Congenital Adrenal Hyperplasia

Practice Essentials

The term congenital adrenal hyperplasia (CAH) encompasses a group of autosomal recessive disorders, each of which involves a deficiency of an enzyme involved in the synthesis of cortisol,^{[1, 36]} aldosterone, or both. Deficiency of 21-hydroxylase, resulting from mutations or deletions of CYP21A, is the most common form of CAH, accounting for more than 90% of cases.^[35] See the image below.

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Steroidogenic pathway for cortisol, aldosterone, and sex steroid synthesis. A mutation or deletion of any of the genes that code for enzymes involved ....

Signs and symptoms

The clinical phenotype of CAH depends on the nature and severity of the enzyme deficiency. Although the presentation varies according to chromosomal sex, the sex of a neonate with CAH is often initially unclear because of genital ambiguity.

Clinical presentation in females

• Females with severe CAH due to deficiencies of 21-hydroxylase, 11-beta-hydroxylase, or 3-beta-hydroxysteroid dehydrogenase have ambiguous genitalia at birth (classic virilizing adrenal hyperplasia); genital anomalies range from complete fusion of the labioscrotal folds and a phallic urethra to clitoromegaly, partial fusion of the labioscrotal folds, or both
• Females with mild 21-hydroxylase deficiency are identified later in childhood because of precocious pubic hair, clitoromegaly, or both, often accompanied by accelerated growth and skeletal maturation (simple virilizing adrenal hyperplasia)
• Females with still milder deficiencies of 21-hydroxylase or 3-beta-hydroxysteroid dehydrogenase activity may present in adolescence or adulthood with oligomenorrhea, hirsutism, and/or infertility (nonclassic adrenal hyperplasia)^[2]
• Females with 17-hydroxylase deficiency appear phenotypically female at birth but do not develop breasts or menstruate in adolescence; they may present with hypertension

Clinical presentation in males

• Males with 21-hydroxylase deficiency have normal genitalia
• If the defect is severe and results in salt wasting, these male neonates present at age 1-4 weeks with failure to thrive, recurrent vomiting, dehydration, hypotension, hyponatremia, hyperkalemia, and shock (classic salt-wasting adrenal hyperplasia)
• Males with less severe deficiencies of 21-hydroxylase present later in childhood with early development of pubic hair, phallic enlargement, or both, accompanied by accelerated linear growth and advancement of skeletal maturation (simple virilizing adrenal hyperplasia)
• Males with steroidogenic acute regulatory (StAR) deficiency, classic 3-beta-hydroxysteroid dehydrogenase deficiency, or 17-hydroxylase deficiency generally have ambiguous genitalia or female genitalia; they may be raised as girls and seek medical attention later in life because of hypertension or a lack of breast development

Other findings

• Patients with aldosterone deficiency of any etiology may present with dehydration, hyponatremia, and hyperkalemia, especially with the stress of illness
• Males or females with 11-hydroxylase deficiency may present in the second or third week of life with a salt-losing crisis; later in life, these patients develop hypertension, hypokalemic alkalosis, or both
• Infants with StAR deficiency (lipoid adrenal hyperplasia) usually have signs of adrenal insufficiency (eg, poor feeding, vomiting, dehydration, hypotension, hyponatremia, hyperkalemia)
• Hyperpigmentation: Occurs in patients with deficiencies of enzyme activity involved in cortisol synthesis; may be subtle and is best observed in the genitalia and areolae

See Clinical Presentation for more detail.

Diagnosis

The diagnosis of CAH depends on the demonstration of inadequate production of cortisol, aldosterone, or both in the presence of accumulation of excess concentrations of precursor hormones, as follows:

• 21-hydroxylase deficiency: High serum concentration of 17-hydroxyprogesterone (usually >1000 ng/dL) and urinary pregnanetriol (metabolite of 17-hydroxyprogesterone) in the presence of clinical features suggestive of the disease; 24-hour urinary 17-ketosteroid levels are elevated
• 11-beta-hydroxylase deficiency: Excess serum concentrations of 11-deoxycortisol and deoxycorticosterone, or an elevation in the ratio of 24-hour urinary tetrahydrocompound S (metabolite of 11-deoxycortisol) to tetrahydrocompound F (metabolite of cortisol); 24-hour urinary 17-ketosteroid levels are elevated
• 3-beta-hydroxysteroid dehydrogenase deficiency: An abnormal ratio of 17-hydroxypregnenolone to 17-hydroxyprogesterone and of dehydroepiandrosterone to androstenedione
• Salt-wasting forms of CAH: Low serum aldosterone concentrations, hyponatremia, hyperkalemia, and elevated plasma renin activity (PRA), indicating hypovolemia
• Hypertensive forms of adrenal hyperplasia (ie, 11-beta-hydroxylase deficiency and 17-alpha-hydroxylase deficiency) are associated with suppressed PRA and, often, hypokalemia
• Subtle forms of adrenal hyperplasia (as in nonclassic forms of 21-hydroxylase deficiency and nonclassic 3-beta-hydroxysteroid dehydrogenase deficiency): Synthetic corticotropin (Cortrosyn) stimulation testing demonstrates the abnormal accumulation of precursor steroids; nomograms are available for interpreting the results^[3]

Imaging studies

• CT scanning of the adrenal gland can help exclude bilateral adrenal hemorrhage in patients with signs of acute adrenal failure without ambiguous genitalia or other clues to adrenal hyperplasia^[4]
• Pelvic ultrasonography may be performed in an infant with ambiguous genitalia to demonstrate a uterus or associated renal anomalies, which are sometimes found in other conditions that may result in ambiguous genitalia (eg, mixed gonadal dysgenesis, Denys-Drash syndrome)
• Urogenitography is often helpful in defining the anatomy of the internal genitalia
• A bone-age study is useful in evaluating for advanced skeletal maturation in a child who develops precocious pubic hair, clitoromegaly, or accelerated linear growth

Other tests

• A karyotype is essential in an infant with ambiguous genitalia, to establish the chromosomal sex
• Genetic testing is essential for genetic counseling and prenatal diagnosis of adrenal hyperplasia
• Newborn screening programs for 21-hydroxylase deficiency may be lifesaving in an affected male infant who would otherwise be undetected until presentation with a salt-wasting crisis^[5]

See Workup for more detail.

Management

Newborns with ambiguous genitalia should be closely observed for symptoms and signs of salt wasting while a diagnosis is being established. Clinical clues include abnormal weight loss or lack of expected weight gain. Electrolyte abnormalities generally take from a few days to 3 weeks to appear, but in mild forms of salt-wasting adrenal hyperplasia, salt wasting may not become apparent until an illness stresses the child.

