Addison's Disease Presenting With Idiopathic Intracranial Hypertension in a Young Female

Addison's disease presenting with idiopathic intracranial hypertension (IIH) is rare but well reported in the literature. IIH has also been reported to occur with other endocrine conditions. We explore some interesting diagnostic and management challenges of a young female that presented with IIH and Addison's disease. We discuss the features of this unifying neuroendocrine diagnosis.  A previously well 17-year-old female presented to the Emergency Department after a syncopal episode. She had been suffering from worsening and increasing headaches over the last eight months, with vomiting once or twice per day. She had papilledema and reduced visual fields bilaterally. CT head and venogram were normal. Lumbar puncture (LP) opening pressure was raised. She was noted to be hypotensive and hyponatremic. Investigations for hyponatremia revealed random cortisol of <28 nmol/L. She was treated for adrenal crisis. Further investigations were performed and she was diagnosed with IIH associated with Addison's disease.  Addison's disease should always be considered in a patient presenting with IIH and hyponatremia. While the mechanism for this association is not completely clear, treating the underlying adrenal insufficiency with steroid replacement alone is an effective treatment and provides symptomatic relief.