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Lung Examination: Signs for Common Clinical Presentations – Lung Disease

by Jeremy Brown, PhD
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    00:00 Right. So we’ve discussed the examination, what you’re looking for, the general reasons why abnormal signs may occur. But, as a doctor, what you need to be able to do is have a synthesis of that: a way of interpreting what information you have and saying what the pathology may be that’s causing that.

    00:20 So, for example, there are very specific signs which are associated with pneumothorax, pleural effusions, lobar collapse, lobar consolidation, bronchiectasis, pulmonary fibrosis which is the synthesis of all that respiratory examination. There’s a pattern of abnormalities that occur that would indicate that that disease of that process might be present.

    00:44 Knowing these makes life considerably more straightforward when you’re trying to interpret the examination. And what you should be doing is saying, “Well, okay. There’s dullness to percussion at the right base. That suggests the patient may have a pleural effusion. So there should be absent breath sounds down there. And if there’s absent breath sounds, that helps. That confirms that there might be an effusion. However, in an effusion the trachea should be deviated away but not towards the side where you’re hearing the dullness to percussion. And if the trachea is deviated towards that side, then that suggests in fact that it’s not an effusion but it may be a collapse instead. So it’s the combination, the constellation of these signs which makes the diagnosis of what the pathological process might be relevant.

    01:30 Right. So just going through some of these processes in more detail.

    01:36 The signs for a pneumothorax: the trachea will be deviated away from the affected side.

    01:41 There’ll be reduced expansion on the affected side. And that will be detectable because the normal side will be moving fine. The percussion will be resonant and in fact should be hyper-resonant but, as I said, it’s quite hard to detect that. When you listen over a pneumothorax, you should hear no breath sounds. Vocal resonance should be reduced as well. And the extent of that depends on the size of the pneumothorax. If there’s a small pneumothorax, you’ll just hear that at the top of the lung. If it’s a very large pneumothorax, you’ll hear it throughout the lung. There may be some evidence of the underlying cause for a pneumothorax and, to be honest, most patients there’s no underlying cause of primary pneumothoraxes.

    02:19 However, they could have Marfan’s syndrome, which would make them very tall with a very large, wide arm span and very, very flexible joints. Or they could have a pre-existing lung disease. Cystic fibrosis, for example, can cause pneumothoraxes.

    02:38 Pleural effusions: that’s fluid in the pleural space as opposed to air, which is a pneumothorax.

    02:42 It has relatively similar signs to a pneumothorax in that you have absent breath sounds, absent vocal resonance, decreased expansion on the affected side. But it’s fluid, not air.

    02:55 So, when you percuss, it will be stony dull. Also the fluid forms at the bottom of the lung due to gravity and therefore the changes are best detected at the bases of the lungs.

    03:07 Occasionally, at the top of a pleural effusion you might get a pleural rub and some bronchial breathing. There could be evidence of the underlying cause of the effusion. For example, the JVP may be higher because they’ve got cardiac failure. They may have peripheral oedema because, again, because they’ve got cardiac failure. Or you might palpate some lymph nodes suggesting they might have a cancer or something similar along the similar lines.

    03:30 The trachea is also going to be deviated by large pleural effusions. But, unlike a pneumothorax, it has to be quite a large pleural effusion before it will shift the trachea across to the other side.

    03:41 Lobar collapse is where a bronchus has been obstructed and, as I mentioned earlier, the air distal to that area has been resorbed making the lobe collapse down into a solid area. And that could be a right main bronchus, a left main bronchus, the right upper lobe bronchus, the right intermediate bronchus, the left upper lobe, the left lower lobe.

    04:00 And so you have different patterns depending on which lobe has been obstructed. They all cause the same constellation of symptoms which is first of all, unlike what this sign – this slide says, the trachea is deviated towards the affected side. So that’s because of the volume loss of the collapse. It pulls the trachea and the mediastinum across to the affected side. There’ll be reduced expansion, dull percussion note, absent breath sounds, absent vocal resonance. And those are all signs which are very similar to a pleural effusion. So the confusion between a pleural effusion and lobar collapse is very easy clinically.

    04:42 And it’s the trachea that gives you the clue that there is a problem with collapse rather than fluid.

    04:49 Lobar consolidation: this is largely pneumonia. Not always, but most cases of consolidation are due to pneumonia. In this situation, what’s happened is the alveoli, instead of being filled with air, are now filled with an inflammatory exudate – white cells, bacteria. And therefore the volume hasn’t changed so the trachea stays central and the mediastinum doesn’t shift. But the affected area, if it’s large enough, will be detectable by the expansion being reduced on the affected side. There’ll be dullness to percussion over the consolidated lobe. Breath sounds though will actually increase. This is where you get the bronchial breathing.

    05:27 There’s increased intensity of the breath sounds: bronchial breathing. And over the affected lung you could get coarse crepitations. And unlike other causes of chronic crepitations, pneumonia is normally a bit asymmetric in its distribution. There’ll be one lung with quite extensive consolidation. The other lung may have some or may have none at all. And that means the crackles themselves will be asymmetric in distribution.


    About the Lecture

    The lecture Lung Examination: Signs for Common Clinical Presentations – Lung Disease by Jeremy Brown, PhD is from the course Introduction to the Respiratory System.


    Author of lecture Lung Examination: Signs for Common Clinical Presentations – Lung Disease

     Jeremy Brown, PhD

    Jeremy Brown, PhD


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