Thermal pleasantness and temperature regulation in man

Thermoregulation and fever are primarily mediated through the hypothalamus and its effector mechanisms. In persons with complete spinal cord injuries above T-6, thermoregulation is substantially impaired because of the interruption of neuronal pathways to and from the hypothalamus. These same pathways are important in the production of fever in response to infections, and injury to these pathways in patients with high-level spinal cord injuries should diminish their ability to mount a febrile response. In clinical practice, however, measurements of body temperature are used to make decisions in patients with spinal cord injuries in a manner similar to that in patients without spinal cord injuries. In this article, we review the literature on thermoregulation and fever in normal persons and in those with complete spinal cord injuries and propose possible mechanisms for fever in persons with high-level spinal cord injuries

https://www.mayoclinicproceedings.org/article/S0025-6196(12)60394-2/pdf

Thermoregulation and Fever in Normal Persons and in Those With Spinal Cord Injuries

Twelve subjects with spinal cord injuries and four controls (all male) were exposed to heat while sitting at rest or working at each of three environmental temperatures, 30, 35 and 40 degrees C, with a relative humidity of 50%. Exercise was accomplished at a load of 50 W on a friction-braked cycle ergometer which was armcranked or pedalled. Functional electrical stimulation of the legs was provided to the subjects with quadriplegia and paraplegia to allow them to pedal a cycle ergometer. The data showed that individuals with quadriplegia had the poorest tolerance for heat. As an example, in this group, accomplishing armcrank ergometry while working at an environmental temperature of 40 degrees C resulted in an increase in aural temperature of 2 degrees C in 30 min. The aural temperature of individuals with paraplegia working for the same length of time under the same conditions rose approximately 1 degree C. There was virtually no change in the aural temperature in the control subjects.

Thermoregulatory stress during rest and exercise in heat in patients with a spinal cord injury.

Five patients with clinically definite multiple sclerosis are reported who presented with acute relapses associated with hypothermia. Repeated episodes of hypothermia were seen in four. Thrombocytopenia was associated with the hypothermia in four patients. Further investigation disclosed a tendency to chronic hypothermia and suggested an altered thermoregulatory set point in one patient, when MRI, endocrine, and autonomic studies failed to localise a lesion in the hypothalamus, but subsequent necropsy showed hypothalamic lesions. In such patients a predisposition to altered thermoregulation may occur due to direct involvement of the hypothalamus or from combined lesions affecting hypothalamic outflow to the brainstem and spinal cord.

https://jnnp.bmj.com/content/jnnp/61/4/369.full.pdf

Hypothermia in multiple sclerosis.

The Effect of Clinically Relevant Pressure Duration on Sacral Skin Blood Flow and Temperature in Patients After Acute Spinal Cord Injury

The thermoregulatory set point in man can be estimated by the aid of quantifying thermal alliesthesial responses. Behavioural and autonomous thermoregulation in a group of nine patients with spinal cord transection was compared against a control group of six non-disabled under various room-climate conditions. Deviation of core temperature from thermoregulatory set point was estimated using a behavioural indicator (thermal alliesthesial responses) at different intervals of the exposure time. General thermal comfort sensation was rated on a subjective thermal comfort scale. The group with spinal cord transections showed, as expected, a state of partial poikilothermia. Mean skin temperature was approximately the same in both groups, but skin temperature distribution was different in the spinal cord transection when compared against the control group. The results of thermal alliesthesial responses indicated that core temperature for those with spinal cord transections were closer to their thermoregulatory set points than in the control group. It has been concluded that under conditions beyond thermal neutrality the spinal man may possess, some time after the injury, a thermoregulatory set point which varies directly with ambient thermal conditions. This phenomenon is viewed as an adaptive thermoregulatory process following spinal cord injury.

/pdf/thermoregulatory-set-point-in-patients-with-spinal-cord-18j11u22tp.pdf

M Attia

Papers

Thermoregulatory set point in patients with spinal cord injuries (spinal man)