Insulin lipodystrophy and lipohypertrophy.

Sir,

A 51-year and a 47-year old Type 2 diabetic male were on premixed human insulin 30:70, administered through insulin syringe for last 1 and 3 year respectively. They achieved reasonable control of their diabetes, until 6 months back when they noticed problems with fluctuating blood glucose concentration, with occasional episodes of unpredictable hypoglycaemia, despite compliance with diet and dose of insulin. On presentation, their HbA1c were 9.8% and 10.4% respectively. Their renal function and thyroid function tests were normal. On reviewing their injection sites: two areas of localized lipohypertrophy [Figure 1a] and a well circumscribed localized lipoatrophy area around umbilicus [Figure 1b] were noted. They were advised not to inject insulin into these sites, to rotate injection sites and reduce the dose of insulin by 10%. At 3 month follow up their glycaemia control improved with latest HbA1c 7.5% and 7.8% respectively, without any episode of hypoglycaemia.

Figure 1

(a) Lipohypertrophy (b) Lipoatrophy

Abnormal reactions in subcutaneous fat to insulin have been recorded since its discovery, called lipodystrophy. Insulin lipohypertrophy denotes to a benign tumor like swelling of fatty tissue at the injection site secondary to lipogenic effect of insulin, whereas lipoatrophy is considered an adverse immunological side effect of insulin therapy. Since the advent of recombinant human insulin and analogue, lipoatrophy, has virtually disappeared, whereas, lipohypertrophy still remains a serious local problem of insulin therapy.[1] Injection into lipodystrophied sites, results in an erratic absorption of the drug, leading to glycaemic variability making it difficult to achieve suitable metabolic control.[2] Lipodystrophy, is exclusive complication of lean children and young Type 1 diabetic, although rarely can be seen in Type 2 diabetic.[23] Lipodystrophy is seen twice as commonly with medium or long acting insulin compare to regular short acting insulin because they stay longer time at the injection site and provide a source for local antigen.[4] Annual examination of injection site is recommended for evidence of lipodystrophy. Visual examination is not sufficient, ideally, sites should be palpated. Prevention, to avoid lipodystorophy, should take first place as there is little cure to it, and the best way is to educate the patient about rotating injection sites. To our knowledge, in addition to local immune reaction to insulin crystals, the frequent use (up to 12 times) of same insulin needle and lack of rotation of insulin injection sites seems to favor the development of lipodystorphy in our patients. Any insulin formulation can in principle cause lipodystrophy-“daily pen needle or syringe change and frequent switching of injection area are more beneficial to avoid lipodystrophy even with recombinant human insulin and analog.”