Neuroendocrine dysfunction following traumatic brain injury (TBI) is frequently missed due to the absence of major symptoms and very often, no appropriate management is prescribed, thus delaying the patient recovery. This study is aimed to determine the frequency and pattern of anterior pituitary dysfunction following TBI.

From June to December 2009, overaperiod of seven months, a total of 156 cases were admitted to a trauma center following TBI. Of the seventy patients, (61 males and 9 females mean age 30 years) included in the study, 39 patients had moderate (GCS; 9 – 12) and 31 cases had severe (GCS < 8) TBI. Patients were tested 6 months after injury for possible secretory abnormalities of anterior pituitary hormones. Anterior pituitary secretary function was assessed by measurement of serum levels of FT4, TSH, basal GH, IGF-1, 8 am Cortisol, FSH, LH, total testosterone and prolactin. Dynamic tests of ACTH and glucagon stimulation were used to evaluate the pituitary-adrenal axis and GH secretory status.

Forty-one patients (58.6%) were found to be suffereding from at least one hormonal secretory abnormality, with patterns and frequencies of: Gonadotropins (LH, FSH), 12.9%, corticotropin (ACTH), 12.9%, somatotropin (GH), 4.3%, and prolactin (PRL), 1.4%. There was no case with thyrotropin deficiency. Hyperprolactinemia was found to be present in 23 cases (31.5%).

The results of this study showed that anterior pituitary hormone deficiencies occur frequently, 6 months following traumatic brain injury. The two most commonly involved axes were the pituitary-gonadal and the pituitary-adrenal. Hypocortisolism may be particularly harmful for the patient's health.

Etiologic diagnosis of cushing’s syndrome is a major challenge in its investigation and treatment. Classical oral HDDST has shown differing sensitivity and specificity in various studies. The IV DEX suppression test with elimination of intestinal absorption factor has been in use since 1973. This study was designed to evaluate the diagnostic power of IV the DEX test in comparison with classic oral HDDST.

Two hundred and seven consecutively referring patients with Cushing’s syndrome diagnosed by screening and LDDST were enrolled. Two days oral HDDST and 7h-h DEX infusion test were performed in all cases. In the infusion test, decrease in serum cortisol to less than 50% of basal level was consistent with a positive response. In the classic oral test suppression of UFC ≥ 50 % and 90% of basal levels assumed as positive response. Etiologic diagnosis was confirmed by imaging and pathologic specimens.

Mean age of patients with ectopic ACTH (EAS) was (58.2±12.6 vs 31.0±10.0) which was higher than athat of pituitary and adrenal cases (p<0.01). Weight loss, weakness and ecchymosis and hypertension were more prevalent in EAS (p<0.05). Positive response to infusion test was detected in 98% of Cushing’s disease cases and no false positive response was detected in EAS and adrenal cases however oral HDDST (90% cutoff level) had 8.1% false positive. In differential diagnosis of pituitary versus non-pituitary tumors, IV DEX test had sensitivity of 98.1%, specificity of 100% and accuracy of 98.5 compared with classic oral which had sensitivity of 98.1, specificity of 93% and accuracy of 97%. ROC curve showed AUC of 0.99 in infusion test versus 0.96 in the classic oral HDDST with 90% suppression.

In the present study, IV DEX test with its increased rapidity and higher accuracy as well as higher specificity, in comparison the classic oral HDDST, can be a better diagnostic choice in the differential diagnosis of Cushing’s syndrome.