Shopping and running

Just a nice picture from 2004

Good news

The gastroparesis article is finished, the editor seems to like it, and has sent a pro-forma invoice for me to submit. They are going to pay me! Given the amount of time it took, the hourly rate probably works out at less than the minimum wage, and I ought to declare it for tax, but on the whole I think this qualifies as good news. Finishing the writing has freed up my Tuesdays for more interesting things.

I have been on a shopping spree. Nearly all online, of course, but still, it felt like going into the street and throwing money at things that I've wanted to get for a very long time but it was just too much effort to go into shops. Quite ordinary things mostly: a dish drainer tray, oven gloves, electronic kitchen scales, a new kitchen bin. The bin is not ordinary because it is a luxury touch-top item from Brabantia and cost more than all the other purchases put together, but it is a thing of beauty while being utterly functional.

I also bought a new mobile phone, or more accurately, a phone contract that comes with a new mobile phone. It had taken me two years to bump up against the limitations of my first smartphone, but eventually I realised that I should be able to download more than two apps and use the camera without it seizing up. It took a few long sessions on the Internet and a fairly extended discussion in a shop, but my new mobile has changed my views on smartphones, and has excelled in an entirely unexpected field - my running.

I downloaded an app that used the GPS signal to track my location and speed. This was hopeless on the old mobile, but the new one coped very well. I turned the app on at the start of the run and then examined it at the end and it told me all about my route and speed and it was great. Then it emailed me a link to create a Spotify playlist, so I thought that would be fun. I no longer need or want the plinky-plonky music that came with the Couch to 5k podcast, but it's much less boring to run when listening to music.

The revelation came when I managed to put all these things together for my second Parkrun. The phone was robust enough to access and play the music, and I started up the running app alongside it and they both worked together, and I plugged in the earphones and I could listen as I ran. It wasn't even raining. All of a sudden, a few minutes into the run, the music was interrupted for a second and the running app gave me an update on how I was doing - how far and how fast I had run. I'm no newcomer to the power of the Interwebnets, but this was a combination of utility and ease of use that I found astounding.

So my running career has culminated in a time of 35-and-a-bit minutes for 5 km, which I am very pleased with. A friend was also there on Saturday, and speaking to him afterwards I was sure that I wasn't going to do any more runs, because all the way through I'd been thinking how tedious it all was, and how much more fun it is playing badminton. Subsequently, however, I looked back on the event with some pleasure, and now I'm not so sure that I won't do it again. I think our holiday will get in the way, but we'll see.

Lastly in the good news category, I spent the best part of a whole day cleaning the oven. Not good news in itself, but it doesn't half look nice when it's clean. That should last about a week.

Bad news

I mentioned that my ipod died and was revived - well, it has died again. Rather than ending my life, Mr A has generously lent me his, which is so far performing as it should, unlike my laptop. The poor laptop has been groaning and shuddering for a while, taking about 20 minutes to boot up and generally being more sluggish than a snail without a home. Mr A bought me a new hard disk and operating system, and once the gastroparesis article was finished I started installing it. Unfortunately, the new and powerful hard disk seems to overtax the geriatric laptop (born in 2009) so that after about 10 minutes of usage the fan fires up noisily and within a minute or two it shuts down without further ado. That's as far as we've got with the laptop. Mr A is experimenting with my ipod to see if he can keep it alive for a bit longer.

Meanwhile at work, there is bad news masquerading as good news. The Dietetic Manager is juggling her many fecund female staff who seem to come back from maternity leave for all of three minutes before admitting to being pregnant again, and that's not counting the ones whose family members require their immediate attention or are themselves needing some time away from the office. Not to make light of a distressing situation, one of the two hospital Dietitians where I work is unavoidably absent, and the Manager is taking none of my excuses or suggestions, and requires me to spend some time On The Wards.

I have tried to keep this to the minimum that is ethically possible, but I notice that I seem to think patients need a lot less attention than the Dietetic Manager does. I am going to have to see people in hospital beds who need nutrition support, and it is not the area of dietetic practice that interests or attracts me, which strongly suggests I am not going to be very good at it. Let's hope my attitude and out-of-date skill set doesn't land me in trouble. I really don't like ward work.

