Monitoring treatment in congenital adrenal hyperplasia. Use of serial measurements of 17-OH-progesterone in plasma, capillary blood, and saliva

Therapy monitoring in congenital adrenal hyperplasia by dried blood samples

Careful monitoring of the therapy is crucial for patients with congenital adrenal hyperplasia (CAH) in order to prevent the effects of increased androgen production as well as life-threatening salt-wasting crisis. The key metabolite, 17α-hydroxyprogesterone (17-OHP) can be detected in serum, saliva or dried blood. In clinical practice there are challenges due to discomfort of venous blood sampling and complicated retrieval of saliva during infancy. Furthermore, the immunoassay method is limited in its specificity due to cross-reactions. In this observational study we prospectively examined over a period of 5 years, 20 patients with CAH due to 21-hydroxylase deficiency using standard immunoassays for serum samples (radioimmunoassay and enzyme immunoassay) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in dried blood spots. Bland-Altman plots show goodness of agreement between both the methods for the desirable therapeutic concentration range of 17-OHP. LC-MS/MS is characterized by a high accuracy in the therapeutic concentration range of 17-OHP <100 nmol/L (r=0.91). Dried blood samples are convenient and reliable specimen for 17-OHP measured by LC-MS/MS. This method could be used for home monitoring of hydrocortisone replacement therapy both in salt-waster and simple virilizer CAH.

Monitoring of therapy in congenital adrenal hyperplasia

BACKGROUND

Congenital adrenal hyperplasia is a group of disorders caused by defects in the adrenal steroidogenic pathways. In its most common form, 21-hydroxylase deficiency, patients develop varying degrees of glucocorticoid and mineralocorticoid deficiency as well as androgen excess. Therapy is guided by monitoring clinical parameters as well as adrenal hormone and metabolite concentrations.

CONTENT

We review the evidence for clinical and biochemical parameters used in monitoring therapy for congenital adrenal hyperplasia. We discuss the utility of 24-h urine collections for pregnanetriol and 17-ketosteroids as well as serum measurements of 17-hydroxyprogesterone, androstenedione, and testosterone. In addition, we examine the added value of daily hormonal profiles obtained from salivary or blood-spot samples and discuss the limitations of the various assays.

SUMMARY

Clinical parameters such as growth velocity and bone age remain the gold standard for monitoring the adequacy of therapy in congenital adrenal hyperplasia. The use of 24-h urine collections for pregnanetriol and 17-ketosteroid may offer an integrated view of adrenal hormone production but target concentrations must be better defined. Random serum hormone measurements are of little value and fluctuate with time of day and timing relative to glucocorticoid administration. Assays of daily hormonal profiles from saliva or blood spots offer a more detailed assessment of therapeutic control, although salivary assays have variable quality.

[Comparative study of prednisolone versus hydrocortisone acetate for treatment of patients with the classic congenital adrenal hyperplasia due to 21-hydroxylase deficiency]

Hydrocortisone acetate is usually employed in the treatment of classic congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency. In Brazil, however, oral hydrocortisone acetate is only available from manipulation pharmacies. Prednisolone has stable oral pharmaceutical formulations commercially available, with the advantage of a single daily dose. The aim of this study was to compare the efficacy of oral prednisolone and oral hydrocortisone in the treatment of CAH due to 21-hydroxylase deficiency. Fifteen patients with mean (SD) chronological age of 7.2 (3.6) years, were evaluated in two consecutive 1-year periods. In the first year, hydrocortisone (17.5 mg/m2/day, divided in three doses) was used in the treatment, followed by the use of prednisolone (3 mg/m2/day, once in the morning) in the second year. The comparison between the two treatments was assessed after a one-year treatment period by: variation of height standard deviation score (SDS) (delta Height SDS), variation of height SDS according to bone age (delta BA SDS), variation of body mass SDS (delta BMI SDS) and serum levels of androstenedione. No significant difference was observed in relation to the delta Height SDS, delta BA SDS and delta BMI SDS. No significant difference was observed in the serum levels of androstenedione. We conclude that the efficacy of prednisolone administered once a day orally is comparable to the oral use of hydrocortisone three times a day. Oral prednisolone may be an option for patients with CAH due to 21-hydroxylase deficiency.

