Endocrine Abstracts

Background: Patients with isolated growth hormone deficiency (GHD) will routinely have an MRI scan of the pituitary and brain to assess pituitary size and presence of any intracranial lesions. The result may change the threshold for monitoring for further hormone deficiencies. However the test may also detect unexpected or unrelated abnormalities.

Aim: To review the incidence of normal and abnormal MRI scans in children with a diagnosis of isolated GHD.

Methods: The biochemistry and MRI reports of children with isolated GHD (peak growth hormone (GH) <7 ug/l) born in a tertiary centre between 1997 from 2017 were reviewed. All children with multiple pituitary hormone deficiencies, septo-optic-dysplasia spectrum, and those children with known malignancies were excluded. Extra-cranial abnormalities such as sinusitis and mucosal thickening were excluded.

Results: 81 children were diagnosed with isolated GHD. 71 children had MRI results available (4 pending). Of these, 38 (54%) were reported as normal and 33 (46%) abnormal. The median age of diagnosis was 5.99 years (range: 0.62 to 18.69), with a median height SDS of −3.45 (−0.33 to −8.41) at diagnosis. The median GH level was 3.25 ug/l. The rate of MRI abnormalities was similar in the group above and below the median GH level. Of those with MRI abnormalities: 12 showed a small or hypoplastic pituitary gland, 2 had a microadenoma and 1 a cyst. 9 had an abnormal infundibulum and in 6 the posterior pituitary gland was not visible. A total of 15 MRI scans showed additional cranial anomalies (Chiari malformation (CM)(n=4), arachnoid cysts (n=3), enlarged ventricles (n=1), small optic nerves (n=1), other (n=6)). 3 of the children with pituitary hypoplasia had a CM.

Conclusions: Nearly half the children with isolated GHD had an abnormal MRI scan. The most frequent abnormality is pituitary hypoplasia, followed by infundibulum and then posterior pituitary abnormalities. One fifth had additional cranial anomalies; with 4 (5.6%) having a CM. CM in GHD is an uncommon but recognised association, and patients with this condition may need additional monitoring if given growth hormone treatment.