As a carrot dangling before my eyes, however, the same Dietetic Manager has suggested that more paid work may be available in Diabetes. This has been mentioned before, and timescales are vague, as are the actual content and location of the extra work required. I'm not holding my breath. I've started to enjoy my Tuesdays and I'm not quite so keen as I used to be to rejoin the world of full time work.

Also in the bad news category is the garden. I have done absolutely no work in the garden this year, which has left us with an attractive meadow instead of a lawn, an enormous amount of foliage covering every inch of soil, most of the walls, and causing the 'paved' area to resemble, well, more garden. We are about to go away for a week, and it keeps raining, so the plants may well have staged their bid to take over the house as well by the time we get back. If you look closely, the picture shows the dominance of the ten-foot thistle over the puny efforts of the human race. Although its two colleagues were broken by wind/rain, it has latched itself on to the rose bush and shows no signs of halting its assault on humanity. Luckily, its legs have not yet formed so we may yet be able to conquer it when the time comes.

Lastly in the bad news category, you may have noticed a lack of book reviews (good news for some, I believe). I have picked on the book 'Middlemarch' for leisure reading, and it is proving to be hard going. I've found a few good audio books though, and shall take some less heavy duty reading on holiday next week. I wonder how many I should pack?

Oh yes, our doorbell has stopped working too.

Gastroparesis (part 2)

Groombridge Place, June 2013

In part 1, I described the symptoms of gastroparesis, what might be causing it in someone with diabetes, and the problems that arise - gastrointestinal symptoms, poor glycaemic control, malnutrition and weight loss, and depression. Now I'm going to write about possible treatments.

Nerve damage, if that's what is causing the problem, is irreversible. We can't (yet) mend nerves: once they're gone, they're gone. There doesn't seem to be an option to fix the faulty pacemaker cells either. But it is always useful to run through a list of things that will definitely not be helping. For example, opiate drugs are known for their constipating effects, and should be replaced with alternative painkillers if pain relief is necessary. Cigarette smoking has been shown to delay the gastric emptying of solids. Unfortunately, high blood sugar has also been shown to significantly delay gastric emptying, which is of no comfort to the person with diabetes who has been trying unsuccessfully to manage wild swings in blood sugar in the face of unyielding opposition from the gastroparesis itself. So I wouldn't bother opening that particular can of worms.

There are three methods used to help improve gastric emptying: pharmacotherapy (i.e. drugs), diet and surgical approaches. Two types of drugs can help with symptoms: prokinetics, which help to speed the intestinal contents on their way, and anti-emetics, which are used to prevent nausea and vomiting. These are routinely used, but changes to diet can be more effective than the medicines.

The Glycaemic Index (GI) is often used to assist with blood glucose control and weight management, and describes the speed at which carbohydrates are digested. High GI foods e.g. foods containing large proportions of monosaccharides and disaccharides (sugars) are digested quickly, and their glucose payload can reach the bloodstream before subcutaneous insulin has had time to get there, causing blood glucose to rise beyond the desired range. Low GI foods (complex starchy carbohydrates) such as oats and pulses are digested more slowly, and therefore deliver glucose to the blood slowly and more controllably, and keep you feeling fuller for longer. Unlike the majority of people with diabetes, high GI foods may help someone with diagnosed gastroparesis. These foods tend to contain simple sugars or processed carbohydrate and little fat and fibre - sweets, white bread, mashed potato.

Another good reason to avoid fibre, apart from its role in slowing gastric emptying, is that as it hangs around in the stomach it can contribute to the formation of unwanted fibrous masses called bezoars. The disadvantage of avoiding fat, however, is that someone with chronic gastroparesis is at risk of malnutrition, and could do with the calories supplied by energy-dense fatty food.

The diabetologist who referred the patient with gastroparesis to me suggested that a low carbohydrate diet might help reduce the volatility in blood glucose levels. The problem with this approach is that taking out the carbs leaves an energy deficit that can either be filled by protein or fat. Protein increases feelings of satiety, which is certainly not what we want, and fat slows gastric emptying. Blood glucose levels may be better managed with a greater proportion of high GI carbohydrate, which might actually be released from the stomach in a more predictable manner.

