Abstract
This case report describes interaction of trauma, endocrine disorder and infection resulting in a complex psychopathology in an 82-year-old, previously healthy lady. One month after a hip replacement, she developed fluctuating cognitive impairment and delusions, associated with hyponatraemia. Shortly afterwards, development of severe depression resulted in a prolonged psychiatric admission. During this time, she suffered recurring urinary tract infections (UTIs). Delusions and fluctuating cognition persisted. Persistent hyponatraemia prompted regular cortisol monitoring. Gradual decline was detected and primary adrenal insufficiency was confirmed with Synachten test. Starting life-long substitution treatment resulted in a normalisation of serum sodium levels, mood and cognition and disappearance of psychotic features. According to our hypothesis, psychopathology was induced by hypoadrenalism triggered by the hip replacement and perpetuated by recurrent UTIs. Although delirium-type symptoms are well known to be associated with hyponatraemia, affective disorders have been only described in one previous case report.