Management is as follows:

• Patients with dehydration, hyponatremia, or hyperkalemia and a possible salt-wasting form of CAH should receive an IV bolus of isotonic sodium chloride solution (20 mL/kg or 450 mL/m²) over the first hour, as needed, to restore intravascular volume and blood pressure; this may be repeated if the blood pressure remains low
• Dextrose must be administered if the patient is hypoglycemic and must be included in the rehydration fluid after the bolus dose to prevent hypoglycemia
• After samples are obtained to measure electrolyte, blood sugar, cortisol, aldosterone, and 17-hydroxyprogesterone concentrations, the patient should be treated with glucocorticoids; treatment should not be withheld while confirmatory results are awaited
• After the patient's condition is stabilized, treat all patients who have adrenal hyperplasia with long-term glucocorticoid or aldosterone replacement (or both), depending on which enzyme is involved and on whether cortisol and/or aldosterone synthesis is affected
• Patients who are sick and have signs of adrenal insufficiency should receive stress dosages of hydrocortisone (50-100 mg/m² or 1-2 mg/kg IV administered as an initial dose), followed by 50-100 mg/m²/day IV divided every 6 hours

The Endocrine Society's 2010 clinical practice guidelines note the following^[5] :

• Prenatal treatment for CAH should be regarded as experimental
• Glucocorticoid therapy should be carefully titrated to avoid Cushing syndrome
• Mineralocorticoid replacement is encouraged; in infants, mineralocorticoid replacement and sodium supplementation are encouraged
• Use of agents to delay puberty and promote growth are experimental
• Psychiatric support should be encouraged for patients with adjustment problems
• Medication should be used judiciously during pregnancy and in symptomatic patients with nonclassical CAH

Surgical care

Infants with ambiguous genitalia require surgical evaluation and, if needed, plans for corrective surgery, as follows:

• The traditional approach to the female patient with ambiguous genitalia due to adrenal hyperplasia is clitoral recession early in life followed by vaginoplasty after puberty^[6]
• Vocal groups of patients with disorders of sexual differentiation (eg, Intersex Society of North America) have challenged this approach
• Some female infants with adrenal hyperplasia have only mild virilization and may not require corrective surgery if they receive adequate medical therapy to prevent further virilization

The Endocrine Society's 2010 clinical practice guidelines note the following^[5] :

• Adrenalectomy should be avoided
• Surgical reconstruction may not be necessary during the newborn period in mildly virilized girls but may be appropriate in severely virilized girls; it should be a single stage genital repair, performed by experienced surgeons

See Treatment and Medication for more detail.

• References

Background

The term congenital adrenal hyperplasia (CAH) encompasses a group of autosomal recessive disorders, each of which involves a deficiency of an enzyme involved in the synthesis of cortisol,^[1] aldosterone, or both.

• References

Pathophysiology

The clinical manifestations of each form of congenital adrenal hyperplasia are related to the degree of cortisol deficiency and/or the degree of aldosterone deficiency. In some cases, these manifestations reflect the accumulation of precursor adrenocortical hormones. When present in supraphysiologic concentrations, these precursors lead to excess androgen production with resultant virilization, or because of mineralocorticoid properties, cause sodium retention and hypertension.

The phenotype depends on the degree or type of gene deletion or mutation and the resultant deficiency of the steroidogenic enzyme. The enzymes and corresponding genes are displayed in the image below.

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Enzymes and genes involved in adrenal steroidogenesis.

Two copies of an abnormal gene are required for disease to occur, and not all mutations and partial deletions result in disease. The phenotype can vary from clinically inapparent disease (occult or cryptic adrenal hyperplasia) to a mild form of disease that is expressed in adolescence or adulthood (nonclassic adrenal hyperplasia) to severe disease that results in adrenal insufficiency in infancy with or without virilization and salt wasting (classic adrenal hyperplasia). The most common form of adrenal hyperplasia (due to a deficiency of 21-hydroxylase activity) is clinically divided into 3 phenotypes: salt wasting, simple virilizing, and nonclassic.

CYP21A is the gene that codes for 21-hydroxylase, CYP11B1 codes for 11-beta-hydroxylase, and CYP17 codes for 17-alpha-hydroxylase. Many of the enzymes involved in cortisol and aldosterone syntheses are cytochrome P450 (CYP) proteins.

• References

Frequency

United States

The most common form of congenital adrenal hyperplasia is due to mutations or deletions of CYP21A, resulting in 21-hydroxylase deficiency. This deficiency accounts for more than 90% of adrenal hyperplasia cases. Mutations or partial deletions that affect CYP21A are common, with estimated frequencies as high as 1 in 3 individuals in selected populations (eg, Ashkenazi Jews) to 1 in 7 individuals in New York City. The estimated prevalence is 1 case per 60 individuals in the general population.

Classic adrenal hyperplasia has an overall prevalence of 1 case per 16,000 population; however, in selected populations (eg, the Yupik of Alaska), the prevalence is as high as 1 case in 400 population. Congenital adrenal hyperplasia caused by 11-beta-hydroxylase deficiency accounts for 5-8% of all congenital adrenal hyperplasia cases.

International

Congenital adrenal hyperplasia caused by 21-hydroxylase deficiency is found in all populations. 11-beta-hydroxylase deficiency is more common in persons of Moroccan or Iranian-Jewish descent.

• References

Mortality/Morbidity

The morbidity of the various forms of adrenal hyperplasia is best understood in the context of the steroidogenic pathway, shown below, used by the adrenal glands and gonads.

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Steroidogenic pathway for cortisol, aldosterone, and sex steroid synthesis. A mutation or deletion of any of the genes that code for enzymes involved ....

The clinical phenotype can be understood by analyzing the location of the enzyme deficiency, the accumulation of precursor hormones, the products of those precursors when one enzyme pathway is ineffective, and the physiologic action of those hormones (see History).

A study by Halper et al of 42 children with congenital adrenal hyperplasia reported that total body bone mineral density was lower in these youngsters than in controls (0.81 g/cm² vs 1.27 g/cm², respectively). However, no significant differences in body composition, including with regard to visceral adipose tissue and android:gynoid ratio, were found between the two groups.^[34]

A study by Yang and White indicated that in children with the salt-wasting form of 21-hydroxylase deficiency congenital adrenal hyperplasia, the risk of postdiagnostic hospitalization is greater in patients younger than 2 years (possibly resulting from a higher susceptibility to viral infections and a lower ability to cope with stress and dehydration) and those who need a greater daily dosage of fludrocortisone (perhaps because these patients are likely to have more severe disease). The study also found that children with noncommercial insurance were more likely to be hospitalized, possibly because they are more likely to experience social barriers to treatment compliance.^[7]

Severe forms of congenital adrenal hyperplasia are potentially fatal if unrecognized and untreated because of the severe cortisol and aldosterone deficiencies that result in salt wasting, hyponatremia, hyperkalemia, dehydration, and hypotension.