One-year clinical evaluation of single morning dose prednisolone therapy for 21-hydroxylase deficiency

Replacement schedules with hydrocortisone (HC) to treat 21OHD are generally unsatisfactory and partially successful regarding growth. Noncompliance is common since its short half-life requires TID administration. Even multiple daily HC doses do not reproduce cortisol chronobiology and may disturb hypothalamic-mediated rhythms. Because synthetic glucocorticoids could improve clinical control, we evaluated the possible benefits of a one-year treatment period with a single morning oral dose of prednisolone (PD) phosphate in 44 patients with 21OHD randomized to two sex and age-matched groups: one (n=23) receiving PD (2.4-3.5 mg/m2 BSA) and the other (n=21) TID HC (10-15 mg/m2 BSA). After one year, bone maturation ratio was kept stable in the PD group (from 1.20 to 1.14), whereas a slight increase was seen in the HC group (from 1.21 to 1.29). Growth velocity (SDS) was preserved in the PD group (from 1.2 to 1.2 in all; 0.79 to 1.13 in pre-pubertals), whereas a slight increase occurred in the pre-pubertal HC-treated patients (from 1.1 to 1.9); height SDS for BA increased significantly in the PD group. Thus, patients with 21OHD treated for one year with a single morning dose of PD appear to achieve a better clinical and hormonal control than those on TID HC, permitting a reduction of the replacement dose. The current PD schedule used by our group (1.5-3 mg/m2 BSA/day) suggests a higher HC:PD bioequivalence ratio of 6-8:1.

Correlation of blood-spot 17-hydroxyprogesterone daily profiles and urinary steroid profiles in congenital adrenal hyperplasia

OBJECTIVE

To compare the value of blood-spot 17-hydroxyprogesterone (17-OHP) daily profiles and urinary steroid excretion in untreated and treated patients with congenital adrenal hyperplasia (CAH).

PATIENTS

Ten patients with CAH were investigated during steroid replacement therapy (Group 1), and 11 patients were investigated without treatment (Group 2).

METHODS

Capillary blood samples were collected for measurement of blood-spot 17-OHP values by non-chromatographic radioimmunoassay. Steroid profiles of 24-h urine samples were analyzed by gas chromatography.

RESULTS

There was a close correlation between the individual daily means of blood-spot 17-OHP measurements and the pregnanetriol/ tetrahydrocortisone ratio in both groups of patients (Group 2: r=0.839, p<0.001; Group 1: r=0.686, p<0.001). Almost the same correlation was found between the blood-spot 17-OHP value and the sum of three 17-hydroxyprogesterone metabolites/the sum of three cortisol/cortisone metabolites ratio (Group 2: r=0.918, p<0.001; Group 1: r=0.741, p<0.001).

CONCLUSIONS

Blood-spot 17-OHP measurements and 24-h urinary steroid profile have the same impact in identification and monitoring therapy of children with CAH.

Development of a highly sensitive nonisotopic immunoassay for the determination of salivary 17-hydroxyprogesterone: reference ranges throughout childhood and adolescence

A sensitive nonisotopic immunoassay for the determination of 17-hydroxyprogesterone (17-OHP) levels in saliva was developed. The new time-resolved fluorometric immunoassay employs a specific polyclonal anti-17-OHP antiserum immobilized onto microtiter plates, a 17-OHP-biotin conjugate as a tracer, and streptavidin-europium a as secondary probe. The lower detection limit of the assay is 23.6 pmol/L (mean -3 s of a 22-fold zero determination) corresponding to 0.39 pg/well. The coefficients of intraassay variation are 8.8, 5.3, and 8.3% at the respective concentrations of 90.9, 454.5, and 1363.5 pmol/L. The coefficients of interassay variation are 8.8, 5.3, and 8.3% at the respective concentrations. Saliva was collected in commercially available devices. Reference ranges were established using 394 saliva samples from 132 healthy children, adolescents, and adults. Morning, midday, and evening levels of 17-OHP levels in saliva varied significantly in all age groups with morning levels being higher than midday and evening levels. Saliva samples (n = 57) were also obtained from 18 children with congenital adrenal hyperplasia (CAH). Salivary 17-OHP levels in the limited number of CAH patients studied ranged from 121 to 106,050 pmol/L. In conclusion 1) a new, sensitive nonisotopic immunoassay for measurement of 17-OHP in saliva has been developed; 2) reference ranges for healthy children, adolescents, and adults have been established; 3) there is a circadian pattern of 17-OHP levels in saliva at all ages; and 4) measurement of 17-OHP in saliva should be further evaluated over a longer period of time as a potentially reliable and powerful technique to monitor metabolic control in patients with CAH. As 17-OHP levels in saliva are stable for > 10 wk at 4 degrees C, the technique is ideally suited for outpatient sampling.

