35y woman presented to haematology with normocytic anaemia and extreme fatigue. Had borderline vitamin B12, but im hydroxocobalamin did not improve Hb. A trial of iv iron was also ineffective. Bone marrow biopsy showed hypocellular bone marrow with suppressed erythropoiesis. In the absence of underlying cause, commenced prednisolone with significant improvement in Hb from 117 to 134 g/l and she felt better. Prednisolone was continued at 5 mg od. Fatigue, musculoskeletal symptoms, joint aches and paraesthesia persisted. Rheumatologist diagnosed fibromyalgia and did 0900 h cortisol, which was borderline. Short synacthen test was suboptimal (basal 143 nmol/l, 30 min: 273 nmol/l), but ACTH- 19, IGF-1- 30 nmol/l, LH-7.9 iu/l, FSH-5.7 iu/l, prolactin- 167 mu/l, TSH-1.34 mu/l, T4-11.5 pmol/l and pituitary MRI were normal. Her adrenal antibodies, renin were normal. Suboptimal SST was initially thought to be due to iatrogenic suppression by prior exogenous prednisolone. She continued Hydrocortisone alone for approximately 12 months with only partial symptomatic improvement. Anaemia persisted (Hb-107118 g/l). Despite normal IGF-1, we proceeded to insulin stress test. This demonstrated severe GH and cortisol deficiency with peak cortisol 59 nmol/l and GH 0. 09 mcg/l. Diagnosis of idiopathic partial hypopituitarism was made, and GH was commenced with dose titration to 0.4 mg a day. At six months post GH initiation, she reported significant improvement in her symptoms and her Hb has normalised to 121 g/l.
Discussion: Hypopituitarism should be considered in normocytic normochromic anaemia in the absence of an alternative explanation. IGF-1 could be normal in severe GH deficiency and if Hb is not improving with hydrocortisone alone, dynamic stress test should be performed to exclude concurrent GH deficiency as GH also affects erythropoiesis. It might take up to six months on steroids + GH to normalise anaemia.