By Jane Elliott
Health reporter, BBC News
Cliff tried a number of different insulins
When diabetic Cliff Saunders became allergic to the insulin he used to control his condition he was worried.
"I felt I was not going to pull through and was thinking, 'how long have I got?'"
Cliff, now 66, from Essex, was first diagnosed 14 years ago with Type 2 diabetes.
His condition was controlled by diet and then tablets to stimulate insulin from his pancreas and to use his body's own insulin better.
But five years ago he had a mild stroke, and doctors prescribed two insulin injections a day to try to stave off another stroke.
These were small amounts at first, but the dosage was rapidly increased and Cliff soon suffered terrible reactions.
"I started to experience itchiness and soreness and lumps on the skin. Then I started to feel hot sweaty, breathless and lethargic.
"During that period I tried five different insulins and still had no improvement.
"I was advised by the doctor that there was nothing he could do for me, and that I should just go home and take the tablets."
Tests showed that not only was he allergic to his own medication, but also to another four types - and it was the insulin molecule itself that was causing the problems.
Doctors painted a gloomy picture about Cliff's future, as it was clear the treatments he could take would not completely control his diabetes.
Determined not to give up, he started to do his own internet research and found that Dr Tahseen Chowdhury at Barts and the London Centre for Diabetes had treated difficult cases like his own.
Insulin is used to treat diabetes
"He said he didn't know that there was a lot he could do for me, but that he would take me on.
"Up to that point I was told 'oh dear, oh dear, what are we going to do?'
"When I got to see him he said we could try various things, and it opened up a dark tunnel.
"I felt much happier about things."
Dr Chowdhury tried out a number of therapies, including a modified insulin but they failed.
Then he hit upon using an insulin pump to put tiny amounts of the drug into Cliff's body every three minutes.
"The amount was so small I did not get the reaction," said Cliff.
"That worked like a dream and I thought 'eureka'."
Now Dr Chowdhury makes continual adjustments to Cliff's dosage to prevent resistance developing again.
Dr Chowdhury said Cliff's case had been a real challenge and he had turned to the internet as part of his search for an answer on how to proceed with his patient.
"I had found one report of a case which was similar to his that had been treated with a pump with moderate success."
Pumps are used for patients with type 1 diabetes who cannot make their own insulin, and allow careful dose adjustment and small doses for meticulous control.
But pumps are rarely necessary for patients with Type 2 diabetes, as they have insulin around, although it does not work properly.
Dr Chowdhury talked to Cliff and they decided to try the pump.
"We thought the little bits of insulin over 24 hours might not provoke the response.
"It was a bit of a leap of faith on Cliff's part. What we were pleased about was that we were able to give a reasonable amount of insulin without the reaction.
Type 2 diabetes
Type 2, or non-insulin dependent diabetes is the most common form of the disease. It usually occurs in people who are over the age of 45 and overweight.
Type 2 sufferers do not make enough insulin, or are unable to make proper use of it.
Without enough insulin, the body cannot move blood sugar into the cells. Sugar builds up in the bloodstream and causes health problems.
Dr Chowdhury said a severe reaction like Cliff's was very uncommon, affecting no more that one in 10,000 people.
And he said the treatment had worked.
"His quality of life was very poor and he felt dreadful. He was getting the terrible reactions from the diabetes.
"Now Cliff's blood sugar control is better and his terrible symptoms have improved.
"If he had not had the pump therapy his quality of life would have been reduced as might his life expectancy."
Diabetes UK care advisor, Caroline Butler, said: "We are very happy to hear insulin pump therapy has worked for Mr Saunders and he is able to enjoy a normal life.
"Dr Chowdhury's excellent work should be commended."