Related Subjects:
|Adrenal Physiology
|Addisons Disease
|Phaeochromocytoma
|Adrenal Adenomas
|Adrenal Cancer
|Cushing Syndrome
|Cushing Disease
|Congenital Adrenal hyperplasia
|Primary hyperaldosteronism (Conn's syndrome)
|ACTH
|McCune Albright syndrome
|Male Infertility
|Prolactin
|Prolactinoma
|Sheehan's syndrome
It is very important to maintain and increase steroids (at least to double) in the event of stress - infection, surgery, trauma, illness. In undiagnosed but suspected hypopituitarism in unwell patient best to give steroids and then sort out diagnosis later
About
- The anterior pituitary releases 6 hormones.
- LH/FSH/GH/TSH/ACTH and Prolactin
Causes
- Pituitary adenoma - may be non-functioning or functioning and producing a hormone e.g. Prolactinoma
- Craniopharyngioma -Tumour in a child
- Infiltration - Sarcoid, Tuberculosis, haemochromatosis
- Vascular - Sheehan's syndrome and the acute form - Pituitary apoplexy
- Meningitis, Encephalitis and syphilis
- Trauma - basal skull fracture
- Congenital - Kallmann's syndrome
- Autoimmune with Pituitary Antibodies
- Anorexia, Starvation
- Radiation damage and chemotherapy
- Kallmann's syndrome - GnRH deficiency + anosmia
- Pituitary apoplexy - sudden headache and visual loss and acutely hypopituitarism
- Empty Sella syndrome - pituitary looks empty but just placed eccentrically. Normal function.
Clinical
- ACTH - reduced cortisol, preserved mineralocorticoids compared with Addison's disease
- Prolactin - see above. Loss of ability to lactate. Raised prolactin may be seen if the pituitary stalk is compressed and there is loss of dopaminergic inhibition/
- LH, FSH infertility, Decreased sex drive, impotence, amenorrhoea
- GH - reduced growth and height before epiphyses fuse. Loss of sense of well-being and muscle bulk,
- TSH - leads to hypothyroidism
- Pressure can affect posterior pituitary - ADH - Cranial diabetes insipidus
Local effects of an expanding Pituitary structural lesion
- Headaches, Bitemporal hemianopia
- Deficiency of local hormones
- Cranial nerve palsies III,IV and VI
Investigations to Assess Pituitary Function
- Serum Prolactin and TSH and T4 and Serum cortisol at 9 am
- Serum IGF-1 and GH, Serum FSH, LH, Oestrogen, Testosterone
- Fasting blood glucose and Hba1c
- Pituitary MRI
Management: Assess and treat the cause and consider replacement therapy
- If patient unwell and you suspect acute hypopituitary then have a low threshold for IV Hydrocortisone 100 mg V 6h. Start Hydrocortisone orally 15-40 mg per day (give 2/3rds in am is ideal but patients forget so can give it all) Typically Hydrocortisone 15 mg am and 5 mg at 4 pm are given.
- Fludrocortisone and other mineralocorticoids are not usually required in hypopituitarism as there is residual adrenal mineralocorticoid activity independent of the pituitary governed by the renin-angiotensin-aldosterone axis
- Give L-thyroxine at a dose to correct T4 level (not TSH level as is usual)
- LH/FSH - Males - testosterone if no wish for fertility, Gonadotrophins if fertility wished. Testosterone via im or orally, transdermally or implant for males.
- LH/FSH - women - oestrogen-progesterone replacement therapy if no wish for fertility. Gonadotropin therapy if fertility wished. Fertility may require Pulsatile GnRH or HCG and FSH
- Growth hormone is not required in most adult patients. Growth hormones administration may be associated with an increase in malignancy