A 45-year-old male is diagnosed with Cushing’s disease. He undergoes a bilateral adrenalectomy and recovers well from the operation. On his return to the work one year later, he complains of a constant dull headache, peripheral visual disturbances and increasing pigmentation of the skin creases of both hands. The most likely diagnosis is:
A. Ectopic ACTH secreting tumourB. Prolactinoma
C. Nelson syndrome
D. Addison’s disease
E. Side effects from iatrogenic steroid intake
The answer
is. C. Nelson syndrome
Nelson syndrome occurs in patients who undergo
bilateral adrenalectomies; the loss of negative feedback over time causes a
macroadenoma to form in the pituitary which secretes adrenocorticotropin
(ACTH). A spectrum of symptoms may arise due to the effects of serum ACTH, as
well as the deficiency in other pituitary hormones. An ectopic tumour secreting
ACTH can produce similar symptoms; however they usually originate from oat cell
of small cell lung carcinomas which are associated with weight loss rather than
headaches and visual disturbances. Iatrogenic steroid side effects would cause
symptoms imitating cortisol excess such as striae, bruising, thin skin and
weight gain. A prolactinoma can cause
some of the symptoms the patient complains of, such as headache and visual
disturbances, due to impingement upon surrounding structures. However, symptoms
in males does not involve hyperpigmentation and usually include loss of libido,
impotence and gynaecomastia. Addison’s disease (D) causes similar symptoms
described in the question stem, however the cause of adrenal function loss is
due to autoimmune action or infection.
