Abstracts

Rationale: Up to 15% of individuals with Cushing Syndrome may experience cycling of their cortisol levels and thus their symptomatology. Without confirmation of the hormonal shifts, diagnosis may be elusive. We report a case of Cyclic Cushing Syndrome in an older male with well controlled epilepsy.

Methods: This is a case study.

Results: A 73-yr-old retired counseling psychologist has well controlled epilepsy, treated with phenytoin monotherapy for many years. His seizures consist of a psychedelic vision with lightheadedness and dizziness prior to loss of awareness. In late 2016, he began having early morning episodes of substernal chest pain, gastric unease and heat followed by cold sweat, lasting 5 seconds without loss of awareness, distinct from his usual seizures. Cardiac evaluation was negative and prolonged EEG revealed hypersomnolence and snoring. Sleep study revealed mild OSA and his anticonvulsant regimen was adjusted empirically. CPAP seemed to reduce the intensity, but not the frequency of the events. By 2019, the events repeated every 18-20 days. He was started on canagliflozin for hyperglycemia; ongoing glucose monitoring showed no hypo- or hyperglycemia on event days so it was stopped. Midnight salivary cortisol, urinary free cortisol and ACTH were elevated only on event days, resulting in the diagnosis of cyclical Cushing Syndrome (CCS). DOTATATE scan showed no ectopic source of cortisol, but there was evidence of thyroid nodule, which was subsequently biopsied and was negative for malignancy. MRI of the pituitary was unremarkable.

Conclusions: Challenges to the diagnosis of CCS include the need to measure both peaks and troughs in cortisol production and the symptoms mimic other common conditions (medication adverse effects, diabetes, depression, etc.). Our patient also lacked the typical clinical signs of hypercortisolism. Enzyme inducing anticonvulsants and other medications may interfere with dexamethasone suppression testing, which was not performed in this case.

Cyclic Cushing Syndrome is underrecognized and may be a physiological mimic for epileptic seizures which requires careful investigation.

Funding: Please list any funding that was received in support of this abstract.: none.