Management of hypothalamic obesity in patients with craniopharyngioma
The presence of a craniopharyngioma, and/or treatment related damage to centres in the hypothalamus that regulate energy balance often results in severe obesity and abnormal eating behaviours. This may be exacerbated by hormonal deficits from coexistent hypopituitarism.
Decreased activity of sympathoadrenal activity, deregulated parasympathetic activity, marked hyperinsulinaemia and elevated leptin disproportionate to fat mass are evident. Plasma levels of alpha-melanocyte stimulating hormone are reduced. Delayed suppression of ghrelin after food intake, and in part the hyperinsulinaemia, along with hyper-responsiveness of GLP1 release to glucose may reflect dysregulation of vagal neural circuits mediating gastro-intestinal function. Intentional and non-exercise associated physical activity decreases. Disruption of the co-ordination of circadian rhythms including the sleep wake cycle and the presence of obstructive sleep apnoea may also be contributory.
Efforts to optimise diet and levels of physical activity and pituitary hormone replacement, including the minimisation of hydrocortisone dose, adequate sex steroid replacement, and use of growth hormone and CPAP may improve overall health and well-being, but have minimal effect on weight and eating behaviour. The long acting somatostatin analogue octreotide lowers insulin levels, but does not produce significant weight loss, nor does low dose dexamphetamine, although they may help to stabilise weight. Dexamphetamine or modafinil may be helpful when daytime somnolence is problematic. Metformin improves metabolic state and may also help to ameliorate weight gain.
Bariatric surgery, in particular the Roux-en-Y gastric bypass (RYGB), has been shown to be a safe and highly effective treatment modality; an illustrative case and review of the evidence will be provided.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.