• References

Epidemiology

Race

Congenital adrenal hyperplasia occurs among people of all races. Congenital adrenal hyperplasia secondary to CYP21A1 mutations and deletions is particularly common among the Yupik Eskimos.

Sex

Because all forms of congenital adrenal hyperplasia are autosomal recessive disorders, both sexes are affected with equal frequency. However, because accumulated precursor hormones or associated impaired testosterone synthesis impacts sexual differentiation, the phenotypic consequences of mutations or deletions of a particular gene differ between the sexes.

Age

Classic congenital adrenal hyperplasia is generally recognized at birth or in early childhood because of ambiguous genitalia, salt wasting, or early virilization. Nonclassic adrenal hyperplasia is generally recognized at or after puberty because of oligomenorrhea or virilizing signs in females.

• References

Prognosis

With adequate medical and surgical therapy, the prognosis is good. However, problems with psychological adjustment are common and usually stem from the genital abnormality that accompanies some forms of congenital adrenal hyperplasia.

• Short stature and infertility are common.
• Gender identity in females with virilizing adrenal hyperplasia is usually female if female gender assignment is made early in life, if adequate medical and surgical support are provided, and if the family (and eventually the patient herself) is given adequate education to understand the disease.
• Females with virilizing adrenal hyperplasia may have more masculine interests.
• Females with adrenal hyperplasia have reduced fertility rates, but fertility is possible with good metabolic control.
• Early death may occur if patients are not provided with stress doses of glucocorticoid in times of illness, trauma, or surgery.

• References

Patient Education

Educate the caretakers and patients about the nature of the disease in order for them to understand the importance of replacement of the deficient adrenal cortical hormones.

Patients must also understand the need for additional glucocorticoids in times of illness and stress in order to avoid an adrenal crisis.

Patients must know the importance of IM injections of glucocorticoids and be educated in the technique of IM administration.

Useful Web sites for patients and parents include the National Adrenal Diseases Foundation and the Congenital Adrenal Hyperplasia Research Education and Support (CARES) Foundation.

• References

History

The clinical phenotype of congenital adrenal hyperplasia depends on the nature and severity of the enzyme deficiency. The most common form is 21-hydroxylase deficiency (CYP21). Approximately 50% of patients with classic congenital adrenal hyperplasia due to CYP21A mutations or deletions have salt wasting due to inadequate aldosterone synthesis. Although the information below is presented according to chromosomal sex, the sex of a neonate with congenital adrenal hyperplasia is often initially unclear because of genital ambiguity.

Clinical presentation in females

Females with severe forms of adrenal hyperplasia due to deficiencies of 21-hydroxylase, 11-beta-hydroxylase or 3-beta-hydroxysteroid dehydrogenase have ambiguous genitalia at birth due to excess adrenal androgen production in utero. This is often called classic virilizing adrenal hyperplasia.

Mild forms of 21-hydroxylase deficiency in females are identified later in childhood because of precocious pubic hair, clitoromegaly, or both, often accompanied by accelerated growth and skeletal maturation due to excess postnatal exposure to adrenal androgens. This is called simple virilizing adrenal hyperplasia.

Still milder deficiencies of 21-hydroxylase or 3-beta-hydroxysteroid dehydrogenase activity may present in adolescence or adulthood with oligomenorrhea, hirsutism, and/or infertility. This is termed nonclassic adrenal hyperplasia.^[2]

Females with 17-hydroxylase deficiency appear phenotypically female at birth but do not develop breasts or menstruate in adolescence because of inadequate estradiol production. They may present with hypertension.

Clinical presentation in males

21-hydroxylase deficiency in males is generally not identified in the neonatal period because the genitalia are normal. If the defect is severe and results in salt wasting, these male neonates present at age 1-4 weeks with failure to thrive, recurrent vomiting, dehydration, hypotension, hyponatremia, hyperkalemia, and shock (classic salt-wasting adrenal hyperplasia). Patients with less severe deficiencies of 21-hydroxylase present later in childhood because of the early development of pubic hair, phallic enlargement, or both, accompanied by accelerated linear growth and advancement of skeletal maturation (simple virilizing adrenal hyperplasia).

In male infants, the disease may be misdiagnosed as gastroenteritis or pyloric stenosis, with potentially disastrous consequences due to delayed treatment with glucocorticoids.

Males with steroidogenic acute regulatory (StAR) deficiency, classic 3-beta-hydroxysteroid dehydrogenase deficiency, or 17-hydroxylase deficiency generally have ambiguous genitalia or female genitalia because of inadequate testosterone production in the first trimester of fetal life.

Other findings

Hyponatremia, hyperkalemia, and/or hypoglycemia suggests the possibility of adrenal insufficiency.

Hypoglycemia and hypotension may, in part, be due to associated epinephrine synthesis in the adrenal medulla due to cortisol deficiency. Cortisol, perfusing the adrenal medulla from the cortex, normally stimulates phenylethanolamine N -methyltransferase, the last enzyme in epinephrine synthesis.

Children with simple virilizing 21-hydroxylase deficiency or 11-hydroxylase deficiency have early pubic hair, phallic enlargement, and accelerated linear growth and advanced skeletal maturation.

Two forms of adrenal hyperplasia (ie, 11-hydroxylase [CYP11B1] and 17-hydroxylase [CYP17] deficiency) result in hypertension due to the accumulation of supraphysiologic concentrations of deoxycorticosterone.^[8] This weak mineralocorticoid has little consequence at physiologic concentrations but causes sodium retention and hypertension at the supraphysiologic concentrations that occur in these conditions. One form of adrenal hyperplasia results in isolated aldosterone deficiency without affecting the synthesis of cortisol or sex steroids. This form is due to a defect in enzymatic activities that have variously been termed CMO I, CMO II, 18-hydroxylase, or 18-hydroxycorticosterone dehydrogenase; however, it is currently thought to represent one protein called aldosterone synthetase (CYP11B2).

A study by Carvalho determined that in 46,XX patients with CAH resulting from CYP17A1 defects, diagnostic factors include amenorrhea, absence/sparseness of pubic hair, and ovarian macrocysts (risk factors for ovarian torsion), along with the aforementioned hypertension. CYP17A1 defects are also indicated by high basal progesterone levels in patients with hypergonadotropic hypogonadism.^[9]

Other forms of adrenal hyperplasia are characterized by disordered genital development in utero, lack of secondary sexual characteristics development, or hypertension. For example, 17-hydroxylase deficiency in females is rarely identified at birth, but these females seek medical attention later in life because of hypertension or failure to develop secondary sexual characteristics at puberty due to an inability to synthesize estrogens. Male patients with this disorder have ambiguous or female genitalia and may be raised as girls and seek medical attention later in life because of hypertension or a lack of breast development.

