The patient may eat and drink freely. An indwelling cannula is inserted before testing, and medications can be taken as usual.
Serum GH and plasma glucose are recorded at 08.30, 11.00, 13.00, 17.00, and 19.00 h.
In normal subjects, the serum GH is usually <0.5 mU/L (0.2 ng/mL) on at least two occasions. In acromegaly, all values are measurable with loss of pulsatility.
HYDROCORTISONE DAY CURVE Indications
Establishment of the correct dose of hydrocortisone replacement in hypopi-tuitary or hypoadrenal patients.
The morning dose of hydrocortisone is omitted, and the patient presents fasting from midnight at 08.00 h. An iv cannula is inserted and the first dose of hydrocortisone is taken after the initial sample.
Serum cortisol at time 0, followed by morning dose of hydrocortisone, sampling at 30 and 60 min. Breakfast is then taken, followed by sampling at 2, 3, and 5 h. Lunchtime hydrocortisone is taken, followed by sampling at 7 and 9 h. Evening hydrocortisone is then given, with further samples obtained at 9.5, 10, and 11 h.
The aim is to have adequate circulating cortisol throughout the day, avoiding excessive peaks after each dose. Usually the basal sample indicates a value <50 nmol/L (1.8 ^g/dL).
Note: Estrogen should be discontinued for at least 4 wk before the test.
METYRAPONE SENSITIVITY TEST Procedure
A 750-mg tablet of metyrapone is given to the nonfasting patient at 09.00 h.
The nadir value of serum cortisol after a single dose of metyrapone gives some indication of the regular therapeutic dose required.
First-line drug: Hydrocortisone—usually given 2 or 3 times/d. Monitoring: Hydrocortisone day curve.
Note: The morning dose must be taken on waking, ideally before leaving bed. The evening dose should be taken before 19.00 h. Extra replacement may be necessary during periods of illness/stress. All patients should carry a steroid card and a Medic-Alert pendant/bracelet. An emergency pack, with a parenteral supply (with instructions), should be supplied. Alternative Drugs: Dexamethasone, Prednisolone, Cortisone acetate.
Mineralocorticoid Replacement (for Adrenalectomy)
Fludrocortisone—usually taken once or twice daily.
Monitoring: Plasma renin activity, aiming for neither marked elevation nor full suppression.
THYROID AXIS First-line drug: Thyroxine (T4)
Monitoring: Serum FT4. Serum SHBG may useful if hyperthyroidism is suspected.
Alternative drug: Liothyronine (T3)
Monitoring: T4 (T3 can be used to assess overtreatment).
GONADAL AXIS Male
Lifelong testosterone replacement is indicated unless there is a specific contraindication (e.g., prostate cancer).
Primoteston depot (testosterone enanthate) Testosterone undecanoate (under trial) Oral
Testosterone undecanoate Topical
Transdermal preparations Andropatch/Androderm Implant
Newer preparations Androgel (topical) Buccal testosterone Long-acting (3 mo) depot injections
Clinical assessment, potency, nadir (trough) testosterone concentraton for intramuscular preparations, steady-state concentration for other forms. Dihydrotestosterone should be measured for those taking oral preparations.
Fertility Induction in the Patient with Hypopituitarism
A combination of Pergonal hMG and hCG are traditionally used with self-administered multiple injections. Recombinant FSH/ LH are now available. Consider using LHRH pump.
Estrogen replacement should be continued on average to at least the age of 50 yr, provided there is no contraindication. Consideration should be given to an extension of treatment at this time based on patient wishes, symptoms, and generated data relating to bone mineral health, lipid status, and breast cancer risk.
Note: In women with a uterus, estrogen replacement should be combined with progestogen to ensure menstruation.
Clinical response and menstruation, in those taking estradiol by mouth or implant. Serum estradiol is a useful measure in those taking estradiol valerate.
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