23-year-old previously well man, with family history significant for autoimmunity, presented after unconscious collapse with a 6month history of anorexia, 3kg weight loss and lethargy. On arrival, he was alert, hypotensive with blood pressure of 60/50mmHg, tachycardic but afebrile. Examination revealed only mild hyperpigmentation in scar tissue.
Investigations suggested adrenal insufficiency with a critically low serum cortisol of 18nmol/L(68-327nmol/L), evidence of hypoaldosteronism with a sodium 120mmol/L, potassium 5.7mmol/L, elevated renin >500mIU/L(4.4-46mIU/L) and a low-normal aldosterone 102pmol/L(61-978pmol/L). Adrenal CT was unremarkable. ACTH measured 6hours after administration of 100mg intravenous hydrocortisone was low-normal at 9ng/L(7.2-63.3ng/L). He had pancytopaenia with haemoglobin of 105g/L(130-170g/L), leucocyte count of 3.1x109/L(4-10x109/L) and platelets of 103x109/L(150-410x109). Low reticulocyte count of <0.5% suggestive of bone marrow suppression. Biochemistry showed subclinical hypothyroidism (TSH 17.56mIU/L(0.27-4.2mIU/L), T4 14.8pmol/L(12-22pmol/L)). Notably, anti-TPO antibodies were negative.
He improved rapidly with intravenous rehydration and hydrocortisone. He was discharged 4days later on hydrocortisone 20mg morning, 10mg afternoon and fludrocortisone 0.1mg daily.
After 2weeks, he had clinically improved and his TSH reduced to 10.29mIU/L. His pancytopaenia normalised (haemoglobin 130g/L, leucocyte count 6.8x109/L and platelets 148x109/L) indicating a possible reactive aetiology. Autoimmune screen showed an elevated antinuclear antibody of 1:160 speckled pattern. Vitamin B12, HIV serology and Epstein-bar virus were normal. Adrenal antibodies and repeat pre-dose ACTH are pending.
Pancytopaenia is a rare complication of endocrinopathies of unclear pathophysiology. It is associated with hypopituitarism in the majority of cases and rarely with primary hypothyroidism (1,2,3,4) and primary adrenal insufficiency (2,4,6). In studies in which bone marrow aspiration was performed, they revealed bone marrow hypocellularity (1,4,7,8,9), however pancytopaenia often improves before bone marrow aspiration is performed, as was in our case. Several in vitro studies show glucocorticoids stimulation of haematopoiesis (10,11,12). In our case, pancytopaenia resolved with steroid replacement alone in a patient with adrenal insufficiency.