Submitted by Health Studies on Wed, 04/29/2009 – 19:36
Diagnosis of Hypopituitarism is based on clinical manifestations and laboratory tests. Such as pituitary hormone abnormalities and lack of hormone. Sella’s skull X-ray determination will prove the existence of tumor. High-resolution CT or MRI is the preferred tests method. When no high-resolution CT, can use multi-layered sellar radiography. angiography can be use only when the X-ray examination prompted parasellar vascular anomalies or hemangioma. For diameter> 10mm pituitary adenoma, simple and low focus tube pituitary lateral film is the preferred tests.
When suspect Hypopituitarism, the first diagnosis should examine the lack of TSH and ACTH, because these diseases may be life-threatening.
Assessment of thyroid function: radioimmunoassay can measure T4, T3 and TSH. At all levels should be reduced, due to increased TSH that primary thyroid dysfunction. TRH200 ~ 500µg synthetic intravenous injection can identify hypothalamic pituitary lesions. TSH response would typically be found in the peak 30 minutes after injection, the hypothalamus was elevated TSH delay disease.
Assessment of ACTH secretion: Some patients with adrenocortical dysfunction is in the normal range of serum cortisol, but reduced the reserve function of one or more of the ACTH-adrenal axis response to the lower stimulation test. Assessment of ACTH (and GH and PRL) reserve the the most reliable way is to insulin tolerance test, a dose of regular insulin 0.1u/kg weight, in 15 ~ 30 seconds, intravenous injection, zero (before injection of insulin), 20,30,45,60 and 90 minutes and then collecting vein Determination of cortisol and GH blood glucose levels. such as a slight decline in serum glucose less than 50% to <40mg/dl (2.22mmol / L), tests should be repeated. (Note: the test for serious full-pituitary dysfunction or elderly patients with DM and can be There are accidents of ischemic heart disease and epilepsy patients are contraindications). usually have only one of hyperhidrosis, tachycardia, nervous. If a patient complained palpitation, loss of consciousness, seizures, tests should be immediately terminated, intravenous injection of 50 % glucose.
PRL assessment: All patients with Hypopituitarism, PRL is not always suppressed. In fact, the hypothalamus of the disease as a result of the loss of dopamine inhibited PRL, PRL can be increased. Hyperprolactinemia a result, there is often accompanied by low gonadotropin and secondary sexual dysfunction.
GH Tests: adults do not advocate the GH lacking routine screening, because even found the lack of GH, customary no process, unless is short and small patient with epiphyseal closure.
GH tests in children. As a result of decreased thyroid and adrenal gland of patients, GH is usually abnormal reaction, so the provocative test must be performed after hormone replacement therapy. Insulin tolerance test can be most effectively excited about the release of GH. The danger of the smaller and less reliable that GH release test arginine (500mg/kg, intravenous drip for 30 minutes), oral L-dopa (adult 500mg, children 10mg/kg), sleep or 20 minutes after strenuous exercise. clonidine (4µg/kg oral ) GH release is another powerful agent, promising to replace insulin. sleepiness side effects and only a mild drop in blood pressure. Generally speaking, determination of GH> 10ng/ml or stimulated GH response> 5ng/ml sufficient to rule out the lack of GH . GH increase <5ng/ml or excited after <10ng/ml, the result difficult to explain.
Serum LH and FSH assessment: menopausal women who no use exogenous estrogen, in the determination of baseline assessment of these hormones on the pituitary hypofunction most helpful. Such menopausal women, usually GnH is high (> 30mIU/ml). Measuring the basis of LH and FSH on the others very little help. although lower GnH pituitary dysfunction, but with the normal LH and FSH overlap. GnRH100µg intravenous synthesis, LH and FSH response should be increased. GnRH injection after the LH peak about 30 minutes, FSH peak in 40 minutes. However, the normal response to GnRH, the low, the lack of can be found in the hypothalamus – pituitary dysfunction. LH and FSH response to GnRH increased significantly change the normal, with no exogenous GnRH help primary and primary hypothalamic pituitary disease identification.
Assessment of a variety of hormone: simultaneous determination of several pituitary hormones reserve is the most effective diagnosis of pituitary function. Insulin (regular insulin 0.1u/kg), TRH (200µg), GnRH (100µg) with 15 ~ 30 seconds with intravenous Note, 180 minutes, many times Determination of blood glucose, cortisol, GH, TSH, PRL, LH, FSH and ACTH. Another way is to use insulin alone, 120 minutes later, given to TRH and GnRH together. GHRH (1µg/kg) , CRH (1µg/kg) and TRH, GnRH should together intravenous injection.