Tuesday, 21 February 2017
Chicken pox is caused by the varicella zoster virus, one of eight herpes viruses known to infect humans, and is thought to have been infecting humans for millennia. The virus is spread through the air, and can also be spread via contact with the blister on the skin before they heal over. Chicken pox presents as a head-downwards rash, usually very distinctively. In patients aged 1 to 15 years, symptoms, although uncomfortable, are rarely serious.
Wednesday, 15 February 2017
Over the past thousand years of medical progress, mankind has seen a slow but steady increase in human longevity. Though the occasion plague, famine or war will lead to a mortality peak in a generation, by and large each new wave of humanity is healthier than the last.
But this trend seems to be about to change. A study published in 2015 revealed that middle-aged white Americans are dying at younger ages than their parents for the first time in decades; and as with all trends, where the US leads, the UK and Europe are sure to follow soon after. In fact, there are many studies suggesting that today's children may lead shorter lives than their parents.
To explain these trends experts have looked to two main factors – firstly “deaths of despair” such as opioid overdoses, suicides and the complications from long term alcohol abuse. In 2015, 52, 000 Americans died of drug overdoses alone, more than died per annum of HIV/AIDS during the epidemic's peak years in the mid 90s. Almost half of these deaths were due to opioid-based drugs, such as heron or the much stronger synthetic opioid fentanyl.
Secondly a more recent study has linked diabetes to the increase in American mortality. Whilst in 1958 only 0.93% of the US population was diagnosed diabetic, now 7.02% (nearly 30 million people) of the country live with the disease. The number has grown three-fold since the early 1990s, rising with the ever increasing obesity rates. Approximately 368 million people on Earth were living with the disease in 2013.
Most of these cases are diabetes mellitus Type 2. This is what used to be known as “adult onset diabetes”, to differentiate it from Type 1 diabetes, which involves the auto-immune destruction of the insulin producing beta cells in the pancreas and usually begins in childhood. Type 2 diabetes now makes up 90% of all diabetes diagnosis in Europe and is seen increasingly in young adults and children.
Type 2 diabetes is associated with a ten-year reduction in life expectancy, and is though to be an under-reported cause of death, likely affecting life expectancy trends. People with diabetes often have multiple co-morbidities such as obesity, high blood pressure, cardiovascular disease, and even cancer.
Diabetes was one of the first diseases that we can recognise as described in an Egyptian manuscript from c. 1500 BCE. They mention “too great emptying of the urine” and that the urine would attract ants. This is due to the high levels of glucose in the urine seen in untreated diabetics. These first cases are believed to all be Type 1.
Type 1 and type 2 diabetes were described as separate conditions a thousand years later, in India, by the doctors Sushruta and Charaka, with Type 1 being associated with youth and Type 2 with obesity. The name “diabetes” was given by the Greek doctor Apollonius of Memphis in 250 BCE, meaning “to pass through”.
So throughout historical times, both types of the disease were recognised, although rare, and treatments were generally unavailable. Aretaeus of Cappadocia offers a list of symptoms of diabetes, although no treatments and notes “life (with diabetes) is short, disgusting and painful”.
However by the late 19th Century the idea of a low-carbohydrate diet was realised. Whilst under rationing in Paris during the Franco-Prussian war, French physician Bouchardat realised his diabetic patients were faring somewhat better. This lead to some doctors going so far as to keep their patients under lock and key to prevent them from breaking particularly restrictive diets.
In 1889 Germany, Oscar Minkowski and Joesph von Mering removed the pancreas from a dog and saw the poor animal developed diabetes. The protein insulin was eventually identified as being the key to blood sugar control in 1921. Sir Frederick Banting and Charles Best went on to purify insulin from cows and successfully treated a 14 year old boy with Type 1 diabetes in 1922.
Advances were made rapidly, in 1936 the two types of diabetes were made distinct from a treatment perspective and in 1944 a standard insulin syringe was developed. The structure of insulin was first determined in 1951 and first genetically engineered, synthetic human insulin for use in patients was produced using E. coli recombinant expression in 1978.
Since then, there has been huge amounts of progress in the treatment of diabetes, both Type 1 and Type 2, including the introduction of the blood glucose meter and the insulin pump. Short and long-acting insulin derivatives that stem from work done within the York Structural Biology Laboratory at the University of York are now the standard treatment for many Type 1 diabetes patients worldwide.
Researchers at the University of Pennsylvania looked at the prevalence of Type 2 diabetes in the US population and looked at the increased risk of death adults ages 30-84. They calculated that, while diabetes was listed as the cause of death in 3.7% of cases, it was more likely to the underlying cause in almost 12% of the total deaths. Amongst the obese cohort alone, the death rate from diabetes was closer to 19%.
There are now many drug treatments available for Type 2 diabetes, however many have complicated side effects. Most disease management regimens focus on lifestyle interventions to lower various risk factors and maintain a healthy blood sugar level.
Annually, the NHS currently spends £8.8 billion (over 8% of its budget) treating Type 2 diabetes and its complications – from outpatient services to amputations. On a societal level too, Type 2 diabetes has a huge impact on levels of absenteeism and early retirement as the various complications of the disease effect the suffers lives.
Prevention of the onset of Type 2 diabetes is the ideal solution from a healthcare prospective, and it can be achieved with both lifestyle changes and medication. Patients with prediabetes who go through lifestyle changes alone (weight-loss, increased physical activity and quit smoking) can reduce their risk of developing Type 2 diabetes by 50 to 60%.
Although it has been known for some time that obesity and the associated co-morbidities are a leading factor in reduced life expectancy, researchers are hopeful that a focus on diabetes and specifically the control of blood sugar might help healthcare workers and policy makers to combat the trends in mortality statistics.
An abridged form of this article appeared in Nouse 14/022017
An abridged form of this article appeared in Nouse 14/022017
Thursday, 2 February 2017
Get short tempered before lunch? Snap at people if you’ve skipped breakfast? Perhaps you are suffering from hanger – the combined effects of hunger and anger.
Self-control requires energy. When our energy levels are low, it follows that our control over our temper is reduced too.
As blood glucose levels drop, the stress hormones cortisol and adrenaline are released to drive us to find our next meal. Along with a chemical identified as neuropeptide Y, these combine to make people more aggressive to those around them.
The effects of blood sugar on aggression were measured in a 2014 trial investigating 107 married couples. In the first part, the couples used voodoo dolls and up to 51 pins to express the level of anger that they felt at their partner at that time, and the blood glucose levels of both was measured.
In the second half, the couples played a competitive game, after which the winner could blast the loser with a loud noise through a set of head-phones. As expected, the lower the blood glucose, the more pins and the longer the noise the partners received.
A 2012 study at Columbia University looked at case sentencing by judges and saw they tended to be more lenient first thing in the morning and right after lunch. On the other hand, this may have been more to do with the ordering of the caseload (shorter cases vs longer and more complicated ones) than the timing of meals.
The hunger hormone, ghrelin, which is produced in the stomach prior to meals and during fasting, has been seen to have a negative impact on the brain’s ability to make rational decisions. During an experiment at the University of Gothenburg in 2016, rats with a higher level of ghrelin (mimicking hunger conditions) behaved more impulsively and erratically.
However this study was done in rats, they can be a good model for humans, and more research is needed to confirm the effect is true in us. But perhaps for now be careful when making decisions on an empty stomach.