Unusual presentation of acute psychosis in a child

This is the authors' abstract. We don't add key points for this paper.

Background: Psychosis is often solely described as a psychiatric presentation; however, it is vital that organic causes are eliminated, especially in children. Case presentation: We report the case of a 14-year-old girl who presented a 2-month history of self-neglect, poor school performance, and a week history of mutism. At initial presentation, her neurological examination was normal except for expressive aphasia, and occasional inappropriate laughing. First-line investigations showed low vitamin B12 and folate and normal magnetic resonance imaging. She was planned for follow up with psychiatrists. She presented about a week later with worsening symptoms. She had further investigations which revealed high homocysteine, in keeping with homocysteine remethylation disorder. She was started on betaine therapy after which she had a significant improvement in her symptoms. Conclusion: This case emphasizes the importance of thorough investigations of children with acute psychosis before making an assumption of a psychiatric cause, as reversible causes have better outcomes.