Pleural Biopsy

00:01 Lots of lymphocytes might suggest that the patient has tuberculosis. The other test that we use to identify the cause of pleural effusion is a pleural biopsy. Now this is a way of obtaining a sample of the actual pleura. And it’s the second line test for investigating the more difficult cases of exudated pleural effusion. There is no need to do a pleural biopsy in somebody with a transudate effusion normally. This is done to identify tumours or tuberculosis in general. So for example, the sensitivity of the pleural biopsy for identifying a pleural metastasis in somebody who has breast cancer or GI malignancy or lung cancer is about 90%.

00:40 The sensitivity of mesothelioma, the primary pleural cancer is actually less than that because the interpretation of the histopathology of mesothelium is quite difficult.

00:49 Pleural biopsies are also very useful for identifying pleural tuberculosis as they will show granulomas infiltrating through the pleura in about three-quarters of cases, and that’s a much more sensitive way of identifying pleural TB than in trying to identify the presence of the bacteria.

01:06 So the second line test for investigating patients with more difficult case of exudated pleural effusions would be a pleural biopsy. Pleural biopsies are not necessary for patients presented with transudate effusions. Pleural biopsies can be obtained either blindly using an Abrams needle, but this is largely out of date now. In fact, for most patients, we do a pleural biopsy under a CT or ultrasound guidance. And that allows us to target the biopsy to the areas which were abnormal. For example, an ultrasound may show in somebody who has metastatic cancer affecting the pleura little areas which are abnormal with apparent lumps, and that means that you can use the ultrasound to put the needle directly into those areas to get the maximum chance of identifying the presence of a cancer.

01:49 The other method of doing a pleural biopsy is thoracoscopy. This can either be a surgical or medical procedure, and it involves inserting an instrument inside the pleural space so that you can visualize the pleural space and using that to guide your biopsies in abnormal areas. With thoracoscopy, you can actually combine that procedure with doing a pleurodesis as well. So, how do you treat pleural effusions? Well, firstly and most obviously, you need to treat the underlying cause. So somebody with transudate due to heart failure, they will need diuretics. If there’s an exudate and it’s due to a tumour, then actually, treatment of the tumour might make the pleural effusion go away. If somebody has systemic lupus erythematosus causing a pleural effusion, then anti-inflammatories may be necessary in their suppression and if somebody has got PE, obviously, they need anticoagulation. The other thing you need to consider is whether the patient can cope with the pleural fluid or not. So when you have a large pleural effusion, it makes you breathless. And pleural aspiration, which is similar to the pleural tap, and instead of just taking 50 ml, you take off a litre or 1.5 litres, can considerably improve the patients, how they feel, and reduce that breathlessness. And that could be done as a one-off procedure in a few minutes to try and improve their ability to cope with the effusion.

03:19 With persisting large effusions, then you may need to drain them to dryness to allow the patient the maximum chance to improve. Now, this requires inserting a pleural drain, letting that drain off all the fluid and that will normally take a few days, and therefore, require hospital stay. Recently, we’ve been starting to use more semi-permanent tunnelled drains which we actually insert under the skin and leave inside the pleural space and the patient can go home and that allows us to have long-term drainage of a persisting pleural effusion in patients, for example, with cancer.

03:57 The ultimate treatment for pleural effusion that keeps coming back, and in fact, patients with cancer, once you've drained an effusion, it will return in most patients.

04:08 Therefore, recurrent effusions is a significant problem with metastatic disease. The ultimate treatment for that would be a pleurodesis. Now, that is where you fuse the visceral and the parietal pleural together so you actually obliterate the pleural space, and that prevents a pleural fluid forming in the first place. This can be done medically via a drain or surgically during a thoracoscopic procedure. The basic principle is to inflame both layers of the pleura using talc or other agents. Surgeons often use a physical abrasion, which means that the inflamed visceral and parietal pleura will stick together and eventually form adhesions, and therefore, obliterate the pleural space. The efficacy of these procedures is a little variable. It’s about 70% for medical pleurodesis rising to 80%, 90% for surgical pleurodesis.