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Hormonal dysfunction is a known consequence of moderate and severe TBI. This study determined the incidence, time course, and clinical correlates of acute post-TBI gonadotroph and somatotroph dysfunction. Patients had daily measurement of serum LH, FSH, testosterone, estradiol, growth hormone, and IGF-1 for up to 10 days post-injury. Values below the 5th percentile of a healthy cohort were considered abnormal as were non-measurable GH values. Outcome measures were frequency and time course of hormonal suppression, injury characteristics and Glasgow Outcome Scale. The cohort consisted of 101 patients (82% males; mean age 35 years; GCS</=8 in 87%). In men, 100% had at least one low testosterone value and 93% of all values were low; in premenopausal women, 43% had at least one low estradiol value and 39% of all values were low. Non-measurable GH levels occurred in 38% of patients while low IGF-1 levels were observed in 77% of patients but tended to normalize within ten days. Multivariate analysis revealed associations of younger age with low FSH and low IGF-1, acute anemia with low IGF-1, and older age and higher BMI with low GH. Hormonal suppression was not predictive of GOS. These results indicate that within 10 days of complicated mild, moderate and severe TBI, testosterone suppression occurs in all men and estrogen suppression in over 40% of women. Transient somatotroph suppression occurs in over 75% of patients. Although this acute neuroendocrine dysfunction may not be TBI-specific, low gonadal steroids, IGF-1 and GH may be important given their putative neuroprotective functions.
PMID: 20214417 [PubMed - as supplied by publisher]