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Students provide new information about rare diabetes complication

Charcot foot is a rare and very serious late complication of diabetes which today is very difficult for doctors to diagnose. But now, there are indications that the temperature distribution in the foot from the ankle to the toe may reveal the disease at an early stage where the chances of recovery are best. Two engineering students are behind the first remarkable results

2013.02.15 | Kim Harel

[Translate to English:] varmefordeling i fødder

Initial studies indicate that the temperature distribution in the foot may detect the disease Charcot foot which is one of the most serious late complications of diabetes.

So far, nobody knows why this happens. The bones in the foot crumble slowly and a fracture occurs. Often, the problem is that the diabetes patient does not notice until it is too late. Charcot foot is always connected to neuropathy which, due too increased blood sugar values, damages the nerves outside the central nervous system and leads to loss of sensation in the feet.

"Since Charcot foot is accompanied by loss of sensation in the feet, most patients do not notice the complication until it has reached a severe stage where he or she often has walked on a foot with several fractures for a long time. It is obvious that the condition must be detected quickly to reduce the extent and complexity of the fractures", says Maria Bæk Jørgensen, engineering student at Aarhus University.

Detects disease before symptoms
The treatment of Charcot foot consists of rest. The foot is put in a cast and any kind of weight on the foot must be avoided for several months. Then, the foot is rehabilitated gently. As much as every third patient has a relapse and has to start the treatment process from the beginning.

But now, two engineering students are on the track of a possible method to spot the disease in the acute phase before the patient feels the symptoms.

"It seems that by calculating the heat distribution in the foot, it is possible to determine whether it is an advantage to put weight on the foot or not", says Maria Bæk Jørgensen.

Charcot foot occures in around 0.3 percent of all diabetics and is therefore a rather rare late complication. Still, on a worldwide level diabetes is so common that millions of people will benefit from this new knowledge.

Often diagnosed too late
Most patients do not see their doctor until they can see that something is completely wrong. However, the doctor does not have the optimal pre-conditions to make a clear diagnose. The symptoms may easily be mistaken for those that occur in connection with more ordinary diabetic late complications in the foot such as phlebitis, and that increases the risk of improper treatment.

"We would very much like to become better at diagnosing and monitoring the Charcot foot continuously. Not only by regular examinations at the hospital but also on a daily basis in the patient's home. The condition may flare from day to day, and therefore it will be a great help in the treatment to be able to determine relapses at an early stage. At the same time, a continuous measurement of the temperature will give us better possibilities of advising the patients in how much they can move the foot in the treatment phase and the following period. Today, we base our advise on bad empirical knowledge and lack the possibility of providing an individual treatment", says Knud Yderstræde, MD at Odense University Hospital.

In connection with a bachelor project at Aarhus University School of Engineering, the two students were put together with the doctor from Odense University Hospital. He introduced them to the problems in connection with Charcot foot and subsequently, they decided to find out how the temperature pattern of the foot may detect the condition.

"We wanted to develop a tele medical method to detect relapses. The current system of regular examinations at the hospital is expensive for society and difficult for the patients and at the same time not sufficient in order to detect new fractures at an early stage", says Bianca Janina Preil, engineering student at Aarhus University.

At the examinations in the hospitals’ diabetes labs, the patients’ average foot temperature is measured with special equipment. There are signs of Charcot if one foot is minimum two degrees warmer than the other.

Heat distribution in the foot reveals condition
The weakness of the present diagnostic practice is that it is time consuming and can only be carried out by specialists at the hospitals. In the future, it may be possible to carry out a continuous and far more precise monitoring of Charcot in the home by looking at the heat distribution in the foot. That is indicated in the initial studies.

The two students have photographed the feet of a number of Charcot patients with an infra red camera. Subsequently, they have analysed the heat patterns in the feet of Charcot patients and compared with the heat patterns in the feet of healthy people.

"When we are data processing the photographs of Charcot feet, we can see that the heat is developing down through the foot in a particular characteristic way that we do not see in healthy people. We have made a line from ankle to toe and examined the difference in temperature five different places on the foot. And we have also made a mathematical calculation model that connects the gradient of the lines with an average temperature on the entire foot", explains Maria Bæk Jørgensen.

In healthy people, there is a change in the heat distribution down through the foot where the area around the toes is the coldest place. In Charcot patients, there is not any temperature difference and this should set off an alarm.

"Imagine a sock with integrated sensors that continuously monitor the feet and spot first time outbreaks in diabetics in the high risk group as well as relapses of the disease in those patients that are already diagnosed with the disease", says Bianca Janina Preil.

To begin with, the students have carried out a very small study on five Charcot patients, and the results are clear and suggest that there may be a diagnostic advantage in looking at the heat distribution in the foot instead of measuring the temperature at one single point.

The two students have cooperated with Odense University Hospital and the company DELTA which develops medical equipment.

The students are hoping that their results may give reason to a larger and more detailed study of the heat distribution in Charcot feet and subsequently a medical technology development project.

Bianca Janina Preil, student, Aarhus University School of Engineering: 30265166; bianca@thobia.dk

Maria Bæk Jørgensen, student, Aarhus University School of Engineering: mariabjorgensen@gmail.com


Department of Engineering, Public / media, Students