Dementia and Homeostasis: Physiological Disruptions Across Systems

Thermoregulation Failure

• Hypothalamic dysfunction → impaired heat conservation/dissipation.
• Risk: Hypothermia (cold environments, inadequate clothing) or hyperthermia (impaired sweating, behavioral inability to cool).

Sleep-Wake Cycle Disruption

• Circadian rhythm fragmentation: Sundowning, reversed cycles, reduced REM.
• Consequences: Daytime sleepiness, nighttime agitation, accelerated cognitive decline.

Electrolyte and Fluid Imbalance

• Impaired thirst (hypodipsia) → dehydration, hypernatremia.
• SIADH or impaired water excretion → hyponatremia.
• Medication effects (diuretics, antipsychotics).

Appetite and Nutritional Dysregulation

• Hyperphagia (frontotemporal dementia) or anorexia (Alzheimer's).
• Forgetting to eat, dysphagia, sensory changes → malnutrition, weight loss.

Continence Impairment

• Cortical inhibition loss → urge incontinence, functional incontinence.
• UTI risk from incomplete emptying, hygiene challenges.

Mobility Decline

• Gait apraxia, parkinsonism, falls, deconditioning.
• Immobility → pressure injuries, contractures, pneumonia.

Clinical Integration

These homeostatic failures interact synergistically, increasing frailty, hospitalization, and mortality. Multidisciplinary care (geriatrics, nursing, PT/OT, nutrition, palliative) targets each domain to preserve function and dignity.