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Factsheet 7 Hormone deficiency caused by the inadequate secretion of one or more of the hormones normally secreted by the pituitary, is known as hypopituitarism. It may commonly be caused by compression of the normal pituitary tissue by an enlarging Pituitary tumour, by pituitary surgery, or Radiotherapy. If hypopituitarism is caused by tumour compression, function may be partially or fully recovered after surgery or medical therapy to reduce the size of the tumour. Pituitary surgery may cause hypopituitarism in a minority of cases and improve pituitary function in others, and deficiencies can be transient (particularly Diabetes Insipidus). Detailed post-operative endocrine assessment is therefore essential. Hypopituitarism after treatment of a pituitary tumour by radiotherapy typically develops slowly and progressively over a period of several years. 
PRESENTING SYMPTOMS Deficient hormone | Symptoms | GH (Growth hormone) | Growth retardation in children
Adults: excessive tiredness, muscle weakness, lack of drive, impaired quality of lifescores | FSH/LH
('secondary Hypogonadism) | Hypogonadism " In men: reduced facial and body hair,
low libido, impotence; in women: Amenorrhoea,
reduced libido, dyspareunia and hot flushes | TSH
('secondary thyroid deficiency) | Weight gain, decreased energy, sensitivity to cold,
constipation, dry skin | ACTH
('secondary adrenal deficiency) | Pale appearance, weight loss, low blood pressure,
dizziness, tiredness, ‘collapse’ during intercurrent illness | AVP/ADH (arginine Vasopressin
or Anti-diuretic Hormone) | Thirst , polyuria and nocturia - diabetes insipidus |
Acute hypopituitarism (e.g., pituitary Apoplexy) - sudden headache, collapse, hypothermia,hypoglycaemia and hypotension - may be a life-threatening emergency. Prompt steroid replacement is required for ACTH deficiency presenting acutely and during intercurrent illness in established ACTH deficiency. INVESTIGATIONS
Tests for hypopituitarism should be performed under the guidance of an Endocrinologist. Please see ‘Who and When to Refer’ (factsheet 15). Growth hormone GH deficiency in children will require referral to a paediatric endocrine centre. Adult GH deficiency requires specialist assessment. Gonadal function FSH, LH, Prolactin, oestradiol and Testosterone are assessed by serum levels. Testosterone in men should be measured at 9AM to avoid falsely low results due to the Circadian rhythm. In women with periods, bloods are normally performed in the follicular phase - but measurement of a Day 21 Progesterone may be used to confirm ovulation. If fertility is desired, then a different approach to hormone replacement will be needed and a full assessment of both partners will be carried out. Thyroid function In pituitary-dependent Hypothyroidism circulating thyroid hormone levels are low or low-normal but TSH can be low, normal or even slightly elevated. Laboratories must be asked for free Thyroxine (free T4) as well as TSH, and thyroid hormone replacement adjusted on the basis of free thyroxine level (many laboratories will now only provide TSH measurements routinely unless free T4 is specifically requested and discussed) Adrenal function ACTH stimulated secretion of Cortisol is assessed using the short synacthen or the insulin stress test. A basal 9:00am cortisol gives limited information but low levels (<200nmol/L) should prompt early (and <100nmol/L urgent) referral. Diabetes insipidus The diagnosis and cause is usually obvious and if so may be confirmed by measurement of basal serum and urine osmolalities but sometimes a water deprivation test is required. TREATMENT POSSIBILITIES (for full details see factsheet 12)
GH - Synthetic GH replacement is given to children. The treatment of adults with GH replacement is clinically effective for many (though not all) patients with GH deficiency. NICE has issued guidelines to identify patients in whom treatment is indicated. ACTH - Treatment is usually with Hydrocortisone (= cortisol), typically 3 times daily. Prednisolone or dexamethasone is occasionally used. Increased doses are required during acute stress including intercurrent illness or surgery. Fludrocortisone is not normally required
in pituitary deficiency. TSH - Treatment with levothyroxine. Free T4 levels must be used for monitoring since TSH levels are not informative. FSH/LH - Treatment with Oestrogen in women (and progestogen in women with a uterus). Testosterone replacement in men given intramuscularly (i.m. every 2-4 weeks or 3-monthly depot), transdermally (usually via gel), orally or by implant. For fertility, treatment with gonadotropins is required which should only be performed at a specialist centre which provides effective monitoring. AVP/ADH - Treatment with Desmopressin (DDAVP) by intranasal spray, tablets or Melts. PATIENT MANAGEMENT
Management of patients with hypopituitarism on multiple hormone-replacement therapy (which the Foundation believes) is best achieved by life-long supervision by a specialist endocrine outpatient clinic. The time interval for specialist monitoring will vary with the patient and the treatment received, but will probably be at intervals of 2-6 months immediately posttreatment, to annual or biennial in the longer term. Patients may need help with managing hydrocortisone therapy (factsheet 12). WATCHPOINTS
Urgent - refer to hospital Deterioration of vision Clear fluid dripping down the back of the throat or through the nose soon after surgery (CSF leak - factsheet 10) As emergency if unable to take increased oral steroid replacement during acute intercurrent illness (e.g., vomiting)
Non-urgent (but still very important) If the patient is on hydrocortisone, ensure that replacement therapy is increased when seriously ill or under major physical or psychological stress Watch for gradual deterioration in endogenous pituitary function and provide replacement therapy as required
QUESTIONS PATIENTS MAY ASK Will I have to take tablets in the long term?
If the pituitary tumour or treatment for it has affected the function of the normal pituitary, its function does not usually recover and will need to be replaced in the long term. Will I need regular check-ups?
Yes, but pituitary tumours are usually well controlled and, if they regrow at all, grow very slowly. Outpatient appointments are usually made 12 months to 2 years apart. Will I need regular scans?
Perhaps, but again, these too are carried out several years apart. Will I still be able to have a family?
Yes, if the reason for infertility is pituitary disease. The effects of pituitary tumours on fertility can be treated, although some treatments are not currently paid for by the NHS (factsheet 12). If I take replacement therapy, will I feel exactly the same as I did before my pituitary tumour developed?
Every patient is different, and replacement therapy remains an inexact science when compared with the intricate balance achieved in normal health, but most patients adapt very well in time and live a full, normal life. Have I inherited this, will my children get it?
In all but very exceptional circumstances there is no hereditary link.
RESOURCES FOR PATIENTS
available from The Pituitary Foundation HelpLine or our website www.pituitary.org.uk or our Endocrine Nurse HelpLine
Patient Information Booklet: Hypopituitarism and Replacement Therapy
Other information and resource links available at www.pituitary.org.uk FOR GPs 
©2011 Version 3 (To be reviewed by 2013)
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