Causes of Chronic Hypothermia
Chronic hypothermia can be caused by various medical conditions including endocrine disorders, neurological diseases, medication effects, and metabolic derangements, with hypothyroidism, hypopituitarism, and certain psychiatric conditions being among the most common underlying causes. 1, 2
Endocrine and Metabolic Causes
- Hypothyroidism - Decreased thyroid hormone production reduces metabolic rate and heat generation, leading to chronic inability to maintain normal body temperature 1
- Hypopituitarism - Dysfunction of the pituitary gland affects multiple hormone systems including thyroid regulation 3
- Hypoglycemia - Can impair thermoregulation and contribute to hypothermia, especially in diabetic patients 3, 4
- Diabetes mellitus - Particularly with diabetic neuropathy, can impair thermoregulatory responses and increase susceptibility to hypothermia 4
Neurological Causes
- Spinal cord injury - Disrupts autonomic nervous system function and thermoregulatory pathways 3
- Shapiro's syndrome - A rare condition characterized by spontaneous periodic hypothermia, often associated with agenesis of the corpus callosum 2
- Hypothalamic dysfunction - Damage to the brain's temperature regulation center can cause chronic hypothermia 2
- Cerebrovascular disease - Strokes or other brain injuries affecting thermoregulatory centers 1
Medication-Related Causes
- Antipsychotics - Interfere with central temperature regulation and can cause hypothermia, especially in elderly patients 5
- Sedatives and benzodiazepines - Depress central nervous system function including thermoregulation 5
- Beta-adrenergic antagonists (beta blockers) - Reduce metabolic rate and impair thermogenesis 5
- Opioids - Can impair thermoregulatory responses 1
Other Medical Conditions
- Advanced age - Reduced thermoregulatory capacity and impaired heat generation make elderly particularly vulnerable 3
- Malnutrition - Reduces metabolic rate and depletes energy reserves needed for thermogenesis 4
- Psychiatric disorders - Associated with self-neglect, poor environmental awareness, and medication effects 5
- Alcohol use disorder - Causes vasodilation and impairs judgment regarding cold exposure 3, 6
Physiological Effects and Complications
- Cardiovascular effects - Chronic hypothermia can cause bradycardia, decreased cardiac output, and increased systemic vascular resistance 3
- Respiratory effects - Decreased respiratory rate leads to carbon dioxide retention and respiratory acidosis 7
- Renal effects - Can cause cold-induced diuresis initially, followed by decreased glomerular filtration rate with prolonged hypothermia 3
- Hematological effects - Impairs platelet function and coagulation factor activity, increasing bleeding risk 3
Clinical Considerations
- Patients with chronic hypothermia often present with subtle symptoms that may be misattributed to other conditions 1
- Diagnosis requires core temperature measurement, as peripheral measurements may be misleading 6
- The presence of multiple risk factors has a synergistic effect on hypothermia risk 5
- Environmental factors like air conditioning can exacerbate hypothermia risk in vulnerable populations 5
Prevention and Management
- Identify and treat underlying medical conditions, particularly endocrine disorders 1
- Review and adjust medications that may contribute to hypothermia 5
- Implement environmental modifications to maintain appropriate ambient temperature 5
- Consider nutritional support for malnourished patients to improve metabolic function 4
Remember that chronic hypothermia differs from acute hypothermia in presentation and management approach, requiring investigation of underlying causes rather than just rewarming strategies 2.