Patients with aldosterone deficiency of any etiology may present with dehydration, hyponatremia, and hyperkalemia, especially with the stress of illness.

Male or female patients with 11-hydroxylase deficiency may present in the second or third week of life with a salt-losing crisis. However, these patients develop hypertension, hypokalemic alkalosis, or both later in life. This paradox is explained by resistance to mineralocorticoids in infancy and the inability of the elevated deoxycorticosterone levels to replace the deficient serum concentrations of aldosterone in infancy. Upon maturation, mineralocorticoid responsiveness increases, and the elevated concentrations of deoxycorticosterone are sufficient to cause sodium retention, potassium excretion, and hypertension.

Infants with StAR deficiency (lipoid adrenal hyperplasia) usually have signs of adrenal insufficiency (eg, poor feeding, vomiting, dehydration, hypotension, hyponatremia, hyperkalemia). Some patients do not receive medical attention until late infancy. Male patients with this form of adrenal hyperplasia have female or ambiguous genitalia. Female patients have normal female genitalia. A curious observation is that girls who survive develop breasts and menstruate at puberty, suggesting preservation of ovarian steroidogenesis.

• References

Physical

Physical findings depend on the nature and severity of the deficient enzyme activity. See the image below.

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Steroidogenic pathway for cortisol, aldosterone, and sex steroid synthesis. A mutation or deletion of any of the genes that code for enzymes involved ....

See the list below:

• Deficiencies of enzyme activity involved in cortisol synthesis result in elevations in concentrations of corticotropic hormone (previously adrenocorticotropic hormone [ACTH]) that often cause hyperpigmentation. This hyperpigmentation may be subtle and is best observed in the genitalia and areolae.
• In virilizing forms (ie, 21-hydroxylase deficiency, 11-beta-hydroxylase deficiency, and 3-beta-hydroxysteroid dehydrogenase deficiency), female patients have ambiguous genitalia at birth that range from complete fusion of the labioscrotal folds and a phallic urethra to clitoromegaly, partial fusion of the labioscrotal folds, or both, as shown in the images below.
• This virilization results from the abnormally high concentrations or steroidogenic precursors that are converted to potent androgens, testosterone, and dihydrotestosterone. Dihydrotestosterone is most potent in terms of virilizing the external genitalia and is synthesized from testosterone by 5-alpha reductase, an enzyme that resides in skin of genital tissue. Recently, human steroidogenic tissues have been shown to have the capability of converting precursors like progesterone and 17-OH progesterone to dihydrotestosterone through a "backdoor pathway" that does not involve testosterone in the pathway.^{[10, 11, 12]}

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  A female patient with the 46,XX karyotype with mild virilization due to congenital virilizing adrenal hyperplasia secondary to 21-hydroxylase deficien....

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  Severe virilization in a female patient with the 46,XX karyotype with congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency. This pati....

  See the list below:

  • In relatively nonsevere forms, genitalia may be normal at birth, but early pubic hair and clitoromegaly (often accompanied by tall stature) may appear in childhood.
  • In mild forms, excess facial or body hair often appears.

   

  

   
• Male patients with 21-hydroxylase deficiency have normal genitalia but may develop signs of dehydration at age 1-4 weeks if they have salt wasting or may have no problems in infancy but develop a salt-wasting crisis with illness during childhood (classic salt-wasting adrenal hyperplasia). Less-severely affected males may present with precocious development of pubic hair, phallic enlargement, and accelerated growth and skeletal maturation in childhood (simple virilizing adrenal hyperplasia).
• Ambiguous genitalia or female genitalia are also observed in male patients with 3-beta-hydroxysteroid dehydrogenase deficiency, 17-hydroxylase deficiency, and StAR deficiency.
• High blood pressure and, sometimes, hypokalemia may be observed in individuals with 11-beta-hydroxylase deficiency and 17-hydroxylase deficiency. These findings are due to the accumulation of the mineralocorticoid deoxycorticosterone.

• References

Causes

The defects that cause congenital adrenal hyperplasia are autosomal recessive disorders due to deficient activity of a protein involved in cortisol synthesis, aldosterone synthesis, or both.

