Would Cortisol Measurements Be a Better Gauge of Hydrocortisone Replacement Therapy? Congenital Adrenal Hyperplasia as an Exemplar.

There is an increase in mortality and morbidity as well as poor quality of life in patients with congenital adrenal hyperplasia (CAH) and other causes of adrenal insufficiency. Glucocorticoid replacement therapy should aim to replace the missing cortisol as close as possible to the normal circadian rhythm using hydrocortisone. Dosing should be based on the individual's absorption and clearance of the drug. Adequacy of dosing should be checked using 24-hour profiles of plasma cortisol with samples drawn preferably every hour or at least every 2 hours. Measurement of cortisol should be the preferred method of assessing replacement therapy as it is over- and undertreatment with hydrocortisone, both of which can occur over a 24-hour period, which leads to the problems observed in patients with CAH and adrenal insufficiency.

Impact of intraoperative parathyroid hormone monitoring on the management of patients with primary hyperparathyroidism.

BACKGROUND/OBJECTIVE: Intraoperative parathyroid hormone (IOPTH) monitoring during surgery for primary hyperparathyroidism (PHPT) could improve cure rate and simplify current care pathways. This study assesses the performance of US, MIBI and IOPTH monitoring and their impact on outcomes and perioperative strategy. DESIGN: This is a retrospective study of a prospectively maintained database of patients who underwent parathyroidectomy guided by preoperative US, MIBI and IOPTH monitoring. Test performance (sensitivity, specificity, PPV, NPV, accuracy) and IOPTH added value (percentage of patients in whom test contributed to achieving cure) were calculated. RESULTS: A total of 617 patients (median age 59 years, 75% females), 603 (97.7%) of them cured, were included in analysis. Sensitivity of US was higher than MIBI (78.2% vs 70%, P < 0.05), but both were inferior to IOPTH (98.6%, P < 0.05). US and MIBI were more sensitive at detecting single gland disease (SGD) than multigland disease (MGD) (85% vs 55% and 77.5% vs 45.5%, respectively, P < 0.05), while IOPTH performed well in both situations (98.8% vs 96.7%, P > 0.05). In 41 patients with incorrect US predictions, MIBI gave correct result only in 12 (29.3%) cases, while IOPTH gave correct predictions in all but one patient (97.6%). Minimally invasive parathyroidectomy (MIP) was completed in 409 patients, with a similar completion rate regardless whether both or one scan was positive. IOPTH added value was significant in whole cohort (14%) and in subgroups of patients with concordant vs discordant scans, minimally invasive vs conventional surgery, and initial vs reoperative surgery. CONCLUSIONS: Intraoperative parathyroid hormone monitoring is more accurate at predicting cure than US and MIBI are at identifying abnormal glands in patients undergoing parathyroidectomy for PHPT and significantly contributes to cure rate in range of clinical scenarios. This implies that its routine use could facilitate successful surgery in patients with single positive imaging and increase number of MIPs while maintaining high cure rate.

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood.

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

Biochemistry of the menopause.

The life of a human female is characterized from teenage years by monthly menstruation which ceases (the menopause) typically between the age of 40 and 60 years. The potential for reproduction declines and ceases as the ovaries become depleted of follicles. A transition period in mid-life, for 2 to 10 years, when menstruation is less regular is called the perimenopause. The menopause is associated with a significant decline in plasma concentrations of sex hormones, an increase in the concentrations of the gonadotrophins and changes in other hormones such as the inhibins. These changes are superimposed with effects of aging, social and metabolic factors, daily activity and well-being. Although the menopause is entirely natural, in some cases ovarian failure can occur earlier than usual; this is pathological and warrants careful biochemical investigations to distinguish it from conditions causing infertility. Elderly females are affected by a range of clinical disorders including endocrine, cardiovascular, skeletal, urogenital tract and immunological systems, body mass, vasomotor tone, mood and sleep pattern. Reference intervals for many diagnostic biochemical tests for the menopause need to be used when interpreting results in clinical investigations for patient management. The standardization and harmonization of assays are being addressed. Many women now choose to develop their career before bearing children, and the health service has had to change services around this. This review does not cover screening for and tests during pregnancy. The review is timely since the population is aging and there will be more demand on healthcare services.

The investigation of children and adolescents with abnormalities of pubertal timing.