Urinary pregnanetriol-3-glucuronide in children: age-related change and application to the management of 21-hydroxylase deficiency

Urinary concentrations of pregnanetriol-3-glucuronide (PT-3-G) were determined in 485 normal Japanese subjects (277 males and 208 females), aged 5 days to 20 years, using an enzyme-linked immunosorbent assay (ELISA). The usefulness of urinary PT-3-G concentrations before giving the morning dose of medications in monitoring the adequacy of glucocorticoid treatment was assessed in eight patients with 21-hydroxylase deficiency (21-OHD). The ratio of PT-3-G to excreted creatinine (PT-3-G/Cre ratio) increased significantly during the first month and did not change from age 1 month to 1 year of life. The ratio decreased to a nadir at age 3 or 4 years followed by continuous, significant increase until late adolescence. In the subjects treated with corticosteroids for 21-OHD, PT-3-G/Cre ratios at the 50th percentile or below suggested a risk of excessive treatment, as judged by the patients' growth. Measurement of the PT-3-G/Cre ratio enabled recognition of corticosteroid overtreatment, which was not demonstrated by determining the serum concentrations of 17 alpha-hydroxyprogesterone (17-OHP). On the other hand, ratios at the upper 95-99% tolerance limits seemed to be required for optimal control. The present study revealed the normal age-related changes in urinary excretion of PT-3-G and showed it to be a reliable marker for evaluating glucocorticoid treatment in young children with 21-OHD.

Loss of therapeutic control in congenital adrenal hyperplasia due to interaction between dexamethasone and primidone

A 14-year-old girl with congenital adrenal hyperplasia showed rapid conversion from undertreatment to overtreatment when primidone, used to treat coexistent epilepsy, was withdrawn while on a constant steroid dose. In addition to signs of hypercortisolism and a decrease in random measurements of plasma testosterone and 170H-progesterone concentrations, the deterioration in control was also illustrated by changes in the pattern of blood spot steroid profiles. Adequate control was achieved only after a 3-fold reduction in steroid dose. The decrease in dose requirement was probably the result of a reversal of liver enzyme induction consequent upon the withdrawal of primidone.

Daily profiles of salivary cortisol in hydrocortisone treated children with congenital adrenal hyperplasia

Daily profiles of salivary cortisol were determined in 14 cortisol-treated children with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency, and in 5 healthy sibs. The results showed considerable individual variation irrespective of the dose of hormone, reflecting the different rates of cortisol metabolism and transport. Maximum salivary cortisol levels were reached 1-2 h following oral administration of hydrocortisone. The determination of salivary cortisol may be useful for optimal dosage timing, i.e. to imitate the daily rhythm of normal cortisol secretion.

Monitoring treatment in congenital adrenal hyperplasia

We report results of monitoring treatment in 41 patients with congenital adrenal hyperplasia controlled over 0.3-13.1 years using standard auxological techniques alone. Doses of glucocorticoid (15-25 mg/m2/day) and mineralocorticoid (0.15 mg/m2/day) replacement were determined initially using biochemical indices and thereafter adjusted according to surface area. Monitoring was solely directed at maintaining a 50th centile height velocity for chronological age. Of 41 patients, 32 were referred after the newborn period. Nearly half of these patients were either overtreated or undertreated before their referral. Of the nine treated from birth, all but one were in good control and only two have had a second hospital admission. Present height standard deviation scores (SDS) for chronological age range from -1.60 to -0.26. Height SDS for bone age were compared with midparental heights in 33 patients: 15 treated with early emphasis on growth had a height prognosis exceeding midparental values; patients who had experienced appreciable prior overtreatment or undertreatment fared less well. In the long term management of congenital adrenal hyperplasia correction of salt loss is of primary importance. Doses of glucocorticoid required in addition to mineralcorticoid replacement should be continuously assessed and adjusted to maintain a normal growth velocity. This is most conveniently achieved by standardising replacement doses on surface area.

Radioimmunoassay of blood-spot 17 alpha-hydroxyprogesterone in the management of congenital adrenal hyperplasia

A robust assay for routine measurement of blood-spot 17 alpha-hydroxyprogesterone (17-OHP) concentrations has been developed using a magnetizable, solid-phase antiserum and an 125I-radioligand. The working range of this assay (13.5-500 nmol/L) is well suited for the initial diagnosis of congenital adrenal hyperplasia (CAH) and for monitoring replacement therapy in CAH patients. Data derived from multiple blood-spot samples, collected on two consecutive days, provide 17-OHP profiles. These profiles have been used to construct a chart allowing a rapid visual assessment of the efficacy of replacement therapy in CAH patients. Measurement of 17-OHP in the blood-spots of overtreated patients and accurate determination of normal range values in healthy infants relied on development of a sensitive assay (range 1.7-34 nmol/L). In the blood-spots of normal male (n = 50) and female (n = 50) infants collected 5-7 days after birth, 17-OHP concentrations were 7.62 +/- 2.55 nmol/L and 7.32 +/- 2.87 nmol/L respectively. Retrospective measurement of this steroid in samples from known CAH patients (n = 4), which had values ranging from 224 to 2145 nmol/L, support a role for measurement of blood-spot 17-OHP in high-risk screening programmes.