Research suggests other dietary recommendations, both to relieve symptoms and to maintain nutritional status. Small frequent meals are digested better than three large meals a day, and 'particle size' makes a difference - food should be chewed well, and liquids seem to leave the stomach more easily than solids. A patient might be prescribed three liquid supplements a day, adding a much needed 900 calories. Positioning during a meal, and sitting up and/or walking post-meal can promote gastric emptying; alcohol and carbonated drinks tend to exacerbate symptoms of bloating.

Placing a feeding tube below the stomach and pylorus in the jejunum (upper small intestine) allows nutrition to bypass the problem area, but brings with it the risk of infections and the inconvenience of having to be hooked up to a feed pump for hours at a time - jejunal feeding has to be much slower than feeding into the stomach. If nutritional status continues to decline, intravenous (parenteral) feeding is a possibility, but brings a whole new range of potential complications.

As well as addressing symptoms and nutrition, there are those pesky blood sugars to consider as well. Eating a meal containing carbohydrate requires a matching dose of insulin in order to maintain blood glucose within the desirable range, but we have seen that giving the insulin at the usual time (before, during or immediately after the meal) doesn't work if the glucose hits the bloodstream over a period greater than the lifetime of the insulin. So we could try splitting the insulin dose, perhaps giving 30% of the total dose just after eating, and the remaining 70% after an hour, or two, or whenever we think blood glucose is rising.

If you don't want to end up as a pincushion, this type of insulin regimen can be managed much more comfortably and conveniently with an insulin pump, which can be programmed to deliver insulin at whatever rate you desire. Delivering 6 units of insulin at one-tenth of a unit every five minutes over five hours can't be done with conventional insulin injection devices, but is a piece of cake with a pump.

Unfortunately the NHS doesn't fund Continuous Glucose Monitoring (CGM) systems, which have a subcutaneous sensor that samples interstitial fluid every five minutes linked to a device that translates the reading into an estimated blood glucose level. We lend these systems to patients to wear for just seven days at a time when we can't work out what their blood glucose is doing. Otherwise, users have to buy the kit and consumables themselves, which works out rather expensive. Although not mentioned in the research papers I have read about this condition, I think that CGM in combination with an insulin pump would be a valuable and effective approach to managing blood glucose with gastroparesis.

Finally, there are more technical and innovative options to try.

• Gastric electrical stimulation (GES) was approved in 2000 in the USA. Similar to a heart pacemaker, the GES device is implanted next to the stomach and mimics the role of the gastric pacemaker cells, stimulating and enhancing vagal function and muscle tone. 
• Botox (Clostridium botulinum toxin) is a muscle relaxant used cosmetically to reduce facial wrinkles, but will relax muscles elsewhere to therapeutic effect. Injecting Botox into the pyloric sphincter may cause it to relax sufficiently to allow better gastric emptying, but trials have shown this effect to be short-lived. 
• In future, that universally-cited panacea 'stem cell therapy' may be relevant, providing a way to replace or rejuvenate those faulty pacemaker cells of Cajal.

Gastroparesis (part 1)

Berlin, March 2013 - no idea about the Star Wars characters...

I saw a patient recently who is suffering with gastroparesis, and I say 'suffering' for a good reason. Gastroparesis is 'a chronic disorder of gastric motility that is characterized by delayed emptying of either solids or liquids from the stomach in the absence of any mechanical obstruction.'

Food is normally chewed and mixed with saliva to form the bolus that you swallow. The bolus passes down the oesophagus into the stomach, where it is mechanically, chemically and enzymatically digested to form chyme: an acidic slurry of food, fluid and enzymes. The pyloric sphincter at the bottom of the stomach is prompted to release chyme from the stomach into the small intestine in small bursts, where the acid is neutralized and further digestion takes place by enzymes released from the intestinal wall and the pancreas. [The release of digestive enzymes into the intestine is the exocrine function of the pancreas, and is usually unaffected by diabetes, which is a disorder of the endocrine system.]

Food normally starts to leave the stomach within minutes of ingestion. After one hour 10% or more will have passed through to the small bowel, after two hours at least 40% should have gone, and four hours post-meal more than 90% of the meal should have left the stomach heading for the intestines. The final products of digestion are nutrients - fatty acids, amino acids, sugars, vitamins and minerals - that are absorbed through the wall of the gut into the body, and the indigestible fraction passes on through to be excreted as faeces.

