ALDOSTERONE SECRETION RATE IN CONGENITAL ADRENAL HYPERPLASIA. A DISCUSSION OF THE THEORIES ON THE PATHOGENESIS OF THE SALT-LOSING FORM OF THE SYNDROME

Adrenal disease in pregnancy

Adrenal disorders in pregnancy are relatively rare, yet can lead to significant maternal and fetal morbidity. Making a diagnosis is challenging as pregnancy may alter the manifestation of disease, many signs and symptoms associated with pregnancy are also seen in adrenal disease, and the fetal-placental unit alters the maternal endocrine metabolism and hormonal feedback mechanisms. The most common cause of Cushing's syndrome in pregnancy is an adrenal adenoma, followed by pituitary etiology, adrenal carcinoma, and other exceedingly rare causes. Medical therapy of Cushing's syndrome includes metyrapone and ketoconazole, but generally surgical treatment is more effective. Exogenous corticosteroid administration is the most common cause of adrenal insufficiency, followed by the endogenous causes of ACTH or CRH secretion. Primary adrenal insufficiency is least common. A low early morning cortisol <3 mcg/dL (83 mmol/L) in the non-stressed state and in the setting of typical clinical symptoms confirms the diagnosis. In the second and third trimester cortisol rises to levels 2-3 fold above those in the non-pregnant state, therefore a baseline level of <30 mcg/dL (823 mmol/L) warrants further evaluation. ACTH stimulated normal cortisol values have been established for each trimester. Hydrocortisone, which does not cross the placenta, is the glucocorticoid treatment of choice, and fludrocortisone is used as mineralocorticoid replacement in patients with primary disease. Congenital adrenal hyperplasia is an autosomal recessive disorder; 21-hydroxylase deficiency (21OHD) is the most common form of the disease. Non-classical 21OHD is most common, followed by the salt-wasting and simple virilizing forms. The treatment of choice for pregnant women affected with CAH is hydrocortisone, and fludrocortisones is added for those with the salt-wasting form of the disease. If the fetus is at risk for classical CAH, dexamethasone treatment can be used prenatally to prevent masculinization of the genitalia in a female infant. Because dexamethasone crosses the placenta, it should not be used to treat pregnant women with CAH if the fetus is not at risk for the disease.

Steroid 21 hydroxylase deficiency congenital adrenal hyperplasia

Steroid 21 hydroxylase deficiency is the most common form of congenital adrenal hyperplasia (CAH). The severity of this disorder depends on the extent of impaired enzymatic activity, which is caused by various mutations of the 21 hydroxylase gene. This article reviews adrenal steroidogenesis and the pathophysiology of 21 hydroxylase deficiency. The three forms of CAH are then discussed in terms of clinical presentation, diagnosis and treatment, and genetic basis. Prenatal diagnosis and treatment are also reviewed. The goal of therapy is to correct the deficiency in cortisol secretion and suppress androgen overproduction. Glucocorticoid replacement has been the mainstay of treatment for CAH, but new treatment strategies continue to be developed and studied.

Steroid 21 hydroxylase deficiency congenital adrenal hyperplasia

Steroid 21 hydroxylase deficiency is the most common form of congenital adrenal hyperplasia (CAH). The severity of this disorder depends on the extent of impaired enzymatic activity, which is caused by various mutations of the 21 hydroxylase gene. This article reviews adrenal steroidogenesis and the pathophysiology of 21 hydroxylase deficiency. The three forms of CAH are then discussed in terms of clinical presentation, diagnosis and treatment, and genetic basis. Prenatal diagnosis and treatment are also reviewed. The goal of therapy is to correct the deficiency in cortisol secretion and suppress androgen overproduction. Glucocorticoid replacement has been the mainstay of treatment for CAH, but new treatment strategies continue to be developed and studied.

Aldosterone-to-renin ratio as a marker for disease severity in 21-hydroxylase deficiency congenital adrenal hyperplasia

CONTEXT

Congenital adrenal hyperplasia (CAH) owing to 21-hydroxylase deficiency (21 OHD) is classified clinically in decreasing order of severity into salt-wasting, simple-virilizing, and nonclassical forms. Causative mutations in the CYP21A2 gene dictate the degrees of adrenal enzyme defect. Salt-wasting crises due to aldosterone deficiency are clinically apparent in the salt-wasting form but not in other forms of 21 OHD.

