History
A 72-year-old woman attends A&E acutely short of breath. She tells you she has been under investigation for breathlessness and is awaiting a computed tomography (CT) scan of her chest for a ‘shadow on the lung’ seen on a recent chest radiograph. She has been breathless for several weeks but has become markedly worse over the last 24 hours and is now very breathless at rest and struggling to complete sentences. She reports a recent history of recurrent chest infections and weight loss. Her past medical history includes a myocardial infarction eight years ago, hypercholesterolaemia and hypertension. Current medications are aspirin 75 mg/day, simvastatin 40 mg at night, ramipril 5 mg at night, bisoprolol 2.5 mg/day and bumetanide 1 mg/day. She is an ex-smoker of 20 years, having previously smoked ten cigarettes a day for 25 years.
Examination
On examination, she is breathless at rest and using accessory muscles. Her oxygen saturations are 90 per cent on air, respiratory rate 20 per minute, blood pressure 110/80 mmHg, pulse 95 bpm, regular, temperature 36.5°C. Heart sounds are normal with nil added. On examination of the chest, she has reduced expansion on the left side. Percussion note is dull on the left side of the chest and, on auscultation, there is reduced air entry throughout the left side of the chest. Her abdomen is soft and non-tender and there is no peripheral oedema.
Investigations
She undergoes blood tests, an arterial blood gas and a chest x-ray. The results are shown below. Her electrocardiogram shows no significant acute changes.
Reference range
Haemoglobin 10.0 g/dL 11.5–16.5 g/dL
Mean cell volume (MCV) 78 fL 76–110 fL
White cell count 13.0 × 109/L 4.0–11.0 × 109/L Neutrophil count 8.5 × 109/L 2.0–7.5 × 109/L
Platelet count 161 × 109/L 150–450 × 109/L
Urea 11 mmol/L 1.7–8.3 mmol/L
Creatinine 110 μmol/L 44–80 μmol/L
Potassium 3.1 mmol/L 3.2–5.1 mmol/L
Sodium 148 mol/L 135–146 mmol/L
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152 Section 2: Radiology
Reference range Arterial blood gas
pH 7.40 7.35–7.45
PaO2 7.0 kPa 11.1–14.4 kPa
PaCO2 5.0 kPa 4.7–6.4 kPa
Anteroposterior (AP) sitting chest x-ray is performed (Figure 32.1).
Figure 32.1
QUESTIONS
1. Describe the appearance of this x ray.
2. What is the differential diagnosis for this appearance?
3. What other x-ray features help to confirm the diagnosis?
4. What other investigations are indicated?
5. What is the on-going management?
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ANSwERS
1. (Answers 1–3) There is complete opacification of the left hemithorax. This is an AP film and the patient is rotated. Allowing for this, there is evidence of mediastinal shift away from the affected side, suggesting mass effect. There are several causes for this – the most common cause is a large pleural effusion. Other causes for hemithoracic opacity might include a large mass, or possibly extensive acute con-solidation (less likely and there is no evidence of concon-solidation, e.g. air broncho-gram on the film).
2. It is important to differentiate an effusion from the other causes of hemithorax opacity which are associated with volume loss, namely mediastinum shifted to the affected side, including lung collapse or previous pneumonectomy/lobectomy (look for evidence of previous surgery, clips at hilum or rib defects). Figure 32.2 is a chest radiograph in a patient with a left lung collapse due to an occluding tumour obstructing the left main bronchus (black arrow); note mediastinal shift to the left.
Figure 32.2
3. We know this patient had a possible lesion on a recent chest radiograph – make sure you always try to look at any previous films – this lung opacification is new and secondary to likely effusion. Underlying lung malignancy needs to be excluded in the first instance and there are likely to be several litres of fluid in her chest.
4. A pleural effusion is the accumulation of fluid in the pleural space. It is not a diagnosis, but a manifestation of underlying disease. There are many causes for effusions, but the most common causes are cancer, pneumonia and heart failure.
Effusions are classified as transudates or exudates based on their protein content
Case 32: Elderly woman with shortness of breath 155
(less than 25 g/L in transudates and more than 35 g/L for exudates; if the protein concentration is between these two, then Light’s criteria are applied). Transudates arise from an imbalance of oncotic and hydrostatic pressures in conditions such as heart failure, liver failure, renal failure or hypoalbuminaemia. Exudate is a result of altered pleural or local capillary permeability in inflammatory or neoplastic conditions, such as malignancy, pneumonia, autoimmune disease, pancreatitis, or secondary to some drugs, such as amiodarone or methotrexate. Effusions may also be haemorrhagic due to trauma, bronchial carcinoma, bleeding disorders, or they may be chylous due to an obstructed thoracic duct. Serum albumin level and serum lactate dehydrogenase (LDH) should be requested to compare with pleural fluid analysis.
5. The patient should be managed using the ABCDE approach (airway, breathing, cir-culation, disability, and exposure). This patient’s effusion is large and causing res-piratory compromise, and should therefore be drained. A drain has been placed and position checked on x-ray. Samples of the pleural fluid should also be sent to seek the underlying cause, fluid sent for microbiology, cytology and clinical chemistry including protein, LDH, pH, glucose, and differential cell count. Amylase can also be checked if there is any suggestion of pancreatitis as a cause.
Do remember, as always, if you are unsure at any stage as to the cause of radiolog-ical appearances, seek senior advice or speak to a radiologist. If the patient is not in extremis, an ultrasound of the chest can help confirm the presence of an effusion and whether it is loculated. The best position for access and also depth of effusion from the skin can also be marked. Ultrasound can be performed in the radiology department or on the ward. Risks of pleural aspiration include infection, bleeding and pneumothorax. Consent the patient appropriately, document all procedural aspects in the patient notes and arrange and review the post-drainage/aspiration chest radiograph. In some institutions, pleural drain insertion is only done under ultrasound guidance by a radiologist to minimize such risks to the patient. When fluid is drained, this patient will need CT of the chest/abdomen to assess the under-lying cause.
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