Hypothermia in Multiple Sclerosis: Beyond the Hypothalamus? A Case Report and Review of the Literature

Figure 2

A schematic view of the main components of the thermoregulatory pathway according to the current main model [5, 6]. It is thought that cool and warm-sensitive cutaneous thermoreceptors detect changes in skin temperature. These are relayed via parallel ascending spinal cords tracts, to the pontine lateral parabrachial nucleus (LPB) [5]. In turn, the LPB transmits these to the anterior hypothalamus [5]. Afferent information is also separately sent to the cortex (thalamocortical tract) [5]. The hypothalamus integrates these signals with sensory information from other areas like visceral thermoreceptors and osmoreceptors to generate an effector response. In physiological conditions, after an increase in cutaneous cool signals is detected by the hypothalamic median preoptic subnucleus (MnPO) of the Preoptic Area (POA), disinhibition of the efferent pathways (in red color) leads to the activation of the three main heat-maintenance/producing mechanisms [5]. The rostral ventromedial medulla, including the rostral raphe pallidus nucleus (rRPa), is considered a key supraspinal area which regulates cutaneous vasoconstriction (CVC) and brown adipose tissue (BAT) thermogenesis (sympathetic (in green color)) and shivering thermogenesis (somatic (in orange color)) [5, 6].