Clinical and laboratory observation

Edema associated with improved glycemic control in an adolescent with type 1 diabetes

Insulin edema is a rare and poorly understood complication of insulin therapy. It has been associated with the initiation of insulin in patients with newly diagnosed diabetes or the intensification of insulin therapy in those with poor glycemic control. This condition is rarely reported in pediatric patients. We describe a case of insulin edema in a 14-year-old boy with potential risk factors of highly elevated glycated hemoglobin at diagnosis and history of unilateral renal atrophy. We also present a discussion of the pathophysiology of this condition and a review of the pediatric literature.

L’œdème lié à l’insuline est une complication rare et mal comprise de l’insulinothérapie. Il a été associé à l’instauration de l’insuline chez les patients qui ont récemment reçu un diagnostic de diabète ou à l’intensification de l’insulinothérapie chez les patients qui ont une mauvaise régulation de la glycémie. On signale rarement cette affection chez les patients de pédiatrie. Nous décrivons un cas d’œdème lié à l’insuline chez un garçon de 14 ans ayant des facteurs potentiels de risque d’hémoglobine glyquée très élevée au diagnostic et des antécédents d’atrophie rénale unilatérale. Nous présentons aussi une discussion sur la physiopathologie de cette affection et une revue de la littérature pédiatrique.

Increased permeability of the cerebral microvasculature occurs during the treatment of diabetic ketoacidosis (DKA). Microvascular changes consistent with diabetic retinopathy have been reported prior to and after the treatment of DKA. This study evaluated the structural and functional aspects of the retina immediately following the correction of DKA.

Seven young patients had comprehensive ophthalmologic examinations, including fluorescein angiography, within 24 h after the correction of severe DKA (pH <7.2).

None of the patients had clinical, photographic, or angiographic evidence of a retinal abnormality.

The blood–retinal barrier (BRB) does not experience the same degree of perturbation as the blood–brain barrier (BBB) does and may be a protected site during the insult of DKA and its treatment. The greater stability of the retinal microvasculature may be due to the increased number of pericytes in the BRB in comparison with the BBB.

The edematogenic properties of insulin have long been documented, although they have been underestimated despite current trends toward intensive insulin therapy. Insulin treatment has been associated with weight gain, mild or moderate edema, and, rarely, generalized edema and cardiopulmonary congestion. In addition, the use in recent years of thiazolidinediones, which improve insulin sensitivity, has been associated with weight gain and peripheral edema, which can progress to pulmonary edema, particularly when thiazolidinediones are used in combination with insulin. This article attempts to raise awareness about the overlooked edematogenic action of insulin. In addition, the potential role of edema-provoking properties of insulin in the development of vascular complications in patients with diabetes is discussed.

The predominant influences on fetal growth are maternal and placental factors. Post-natal growth is regulated by a complex interaction between genetic, environmental and hormonal influences. The role of the growth hormone insulin–like growth factor (GH–IGF) system is explored, including the emerging role of IGF-2 in fetal growth. Increasing understanding of the genetics of overgrowth and short stature syndromes is contributing greatly to basic understanding of growth regulation. A range of prenatal overgrowth syndromes is discussed, including those associated with neonatal hyperinsulinism and hypoglycaemia.

Post-natal overgrowth may be caused by a diverse range of normal variant conditions, endocrine disorders, chromosomal abnormalities and other genetic syndromes. An approach to diagnosis is presented and major conditions discussed in detail. Sex-steroid therapy for height limitation continues to be a controversial area with uncertainty about height prediction, benefits achieved and possible long-term side-effects.

The acute complications of diabetic ketoacidosis in children and adolescents are well recognized but not completely understood. Clinical studies have focused primarily on brain edema. We have investigated the prevalence and course of interstitial pulmonary edema in patients with severe diabetic ketoacidosis all of whom had uneventful clinical courses. High resolution computed tomography scans of the lungs were analyzed by determining the Hounsfield attenuation level and then converting to physical density values. All seven patients had evidence of interstitial pulmonary edema on the first scan, which was performed within 1 h of hydration and prior to receiving insulin; six of the seven patients had increased pulmonary density 6–8 h into treatment, and all had complete resolution of the interstitial changes at discharge. Our study suggests that subclinical interstitial pulmonary edema may be a frequent occurrence in children and adolescents with severe diabetic ketoacidosis and may very well be present prior to treatment. The study also supports the philosophy of cautious rehydration and the close monitoring of children and adolescents with diabetic ketoacidosis until a more complete understanding of this pathophysiologic event is achieved.