Thyroid morphology in lethal non-thyroidal illness: a post-mortem study

Objective: Non-thyroidal illness (NTI) is associated with alterations in th yroid hormone metabolism. Whether morphological changes of the thyroid glan d accompany NTI is unknown. The aim of the present study was to describe th yroid morphology in patients with lethal non-thyroidal disease. Design: In an autopsy study 267 cases have been examined. Methods: Clinical data were obtained from medical records. Subjects were pa tients with chronic disease (group A), intensive care patients (group B) or persons who had died suddenly without pre-existing illnesses (group C). Pa tients (n = 93) who did not fit into one of these categories and subjects w ith pre-existing thyroid disorders were excluded. Thyroid histology was ass essed semi-quantitatively: grade I < 25%, grade II 25-50% or grade III > 75 % occupation of the thyroid gland by follicles with a diameter < 200 <mu>m. Results: Mean thyroid weight was 19.9 g in group A (n = 75, age 19-96 (medi an 75) years, 48 males); 25.7 g in group B (n = 64, age 24-93 (median 69) y ears, 43 males); and 26.0 g in group C (n = 35, age 31-89 (median 69) years , 22 males) (P < 0.0005, A vs BIG), Grade I thyroid histology was present i n 6 out of 75 patients with chronic illness, in 3 out of 64 intensive care patients and in 33 out of 35 sudden-death subjects. Grade III thyroid histo logy occurred in 30 out of 75 chronically ill patients, in 17 out of 64 int ensive care patients and in 30 out of 35 sudden-death subjects (P < 0.0005, C vs A/B). Conclusions: NTI is associated with reduced thyroid follicular size that is accompanied by lower thyroid weight in chronically ill patients but not si gnificantly in intensive care patients.