Endocrine Abstracts

Random serum cortisol levels should be carefully interpreted in the clinical setting of hypoadrenalism, when clinicians have a high index of suspicion. We describe an 81year old lady who was admitted with symptoms and signs of hypoadrenalism, though her random cortisol levels were 800nmol/l. She was admitted following a collapse at home. She also gave a history of weight loss of about 5 kgs over the previous 6 months, and complained of breathlessness. On examination she was slim and tanned. Her electrocardiograph showed sinus tachycardia. Blood pressure was 90/60mmHg with a postural drop of 20mmHg in the systolic readings. Thyroid function tests revealed a suppressed TSH of less than 0.01mu/l and raised free T4 of 37.6 pmol/l (Reference range: 10-25 pmol/l). Free T3 was 4.4pmol/l (Reference range: 2.8-6.5pmol/l). Glucose, Urea and Electrolytes on admission and four days later are shown (Table 1). Carbimazole therapy at 30mgs once daily had been commenced. A short synacthen test was done in view of her clinical signs and biochemistry results (Table 2). This suggested adrenal insufficiency.

A random cortisol, which was done on the day of admission showed a value of 817nmol/l. The serum ACTH was raised on two occasions (124 & 496 ng/l). She was commenced on treatment with Hydrocortisone 25mg daily and Fludrocortisone 50micrograms daily. Within a few days of treatment her serum electrolytes had normalised. Computed tomography scans of the adrenal glands showed small volume shrunken adrenal glands and adrenal antibody tests were negative. Blood pressure improved to 126/70mmHg with no significant postural drop. The urea and electrolytes remained within the normal reference range. Repeat synacthen tests (off treatment) were done six months after the initial presentation (Table 3).

The possibility of hypoadrenalism must be considered in patients with clinical symptoms and signs, and random cortisol measurements should be carefully interpreted.