• In most cases, this disorder is due to a mutation or deletion of the gene that codes for the involved protein. When both genes carry the same mutation or deletion, the condition is homozygous. When the 2 affected genes carry different mutations or deletions, the patient is said to be a compound heterozygote. In general, the clinical severity reflects the least affected allele. Carriers or heterozygotes who carry only one abnormal gene are asymptomatic.
• Many of the genes involved in cortisol and aldosterone synthesis code for CYP proteins. The best-studied gene is the 21-hydroxylase gene (CYP21, CYP21A). The 21-hydroxylase gene is located on chromosomal band 6p21.3 among genes that code for proteins that determine human leukocyte antigen (HLA) types. The gene for 21-hydroxylase has a pseudogene (CYP21P) 30 kb away from CYP21 that is 98% homologous in structure to CYP21A; however, it is rendered inactive because of minor differences in the gene. The proximity of CYP21P with CYP21A is thought to predispose the CYP21A gene to crossovers in meiosis between CYP21A and CYP21P, resulting in loss of genetic function.
• Other defects occur because of gene deletions or mutations. Among abnormalities of CYP21A, approximately 95% are thought to be due to recombinations with CYP21P, 20% are thought to represent deletions, and 70% are point mutations. The phenotype depends on the function of the less-severely affected gene rather than on the more severely affected gene because the former determines the level of enzyme activity. In general, genotype-phenotype correlations are strong, although exceptions occur. Because aldosterone secretion is approximately 1000-fold less than cortisol secretion, the enzyme activity required for aldosterone synthesis is less than that required for cortisol synthesis. Therefore, patients with only the most severe loss of function of CYP21A have salt wasting.
• The 11-beta-hydroxylase gene (CYP11B1) is on chromosomal band 8q21. CYP11B1 has no pseudogene, and no HLA association is found. CYP11B1 catalyzes the conversion of 11-deoxycortisol to cortisol in the glucocorticoid pathway and the conversion of deoxycorticosterone to corticosterone in the mineralocorticoid pathway. A neighboring gene codes for CYP11B2, or aldosterone synthetase, which catalyzes the conversion of corticosterone to aldosterone in the zona glomerulosa. Mutations and deletions of the CYP11B2 gene result in diminished aldosterone synthesis. Therefore, individuals with CYP11B2 deficiency develop hyponatremia, hyperkalemia, and dehydration. Sexual differentiation occurs normally because sex steroid synthesis and cortisol synthesis are not impaired. The genes for CYP11B1 and CYP11B2 share 95% sequence homology for coding sequences. Nonetheless, gene conversion from chromosomal crossover at meiosis does not appear to play a major role in the mutations and deletions thatrendereither gene inactive.
• Two tissue forms of 3-beta-hydroxysteroid dehydrogenase are described. Type I occurs primarily in the adrenal and gonad, whereas type II occurs primarily in the placenta and liver. The genes for both forms reside on chromosomal band 1p13. The classic form of 3-beta-hydroxysteroid dehydrogenase deficiency results from mutations or deletions in the gene for the adrenal form of the enzyme.
• Some patients appear to have nonclassic forms of this disease, as evidenced by symptoms and signs of virilization such as hirsutism, oligomenorrhea, and infertility. Laboratory studies may reveal mildly abnormal precursors-to-product ratios (ie, increased ratio of 17-hydroxypregnenolone to 17-hydroxyprogesterone and of dehydroepiandrosterone to androstenedione). These patients have not had mutations or deletions in any of the genes that code for adrenal 3-beta-hydroxysteroid dehydrogenase. The molecular basis for this disorder remains undefined. Clinical and hormonal findings of this condition and polycystic ovary disease overlap considerably. Some patients benefit from suppression of adrenal steroidogenesis with dexamethasone.
• 17-alpha-hydroxylase activity and 17,20-desmolase activities are thought to be due to a single protein (CYP17) with separate enzymatic activity sites.
• Some patients with lipoid adrenal hyperplasia, which was originally thought to be due to deficiency of CYP450 side-chain cleavage (scc) enzyme activity, have had mutations in a gene that codes for StAR. This protein appears to be involved in the transport of cholesterol across the mitochondrial membrane, where CYP450 scc can act on it. This enzyme converts cholesterol to pregnenolone, which is then processed in the various steroidogenic tissues into cortisol, aldosterone, or sex steroids. Thus, a deficiency of StAR results in a global steroid deficiency state. Affected 46 XY individuals may have female external genitalia, and affected 46 XX individuals have normal female genitalia. Both develop signs of adrenal insufficiency with onset from early infancy to age 6 months.
• A curious observation is that females with this disorder who survived as the result of early replacement of glucocorticoids and mineralocorticoid have developed breasts and spontaneous nonovulatory menses at puberty. Researchers postulate that the accumulation of cholesterol esters in steroidogenic cells, which results from StAR deficiency, is eventually toxic to the steroidogenic cells. According to this theory, some ovarian function is preserved because ovarian steroidogenesis does not occur until puberty, and then steroidogenesis occurs in only one follicle at a time, thereby allowing some preservation of steroidogenesis.
• Mutations in the gene that code for CYP oxidoreductase were recently found to cause deficiencies of several enzymes involved in steroidogenesis. CYP oxidoreductase facilitates electron transfer from nicotinamide adenine dinucleotide phosphate (NADPH) reduced form to the 21-hydroxylase and 17-hydroxylase enzymes required in steroidogenesis (Online Mendelian Inheritance in Man [OMIM] 201750 and 124015).^[13] Some individuals with these mutations have craniosynostosis and skeletal abnormalities known as the Antley-Bixler syndrome (OMIM 207410).^[14] However, mutations in the fibroblast growth factor receptor-2 can also cause the phenotypic picture of Antley-Bixler syndrome without problems in steroidogenesis.

• References

Laboratory Studies

The diagnosis of congenital adrenal hyperplasia depends on the demonstration of inadequate production of cortisol, aldosterone, or both in the presence of accumulation of excess concentrations of precursor hormones.^[36] For example, the distinguishing characteristic of 21-hydroxylase deficiency is a high serum concentration of 17-hydroxyprogesterone (usually >1000 ng/dL) and urinary pregnanetriol (metabolite of 17-hydroxyprogesterone) in the presence of clinical features suggestive of the disease (eg, salt wasting, clitoromegaly or ambiguous genitalia, precocious pubic hair, excessive growth, premature phallic enlargement in the absence of testicular enlargement, hirsutism, oligomenorrhea, female infertility).

Likewise, 11-beta-hydroxylase deficiency is indicated by excess concentrations of 11-deoxycortisol and deoxycorticosterone or by an elevation in the ratio of 24-hour urinary tetrahydrocompound S (metabolite of 11-deoxycortisol) to tetrahydrocompound F (metabolite of cortisol).

Both forms of adrenal hyperplasia are accompanied by elevated levels of 24-hour urinary 17-ketosteroids, the urinary metabolites of adrenal androgens.

3-beta-hydroxysteroid dehydrogenase deficiency is indicated by an abnormal ratio of 17-hydroxypregnenolone to 17-hydroxyprogesterone and dehydroepiandrosterone to androstenedione.

Salt-wasting forms of adrenal hyperplasia are accompanied by low serum aldosterone concentrations, hyponatremia (see Serum Sodium), hyperkalemia (see Potassium), and elevated plasma renin activity (PRA), indicating hypovolemia. In contrast, hypertensive forms of adrenal hyperplasia (ie, 11-beta-hydroxylase deficiency and 17-alpha-hydroxylase deficiency) are associated with suppressed PRA and, often, hypokalemia.

Subtle forms of adrenal hyperplasia (as in nonclassic forms of 21-hydroxylase deficiency and nonclassic 3-beta-hydroxysteroid dehydrogenase deficiency) often require a synthetic corticotropin (Cortrosyn) stimulation test to demonstrate the abnormal accumulation of precursor steroids. Nomograms are available for interpreting the results.^[3]

• References

Imaging Studies

Imaging studies of the adrenal gland are generally not useful in the evaluation of patients with suspected adrenal hyperplasia. However, CT scanning of the adrenal gland can be useful in excluding bilateral adrenal hemorrhage in patients with signs of acute adrenal failure without ambiguous genitalia or other clues of adrenal hyperplasia.^[4]

Pelvic ultrasonography may be performed in an infant with ambiguous genitalia to demonstrate a uterus or associated renal anomalies, which are sometimes found in other conditions that may result in ambiguous genitalia (eg, mixed gonadal dysgenesis, Denys-Drash syndrome).

Urogenitography is often helpful in defining the anatomy of the internal genitalia.

A bone-age study is useful in evaluating a child who develops precocious pubic hair, clitoromegaly, or accelerated linear growth. Patients who have these symptoms because of adrenal hyperplasia have advanced skeletal maturation.

• References

Other Tests

A karyotype is essential in the evaluation of an infant with ambiguous genitalia to establish the patient's chromosomal sex.