OBJECTIVES

This study examined the ratio of serum aldosterone to plasma renin activity as an index of sodium wasting in patients with 21 OHD CAH, heterozygotes, and normal individuals.

DESIGN

This was a cross-sectional, retrospective, noninterventional study.

PATIENTS AND OTHER PARTICIPANTS

A total of 402 individuals were included: 224 patients affected with 21 OHD CAH and 178 unaffected subjects. Classification into each diagnostic group was made primarily on the basis of clinical and hormonal features. Affected or unaffected status was confirmed by genotype of CYP21A2. All subjects were on ad lib diets without restrictions. Salt-wasting status was examined by sodium deprivation testing in 32 salt-wasting subjects and 14 simple virilizing subjects.

RESULTS

The ratio of serum aldosterone to plasma renin activity was found to discriminate well between the different groups of disease severity. The lowest ratios, indicative of the least sodium conservation, were seen in the salt-wasting group with increasing ratios in the simple virilizing, nonclassical, and unaffected groups. This ratio remained stable with age.

CONCLUSION

The ratio of serum aldosterone to plasma renin activity provides a simple index to compare groups of patients with varying degrees of 21 OHD.

Anatomical and functional outcomes of feminizing genitoplasty for ambiguous genitalia in patients with virilizing congenital adrenal hyperplasia

The ideal surgical technique and appropriate age for performing feminizing genitoplasty are debatable, and few long-term outcome studies have been reported.

PURPOSE

To report a retrospective study on anatomical and functional outcomes of feminizing genitoplasty in patients with virilizing congenital adrenal hyperplasia.

METHODS

We selected 34 patients (mean age = 3.4 +/- 2.5 yr) with genital ambiguity classified according to Prader stage. Follow-up ranged from 2 to 16 years. Clitoral length ranged from 1.9 to 5.0 cm; 28 patients had a single perineal orifice, and 6 had a double orifice. The surgical technique included clitorovaginoplasty in a single procedure and was carried out before 2 years of age in 18 patients. Clitoroplasty was performed with glans preservation in all patients. Blood supply was exclusively maintained by the frenular pedicle in 97% of the cases, whereas clitoral dorsal nerves and vessels were preserved in the remaining 3%. The opening of the urogenital sinus was performed using either the Y-V perineal flap procedure (25 patients) or the cut-back incision procedure (8 patients).

RESULTS

Good morphological and functional results were achieved in 68% of the patients; 21% of the patients had surgical complications, such as incision bleeding (2 cases), glans necrosis (1 girl with Prader V), and vaginal introitus stenosis (4 cases). Three of the latter underwent dilation with acrylic molds in the post-pubertal period with good functional results.

CONCLUSIONS

We conclude that single-stage feminizing genitoplasty consisting of vulvoplasty, clitoroplasty, and Y-V perineal flap produced good cosmetic and functional results in virilized girls with congenital adrenal hyperplasia, with few complications. In addition, this surgical approach prevented the need for neovaginaplasty even in patients with high vaginal insertion.

Temporal and individual variations in the dose of glucocorticoid used for the treatment of salt-losing congenital virilizing adrenal hyperplasia due to 21-hydroxylase deficiency

The dose of glucocorticoid was evaluated in the treatment of 19 patients with salt-losing congenital adrenal hyperplasia due to complete or nearly complete 21-hydroxylase deficiency. In most cases, follow-up was from infancy to puberty. The dose of steroid was expressed as oral cortisol (mg/m2 body surface area/24 hours); the equivalent doses of the various glucocorticoid preparations was as follows: 100 mg oral cortisol = 120 mg oral cortisone acetate = 25 mg oral prednisone = 50 mg intramuscular cortisol = 60 mg intramuscular cortisone acetate. The dose of glucocorticoid producing good laboratory and clinical control varied significantly with age. The dose fell from 26 mg/m2/24 hours in early infancy to 19 mg/m2/24 hours between 6 and 8 years of age, and then rose to 23-24 mg/m2/hour in adolescence. In addition to these age-related changes, there were large individual variations at each age. Indeed, the values from 4 of the 19 patients were not included in the calculation of the mean because they were more than 3 SD either above or below the mean. For the rest of the patients, the coefficient of variation ranged from 14.5% to 37.2%. It is concluded that glucocorticoid therapy must be adjusted carefully to the age and needs of each patient.

