Why this test?
For preventive medical examination of newborn children - in order to find out whether the baby has congenital hyperplasia of the adrenal glands or any hereditary disease caused by specific gene mutations associated with a deficiency of enzymes involved in the formation of cortisol. The cause of almost 90% of cases of congenital adrenal hyperplasia are mutations of the CYP21A2 gene, which leads to a deficiency of 21-hydroxylase and the accumulation of 17-hydroxyprogesterone in the blood. To screen for congenital adrenal insufficiency before its symptoms appear or to confirm adrenal hyperplasias if symptoms of the disease are already present.
For the diagnosis of congenital hyperplasia of the adrenal glands in older children and in adults who have a milder form of «late» hyperplasia. In the case of a diagnosis of «deficiency of the enzyme 21-hydroxylase», treatment associated with suppression of the production of adrenocorticotropic hormone and replacement of deficient cortisol with glucocorticoid hormones is prescribed. At the same time, the analysis of 17-hydroxyprogesterone may be periodically necessary to monitor the effectiveness of treatment. Together with tests for other hormones - to rule out hyperplasia of the adrenal glands in patients with such symptoms as hirsutism and irregularity of the menstrual cycle. To control the condition of women suffering from polycystic ovary syndrome, infertility, and occasionally to control the condition of patients with suspected adrenal gland or ovarian cancer.
In what cases is it prescribed?
During preventive medical examination of newborns. When obtaining increased results, it is carried out again to confirm the initial result. It can be prescribed if the child has symptoms of adrenal insufficiency or disorders related to the loss of salts in the body. Symptoms of the disease may include lethargy, weakness, lack of appetite, dehydration, and low blood pressure. If congenital hyperplasia of the adrenal glands is suspected in a child (blurred genitalia, signs of masculinization, acne and early pubic hair growth). Sometimes - when a milder (late) form of congenital adrenal hyperplasia is suspected in older children or adult patients.\ For girls and women with hirsutism, menstrual irregularity, masculinization or infertility (these symptoms are very similar to the symptoms of polycystic ovary syndrome). Periodically with 21-hydroxylase enzyme deficiency (to monitor the effectiveness of treatment).
The analysis determines the amount of 17-hydroxyprogesterone (17-OPH) in the blood. 17-Hydroxyprogesterone is a precursor of cortisol and is used by the body for its production.
Cortisol is a hormone produced by the glands, it is involved in the breakdown of proteins, glucose and fats, in maintaining normal blood pressure and regulating the activity of the immune system. The formation of cortisol is stimulated by adrenocorticotropic hormone (ACTH), which is produced by the pituitary gland.
The concentration of cortisol usually fluctuates throughout the day, with a peak in the level of the hormone at 8 in the morning, followed by a decrease in the evening. In addition, the cortisol content in the blood increases with illness and stress.
The formation of cortisol requires several special enzymes. If one or more of them are lacking or their function is impaired, an abnormal amount of cortisol and its precursors is formed, due to which 17-hydroxyprogesterone accumulates in the blood.
The adrenal glands use an excessive amount of 17-hydroxyprogesterone, while producing a lot of androgens. Excess androgens, in turn, can cause masculinization, contribute to the development of male sexual characteristics not only in men, but also in women.
Therefore, the hereditary deficiency of special enzymes and, as a result, an excessive amount of androgens lead to a whole group of functional disorders in the body, known under the general name «hyperplasia of the adrenal glands».
Most often, it is caused by a lack of the enzyme 21-hydroxylase, which is the cause of the disease in 90% of cases. Hyperplasia of the adrenal glands is inherited in a mild or severe form. In more serious cases of congenital adrenal hyperplasia, a deficiency of 21-hydroxylase and an excess of androgens can lead to the fact that a female child will be born with unexpressed genitalia - this will make it difficult to determine the sex of the baby.
Boys with this disease have a normal appearance at birth, but later their sexual characteristics begin to develop prematurely. In case of girls, hirsutism is likely first in childhood and later in puberty, then irregular menstruation occurs and signs of masculinization appear.
Almost 75% of patients of both sexes, prone to 21-hydroxylase deficiency in congenital adrenal hyperplasia, produce less aldosterone - a hormone that regulates salt retention. In newborns of both sexes, this can lead to a life-threatening «salt loss crisis»: their body accumulates too much fluid and therefore a very large amount of salt is excreted in the urine. It happens that patients with these symptoms may have a low level of sodium in the blood (hyponatremia), an increased level of potassium (hyperkalemia), a decrease in aldosterone, and an increased activity of renin.
Although such a severe form is less common, the disease is often detected during a preventive medical examination of newborns. In the milder, most common form of the disease, only a partial lack of the enzyme can be observed. Sometimes this form is called late-onset, or non-classic, congenital adrenal hyperplasia - its symptoms can appear at any time in childhood, during puberty or in adults.
At the same time, they can be weakly expressed, their slow development over time is possible. And although this form of hyperplasia of the adrenal glands does not pose a threat to life, it is still dangerous due to problems with growth and development of the body, as well as abnormal puberty in children, which can cause further infertility. 75% of newborns with 21-hydroxylase deficiency caused by adrenal hyperplasia also produce less aldosterone, a hormone that regulates salt retention in cells. Loss of too much fluid and salts together with urine threatens with acute insufficiency of the function of the adrenal cortex and the so-called crisis of loss of salts.