Hypopituitarism

• Hypothalamus
  • Kallman’s syndrome
  • Tumour
  • Inflammation
  • Infection
  • Ischaemia
• Pituitary stalk
  • Trauma
  • Surgery
  • Mass lesion
  • Meningioma
  • Carotid artery aneurysm
• Pituitary
  • Tumour
  • Irradiation
  • Inflammation
  • Infiltration e.g.haemochromatosis, amyloidosis, metastatic carcinoma
  • Ischaemia e.g. pituitary apoplexy

Features

• Due to both reduced levels or hormones and the actual cause of the hypopituitarism
• Hormones
  • GH lack – central obesity, atherosclerosis, dry wrinkly skin, reduced strength, reduced balance, reduced CO, low glucose and osteoporosis
  • Gonadotrophin lack – oligo or amenorrhoea, reduced libido and fertility, osteoporosis, breast atrophy, erectile dysfunction, hypogonadism
  • Thyroid hormone lack – as for hypothyroidism
  • Corticotrophin lack – as for adrenal insufficiency (NB no skin pigmentation)
  • Prolactin lack – rare, failure to lactate
• Cause;
  • Pituitary tumour causing mass effect or hormone secretion with reduced secretion of other hormones e.g. prolactinoma, acromegaly

Tests

• Basal LH, FSH, testosterone, oestradial, TSH, T4, prolactin (may be high due to loss of dopamine which inhibits secretion), IGF-1, cortisl=ol
• Also U&Es (Na may be low due to dilution) and low Hb (normocytic normochromic anaemia)

Dynamic tests;

• Short synacthen test
• Insulin tolerance test
  • Assesses the adrenal and GH axis
  • CI – epilepsy, heart disease, adrenal failure
  • Give IV insulin to induce hypoglycaemia, causing stress to induce cortisol and GH
  • Have 50% glucose and hydrocortisone and hand to give IV
  • Glucose must fall below 2.2mmol/L and the patient must become symptomatic
• Arginine and GH releasing hormone test
• Glucagons stimulation test
• Investigate cause by MRI to look for pituitary or hypothalamic cause

Treatment

• Involves hormone replacement and treatment of underlying cause
• Hydrocortisone for secondary adrenal failure
• Thyroxine if hypothyroid
• If hypogonadal give testosterone enanthate or oestrogen (OCP exceeds replacement requirements). Gonadotrohin therapy is needed to induce fertility in men and women
• Somatrophin in GH deficiency