Congenital adrenal hyperplasia causes a reduction in the activity of certain enzymes responsible for the secretion of hormones by the adrenal glands. Thus, the secretion of adrenaline, cortisol, aldosterone and androgens becomes deficient. This pathology requires medical treatment to avoid potentially fatal complications. Find out what congenital adrenal hyperplasia is, its diagnosis and treatments.
Definition of Congenital Adrenal Hyperplasia (CAH)
Congenital adrenal hyperplasia is a rare endocrine disease. It is a pathology of genetic origin whose transmission is called autosomal recessive. This means that for there to be transmission to the child, both parents must carry the genetic anomaly. According to the Ministry of Health and Prevention, it affects 1 in 20,000 births in France.
The two adrenal glands are made up of two parts: on the one hand the adrenal medulla, and on the other hand, the adrenal cortex. The adrenal medulla is responsible for the secretion of adrenaline, while the adrenal cortex controls the production of cortisol (which participates in the regulation of blood sugar), aldosterone (which controls the level of hydration and salt in the body) and androgens (male sex hormones). This hormonal production of the adrenals depends on specific enzymes. Depending on the category of deficient enzymes, various types of hyperplasia are observed. The most common form of congenital adrenal hyperplasia, which represents 9 out of 10 cases according to the Adrenal Association, is that which involves a 21 hydroxylase deficiency. Other cases of congenital adrenal hyperplasia are due to 11 beta hydroxylase deficiency.
Diagnosis of congenital adrenal hyperplasia
Lyon University Hospital specifies that the diagnosis of congenital adrenal hyperplasia requires a clinical examination, a blood test, or even genotyping.
- Clinical signs: we observe an anomaly of the external genitalia in females, abundant and early hair growth in both boys and girls, accelerated bone growth, dehydration, nausea, vomiting, lack of weight gain in newborns, fatigue.
- Blood tests: the doctor prescribes a serum dosage of 17-hydroxyprogesterone, measurement of cortisol, DHEA, testosterone and androstenedione levels. These measurements are taken before and one hour after the administration of ACTH (adrenocorticotropic hormone which stimulates the adrenal cortex): this is what we call the ACTH stimulation test.
- Genotyping: this test can be performed during pregnancy for prenatal diagnosis. This involves detecting a possible 21-hydroxylase deficiency by analyzing the CYP21 genes. The screening test is generally carried out if a family history has been observed, and if the pregnancy is therefore at risk.
Symptoms of congenital adrenal hyperplasia
Congenital adrenal hyperplasia (CAH) results in the majority of cases by a loss of salt, and therefore by signs of dehydration, hypotension, hyperkalemia (too high potassium level leading to arrhythmias, fatigue, muscle weakness, nausea and vomiting). Congenital adrenal hyperplasia also results in virilization of the external genitalia in girls (clitoral hypertrophy), in premature pubic hair growth in both sexes, and finally, in accelerated growth and maturation of bones.
Treatments for congenital adrenal hyperplasia
Treatments for congenital adrenal hyperplasia are personalized. In infants, adrenal crisis must be treated urgently. It indeed constitutes a risk for the baby’s survival, due to the hypotension and the shock it can cause. Emergency treatments for infants are therefore the administration of continuous infusion of stress doses of hydrocortisone, at a rate of 100 mg/m2/day, specifies the MSD Manual.
During growth, and in adults, maintenance treatments for congenital adrenal hyperplasia involve the prescription of corticosteroids and mineralocorticoid replacements, at a dosage regularly adjusted to growth, weight, bone maturation, blood pressure and effects of hyperandrogenism. This treatment must be taken throughout life. In addition, surgery is sometimes necessary. This is the case for girls affected by this pathology, who suffer from an enlarged clitoris: a reconstructive surgical intervention can make it possible to find normal-appearing external organs.
Sources
- Congenital adrenal hyperplasia caused by 21-hydroxylase deficiencyThe MSD Manual – Healthcare Professional Version, August 2022
- Congenital adrenal hyperplasia (HCS), Lyon University Hospital, August 31, 2021
- Congenital adrenal hyperplasiaAdrenal Association, 2014
- What you need to know about congenital adrenal hyperplasiaMinistry of Health and Prevention, April 2021
Read also :
⋙ Adrenal glands: functions and associated diseases
⋙ Adrenal insufficiency: symptoms to recognize and treatments
⋙ Adrenal gland surgery: how does it work?