Hypothalamic Obesity: Prologue and Promise

Hypothalamic obesity (HO) frequently occurs following damage to the medial hypothalamic region, encompassing the arcuate nucleus, the paraventricular nucleus, the ventromedial nucleus, the dorsomedial nucleus, and the dorsal hypothalamic area, which are critically involved in the regulation of satiety and energy balance through neural and humoral connections. HO is most commonly described in the context of craniopharyngioma and its treatment, but it can also occur following other suprasellar tumors, radiation, trauma, or a surgical insult to the hypothalamus. A constellation of loss of satiety and a reduction of the metabolic rate, thermogenesis, and physical activity as well as increased vagal tone and hyperinsulinism with insulin and leptin resistance results in rapid weight gain due to a decreased energy expenditure and increased energy storage in adipose cells. To date, no viable long-term solution for HO has been found, due either to the requirement of intact hypothalamic pathways or to significant side effects. Newer therapeutic modalities focused on the unique pathophysiology of this condition offer potential for successful treatment. In this review, we describe the etiology of HO as well as past/current treatment approaches in the categories of hyperinsulinism, surgical approaches, and targeting energy expenditure/anorectic drugs. We conclude by providing an overview of the clinical trials currently underway.