The symptoms of gastroparesis include nausea, reflux, bloating, early satiety and post-prandial fullness, abdominal discomfort and pain. Putting a camera down into and beyond the stomach, which is usually the first line of investigation in most disorders of the gastrointestinal tract, is done to see if there's mechanical obstruction (from a tumour, for example), and in the patient that I saw, showed the remains of a meal that had been eaten the day before.

So the symptoms of gastroparesis simply arise because the stomach is not emptying - the pyloric sphincter is not being prompted appropriately to allow the chyme through to the small bowel. The next diagnostic test might be to follow a radioactive meal through the GI tract. Using this technique, delayed gastric emptying has been found in 25-55% of people with Type 1 diabetes, and in 30% of people with Type 2 diabetes.

Hyperglycaemia, or high blood glucose, is pretty toxic to the smallest blood vessels in the body, found in the retina and the kidneys, and also damages nerves. Often the nerves that are damaged are the smallest ones furthest from the brain, which is why foot care is so important. For some very unlucky people, the nerve that is affected is the vagus nerve, which transmits the signals that manage the extremely complex processes going on in the intestinal tract. But it turns out that hyperglycaemia affecting the vagus nerve is not usually the culprit in diabetes, but more often it is due to destruction of the pacemaker cells ('cells of Cajal') that link the vagus nerve with the smooth muscle of the stomach, and the result is the absence of peristalsis and atrophy of gastric smooth muscle.

Let's look next at what happens to the food once it has been digested, and glucose from carbohydrate in food has been transferred from the gut to the bloodstream. Insulin is secreted from the pancreas in order to allow the glucose to enter cells of the body where it is used for energy. In someone without diabetes, the pancreas simply responds to the level of glucose in the blood: lots of glucose leads to lots of insulin, little glucose means little insulin. It's automatic, and maintains tight control of blood glucose levels very effectively, to prevent those toxic effects of hyperglycaemia (or the unpleasant and potentially dangerous effects of hypoglycaemia, low blood sugar).

Now, we'll throw Type 1 Diabetes into the mix. Insulin secretion by the pancreas is non-existent, so the diabetic patient has to supply the insulin by injection. Usually it takes about the same time for glucose to reach the bloodstream from digested food as it takes for rapid-acting insulin to reach the bloodstream from the injection site. This type of insulin is effective over about 4 to 6 hours, which is about the time it usually takes for the whole meal to leave the stomach, be digested, and all the glucose to be delivered to the bloodstream.

With gastroparesis, there is a delay. Some glucose may turn up in the bloodstream straight away, but there is no way of knowing how much, or how long it will take for the whole lot to come through, and at what rate. So you can calculate the insulin that is needed to match the carbohydrate in the meal, but if you inject it all at once, it will arrive in the bloodstream before the glucose, and your blood glucose level will drop. The way to deal with low blood glucose from too much insulin is to consume some sugary carbohydrate that should be quickly digested, but - will it reach the bloodstream in time, given that the pyloric sphincter is mostly stuck shut? Later, when the rest of the carbohydrate from the meal finally gets through to the bloodstream, the insulin will no longer be there to deal with it, and your blood glucose level will rise. And there is no reliable way to predict how long this will take. The insulin and blood glucose graphs look like roller coasters.

Meanwhile, you feel uncomfortably full all the time and find it difficult to eat even a small amount of food. Eating is no longer pleasurable, you're losing weight, your family are initially sympathetic but you keep vomiting after a trivial amount of food, your breath smells terrible and with the constipation alternating with diarrhoea, the bathroom is never free. The diabetes team give the impression that your terrible glycaemic control is because of something you're doing wrong with the carb counting or insulin dosage, but you're doing everything you can think of to try and avoid high or low blood sugar, it's just that nothing's working. The high and low blood sugars make you feel awful too. Depression is a well-documented side effect of diabetes, and if you have gastroparesis too, well, there aren't many happy days.

Although part 1 ends on a low note, part 2 should provide some reassurance that treatments are available and can help.