Vaginal reconstruction after initial construction of the external genitalia in girls with salt-wasting adrenal hyperplasia

A total of 28 patients with salt-wasting adrenal hyperplasia who underwent revision of the external genitalia at an early age (mean age 21.4 months) has been followed for 12 to 20 years (mean 16.3 years). The age at initial surgery ranged from 3 weeks to 5 years. Twenty-five patients had a low and 3 had a high takeoff of the vagina from the urogenital sinus. Of these children 22 (78.5%) required further vaginal reconstructive procedures to achieve a normal vaginal outlet. Of the 22 patients requiring further repair 18 have undergone vaginal reconstructive procedures with an initial success rate of 72.2%. These long-term data suggest that if vaginal reconstructive surgery is performed in infancy details, such as placement of the perineal flap well into the vagina and careful followup of the vaginal outlet, are mandatory for success. If there is evidence of outlet narrowing, periodic dilation will be needed to prevent vaginal stenosis and further vaginal surgery.

Prevalence of polymorphic 21-hydroxylase gene (CA21HB) mutations in salt-losing congenital adrenal hyperplasia

Using genomic restriction analysis of 14 unrelated patients with salt-losing congenital adrenal hyperplasia, we identified three different CA21HB mutation patterns: no detectable restriction fragment abnormalities (16/28 haplotypes), deletion of the active CA21HB gene (9/28), and apparent conversion of the active CA21HB gene to the pseudogene CA21HA (3/28). CA21HB gene deletion was associated with HLA-Bw47 in 6 haplotypes and with absent C4B expression in 7. A variety of HLA and C4 types was associated with the other mutations. Apparent conversion of CA21HB to CA21HA was identified by the disparity between the intensity ratios for the major TaqI and BglII hybridization fragments.

Identification of a mineralocorticoid receptor binding substance in the urine of patients with congenital adrenal hyperplasia

Increased amounts of circulating mineralocorticoid receptor binding substances presumed to be natural antagonists were previously demonstrated in congenital adrenal hyperplasia. In this study the feasibility of using urinary extracts for the identification of such binding substances was investigated. Urinary extracts from patients with the 21-hydroxylase defect did contain greater than normal amounts of mineralocorticoid receptor binding material. When subjected to chromatographic separation using a radioreceptor assay to follow the course of fractionation, a major aldosterone binding competitor was identified. On the basis of its chromatographic mobility in comparison with the labeled steroid, radioimmunoassay, ultraviolet absorption and radio-receptor assay of the native and acetylated derivative, the component was identified as 11-deoxycorticosterone and its structure confirmed by mass spectrometry. Although the major mineralocorticoid receptor binding component proved not to be an antagonist but an agonist, the results are in keeping with other evidence for overproduction of 11-deoxycorticosterone in the simple virilizing form of the disorder. Our finding did not disprove the existence of a circulating mineralocorticoid antagonist in congenital adrenal hyperplasia, but demonstrate that the major receptor binding substance in urinary extracts in that disorder is the mineralocorticoid agonist, 11-deoxycorticosterone.

Fertility rates in female patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Among 80 women with congenital adrenal hyperplasia due to 21-hydroxylase deficiency (40 with the simple virilizing form and 40 with the salt-losing form), 40 reported having an adequate introitus and being heterosexually active. In 15 of 25 patients with the simple virilizing form, 25 pregnancies resulted in 20 normal children, whereas only 1 of 15 women with the salt-losing form became pregnant; this pregnancy was electively terminated. Several factors seem to be responsible for the low fertility rates: noncompliance with therapy was probably high, as suggested by hirsutism and poor endocrine follow-up in 25 percent of patients; whereas 49 patients had regular menstrual periods, 14 had irregular periods, 10 had amenorrhea, 5 had undergone hysterectomy, and 2 had entered menopause; 87 percent of patients with salt loss and 50 percent of those with simple virilization (P less than 0.001) had remained single; the vaginal introitus was reported to be inadequate for intercourse by 35 percent of patients (53 percent of those with salt loss and 18 percent of those with simple virilization; P less than 0.002); and heterosexual activity was reported less frequently among patients with an inadequate introitus. The status of the introitus seemed to have a more important role in the sexual activity reported than did the degree of prenatal exposure to androgen (which was higher among patients with salt loss than among those with simple virilization). However, our data did not rule out an effect of androgen exposure on female fetuses. Our experience indicates that improved surgical correction of the external genitalia and better compliance with therapy will be necessary to improve fertility rates among women with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

