar kings peripherally. Blunting of the ipsilateral costophrenic angle due to bleeding into the pleural space is common. Pneumothoraces are dif \201 cult to visualize on supine \201 l ms: look for a sharply delineated heart border, hemidiaphragm depression, and increased luc ency on the affected side \200 Width of the rim of air surrounding the lung on CXR may be used to classify pneumothoraces into small (rim of air <2 cm) and large ( \211 2 cm). A 2-cm rim of air approximately equat es to a 50% pneu- mothorax in volume Tiny pneumothoraces that are not apparent on PA CXR ma y be visible on lateral chest or lateral decubitus radiographs CXR appearance may also show features of underlying lung disease, although this can be dif \201 cult to assess in the presence of a large pneumothorax CT chest may be required to differentiate pneumothorax from bullous disease, and is useful in diagnosing unsuspected pneumothorax following trauma and in looking for evidence of unde rlying lung disease ABGs frequently show hypoxia and sometimes hypercapnia in sec- ondary p neumothorax