The thymus in infants dead from acute disorders. Thymus weight and cortico-medullary ratio.

Abstract

Thymus weight and cortico‐medullary size ratio were studied at autopsy in 49 infants between two weeks and two years and a half of age, who died either from sudden unexpected and unexplained death (SUD), or from accidents or other explained non‐infectious causes (ACC), or from acute infections of less than two weeks' duration (ILL). Thymus weight was slightly lower in the SUD group than in the ACC group. Approximate normal curves for absolute and relative thymus weights and for cortico‐medullary ratio as estimated from planimetric measurements on histological sections were drawn on the basis of the combined SUD and ACC groups. Thymus weights and ratios in the ILL group were expressed as per cent of the normal curves and related to the duration of disease. Cortico‐medullary size ratio showed less individual variation than thymus weight and may give a more useful estimate of the functional state of the organ. When disease has lasted for from one to two days, thymus weight and cortico‐medullary ratio may or may not be within normal range. When disease has lasted for more than two days, the values are below normal range. Little or no significant deviation from normal can be expected when disease has lasted for less than 8–12 hours.