?Panhypopituitarism refers to the situation in which more than 80% of the anterior pituitary is lost.
Aetiology
?neoplasms in the suprasellar region:
?pituitary adenoma in adults
?craniopharyngioma in children
?glioma
?meningioma
?metastatic cancer
?infiltration:
?sarcoid
?histiocytosis X
?haemochromatosis
?infection:
?tuberculous meningitis
?syphilis
?encephalitis
?vascular:
?Sheehan's syndrome (post-partum infarction)
?pituitary apoplexy
?carotid artery aneurysms
?autoimmune
?iatrogenic:
?surgery
?radiotherapy
?chemotherapy
?miscellaneous:
?head injury
?empty sella syndrome
?emotional deprivation
?starvation & anorexia nervosa
Clinical Features
?loss of anterior or posterior pituitary hormones
?local effects in the region of the pituitary fossa
?headache
?visual field defects:
?most commonly a superior bi-temporal quadrantanopia
?progressing to a bitemporal hemianopia
?cerebrospinal fluid rhinorrhoea d/t inferior extension of the tumour
?III, IV and VI nerve palsies due to lateral extension of the tumour
?loss of anterior pituitary hormones is usually partial and occurs in the order:
?Growth Hormone Deficiency:
?pituitary dwarfism in children - diminished skeletal growth, retarded sexual development, normal intelligence, hypoglycaemic episodes
?wrinkling of skin, tendency to hypoglycaemia in adults
?Gonadotrophin Deficiency:
?delay in puberty in children
?amenorrhoea, impotency, loss of libido in adults
?TSH Deficiency:
?isolated TSH deficiency is very rare
?secondary hypothyroidism - sensitivity to cold, dry skin, physical and mental sluggishness, coarseness of hair
?ACTH Deficiency:
?decreased skin pigmentation
?poor appetite, nausea, vomiting, fatigue, muscle weakness, loss of axillary and pubic hair in females
?Prolactin Deficiency:
?failure of lactation in post-partum patients
?Loss of posterior pituitary hormones:
?ADH Deficiency:
?polyuria, thirst
Investigations:
?basal levels of T4, T3, TSH, prolactin, gonadotrophins, testosterone, cortisol,
?U+Es (dilutional hyponatraemia),
?FBC (normochromic normocytic anaemia).
?assessment of visual fields
?skull radiology
?CXR may show signs of a primary tumour that has produced metastases, sarcoidosis or tuberculosis
?MRI/CT scan
[combined pituitary test]
?absence of the normal rises in gonadotrophins, TSH and cortisol after GnRH, TRH and insulin injection.
?a basal cortisol measurement MUST be made before undertaking a C.P.T. in patients suspected of hypopituitarism
?If cortisol is already low, insulin could be dangerous and ACTH should be measured to differentiate between primary and secondary hypocortisolaemia
?alternatives testing agents include metyrapone, glucagon or depot synacthen.
Treatment
?Sex Hormones:
?cyclical oestrogen with low-dose progesterone if uterus intact in women; if premenopausal, consider an oral oestrogen contraceptive since ovulation and conception may occur in hypopituitarism
?testosterone in men - depot or subcutaneous
?Thyroxine - 100-200 mcg daily in a single dose
?Hydrocortisone - 10-20 mg in the morning, 10 mg in late afternoon - mineralocorticoids not needed
?Growth hormone replacement therapy in adults
?Intranasal desmopressin if diabetes insipidus - 10 mcg once or twice daily
?Note that if there is combined adrenal and thyroid failure, an adrenal crisis may be precipitated by starting thyroxine replacement before corticosteroids
Follow-up
?Review should be every 6-12 months or more frequently if there is progressive pituitary damage.
Ibrahim Lodhi has sinced written about articles on various topics from Religion, Nutrition and Pets. Dr. D.S. Merchant is a Gold Medalist in (Anatomy & Histology),Fellow Nephrology Aga Khan University Hospital, Pakistan. For more articles on or. Ibrahim Lodhi's top article generates over 90500 views. to your Favourites.