Genetic testing is rarely necessary to diagnose classic forms of adrenal hyperplasia but is essential for genetic counseling and prenatal diagnosis of adrenal hyperplasia.^[36]

Newborn screening programs for 21-hydroxylase deficiency should be encouraged as they may be lifesaving in an affected male infant who would otherwise be undetected until presentation with a salt-wasting crisis.^[5]

• References

Histologic Findings

Histologic features of congenital adrenal hyperplasia include hyperplasia of the adrenal cortex and disorganized architecture of both the adrenal cortices and medullae.

Lipoid deposits in the adrenal cortical cells characterize lipoid adrenal hyperplasia due to a deficiency of StAR. Lipoid deposits are thought to represent cholesterol esters that have accumulated from the inability of the cell to transport cholesterol into the mitochondria.

With salt wasting, hypertrophy of the juxtaglomerular apparatus of the kidney occurs due to hypovolemia stimulating enhanced renin activity.

• References

Medical Care

Infants with ambiguous genitalia should be closely observed for symptoms and signs of salt wasting while a diagnosis is being established. Clinical clues include abnormal weight loss or lack of expected weight gain. Electrolyte abnormalities generally take from a few days to 3 weeks to appear because the placenta maintains the fetal electrolytes in utero. In mild forms of salt-wasting adrenal hyperplasia, salt wasting may not become apparent until an illness stresses the child.

• Patients with dehydration, hyponatremia, or hyperkalemia and a possible salt-wasting form of adrenal hyperplasia should receive an intravenous (IV) bolus of isotonic sodium chloride solution (20 mL/kg or 450 mL/m²) over the first hour, as needed, to restore their intravascular volume and blood pressure.

  • This dosage may be repeated if the blood pressure remains low.
  • Dextrose must be administered if the patient is hypoglycemic and must be included in the rehydration fluid after the bolus dose to prevent hypoglycemia.
  • After samples are obtained to measure electrolyte, blood sugar, cortisol, aldosterone, and 17-hydroxyprogesterone concentrations, the patient should be treated with glucocorticoids based on suspected adrenal insufficiency. Treatment should not be withheld while confirmatory results are awaited because it may be life preserving (see Medication).

   

  

   
• After the patient's condition is stabilized, treat all patients who have adrenal hyperplasia with long-term glucocorticoid or aldosterone replacement (or both), depending on which enzyme is involved and on whether cortisol and/or aldosterone synthesis is affected.
• Another approach currently under investigation is the combined use of glucocorticoid (to suppress ACTH and adrenal androgen production), mineralocorticoid (to reduce angiotensin II concentrations), aromatase inhibitor (to slow skeletal maturation), and flutamide (an androgen blocker to reduce virilization).
• Some patients develop precocious puberty, which further compromises adult height. Suppression of puberty with long-acting gonadotropin-releasing hormone (GnRH) agonists while simultaneously stimulating growth with growth hormone may partially improve the patient's height.^{[15, 16]}

The Endocrine Society's 2010 clinical practice guidelines note the following:^[5]

• Prenatal treatment for CAH should be regarded as experimental.
• Glucocorticoid therapy should be carefully titrated to avoid Cushing syndrome.
• Mineralocorticoid replacement is encouraged. In infants, mineralocorticoid replacement and sodium supplementation are encouraged.
• Use of agents to delay puberty and promote growth are experimental.
• Psychiatric support should be encouraged for patients with adjustment problems.
• Medication should be used judiciously during pregnancy and in symptomatic patients with nonclassical CAH.

• References

Surgical Care

Infants with ambiguous genitalia require surgical evaluation and, if needed, plans for corrective surgery. The traditional approach to the female patient with ambiguous genitalia due to adrenal hyperplasia is clitoral recession early in life followed by vaginoplasty after puberty.^[6]

Vocal groups of patients with disorders of sexual differentiation (eg, Intersex Society of North America) have recently challenged this approach.

Some female infants with adrenal hyperplasia have only mild virilization and may not require corrective surgery if they receive adequate medical therapy to prevent further virilization.

A study by Roth et al determined that between 2004 and 2014, 12% of girls in the Pediatric Health Information System database with congenital adrenal hyperplasia were treated with female genital restoration surgery. A vaginal procedure was performed in 92% of those who underwent the surgery, a clitoral procedure in 48%, and a perineal procedure (nonclitoral) in 85%. The initial operation was carried out at a median patient age of 9.9 months. Perioperative surgical complications occurred in 4% of the operative group.^[33]

A retrospective study by Dangle et al on feminizing reconstructive surgery in 26 toddlers with congenital adrenal hyperplasia reported that the procedures are typically well tolerated and successful. Although complications were found in seven patients (27%), including dysuria, stitch dehiscence, wound separation, and urinary tract infection, revision surgery was needed in only two individuals (7.7%). The patients were followed up for an average of about 6 years.^[17]

Bilateral adrenalectomies have been suggested in the management of virilizing forms of adrenal hyperplasia in order to prevent further virilization and advancement of skeletal maturation.^[18] This approach is experimental and should be considered only in the context of a controlled study.

The Endocrine Society's 2010 clinical practice guidelines note the following:^[5]

• Adrenalectomy should be avoided.
• While surgical reconstruction may not be necessary during the newborn period in mildly virilized girls, it may be appropriate in severely virilized girls. It should be a single stage genital repair, performed by experienced surgeons.

• References

Consultations

An endocrinologist should be consulted when adrenal insufficiency is suspected.

An experienced surgeon is required if genitalia are ambiguous or inconsistent with genetic sex and corrective surgery is contemplated.

A consultation with a geneticist is useful in establishing the genetic defect causing the disorder. In parents contemplating a subsequent pregnancy, genetic counseling for prenatal diagnosis and treatment of this disorder is important.

• References

Diet

Patients with congenital adrenal hyperplasia should be on an unrestricted diet.

Patients should have ample access to salt because salt wasting is common in some forms of the disease.

Infants who have salt wasting generally benefit from supplementation with NaCl (2-4 g/d) added to their formula.

Caloric intake may need to be monitored and restricted if excess weight gain occurs because glucocorticoids stimulate appetite.

• References

Activity

Activity restriction is not necessary if appropriate glucocorticoid and mineralocorticoid therapy is provided.

• References

Complications

Complications of congenital adrenal hyperplasia are common. Too little glucocorticoid results in adrenal insufficiency and further virilization in the virilizing forms. Complications of excessive administration of glucocorticoids include growth failure, obesity, striae, hypertension, hyperglycemia, and cataracts. The complications of excess mineralocorticoid administration include hypertension and hypokalemia.

