A 46-year-old woman on long-term lithium presents with confusion, ataxia and coarse tremor after gastroenteritis. Sodium is 150 mmol/L, creatinine

Question

A 46-year-old woman on long-term lithium presents with confusion, ataxia and coarse tremor after gastroenteritis. Sodium is 150 mmol/L, creatinine 196 micromol/L and urine output is 5 L/day. Lithium level is 2.1 mmol/L. What is the most likely mechanism of her hypernatraemia?

Accepted Answer

Nephrogenic diabetes insipidus from lithium toxicity

Answer

Syndrome of inappropriate antidiuretic hormone secretion

Answer

Acute glomerulonephritis causing salt retention

Answer

Psychogenic polydipsia causing water excess

Answer

Primary adrenal insufficiency

Lithium toxicity with nephrogenic diabetes insipidus — SCE Acute Medicine MCQ

A 46-year-old woman on long-term lithium presents with confusion, ataxia and coarse tremor after gastroenteritis. Sodium is 150 mmol/L, creatinine 196 micromol/L and urine output is 5 L/day. Lithium level is 2.1 mmol/L. What is the most likely mechanism of her hypernatraemia?