Lipodystrophy at the insulin injection sites: current trends in epidemiology, diagnostics and prevention

Abstract

Lipodystrophy at the injection sites is most common local complication of insulin therapy. The history of its study started in 1926, when first cases of lipoatrophy at the sites of insulin injections were described. As we moved to human insulin and insulin analogues, immune mediated atrophic form of lipodystrophy has been replaced by hypertrophic one, which reflects anabolic and mitogenic effect of insulin.
 Lipohypertrophy at the injection sites is detected by physical examination in 40-70% of insulin-treated subjects. The detection efficiency depends on health care provider`s skills. Therefore, training of medical doctors and nurses in physical examination of injection sites seems to be reasonable.
 In recent years, ultrasound was introduced for diagnostics of insulin-induced lipohypertrophy. The method is more sensitive compared to palpation; ultrasound-verified lipohypertropthy was detected in more than 80% of cases. In patients with wide-spread lipohypertrophy ultrasound can be used to find suitable sites for injections (ultrasound injection map). Strain sonoelastography and 3D-power Doppler ultrasound can be used for quantitative estimation of rigidity and vascularization of lipohypertrophy. Both MRI and infrared images are considered as promising diagnostic tools.
 In a number of studies, it has been shown that the presence of lipohypertrophy is associated with high HbA1c levels, enhanced glycemic variability, unexplained hypoglycemia, and increased insulin doses. Thereby, lipohypertrophy aggravates the diabetes-related costs.
 The main risk factor for lipohypertrophy is inappropriate injection technique, including the lack of the site rotation, injections into lipodystrophic lesions, small injection area, reuse or excessive length of the needles. Accordingly, training patients in the injection technique is the basis for prevention of complication. The cessation of injections in lipohypertrophy areas and regular site rotation is essential for adequate titration of insulin dose and achievement of glycemic targets.

Characteristics and morphology of lipohypertrophic lesions in adults with type 1 diabetes with ultrasound screening: an exploratory observational study

“…Advanced imaging techniques (compression elastography, Doppler scanning, MRI and thermography) are also beginning to reveal more on the structural and vascular changes that are associated with lipohypertrophy. 39 While these observations are restricted to small case reports, they generally concur with our observations showing tissue changes consistent with dermal thickening, inflammation, reduced vascular activity and potential necrosis. Future studies may consider these techniques to provide more detailed images of the structures, density and nature of lipohypertrophy.…”

“…Inflammatory cells have been reported in lipohypertrophic tissue samples, 31 with a recent histological study of lipohypertrophy in five people with diabetes showing the presence of fibrous bundles and in two cases perivascular inflammatory infiltration from lymphocytes and neutrophils. 32 Rodent studies have shown that phenolic compounds found in insulin are associated with increased inflammatory stress and increased leucocyte activation. 33 Insulin antibodies have also been associated with the development of lipohypertrophic tissue.…”

Insulin-induced Lipo hypertrophy and factors affecting it in children and adolescents with type 1 diabetes mellitus: Review of Literature in the past 12 years

“…This can be easily missed by visual inspection and so areas should be palpated. It is recommended that to feel subtle skin thickening, the hand should be stroked firmly in a sweeping motion rather than using traditional techniques of light and deep palpation (39,40).…”