What is the diagnosis and treatment for Crepuscular Syndrome (also known as Sundowning Syndrome)?

From the Guidelines

Syndrome crépusculaire, also known as sundowning syndrome, is a neuropsychiatric condition that requires a comprehensive approach to manage its symptoms, focusing on establishing a consistent daily routine, creating a calm environment, and using non-pharmacological interventions as the first line of treatment. To manage this condition, several strategies can be employed:

• Establish a consistent daily routine and create a calm environment as evening approaches.
• Reduce noise, dim lights, and close curtains to minimize shadows.
• Engage the person in relaxing activities like soft music or gentle conversation.
• Avoid caffeine and large meals in the evening.
• Ensure the person's basic needs are met, including thirst, hunger, and toileting, as unmet needs can exacerbate symptoms.
• Keep a night light on to reduce disorientation if the person wakes during the night.
• Understanding that this behavior is part of the disease process and not intentional can help caregivers respond with patience and compassion. According to the American Academy of Sleep Medicine clinical practice guideline 1, non-pharmacological approaches should be prioritized, and if necessary, low-dose antipsychotics like risperidone (0.25-1mg) or quetiapine (12.5-50mg) may be prescribed for short-term use. Melatonin (2-5mg) before bedtime can help regulate sleep-wake cycles. It is essential to note that the treatment of sundowning syndrome should focus on improving the quality of life, reducing morbidity, and minimizing mortality risks associated with the condition. The provided evidence highlights the importance of a multidisciplinary approach to managing sundowning syndrome, including the use of light therapy, sleep-promoting medications, and other somatic interventions. However, the effectiveness of these interventions may vary depending on the individual patient and the specific context. Therefore, a personalized treatment plan that takes into account the patient's unique needs and circumstances is crucial for effectively managing sundowning syndrome.

From the Research

Diagnosis of Crepuscular Syndrome (Sundowning Syndrome)

• The diagnosis of sundowning syndrome is characterized by the emergence or increment of neuropsychiatric symptoms such as agitation, confusion, anxiety, and aggressiveness in late afternoon, in the evening, or at night 2.
• The syndrome is often associated with impaired circadian rhythmicity, environmental and social factors, and impaired cognition 2.
• The etiology of sundowning remains unclear, despite pathophysiological hypotheses implying an alteration of the circadian rhythm by the reach of the suprachiasmatic nucleus and the decrease in the production rate of melatonin 3.

Treatment of Crepuscular Syndrome (Sundowning Syndrome)

• Treatment options for sundowning syndrome include bright light therapy, melatonin, acetylcholinesterase inhibitors, N-methyl-d-aspartate receptor antagonists, antipsychotics, and behavioral modifications 2.
• Nonpharmacological interventions such as restriction of daytime sleep, exposure to bright lights during the day, and mild activity schedules may also be effective in managing sundowning behavior 4.
• Pharmacological approaches, including low doses of specific neuroleptics, may be used to manage sundowning behavior, but the effectiveness of these approaches has not yet been proven 3.
• Identification and treatment of any physiologic factors contributing to sundowning behavior is also an important aspect of management 4.

Differential Diagnosis

• The main differential diagnosis of sundowning syndrome is delirium 3.
• Sundowning syndrome may pose diagnostic challenges in relation to other common causes of behavioral disruptions, and a careful evaluation of the patient's symptoms and medical history is necessary to make an accurate diagnosis 5.