Differential Diagnosis for Excessive Daytime Sleepiness

• Single most likely diagnosis
  • Obstructive Sleep Apnea (OSA): This condition is characterized by repeated episodes of partial or complete upper airway obstruction during sleep, leading to frequent awakenings and daytime sleepiness. It's a common cause of excessive daytime sleepiness, especially in overweight individuals.
• Other Likely diagnoses
  • Narcolepsy: A neurological disorder that affects the brain's ability to regulate sleep-wake cycles, leading to excessive daytime sleepiness, cataplexy, sleep paralysis, and hypnagogic hallucinations.
  • Insomnia: Chronic difficulty initiating or maintaining sleep, or both, despite adequate opportunities to sleep, leading to daytime fatigue and sleepiness.
  • Restless Leg Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD): Conditions that disrupt sleep due to uncomfortable sensations in the legs or involuntary movements during sleep, respectively.
  • Sleep Deprivation: Inadequate sleep duration or poor sleep quality due to various factors such as lifestyle, work schedule, or environmental factors.
• Do Not Miss diagnoses
  • Sleep-related breathing disorders other than OSA, such as central sleep apnea or hypoventilation syndrome: These conditions can lead to significant morbidity and mortality if left untreated.
  • Hypothyroidism: A condition where the thyroid gland doesn't produce enough thyroid hormones, which can cause fatigue, sleepiness, and other symptoms.
  • Anemia: A condition characterized by a decrease in red blood cells or hemoglobin, leading to fatigue, weakness, and sleepiness.
  • Medication side effects: Certain medications, such as sedatives, antidepressants, or antihistamines, can cause excessive daytime sleepiness as a side effect.
• Rare diagnoses
  • Idiopathic Hypersomnia: A rare neurological disorder characterized by excessive daytime sleepiness, prolonged nighttime sleep, and difficulty waking up from sleep.
  • Kleine-Levin Syndrome: A rare condition that causes recurring periods of excessive daytime sleepiness, often accompanied by automatic behavior, confusion, and hallucinations.
  • Prion diseases, such as Fatal Familial Insomnia: Rare, degenerative brain disorders that can cause progressive insomnia and excessive daytime sleepiness.
  • Brain tumors or cysts: Rarely, excessive daytime sleepiness can be a symptom of a brain tumor or cyst that affects the brain's sleep-wake regulatory centers.