Recently, the occurrence and potential impact of pituitary dysfunction after aSAH has gained increasing interest. Several studies have demonstrated pituitary dysfunction after SAH suggesting that pituitary dysfunction may be a contributing factor for residual symptoms after SAH. This is an observational multicentric study aimed to test the prevalence of thyroid abnormalities, other neuroendocrinological dysfunction and their influence on outcome of patients affected by aSAH.

The incidence of aneurysmal subarachnoid hemorrhage (aSAH) varies between 6 to 10/100,000 subjects per year and it is a major cause of death and disability. The mortality rate ranges from 40 to 50%, and those who do survive SAH have high rates of functional limitations that could lead to impaired quality of life, including fatigue, depression, and loss of motivation. Because aSAH affects patients in their most productive years of life, the disease has important social, and economic implications, and early prediction of long-term outcome is based on multiple factors including the primary injury secondary insults as well as neurorehabilitation interventions. Recently, the occurrence and potential impact of pituitary dysfunction after aSAH has gained increasing interest. Several studies have demonstrated pituitary dysfunction after SAH suggesting that pituitary dysfunction may be a contributing factor for residual symptoms after SAH. However, questions remain about the real prevalence and impact of such dysfunction on patients' outcome both in the acute and chronic phase after these events. In two recent metanalysis, the prevalence of total pituitary dysfunction was found with pooled frequencies of 0.31 (95% confidence interval CI: 0.22-0.43) \[Can et a.\] and 49.3.0% (95% CI 41.6%-56.9%) \[Robba et al\] during the acute phase (\< 6 months from aSAH) and decreasing in the chronic phase to 0.25 (95% CI: 0.16-0.36) \[Can et al.\] and 25.6% (95% CI 18.0%-35.1%) \[Robba et al\]. However, the authors found high heterogenicity and different results between the available literature; many differences were found in the in the choice of time of pituitary function assessment and SAH, of diagnostic criteria and units of measurement used to establish the diagnosis of hypopituitarism after SAH. Finally, it is not clear which is the hormone axis more likely to be affected after aSAH. It is believed that, among the other, the incidence of thyroid dysfunction is the most relevant, as it is associated with severe clinical impairment and symptoms. In literature, the prevalence of thyroid dysfunction after aSAH is reported from 0 to 35%.\[Karaka, Tanrivedi\]. Hypothyroidism includes a wide variety of symptoms including weakness, fatigue, depression, irritability, memory loss and decreased libido. Should these abnormalities complicate more than one third of the patients, hormone testing and eventually replacement should become "standard of care" to test. In order to define the actual incidence of these abnormalities, an observational multicentric study to test thyroid abnormalities, including TSH, fT4 (free thyroxine) and fT3 (free triiodothyronine) changes, is warranted. Secondary endpoints of such study include the prevalence of other neuroendocrinological dysfunction and their influence on the patients' outcome.