Endocrine Abstracts

A 17-year-old female was referred to the adult endocrine clinic with a history of primary amenorrhoea. She was short in stature with a height below the 4th centile for her age. Her BMI was 24 kg/m² with a weight below the 25th centile and there was delay in bone-age 2 years.

She had an interesting past medical history of late-onset central nocturnal hypoventilation from the age of 8 years when she presented with apnoeic episodes and weight gain. This was classified as central hypoventilation syndrome following sleep studies and was subsequently managed with nocturnal BIPAP. At this time, she was also noted to be short in stature with a delayed bone age and had a elevated prolactin of 2099 mU/l.

A series of dynamic combined pituitary function tests were subsequently undertaken, indicating significantly subdued GH responses to insulin-stimulated hypoglycaemia (peak 9.1 IU/l), with cortisol, TSH, FSH and LH indicating normal responses to stimulation.

The endocrine anomalies of hyperprolactinaemia and GH deficiency along with central hypoventilation raises the possibility of a rare clinical syndrome known as late onset central hypoventilation with hypothalamic dysfunction, (LO-CHS/HD). This rare syndrome presents with obesity, sleep disturbance associated with hypothalamic/endocrine dysfunction. The genetic basis of this condition has not so far been delineated. In view of the association of hypothalamic–pituitary dysfunction in LOHS patients, baseline pituitary function testing should be considered as part of their routine clinical monitoring of this condition, with further assessments and treatments appropriated.

Further studies are clearly needed to explore the relationship between hypothalamic function and respiratory physiology as highlighted in this presentation. This patient received cabergoline therapy that successfully reduced her hyperprolactinaemia, leading to menstruation. GH replacement is also being offered to this patient.