What is hypothermia?
In hypothermia, the core body temperature (the highest temperature in the centre of the abdomen) drops so far that normal metabolism is compromised. Body temperature varies in normal healthy people between about 37.5℃ (sometimes higher during exercise) and 35.5℃ (or even lower early in the morning when sleeping).
The body temperature is primarily regulated in the hypothalamus. Assuming that the cause of an intellectual disability is often a form of brain development disorder , it is not surprising that the mechanism for regulating temperature can be easily disturbed. In addition to brain damage, there are other known risk factors for hypothermia. These are environmental factors (cold), a slow-acting thyroid (hypothyroidism), immobility, skin diseases, infections, psychopharmaceuticals, malnutrition, dehydration, and severe liver and kidney conditions.
What are the complaints associated with hypothermia?
The effects of hypothermia depend on the extent to which temperature is lowered. Between 34°C and 35.5°C, the body itself will work to counteract the fall in body temperature. At a body temperature of less than 34°C, the basal metabolic rate slows down, the person becomes drowsy and sleepy, breathing becomes slower, the heart rate slows and the heart muscle is affected. At lower body temperatures, there is a risk of atrial and ventricular fibrillation (cardiac arrhythmias).
How common is hypothermia in the general population?
It is not easy to find data in the medical literature about rates of hypothermia. The annual incidence of accidental hypothermia is 1.1 per 100,000 in the Netherlands. 154
It results from exposure to cold inside or outside, immersion in cold water and submersion involving hypoxia (oxygen deprivation). 496
How common is hypothermia in people with intellectual disabilities?
An American study of hypothalamic dysthermia in 1100 people with intellectual disabilities showed that 3.6% had abnormal temperatures, and that 98% of those people had an IQ <30, with most of them having epilepsy, and 96% identifiable brain damage. It was also found that higher age affects circadian changes in body temperature and that it can result in lower body temperature. 155
A case control study of 266 people with severe or very severe intellectual disabilities identified hypothermia in 7.9%. The significant determinants for hypothermia were epilepsy, spasticity and the use of benzodiazepines. 156
Segers M, Diephuis J, Kesteren R van, Werken C van der. Drie patiënten met accidentele hypothermie; opwarmenop maat. NTvG 1997;141(28) :1369-1372.
Van der Ploeg GJ, Goslings JC, Walpoth BH, Bierens JJ. Accidental hypothermia: rewarming treatments, complications and outcomes from one university medical centre. Resuscitation. 2010 Nov;81(11):1550-5
Chaney RH, Olmstead CE. Hypothalamic dysthermia in persons with brain damage. Brain Injury 1994 Jul; 8 (5): 475-81.
Bruin J, Bakhtiari E, Boot E. Prevalentie en determinanten van hypothermie bij (zeer) ernstig verstandelijk gehandicapten; een geneste case controle studie. Leeronderzoek Erasmus MC 2004. www.erasmusmc.nl/avgopleiding