Hypothalamo-pituitary response before and after surgical stress [splenectomy] in Thalassemic patients

ABSTRACT

Multiple endocrinopathy is a common manifestation in thalassemia. Although the response of the stress hormones to induced hypoglycemia has been studied in these patients, the impact of surgical stress is not yet determined. The hypothalamo-pituitary-adrenal axis of 27 thalassemic patients [TP], [4-15 years old [y.]] admitted for splenectomy, was evaluated before and after surgical stress during 1996-8. Blood samples for measurement of ACTH, cortisol, growth hormone [GH], thyroid stimulating hormone [TSH] and prolactin [PRL] were taken a day before and also approximately two hours after surgical insult. For comparison, 22 non-thalassemic patients [NTP] [3.5-14 y.] admitted for elective laparotomy, were selected as the control group. The cortisol response after surgical stress was significantly higher than baseline in both the TP [17.4 +/- 6.3 vs 30.81 +/- 11.49 micro g/dl; P<0.001] and the NTP [20.65 +/- 9.1 vs 36.87 +/- 11.08 micro g/dl; P<0.001]. NTP showed a significant elevation of ACTH upon surgical stress [P<0.001], while the difference between pre- and post-stress ACTH was not statistically significant in TP [P=0.123]. However, the ACTH concentration before operation in TP. was significantly higher than that of NTP [P<0.042] with no remarkable difference after surgical stress between the two groups [P=0.261]. GH increased significantly after operation in TP and NTP [P< 0.016 and <0.05, respectively]. A significant change in TSH [P< 0.03] and PRL [P< 0.004] was also observed in TP after operation. The hypothalamo-pituitary as well as the pituitary-adrenal axes are usually intact and responsive in TP. It is concluded that, the remarkable increase in ACTH concentration before operation may be due to a decreased adrenal reserve. Thus, the possibility of primary partial adrenal insufficiency, particularly under stress situations, should be considered in every thalassemic patient