Restriction maps and restriction fragment length polymorphisms of the human 21-hydroxylase genes

Restriction maps were constructed for the two human 21-hydroxylase genes (21-OHA and 21-OHB) by using DNA from subjects homozygous for a deletion of each gene. Comparing the patterns of these two genes, a KpnI restriction site occurred in the 21-OHA gene in place of a TaqI site in the 21-OHB gene about 1-kb from the 5' end of the gene, and an extra EcoRI site was located 500 bp 5' to the common EcoRI site. The DNA of fourteen unrelated normal subjects was digested with nine restriction endonucleases (AccI, BamHI, BgIII, EcoRI, HindIII, KpnI, MspI, SacI and TaqI). Restriction fragment length polymorphisms were found with EcoRI, HindIII and AccI that resulted from polymorphic endonuclease sites outside the genes.

Is salt-wasting in congenital adrenal hyperplasia due to the same gene as the fasciculata defect?

Clinical studies in patients with 21-hydroxylase deficiency congenital adrenal hyperplasia (CAH) were designed to ascertain the genetics of the salt-wasting component of the disorder. The gene controlling aldosterone biosynthesis may not be the same gene that controls 21-hydroxylase in the adrenal zona fasciculata. This we infer from the following clinical observations: (1) concordance for salt-wasting is not observed in all HLA-identical sibs with CAH; (2) the defect in aldosterone biosynthesis does not persist throughout life as does the fasciculata defect; (3) there is a significantly increased gene frequency of B40 and Bw47 in salt-wasting CAH; (4) obligate heterozygote parents of patients with salt-wasting CAH do not express a partial defect in aldosterone biosynthesis, as they do in the fasciculata. These observations cast doubt on the accepted concept of the autosomal recessive transmission of the glomerulosa 21-hydroxylase deficiency.

Influence of breast feeding on the clinical features of salt-losing congenital adrenal hyperplasia

Feeding habits before diagnosis were reviewed in 32 infants with salt-losing congenital adrenal hyperplasia who were admitted to hospital in adrenal crisis. Most breast-fed babies failed to thrive, seldom vomited, and despite severe salt wasting, presented at a later age than their formula-fed counterparts.

Supplementary water for breast-fed babies in a hot and dry climate--not really a necessity

Urine osmolarity under hot and dry climatic conditions remains within the expected physiological ranges and thus shows that supplementary water for breast-fed infants is not necessary.

Glucocorticoid treatment of girls with congenital adrenal hyperplasia: effects on height, sexual maturation, and fertility

Ninety-eight females with congenital adrenal hyperplasia due to a defect in either the 21-hydroxylase or the 11 beta-hydroxylase enzyme were evaluated to determine the effects of glucocorticoid treatment on growth, pubertal development, and fertility. When treatment was begun prior to one year of age, mean final height was 157.4 +/- 7.3 com, well within the normal adult female range, and significantly (p less than 0.001) greater than the mean final height of 150.9 +/- 4.3 cm found in untreated patients. The mean age of menarche in patients treated prior to the age of six years was 13.8 +/- 3.7 years which is significantly (p less than 0.01) delayed compared to that in the normal population of the United States. However, 92% of patients with menstrual delay had inadequate suppression of adrenal androgens and urinary excretion of 17 ketosteroids larger than 7.0 mg/24hours. The increased production of adrenal androgens was the result of poor compliance or an insufficient prescribed dose of glucocorticoids. The fertility rate in patients first treated between six and 20 years of age was 64%. The excretion of urinary 17 KS at the time of pregnancy was 2.5 to 5.3 mg/24 hours. All of the patients who delivered term infants required delivery by cesarean section because of cephalopelvic disproportion. The major problems encountered in the management of adolescent patients were patient noncompliance and physician failure to increase the glucocorticoid dose as the patient's body size increased.

