Poster Presentation ESA-SRB-ANZBMS 2024 in conjunction with ENSA

Challenges in Diagnosis and Management: A Case of Cyclical Cushing’s Syndrome (#612)

Mitchell Munnings 1 , Hang DT Nguyen 1
  1. Endocrinology, Launceston General Hospital, Launceston, TAS, Australia

Background

Cyclical Cushing's syndrome, characterised by fluctuating periods of hypercortisolaemia and normal cortisol levels is challenging to diagnose, leading to increased morbidity for patients.

 

Clinical Case

A 54-year-old female was referred two years ago with a five-year history of fluctuating phases of hypertension, hypokalaemia, peripheral oedema, facial plethora, weight gain, insomnia, low mood, neutrophilia, and proximal myopathy. Episodes were increasing in frequency and duration. Past medical background includes hypertension, asthma, and Barrett’s oesophagus. She developed osteoporosis with a fragility fracture and depression.

 

Investigations (Table 1) confirmed ACTH-dependent hypercortisolaemia. Intravenous 4mg DST was more consistent with pituitary Cushing’s disease. MRI pituitary revealed a stable 4mm fluid locule in the posterosuperior aspect of the sella without a definite focal lesion within the pituitary gland. No high-grade avidity was detected on FDG-PET, but mildly increased avidity was noted near the head of the pancreas on 68Ga-DOTATATE PET, without a detectable pancreatic lesion on multiphase CT.

 

Three inferior petrosal sinus sampling studies performed at two sites failed to achieve biochemical bilateral cannulation simultaneously, with unilateral successful cannulations performed each time without ACTH central: peripheral gradients.

 

Due to patient’s morbidity, empirical treatment for ACTH-dependent Cushing’s was commenced with cabergoline 0.5mg twice weekly, resulting in the normalisation of biochemistry and resolution of symptoms of cortisol excess from December 2023 to date.

 

Discussion

Cyclical Cushing’s syndrome is most often due to ACTH-dependent aetiologies, predominantly ACTH-secreting pituitary adenoma (80%). One study showed a rate of 15% of patients with diagnosed Cushing’s syndrome showing evidence of cyclicity.1 Difficulties in diagnosis arise due to unpredictable phases of hypercortisolaemia, making timely sampling paramount to capture biochemical evidence of cortisol excess.

 

Conclusion

We describe a case of ACTH-dependent cyclical Cushing’s syndrome that we have yet to localise the source. Cabergoline may be useful in pituitary, ectopic, or occult Cushing’s disease.2

 

66a841c495c7a-Cyclical+Cushing's+Table+1.jpg

  1. 1. Alexandraki KI, Kaltsas GA, Isidori AM, Akker SA, Drake WM, Chew SL, et al. The prevalence and characteristic features of cyclicity and variability in Cushing’s disease. Eur J Endocrinol. 2009 Jun;160(6):1011–8
  2. 2. Ilie MD, Raverot V, Tronc F, et al. Cabergoline in severe ectopic or occult Cushing’s syndrome. Eur J Endocrinol. 2019 Jul;101(1):K1-K9