Clubbing is one of the signs in the hands that you only hear about when you start looking at real-life medicine, but it's actually very useful. Unfortunately it's something which simultaneously is poorly understood. We know a lot about what diseases it's seen in, but not exactly how it's caused.
Clubbing is basically a sign at the end of the fingers where the finger and fingernails don't have the shape that they're supposed to. Because it was Hippocrates who first describes the feature, clubbing is sometimes (but only rarely!) called Hippocrates Fingers.
To find out if a patient has clubbed fingers, you need to look for the angle between the nail and the nailbed. Usually you can see that as you go from the end of the finger towards the hand, the nail dives under a bit of skin, giving an angle between the nail and the nailbed. However, when clubbing occurs, this angle is lost, giving the impression of some kind of 'club-shaped' fingers.
Clubbing can actually occur in a number of stages. The area of skin that the nail dives under can feel a bit spongey or doughy when clubbing starts. It can then progress to a loss of the angle between the nail and the nailbed (the most common definition of clubbing), then the nail becomes more curved, and finally it can be painful. Significantly, though, it's normally just a sign that the patient may not even have noticed.
In fact, it might be quite difficult for you to notice it. This is why it might be worth looking for the diamond sign, where the middle fingers are pushed against each other with the nails touching so that you can see a diamond shape in the middle. It is the angle between the nail and the nailbed which produces this diamond, so if you can't see daylight (or anything else!) through the middle then the angle has been lost.
If a patient has got clubbing, there's some key things to think about. If you're already worried about a heart problem, then it might be worth considering infective endocarditis or, more rarely, atrial myxoma or cyanotic congenital heart disease. Problems in the lung can also cause clubbing, including a long-term lung condition like cystic fibrosis, something called fibrosing alveolitis, or certain kinds of lung tumour. Chronic obstructive pulmonary disease (COPD) does not normally cause clubbing on its own, but if someone has low oxygen in their blood for a long time, it might lead to clubbing. Crohn's disease and ulcerative colitis can also cause it. However, it can be difficult to know if someone really does have clubbing, so a condition should be diagnosed on the basis of other findings too. There's no point in concluding that you have infective endocarditis if there's nothing else to show for it!!
The best guess about what's causing the clubbing is that in these conditions, when platelets form clots and find their way to the ends of the fingers, they cause changes to the blood supply and the shape of the end of the finger which we see as clubbing. However, we're not really that sure...!
When you look at your fingernails, you might see short, browny-black lines following the direction of the finger (i.e. a 'vertical' line, pointing away from the hand). This could be an absolutely normal sign, as it can often be present in people - sometimes it's just because you've hit the nail on something and not noticed. Although it's called a 'haemorrhage', it might be something that's just not worth worrying about. But if you start to see quite a few of them, it might be a sign of something else.
In certain conditions (and particularly you'd be wanting to think about infective endocarditis) you can get clots shooting off (e.g. from the heart valve affected) and finding their way into interesting parts of the body. If this happens in the finger, it can cause damage to the tiny blood vessels and then you get the sign of a splinter haemorrhage.
Unfortunately splinter haemorrhages aren't always the most useful sign in the world. Because they are often found in people who haven't got anything wrong with them, you can't make that many conclusions on the basis of splinter haemorrhages being around. They could be due to hitting the nail ('trauma'), they could be a sign that there's inflammation in blood vessels all around the body ('systemic vasculitis'), or they could be where a bit of cholesterol has got lodged in the finger's capillaries. Even if a patient does have infective endocarditis, probably 5 in every 6 patients won't have splinter haemorrages anyway!!
However, if you have a murmur, splinter haemorrhages, and blood tests that show signs of infective endocardiits, then you know that something's not right, and you'd want to pursue other ways of looking at the heart to check everything's ok!!
So, you're starting a clinical examination of the cardiovascular system. As you come to the hands you've probably looked to see a number of things, and then you notice that the patient looks a bit blue. The hands aren't the colour you'd expect them to be, instead they're a kind of blue-ish purply colour. OK, so they're not bright raving purple, they've not been painted. But there's definitely a hint of blue in there. What's going on?
