ESPE Abstracts

Background: Wernicke Encephalopathy (WE) is an acute life-threatening neuropsychiatric disorder caused by vitamin B1 (thiamine) deficiency. Although commonly associated with alcohol abuse in adults, it can also arise from non-alcoholic causes. WE is rarer in children. To our knowledge, WE has never been described in patients with extreme insatiable hunger due to genetic obesity, which seems paradoxical. We present a case of WE due to acute avoidance, restrictive food intake and malnutrition in an adolescent with genetic obesity caused by MC4R deficiency.

Case: A 16-year-old girl was admitted for diagnostic work-up after presenting at the emergency department with diplopia, headache and unstable gait. She was confused and neurological examination showed vertical nystagmus with evident bilateral Abducens nerve palsy and ataxic gait. The medical history of the patient included early-onset severe obesity due to extreme and insatiable hunger (hyperphagia) caused by MC4R deficiency, additionally she was known with mild central hypothyroidism e.c.i. and signs of autism. Two month prior, the patient developed acute avoidance and restrictive intake of food after an episode of gastric pain and fear of vomiting, resulting in 25 kg weight loss. Brain MRI showed lesions in the medial thalamus, typical for WE, leading to prompt diagnosis and treatment with daily intravenous thiamine. A low vitamine B1 value (45 nmol/L) was later demonstrated. Over the course of a few days, the neurological symptoms vastly improved. Her eating pattern gradually normalized.

Discussion: WE in children has been described before, in conditions such as Avoidant Restrictive Food Intake Disorder (ARFID) or anorexia nervosa. Our patient also fulfilled the DSM-V criteria for ARFID. What is striking, is that this patient is known with hyperphagia, due to MC4R dysfunction, causing extreme hunger and obesity from early life onwards. During the restrictive eating episode, the patient kept experiencing hunger feelings, however, she explained that her fears overpowered her hunger. Further research into the pathways of fear and hunger could enhance our understanding of the pathophysiology of hyperphagia and potentially lead to new therapeutic targets for MC4R deficiency.

Conclusion: ARFID and hyperphagia can co-exist, even though it appears contradictory. This case demonstrates that even patients with hyperphagia due to genetic obesity can present with ARFID and are at risk for malnutrition. Additionally it highlights the importance of including WE in the differential diagnosis in patients with ARFID, extreme weight loss and neurological symptoms. Prompt thiamine treatment is crucial when WE is suspected.