Adrenal Medullary Fibrosis in IDDM of Long Duration

We conducted a retrospective pathology study to determine whether subjects with long-standing insulindependent diabetes mellitus (IDDM) have abnormalities of the adrenal medulla compared with subjects with non-insulin-dependent diabetes mellitus (NIDDM) and nondiabetic individuals. Slides were scored from 0 (no fibrosis) to 3+ (complete fibrosis). Nineteen IDDM subjects aged 30–60 yr (mean ± SE 44.9 ± 2.5 yr) at autopsy and with duration of diabetes 13–45 yr (26.8 ± 1.8 yr) were studied. Twelve NIDDM subjects aged 61–84 yr (73.3 ± 2.5 yr) with duration of diabetes 17–33 yr (22.8 ± 1. 9 yr) were studied. Twenty-two nondiabetic subjects aged 32–77 yr (53.7 ± 2.9 yr) were studied. Four of 19 (27%) IDDM subjects had moderate to severe fibrosis compared to 1 of 12 (8.3%) NIDDM subjects and 1 of 22 (4.5%) control subjects. Thirteen of 19 (68%) IDDM subjects had a score of 1, 2, or 3 compared to 3 of 22 (13.6%) control subjects (P < .0005). There was an association between duration of IDDM and fibrosis score (r = .46, P < .05) and between age and fibrosis score among IDDM subjects (r = .57, P = .01). No association between age or duration of diabetes and /ibrosis score was observed for NIDDM or control subjects. Adrenal medullary fibrosis may be an anatomical correlate of the diminished epinephrine secretion that occurs in response to insulin-induced hypoglycemia in some IDDM subjects.