Well, this is a sign called peripheral cyanosis - you can see the link because 'cyan' is a kind of blue colour. The extremeties, or the parts of the body furthest away from the heart (so this includes toes and feet too) will bear a hint of blue because there is less oxygen in the blood there. It's a sign that there might be poorer circulation in these parts, but that doesn't mean there's something wrong with the patient. In fact, it could just be due to cold weather!
The important thing to remember is that this is peripheral cyanosis, not central cyanosis. Central cyanosis is shown in different ways, and is probably more of a sign that the lungs aren't working. Peripheral cyanosis means that instead, the oxygen isn't getting to the ends of the hands so well. If it's permanent or lasting for a long time, it might be a sign that the heart isn't working as well as it should be. When the heart fails, it won't be pumping blood properly to the furthest vessels in the body, and so the blood in those vessels is less likely to be the fresh, oxygenated blood that it needs to be.
The hands are a slightly more blue colour than normal, and the observant among you will already have wondered if this relates to veins, which are also blue when you see them through the skin. The answer, simple as it is, is yes.
The hands look blue in the same way that veins look blue because you're looking at deoxygenated blood (rather than the more normal oxygenated blood) through the skin. As explained when thinking about why veins are the colour that they are, carbon dioxide (which is much more prevalent in blood that has not been through the lungs recently) looks blue when it's dissolved in the blood. If you've got a lot more carbon dioxide in all of the vessels around the end of the hand because less fresh blood is getting in, there'll be a lot more blue around, and you'll end up with the blue tint that you see in cyanosis.
As already mentioned, there's a couple of signs to look out for when you're thinking about endocarditis. Osler's nodes and Janeway lesions are both examples of these. In infective endocarditis, a growth of bacteria forms on a heart valve and this isn't a very stable thing - it's known as 'friable', which means it can easily be broken apart. If bits of it do break off, then they could land in the small vessels of the hand or foot, and this is what happens in the case of these two signs. You're not looking at the immune complex itself, but you're looking at a sign that it has been deposited in the small blood vessels of the finger.
Named after Sir William Osler (1849-1919), Osler's nodes are the painful of these two signs. They're like red spots on the end of the fingers, on what is called the 'pulp' part of the finger (the bit which you would press a button with), and they're very distinctive. They're more painful than the kind of spot that you'd find on the face of a teenager, and they're more distinctly deep red, rather than the pinky-white which you might see on an acne spot. Importantly, although not everyone with endocarditis gets them, if they're present, they should be making you think "This patient has infective endocarditis".
The Janeway family have produced a large number of doctors, with the health commissioner of New York Edward Gamaliel Janeway a noted ancestor. In fact, his pupil Emanuel Libman is reported to have named Janeway lesions after him. However, it is more frequently suggested that the commissioner's son, Theodore Caldwell Janeway (1847-1917), is the doctor who these lesions are named after. Once again they're a sign that we have infective endocarditis going on - in fact, if you see them, you're simply not allowed to think of anything else!! Unlike Osler's nodes, they're not painful, and they're found on the palms or soles instead of the finger pulps.
Your heart is pumping blood furiously all the time, and it manages to maintain a high blood pressure all the time (in a normal person). Imagine if the pressure shifted wildly from a really high pressure to a really low pressure. Your arteries would have really high-pressure blood in them one moment, and when the heart relaxes there'd be no pressure in them anymore.
To some extent this is exactly what's happening normally - when the heart pumps, the pressure is high, when it relaxes the pressure is lower. This is why you can feel a pulse. However, it's not usually a big difference. Usually the pressure is high even when the heart is relaxed; so it's only when you're feeling for a larger artery that you can feel the pulse.
However, in the case of aortic regurgitation, the blood seeps back into the heart through a failing aortic valve. This means that the high pressure isn't maintained in the system anymore. You get a high pressure when the heart is contracting, but not when it's relaxed.
This is felt as a pulsation in the nailbed, which you can feel by pressing on top of the nail. It's not an easy sign to find, but if it's there, you should be wondering if perhaps there's a bit difference between the blood pressure when the heart is contracting, and the blood pressure when it's relaxed.