Makindo Medical Notes.com

Related Subjects: |Adrenal Physiology |Cushing Syndrome |Cushing Disease

In 25% of patients the pituitary tumour may continue to grow and release the hormone ACTH after removal of adrenals (TBA). Surgical removal of both adrenal glands to treat Cushing's disease is rarely performed nowadays due to improvements in other treatment options for this condition.

About

• Pituitary tumour enlargement post total bilateral adrenalectomy (TBA)
• Seen in 5-10% of those with TBA
• TBA done for the treatment of refractory Cushing's disease
• Underlying ACTH-secreting pituitary adenoma
• Described by Don Nelson in 1958

Aetiology

• Residual tumour post pituitary surgery
• Failure to administer prophylactic neo-adjuvant pituitary radiotherapy at the time of TBA
• rapid rise in ACTH in the 1st year post TBA

Clinical

• Headache, visual disturbance, skin pigmentation
• Hyperpigmentation of skin and mucous membranes
• Bitemporal visual loss, pituitary failure and headaches
• Amenorrhoea

Investigations

• High ACTH levels are high from 450 to 8000 ng/L
• MRI may show enlarged pituitary mass which can invade the optic chiasm and cavernous sinus

Management

• Surgical removal of the pituitary adenoma is the ideal treatment; however, it is not always possible. Surgical removal requires advanced surgical approaches, including delicate procedures involving the cavernous sinus. If surgery is required, typically the best procedure is through a nasal approach.
• Radiation therapy can be effective in controlling the growth of the tumour .
• Somatostatin-analogs may help some
• Cabergoline in high doses may be tried
• Ketoconazole may be tried to block cortisol formation
• Temozolomide may improve symptoms, reduce ACTH and cause regression of tumour on MRI. This is a type of chaemotherapy used to treat primary brain tumour called glioblastoma.
• Pituitary hormone replacement may be needed

References

• Nelson's syndrome: Review