(108) Case-Report: Late-Onset Anorexia Nervosa complicated by Psychosis and Wernicke Encephalopathy

Abstract:
Background: 
Anorexia nervosa (AN) is an eating disorder that is most commonly diagnosed in adolescence and early adulthood (Volpe, 2016). Here, we report a rare and unusual case of late onset AN also complicated by psychosis and Wernicke Encephalopathy (WE).  

Case: 
The patient was a 54-year-old female with no history of psychotic, mood, or eating disorders who presented to the ED with confusion, weight loss, and falls. Exam findings of severe emaciation and hypotension were complemented by neuropsychiatric symptoms of paranoia, cognitive impairment, disorientation, ataxic gait, and extraocular movement abnormalities. Lab work showing malnutrition was evident, and a BMI of 12 was recorded.   

History uncovered a rapidly progressive decline over ten months. Initial signs of generalized anxiety, panic attacks, and social withdrawal escalated to excessive exercise, restricted food intake, insomnia, and psychosis. Paranoid delusions and a belief in government surveillance manifested, leading to profound social isolation. After encounters with medical and psychiatric providers, the patient received a diagnosis of bipolar disorder, but further deteriorated despite outpatient treatment with aripiprazole.

While admitted, cognitive impairment and psychosis resolved with thiamine and olanzapine, respectively. However, the patient exhibited eating disorder compensatory behaviors including exercising in stairwells and her room, extensive time in the bathroom, complaints regarding food quality and caloric intake, and frequent caffeine and laxative requests.  The patient was ultimately transferred to residential eating disorder treatment.  

Discussion:
A literature review reveals only 12 reported cases of AN with WE (Safran, 2023), and further case reports of AN complicated by both psychosis and WE are even more sparse (Altinyazar, 2010; Brigadeiro 2016). Moreover, uncomplicated late-onset AN alone has only been described sparingly in the literature, with studies suggesting late-onset presentations account for only 1% to 7.1% of all cases (Tan, 2018; Beck, 1996). This case therefore uniquely dissects an otherwise unreported presentation of AN that is of late-onset and that of which is also complicated with both psychosis and WE. 


Conclusion/Significance: 
This case underscores the imperative nature of thorough diagnostic exploration when faced with a farrago of overlapping psychiatric and neurological symptoms in an age demographic not often associated with new-onset AN.  Further, it is important to recognize this disorder’s exceedingly rare complications and presentations.  

References: 

Volpe U, et al. Eating disorders: What age at onset? Psychiatry Res 2016; 238:225-227.  

Safran, J. T., et al. Wernicke's encephalopathy in adolescents with anorexia nervosa. Psychiatry Research Case Reports 2023; 2(1):100091.  

Brigadeiro, D., et al. Wernicke-Korsakoff syndrome with psychotic symptoms in a severe case of anorexia nervosa: A case report. European Psychiatry 2016; 33(S1), S346-S346. 

Altinyazar, V., et al. Anorexia nervosa and Wernicke Korsakoff's syndrome: atypical presentation by acute psychosis. International Journal of Eating Disorders 2010; 43(8), 766-769. 

Tan, S. M., et al. Does late-onset anorexia nervosa exist? Findings from a comparative study in Singapore. Journal of Psychiatric Practice® 2018; 24(2), 97-103

Beck, D., et al. Truly late onset of eating disorders: a study of 11 cases averaging 60 years of age at presentation. International Journal of Eating Disorders 1996; 20(4), 389-395. 


Presentation Eligibility: Not previously published or presented

Diversity, Equity, and Inclusion: Historically, anorexia nervosa (AN) has been mostly described as a disorder in the SWAG stereotype, i.e. young "skinny white affluent girls", which has unfortunately, frequently precluded individuals from outside that demographic from seeking care, or from obtaining the care they require. In our case report, due to this patients age demographic and provider's biases of the stereotypical AN presentation, she did not receive an appropriate diagnosis, instead receiving infelicitous misdiagnoses resulting in multiple missed opportunities to treat her condition earlier. This case reports help elucidate these unusual, but important, presentations of AN.