It has been reported for long (even decades ago) about sudden feeling of neuropathic pain on poorly controlled diabetes patients on starting medications to control their diabetes. It was also observed that this pain will gradually subside, once diabetes comes under control.

   To describe this phenomenon, researchers selected 16 patients who were then referred to a Boston diabetic neuropathy clinic to undergo neurological and retinal examinations, laboratory studies, autonomic testing, and pain assessments over 18 months. Nine patients (age range, 19–29) had type 1 diabetes, and 7 patients (age range, 31–58) had type 2 diabetes. Other common causes of neuropathy were ruled out. Each patient developed severe neuropathic pain within 8 weeks of initiating intensive glycemic control and retinopathy worsened in all subjects.

   Average glycosylated hemoglobin levels were about 14% before intensive glycemic control and about 7% afterward. Pain was in a stocking-glove distribution in 13 patients and was diffuse in 3 patients. After 18 months of glycemic control, there were substantial improvements in pain, autonomic symptoms, autonomic test results etc. The pathophysiology and incidence of this clinical entity are unclear. However, the parallel worsening of neuropathy and retinopathy suggests a common mechanism, and, interestingly, transient worsening of retinopathy during the first year of intensive insulin therapy has occurred previously in clinical trials.