A study by Maccabee-Ryaboy et al of 180 pediatric patients indicated that children with CAH are more likely to experience hypertension than are children in the general population, with the incidence of hypertension varying according to sex and the type of CAH. In children with classic CAH, 55% of those who received fludrocortisone had hypertension, compared with 31% of those who did not.  Moreover, 58% of children with salt-wasting CAH had hypertension, compared with 35% of those with simple virilizing CAH. In 91% of salt-wasting males and 50% of salt-wasting females, hypertension developed prior to age 5 years, while hypertension usually occurred between the ages of 10 and 18 years in children with simple virilizing CAH. Higher hypertension rates were seen in children in whom at least three measurements of 17-hydroxyprogesterone were below 400 ng/dL, with the difference being significant in salt-wasting males.^[19]

Short stature is a frequent complication of virilizing forms of congenital adrenal hyperplasia (see the image below). In general, patients have final heights 1-2 standard deviations below their estimated genetic potential.^[20] This difference results from exposure to excessive concentrations of adrenal androgens that cause rapid skeletal maturation or from excessive exposure to glucocorticoids that limit growth. Early central puberty is often observed in children with advanced skeletal maturation and can contribute to the limitation in growth.

View Image

Short stature in a male patient with congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency. His compliance with medical therapy was po....

Growth hormone in combination with GnRH agonist therapy may improve adult height.^{[15, 16]}

Female patients with virilizing forms of adrenal hyperplasia have a decreased fertility rate.^[21] The reasons are believed to be multifactorial and include abnormal genital anatomy, vaginal stenosis, and poor control of adrenal androgen production that results in diminished ovulation. When pregnancy does occur, the baby is generally born by means of caesarian delivery because of vaginal stenosis or an android pelvis. Virilization of female infants born to mothers with congenital adrenal hyperplasia has not been reported but is potentially possible if the condition is uncontrolled.

Males with uncontrolled congenital adrenal hyperplasia may develop masses in the testes (adrenal rests or adrenal tissue) because the gonads and adrenal glands are derived from the same embryologic anlage. Because the adrenal rests are under ACTH control, the adrenal rests enlarge when ACTH concentrations are elevated. The adrenal rests may cause discomfort and may be mistaken for testicular tumors, resulting in unnecessary surgery. Furthermore, these rests may cause oligospermia or azoospermia and infertility.

• References

Prevention

Prenatal testing using amniocentesis or chorionic villus sampling has been successful in diagnosing congenital adrenal hyperplasia secondary to 21-hydroxylase deficiency and 11-beta-hydroxylase deficiency if a sibling had a known mutation or deletion in a previous pregnancy.

Prenatal treatment of congenital adrenal hyperplasia appears to be somewhat successful in preventing the virilization due to 21-hydroxylase deficiency in a female fetus.^[22]  According to the protocol Carlson et al proposed, the mother is treated with 20 mcg/kg/d of dexamethasone divided into 3 doses as soon as the pregnancy is recognized to suppress fetal ACTH secretion and to prevent the fetal adrenal gland from overproducing adrenal androgens.^[23]

Dexamethasone treatment is discontinued if chorionic villus sampling (done at 8-12 weeks' gestation) or amniocentesis (done at 18-20 weeks' gestation) indicates that the fetus is male or if genetic analysis indicates that the fetus is unaffected.

• Because only the female fetus is at risk of disfigurement from virilization, this strategy results in unnecessary treatment in 7 of 8 fetuses. However, because virilization occurs within the first 12 weeks' gestation, the virilization of an affected female fetus will have already occurred if one waits until the sex and diagnosis of the fetus are known.
• So far, this strategy has not resulted in an increase in fetal wastage or congenital malformations in treated pregnancies.^[24]  However, it is associated with considerable maternal adverse effects during the pregnancy.
• Long-term follow-up studies are ongoing and required to determine whether dexamethasone treatment in early pregnancy results in any long-term adverse effects.^{[25, 26]}  This issue remains highly controversial. Therefore, it is recommended that prenatal treatment be done within the confines of clinical research.^[5]

Methods have been developed to screen neonates for congenital virilizing adrenal hyperplasia secondary to 21-hydroxylase deficiency and 11-hydroxylase deficiency by measuring 17-hydroxyprogesterone and 11-deoxycortisol, respectively, from heel blood samples collected on filter paper.^{[27, 28]}

• This approach has permitted early identification of newborns with this disorder. This strategy has prevented salt-wasting crises in males whose condition is unrecognized at birth and resulted in the identification of both completely virilized females who may be mistaken for males with cryptorchidism and patients of both sexes with simple virilizing adrenal hyperplasia, enabling early treatment before undue advancement in skeletal maturation.
• Whether these benefits are deemed to be worth the economic cost of screening to justify more global screening remains to be determined.^[27]

• References

Long-Term Monitoring

Closely monitor patients with adrenal hyperplasia for adequacy of dosing of glucocorticoids, mineralocorticoids, or both.

• Too little glucocorticoid results in symptoms of adrenal insufficiency (eg, anorexia, nausea, vomiting, abdominal pain, asthenia) and progressive virilization and advancement of skeletal maturation in virilizing forms.
• Too much glucocorticoid results in excess weight gain, Cushingoid features, hypertension, hyperglycemia, cataracts, and growth failure.

Growth failure is one of the more sensitive indicators of excess exposure to glucocorticoids. Short stature in adulthood is frequently the outcome in virilizing forms of adrenal hyperplasia because of the effect of uncontrolled adrenal androgens on skeletal maturation or the effects of excess glucocorticoid administration on growth.

Some patients develop precocious puberty, perhaps secondary to the advanced growth and skeletal maturation that occurs with androgen exposure. This may be treated with GnRH analogue therapy.

As puberty progresses, monitor for adrenal rests within the gonads. If ACTH is inadequately suppressed, these maybe mistaken for gonadal tumors and may cause gonadal pain. Adrenal rests are more commonly found in the testes than in the ovaries.

As adulthood approaches, vaginal adequacy should be assessed because many females with adrenal hyperplasia suffer from dyspareunia due to vaginal stenosis.

The Endocrine Society's 2010 clinical practice guidelines recommend that when patients with CAH reach adulthood, they should be assessed for known complications of CAH.^[5]

• References

Medication Summary

Short-term medical therapy

In patients with hypotension, 0.9% (isotonic) sodium chloride solution (450 mL/m² or 20 mL/kg IV) must be rapidly administered over the first hour. This is followed by a continuous IV infusion of 3200 mL/m²/d or 200 mL/kg per 100 cal/d of estimated resting energy expenditure as isotonic or half-isotonic sodium chloride solution to restore intravascular volume. Dextrose must also be provided.

