Axial length in patients with diabetes.

PURPOSE: To investigate the relationship between axial length and retinal involvement in patients with diabetes. METHODS: A total of 157 consecutive patients with diabetes underwent biometry. The patients were divided into three groups, according to retinopathy: 44 without retinopathy, 37 with background retinopathy, and 76 with proliferative retinopathy. To compare axial length in diabetic versus nondiabetic subjects, a control group of 157 healthy subjects with age and sex distribution similar to the diabetic group was selected from an orthopedic clinic. We investigated in the diabetic group whether the axial length was related to specific type of diabetes (non-insulin-dependent or insulin-dependent), duration of disease, presence of retinopathy, or laser treatment. To eliminate the confounding effect of myopia, we excluded all patients with axial length greater than 24 mm from the two groups. Comparison of diabetic patients without retinopathy versus nondiabetic subjects was also performed. RESULTS: Diabetic patients presented shorter axial lengths compared with the controls (mean +/- standard deviation, 22.4+/-1.3 mm versus 23.4+/-1.3 mm; P<0.001). Significantly shorter axial lengths were found in the background and proliferative retinopathy groups compared with the group without retinopathy (22.0+/-1.2 mm and 22.1+/-1.1 mm versus 23.2+/-1.4 mm, respectively; P<0.05). No difference in axial length was found between the diabetic patients without retinopathy and the nondiabetic subjects (P = 0.3). Multivariate analyses showed that retinopathy was negatively correlated with axial length (P<0.01). Including only the patients with axial length under 24 mm, we obtained similar results. CONCLUSION: Axial length is shorter in diabetic patients than in nondiabetic subjects. Within the diabetic group, patients with retinopathy had shorter axial lengths than did patients without retinopathy.

[Pseudohyponatremia and anion gap changes in multiple myeloma]. / Pseudo hiponatremia y cambios en el anion gap en un mieloma múltiple.

Pseudo-hyponatremia is a rare condition characterized by a decrease in plasma sodium concentration associated with a normal or increased effective plasma osmolarity. We present the case of a 62 year old woman with multiple myeloma (IgG) who had a plasma sodium of 84.5 mEq/l (as measured with flame photometry) and an anion gap of -8.8 mEq/l. However, when determined with an ion-selective electrode, plasma sodium was 135 mEq/l. The patient was treated with chemotherapy and did not receive sodium. One week later, plasma sodium--again measured by flame photometry--was 134 mEq/l and the anion gap 4.0 mEq/l. The pathophysiological and clinical aspects of pseudo-hyponatremia and the anion gap are discussed.