Acute confusion secondary to steroid eye drops

We present a case of a 90-year-old woman who presented to the acute medical unit with a new onset presentation of confusion. Her abbreviated mental test on admission was 5/10. Biochemical screen including full blood count, urea and electrolytes, C reactive protein and liver function test and imaging such as chest X-ray and CT of the head were normal. The patient had recently been started on steroid eye drops for shingles. Suspension of this medication was followed by a resolution of confusion with the abbreviated mental test on discharge improving to 9/10. To the best of our knowledge, this is the first presentation of a link between steroid eye drops and acute confusion.