"Day or Night": The Sundown Syndrome and Performance of Nuclear Medicine Studies During the COVID-19 Pandemic

Author Type(s)


Document Type


Publication Date


Journal Title

Journal of Nuclear Medicine




Objectives: Sundown syndrome, or sundowning, is a state of confusion occurring in the late afternoon and continues into the night. Sundowning can cause a variety of behaviors such as confusion, anxiety, aggression, agitation, and hallucinations. Sundown syndrome commonly occurs in patients with dementia, in inpatient elderly facilities and hospitals. This project seeks to identify the effects of sundowning on nuclear medicine studies, especially during the COVID-19 pandemic.

Methods: Elderly patients with dementia can experience sundown syndrome when their daily routines are distorted. Sundowning in elderly patients can be avoided by maintaining a consistent daily schedule and routine. An appropriate schedule to prevent sundowning may include getting the patient out of bed, walking, regular meal intervals, frequent reorientations, and regular patient to staff interactions. During the COVID-19 pandemic, patient-staff interactions have been limited which alters a patient’s daily schedule, thus potentiating sundown syndrome. Elderly patients can undergo nuclear medicine studies at varying times during the day or night. The irregular timing of nuclear medicine studies can exacerbate and potentiate sundowning in elderly patients with dementia. Even prior to the pandemic, the performance of nuclear studies can be affected by sundowning, especially ones that are long and requiring the patient’s cooperation. Anxious, agitated, and disoriented patients with sundown syndrome can make the practice of nuclear medicine studies challenging and effect the potential efficacy of the study.

Results: Nuclear medicine plays an important role in the care of elderly patients. Sundown syndrome in specific patient populations may present as a challenge during nuclear medicine scans, therefore limiting the performance, diagnosis and efficacy of potential studies. We review the ways sundown syndrome occurs in the hospital during the COVID-19 pandemic, prior to the pandemic and present methods to manage these challenges.

Conclusions: Nuclear medicine provides important diagnostic information in the health of elderly patients. We discuss the implications of elderly patients with sundown syndrome and identify the challenges nuclear medicine physicians and technologists face with sundowning patients in the practice of nuclear medicine, especially during COVID-19. We explore methods to prevent sundowning to ensure the best performance of nuclear medicine studies in elderly patients. Bibliography Graff-Radford J. Sundowning: Tips for dealing with late-day confusion. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/expert-answers/sundowning/faq-20058511. Published April 23, 2019. White J. Avoid 'sundowning' in elderly hospital patients. https://www.healthcarebusinesstech.com/sundowning-elderly-patients/. Published November 18, 2020.