Endocrine Abstracts

Encephalocoeles are congenital defects in the skull through which meninges and brain tissues herniate. Basal encephalocoeles represent 1.5% of all encephalocoeles and are found in 1:35,000 live births. Transphenoidal basal encephaloceles are very rare, representing only 5% of all basal encephaloceles. The pituitary and surrounding structures are drawn into the encephalocele with visual and hormonal disturbances being recorded in the few cases described.

A 28-year-old man presented with an 18-month history of progressively worsening fatigue, thirst, polydipsia and polyuria. At 4 years of age craniofacial abnormalities had been recorded including hypertelorism, bilateral strabismi, tight labial fraenium, maxillary and nasal hypoplasia.

At 14 years of age he was investigated for short stature and an impaired growth hormone response to clonidine recorded but not followed up. Hair growth was sparse with shaving at 6 weekly intervals but erectile problems were denied.

Examination revealed features of hypopituitarism with a height of 170 centimetres, sparse facial, axillary and pubic hair. Testicular volume was 10 millilitres bilaterally. Optic discs were normal but visual fields grossly abnormal.

Investigations:

Urine volume 7-8 litres per day, fT4 7.8 picomoles per litre, TSH 1.53 milliunits per litre, cortisol (random) 98 nanomoles per litre, prolactin 407 micro International units per millilitre, FSH 1.6 units per litre, LH 1.9 units per litre, testosterone 2.7 nanomoles per litre and IGF-1 7.6 nanomoles per litre.

Short Synacthen test (cortisol levels) 09:00 hours pre-stimulation 163, 09:30 hours 330 and 10:00 hours 417 nanomoles per litre.

MRI scanning revealed a transphenoidal encephalocoele which herniated through the sphenoid sinus and into the nasopharynx. . The encephalocoele was in continuity with the third ventricle. The optic chiasm, pituitary stalk and pituitary gland could not be convincingly identified.

Treatment was with standard pituitary replacement. No neurosurgical intervention is planned at present.