Lethargy

A state of prolonged drowsiness, decreased mental alertness, and an unusual lack of energy, resulting in reduced physical and cognitive performance.

Causes

• Endocrine and metabolic causes

  • Hypothyroidism

  • Hyperthyroidism

  • Diabetes mellitus

  • Adrenal insufficiency

  • Electrolyte disturbances

• Hematologic causes

  • Anemia

  • Iron deficiency

  • Vitamin B12 deficiency

  • Folate deficiency

• Sleep-related causes

  • Obstructive sleep apnea

  • Chronic sleep deprivation

  • Insomnia

  • Narcolepsy

• Infections: Viral, bacterial, chronic, sepsis

• Psychiatric causes: Depression, anxiety disorders

• Neurological causes

  • Traumatic brain injury

  • Stroke

  • Neurodegenerative disorders

  • Multiple sclerosis

• Kidney failure

• Liver failure with toxin accumulation

• Cancer

• Autoimmune and inflammatory causes

• Medication and substances

  • Sedatives

  • Antidepressants

  • β-blockers

  • Alcohol

  • Opioids

  • Antihistamines

• Nutritional and systemic causes

  • Dehydration

  • Malnutrition

  • Vitamin deficiencies