An 80-year-old woman presented with a 5-week history of increasing confusion. Examination was remarkable only for deficits in short-term memory and paranoid thoughts. Blood tests revealed hyponatraemia, and further biochemical testing was consistent with syndrome of inappropriate antidiuretic hormone (SIADH). After an exhaustive diagnostic workup for causes of SIADH, the only abnormal finding was a mildly raised antivoltage-gated potassium channel (VGKC) titre of 185 pmol/L (0–69) consistent with possible anti-VGKC autoimmune limbic encephalitis. However, other diagnostic features were absent. She is currently undergoing outpatient investigation for other causes of memory loss.
- pituitary disorders
- memory disorders
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Contributors NB is an FY2 doctor at the Manchester Royal Infirmary who was the junior doctor looking after the patient during her inpatient admission. He researched the topic and prepared this manuscript. HH is a consultant geriatrician at the Manchester Royal Infirmary. He was the consultant looking after this patient and made the initial diagnosis of anti-VGCK encephalitis. He reviewed the manuscript and provided feedback with suggestions for improvement which have been incorporated into the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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