Concerns with pubertal development are common and can cause considerable distress to patients and their carers. Many presentations reflect normal variations of pubertal timing and primarily require reassurance, although patients may opt for interventions. Other presentations need active management to avoid significant adverse effects on growth and psychosocial development. All should undergo careful assessment, particularly as some children or adolescents presenting with abnormalities in pubertal timing may have serious pathology which requires urgent investigations and treatment. This review describes the appropriate investigations and their interpretation for young people presenting with disorders in pubertal timing.

Elevation of brain allopregnanolone rather than 5-HT release by short term, low dose fluoxetine treatment prevents the estrous cycle-linked increase in stress sensitivity in female rats.

Withdrawal from long-term dosing with exogenous progesterone precipitates increased anxiety-linked changes in behavior in animal models due to the abrupt decrease in brain concentration of allopregnanolone (ALLO), a neuroactive metabolite of progesterone. We show that a withdrawal-like effect also occurs during the late diestrus phase (LD) of the natural ovarian cycle in rats, when plasma progesterone and ALLO are declining but estrogen secretion maintains a stable low level. This effect at LD was prevented by short-term treatment with low dose fluoxetine. During LD, but not at other stages of the estrous cycle, exposure to anxiogenic stress induced by whole body vibration at 4 Hz for 5 min evoked a significant decrease in tail flick latency (stress-induced hyperalgesia) and a decrease in the number of Fos-positive neurons present in the periaqueductal gray (PAG). The threshold to evoke fear-like behaviors in response to electrical stimulation of the dorsal PAG was lower in the LD phase, indicating an increase in the intrinsic excitability of the PAG circuitry. All these effects were blocked by short-term administration of fluoxetine (2 × 1.75 mg kg(-1) i.p.) during LD. This dosage increased the whole brain concentration of ALLO, as determined using gas chromatography-mass spectrometry, but was without effect on the extracellular concentration of 5-HT in the dorsal PAG, as measured by microdialysis. We suggest that fluoxetine-induced rise in brain ALLO concentration during LD offsets the sharp physiological decline, thus removing the trigger for the development of anxiogenic withdrawal effects.

17-Hydroxyprogesterone in children, adolescents and adults.

17-Hydroxyprogesterone (17-OHP) is an intermediate steroid in the adrenal biosynthetic pathway from cholesterol to cortisol and is the substrate for steroid 21-hydroxylase. An inherited deficiency of 21-hydroxylase leads to greatly increased serum concentrations of 17-OHP, while the absence of cortisol synthesis causes an increase in adrenocorticotrophic hormone. The classical congenital adrenal hyperplasia (CAH) presents usually with virilisation of a girl at birth. Affected boys and girls can have renal salt loss within a few days if aldosterone production is also compromised. Diagnosis can be delayed in boys. A non-classical form of congenital adrenal hyperplasia (NC-CAH) presents later in life usually with androgen excess. Moderately raised or normal 17-OHP concentrations can be seen basally but, if normal and clinical suspicion is high, an ACTH stimulation test will show 17-OHP concentrations (typically >30 nmol/L) above the normal response. NC-CAH is more likely to be detected clinically in females and may be asymptomatic particularly in males until families are investigated. The prevalence of NC-CAH in women with androgen excess can be up to 9% according to ethnic background and genotype. Mutations in the 21-hydroxylase genes in NC-CAH can be found that have less deleterious effects on enzyme activity. Other less-common defects in enzymes of cortisol synthesis can be associated with moderately elevated 17-OHP. Precocious puberty, acne, hirsutism and subfertility are the commonest features of hyperandrogenism. 17-OHP is a diagnostic marker for CAH but opinions differ on the role of 17OHP or androstenedione in monitoring treatment with renin in the salt losing form. This review considers the utility of 17-OHP measurements in children, adolescents and adults.

A comparison of pain measures in newborn infants after cardiac surgery.