A perspective on aldosterone abnormalities

Not all the varied clinical disorders in which aldosterone and the mineralocorticoid hormones are involved have been reviewed. Only those disorders in which the mineralocorticoid hormones and their regulatory factors are the principal cause of the biochemical and clinical abnormalities have been examined. These are many and varied. Appreciation of the extent and magnitude of their involvement in the regulation of blood pressure, body fluids, and electrolyte composition continues to grow. The major direct clinical impact of the mineralocorticoid hormones appears to be in two areas: hypertension and potassium homeostasis. Their part in the mosaic of hypertension is established in primary hyperaldosteronism, but they also appear to affect and modify the hypertensive process in primary or essential hypertension. The probe continues. Hypoaldosteronism is more than the rare occurrence associated with Addison's disease. It may be the clue to the presence of nonaldosterone mineralocorticoid excess syndromes, and is obviously of critical importance in an increasing number of patients with chronic renal failure of varied aetiologies.

Familial congenital absence of adrenal glands; evaluation of glucocorticoid, mineralocorticoid, and estrogen metabolism in the perinatal period

The patient was the fourth of affected male siblings. Cortisol (1.3 micrograms per cent), cortisone (9.6), and corticosterone sulfate (0.1) concentrations were low in cord blood. The larger amount of cortisone may have originated from maternal cortisol. Aldosterone was undetectable in cord blood, indicating lack of fetal secretion or maternofetal transfer. Unexpectedly normal concentrations of 11-deoxycorticosterone (DOC) sulfate in cord serum could represent maternal transfer of DOC, with subsequent fetal sulfurylation. Low estrone and estradiol concentrations in maternal and cord serum were consistent with absence of the fetal adrenals. Despite the low levels of the steroids, the propositus had a normal lecithin-sphingomyelin ratio at 38 weeks' gestation. Circulatory insufficiency developed within half an hour after birth and responded to gluco- and mineralocorticoid therapy. The three untreated siblings died between 14 and 67 hours of age. It is evident that early recognition of this condition may be lifesaving.

Aldosterone hypersecretion in "non-salt-losing" congenital adrenal hyperplasia

Patients with the "non-salt-losing" form of the adrenogenital syndrome were studied before and after suppression of adrenal cortical activity with carbohydrate-active steroids. The response of aldosterone secretion to sodium deprivation was measured; in some patients response to adrenocorticotropic hormone (ACTH) was measured as well. The aldosterone secretion was normal and responded normally to sodium deprivation in all patients studied during suppression with carbohydrate-active steroids. This finding suggests that 21-hydroxylation of progesterone is normal in this syndrome. The sole abnormality in the production of aldosterone in these patients was found to be excessive secretion of aldosterone while they were not receiving suppressive doses of carbohydrate-active steroids. This finding strongly supports the view that the biogenetic pathways through which aldosterone is produced from progesterone are intact in this syndrome. No patient showed hypertension or hypokalemic alkalosis despite very high aldosterone secretion rates. This observation suggests that the hyper-aldosteronism is secondary to a tendency to sodium loss in the patient whose ACTH production is not suppressed. These studies provide additional evidence in support of the hypothesis that the salt-losing and "non-salt-losing" forms of adrenogenital syndrome are genetically and biochemically distinct.

Hypertension, increased aldosterone secretion and low plasma renin activity relieved by dexamethasone

A father and son are described with a condition characterized by benign hypertension, potassium deficiency, increased aldosterone secretion rate (ASR), raised plasma volume and suppressed plasma renin activity (PRA). There were intermittent elevations of urine 17-ketosteroids and 17-hydroxycorticoids (17-OHCS) but no increase in urine THS, normal circadian rhythm of plasma 17-OHCS, and normal urine 17-OHCS response to dexamethasone and intravenous ACTH. Plasma ACTH and corticosterone secretion were not elevated. Pregnanetriol excretion was normal but urine pregnanediol was increased. At operation on the father no adrenal tumour was found; the excised left adrenal weighed 7 g. and showed nodular cortical hyperplasia; juxtaglomerular cells showed only occasional granules. Following operation hypertension persisted and ASR was half the preoperative value. All abnormalities in father and son were relieved by dexamethasone (DM) 2 mg. daily. The condition recurred following cessation of DM but was relieved by a second course of treatment. No such response to DM was seen in a normal subject or in a patient with Conn's syndrome. For a number of reasons it is suggested that patients with hypertension, increased ASR and low PRA be given a trial of dexamethasone treatment before undergoing adrenal surgery.

Aldosterone excretion in normal children and in children with adrenal hyperplasia

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