If the patient is hypoglycemic, 2-4 mL of dextrose 10% in water (D10W) should be administered to increase the blood sugar, followed by a continuous infusion of dextrose 5% in water (D5W). If the patient is not hypoglycemic, D5W should be administered to prevent hypoglycemia. Patients with salt-wasting forms of adrenal hyperplasia do not need potassium supplementation because they are usually hyperkalemic. However, patients with 11-hydroxylase and 17-alpha-hydroxylase deficiency may be hypokalemic and may require potassium. After appropriate diagnostic studies are performed or after the results are known, glucocorticoid therapy, mineralocorticoid therapy, or both may be started.

In patients who are sick and who have signs of adrenal insufficiency, therapy should consist of stress dosages of hydrocortisone (50-100 mg/m² or 1-2 mg/kg IV administered as an initial dose), followed by 50-100 mg/m²/d IV divided every 6 hours. Comparable stress dosages include 10-20 mg/m² of methylprednisolone administered IV or intramuscularly (IM) and 1-2 mg/m² of dexamethasone. Methylprednisolone and dexamethasone have negligible mineralocorticoid effects. Therefore, if the patient is hypovolemic, hyponatremic, or hyperkalemic, large dosages of hydrocortisone (double or triple the stress dosages mentioned above) are preferred because of its mineralocorticoid effect.

No parenteral form of mineralocorticoid is currently available in the United States; however, if the patient has good GI function, administer 0.05-0.2 mg of fludrocortisone by mouth (PO).

Long-term medical therapy

The goal of therapy for adrenal hyperplasia is the replacement of glucocorticoid and mineralocorticoid to prevent signs of adrenal insufficiency and to prevent the accumulation of precursor hormones that cause virilization. Adequate glucocorticoid replacement should prevent excessive concentrations of ACTH from stimulating the adrenal glands to produce abnormal concentrations of adrenal androgens that result in further virilization. In the growing child with adrenal insufficiency, long-term glucocorticoid replacement must be balanced to prevent symptoms of adrenal insufficiency while still allowing the child to grow at a normal rate and prevent symptoms of glucocorticoid excess. The dosage must be tailored to each patient, but the general average dosage is 10-25 mg/m²/d of hydrocortisone PO divided in 2-3 doses.

Hydrocortisone is available in 5-mg, 10-mg, and 20-mg tablets. Hydrocortisone is recommended in the pediatric population because of its lower potency, which permits easier titration of appropriate doses. Unfortunately, hydrocortisone suspension (Cortef solution) is no longer available in the United States.

Prednisone, prednisolone, or even dexamethasone suspensions may be used. Prednisone is available in a suspension of 1 mg/mL, and prednisolone is available in a solution of 5 or 15 mg/5 mL. The estimated equivalencies are as follows:^[29]

• One mg of prednisone is equal to 4 mg of hydrocortisone.
• One mg of prednisolone is equal to 5 mg of hydrocortisone.
• One mg of dexamethasone is equal to 50 mg of hydrocortisone.

These forms of glucocorticoid have the advantage of half-lives longer than those of hydrocortisone, permitting twice-daily or even once-daily dosing (dexamethasone), which often aids compliance. However, because of their increased potency, growth suppression and other signs of glucocorticoid excess are common.

Administer fludrocortisone (0.05-0.2 mg/d PO) to patients with mineralocorticoid deficiency. Administer NaCl (2-5 g/d) to infants to counteract salt wasting. Older children can usually scavenge adequate salt to provide for their needs and may lose their salt-wasting tendencies as they mature. The dose of glucocorticoid is adjusted by clinically evaluating the patient (for an absence of symptoms of glucocorticoid deficiency and normal growth) and by periodically measuring the concentrations of precursor hormones. For example, in 21-hydroxylase deficiency, keeping plasma concentrations of 17-hydroxyprogesterone in the 200- to 500-ng/dL range and keeping androstenedione in the normal physiologic range is desirable.

Plasma ACTH concentrations are of little help in adjusting doses of glucocorticoid in patients with primary adrenal insufficiency. Monitoring symptoms of salt craving and blood pressure, PRA, and electrolyte levels are helpful in adjusting the dose of fludrocortisone. High blood pressure with suppressed PRA should prompt a reduction in fludrocortisone dose.

Stress or illness

One of the important physiologic responses to stress is an increase in the cortisol production that ACTH mediates. Patients with adrenal insufficiency of any etiology cannot mount this response and must be given stress doses of glucocorticoid. In the patient with a minor illness (temperature of < 38°C), the dosage of hydrocortisone should be at least doubled. For patients with relatively severe illness (temperature of >38°C), the dosage of glucocorticoid should be tripled. If the patient is vomiting or listless, administer parenteral glucocorticoid (50-75 mg/m² of hydrocortisone IM or IV or an equivalent dosage of methylprednisolone or dexamethasone). Because hydrocortisone succinate has a short duration of action, the dose must be repeated every 6-8 hours at a dosage of 50-100 mg/m²/d until the patient is well.

All patients with adrenal insufficiency must have injectable glucocorticoid available, and the caretaker must be instructed in its use and importance. Glucocorticoid or mineralocorticoid replacement has no contraindications when it is needed, and it has few drug-drug interactions.

• References

Hydrocortisone (A-Hydrocort, Cortef, Hydrocort)

• Dosing, Interactions, etc.

Clinical Context:  Same as cortisol, which is the primary steroid hormone secreted by adrenal zona fasciculata and reticularis. DOC in children due to short half-life and decreased potential for growth suppression. Mineralocorticoid effect at large doses.

• References

Class Summary

The purpose of glucocorticoid therapy in congenital adrenal hyperplasia is (1) to replace the body's requirement for glucocorticoids under normal conditions and during stress and (2) to suppress ACTH secretion, thereby reducing the stimulus for the adrenal glands to overproduce adrenal androgens in virilizing forms of congenital adrenal hyperplasia. Unfortunately, no currently available preparation is able to mimic the diurnal rhythm of physiologic cortisol secretion. Thus, in an attempt to suppress androgen secretion from the adrenal glands in response to early morning rises in ACTH, overtreatment often occurs, resulting in inhibition of linear growth and Cushingoid features. Delayed-release preparations of hydrocortisone have been formulated but are not commercially available.

• References

Fludrocortisone acetate (Florinef)

• Dosing, Interactions, etc.

Clinical Context:  Synthetic steroid with predominantly mineralocorticoid activity. Acts on renal tubule to promote sodium retention in exchange for potassium or hydrogen ion and thus maintain intravascular and extracellular volume. For patients who require parenteral mineralocorticoid therapy, high-dose hydrocortisone must be used. Available only as tab; may be crushed for infants and children.

• References

Class Summary

Replacement of mineralocorticoids is required in patients who have salt-wasting congenital adrenal hyperplasia. This treatment is necessary to replace the aldosterone that is insufficiently produced by the adrenal cortex.

• References