Accurate pain assessment tools to evaluate pain in critically ill neonates in the postoperative period are lacking. Therefore, we compared a number of potentially useful indices of pain in critically ill neonates following cardiac surgery. Eighty-one full-term infants were studied during the first 48 postoperative hours and the following indices were measured: heart rate, mean arterial blood pressure, heart-rate variability, urinary and plasma cortisol, and 4 composite pain measurement scales: Children's and Infants' Postoperative Pain Scale (CHIPPS), CRIES, COMFORT, and Premature Infant Pain Profile (PIPP). Regression models were used to investigate relationships between individual pain indices or composite pain assessment scales with respect to procedural intensity and opioid dose and plasma levels. COMFORT score performed best, with a 27% difference in score between procedures causing tissue damage and those that did not (P<0.001). COMFORT score and the high-frequency component of heart-rate variability showed inverse correlations with opioid dose and plasma levels over the first 48 hours postoperatively, but after accounting for clinical variables, only COMFORT score remained significant (eg, 52% of variance in morphine level at 24 hours, P<0.001). The factor structure of the COMFORT score revealed that both behavioural and physiological variables account for a significant proportion of the variance (45% and 15%, respectively; P<0.001). Plasma concentrations of cortisol increased postoperatively but urinary cortisol excretion did not change significantly. Of the pain indices studied, the COMFORT score performed best, with both behavioural and physiological components providing significant contributions.

Recognition of 5α-reductase-2 deficiency in an adult female 46XY DSD clinic.

CONTEXT: The late presentation of steroid 5α-reductase-2 (SRD5A2) deficiency in females is poorly characterised. The ratios of 5α/5ß-reduced metabolites of adrenal steroids in a urine steroid profile (USP) can give an indication of SRD5A2 deficiency, although the diagnostic cut-off for 5α/5ß ratios are not clearly defined in genetically confirmed cases. OBJECTIVE: The aim of this study was to establish the frequency of SRD5A2 deficiency in an adult clinic for disorders of sexual development (DSD) focussing on 46XY partially virilised adult female subjects. We investigated the relationship between USP results and SRD5A2 genetic sequence and determined the cut-off for USP 5α/5ß-reduced steroid ratios compared with gene sequencing for the identification of SRD5A2 deficiency. METHODS: USP and SRD5A2 genetic analyses were performed in 23 adult females, aged 19-57 years, with 46XY DSD and in four males with confirmed SRD5A2 deficiency. 5α-Reductase activity was assessed using the USP ratio of androsterone to aetiocholanolone (A/Ae), 5α-tetrahydrocortisol (5α-THF)/tetrahydrocortisol (THF) and 5α-tetrahydrocorticosterone to tetrahydrocorticosterone (5α-THB/THB). RESULTS: The SRD5A2 gene mutations were found in 10/23 (43%) females and in all four males. Totally, four novel mutations were identified. All mutation-positive subjects had A/Ae and 5α-THB/THB ratios below the lower limit of normal (100% sensitivity) while the sensitivity of 5α-THF/THF ratio was 90%. CONCLUSION: SRD5A2 deficiency is more prevalent than expected in the adult female 46XY DSD population. The clinical spectrum of this disorder may extend to a more female phenotype than previously considered to include individuals with little or no virilisation.

Development and validation of a quantitative assay based on tandem mass spectrometry.

Many routine hospital and clinical research assays have relied upon immunoassay procedures to achieve sensitive measurements of a range of important analytes. Some of the methods have been developed in-house but increasingly commercial kits and automated analysers have become commonplace. The accuracies of these methods are under question in health care. Mass spectrometry (MS) is potentially a more accurate technique with the ability to demonstrate specificity. An introduction of the basic analytical aspects of liquid chromatography (LC)-MS/MS leads on to the validation of the method before general use. LC coupled with MS and tandem mass spectrometry (MS(n)) is being adopted in a number of hospital laboratories for the quantitative analysis of a number of analytes from physiological matrices, but standards for development and validation of such assays are not easily available. Most assays can be regarded as in-house methods and herein may lay the failure so far for mass spectrometric methods to improve quality of results between laboratories for an analyte using the same technology. Manufacturers are taking on board the experience of clinical laboratories with kits containing all or most of the disposable items and reagents. A number of documents and guidelines have been consulted. These documents are expensive to purchase, are often very long and not easy to read. This review highlights the specific requirements for introduction of a tandem mass spectrometric test for small molecules into a routine hospital laboratory. A number of experiments need to be planned and executed in order to describe a new quantitative method in terms of selectivity, accuracy, imprecision, sensitivity and stability. The introduction of a quantitative method based on tandem MS requires careful validation. This review has distilled out important points from a number of key documents in order to provide a working validation guideline for clinical laboratories. In a supplementary file a working document for assembling the assay validation is proposed.