Cushing's syndrome in children and adolescents: current diagnostic and therapeutic strategies

Diagnostic and management challenges in paediatric Cushing's syndrome

OBJECTIVE

Cushing syndrome (CS) is the result of chronic exposure to glucocorticoid excess. CS in children is most often caused by the administration of exogenous steroids. Endogenous CS is rare in the paediatric population and is caused mainly by tumours of the pituitary and adrenal glands, with ectopic sources being extraordinarily rare before the age of 18 years. In addition, children and young adults with CS present with different epidemiology, management issues, prognosis and outcomes than older adult patients. This complex disorder needs early diagnosis and management to avoid the significant morbidity and even mortality that can result from chronic untreated CS.

METHODS

In this review, we present the complex case of a 7-year-old boy with CS that highlights the diagnostic and management challenges of paediatric CS patients, including the considerations for genetic predisposition and life-long consequences of CS in children and young adults.

RESULTS

The diagnostic protocols for the evaluation of CS have been devised for adults and tested predominantly on adults. In this review, we discuss necessary modifications so that the testing can be adjusted for use in children. Additionally, pituitary adenomas in children are generally smaller and thus more difficult to recognize on pituitary imaging.

CONCLUSIONS

The management of the case and its complexities underline the need for children with CS to be managed in a centre with experienced paediatric endocrinologists and skilled neurosurgeons both for their initial diagnosis and treatment as well as for their long-term follow-up and management.

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 2, specific diseases

Pituitary adenomas are rare in children and young people under the age of 19 (hereafter referred to as CYP) but they pose some different diagnostic and management challenges in this age group than in adults. These rare neoplasms can disrupt maturational, visual, intellectual and developmental processes and, in CYP, they tend to have more occult presentation, aggressive behaviour and are more likely to have a genetic basis than in adults. Through standardized AGREE II methodology, literature review and Delphi consensus, a multidisciplinary expert group developed 74 pragmatic management recommendations aimed at optimizing care for CYP in the first-ever comprehensive consensus guideline to cover the care of CYP with pituitary adenoma. Part 2 of this consensus guideline details 57 recommendations for paediatric patients with prolactinomas, Cushing disease, growth hormone excess causing gigantism and acromegaly, clinically non-functioning adenomas, and the rare TSHomas. Compared with adult patients with pituitary adenomas, we highlight that, in the CYP group, there is a greater proportion of functioning tumours, including macroprolactinomas, greater likelihood of underlying genetic disease, more corticotrophinomas in boys aged under 10 years than in girls and difficulty of peri-pubertal diagnosis of growth hormone excess. Collaboration with pituitary specialists caring for adult patients, as part of commissioned and centralized multidisciplinary teams, is key for optimizing management, transition and lifelong care and facilitates the collection of health-related quality of survival outcomes of novel medical, surgical and radiotherapeutic treatments, which are currently largely missing.

Pediatric Macrocorticotropinoma: Do They Differ from Microcorticotropinoma?

INTRODUCTION

Cushing's disease (CD) due to macrocorticotropinoma (MC) in children and adolescents is a rare entity with limited information regarding its characteristics. The objective of the study is to describe the clinical, biochemical, imaging, management, outcome, and genetic characteristics of children and adolescents with CD due to MC and compare them with those of microcorticotropinoma (mc).

METHODS

This retrospective study was conducted at a single tertiary care center. Thirty-two patients with CD and MC (maximum tumor dimension ≥10 mm on imaging) and 65 patients with mc (<10 mm on imaging) aged ≤20 years at presentation were enrolled.

RESULTS

Nineteen girls and 13 boys with MC presented at a median (IQR) age of 14.5 (12.0-17.9) years. Patients with MC had higher body mass index-standard deviation score (BMI-SDS) (3.70 ± 2.60 vs. 2.59 ± 2.01, p = 0.04), more frequent neuro-ophthalmic symptoms (25% vs. 9% p = 0.04) and short stature (59% vs. 34%, p = 0.049) but less frequent livid striae (53% vs. 77%, p = 0.01), hypokalemia (12% vs. 36%, p = 0.04), and lower cortisol (nmol/L) to corticotropin (pmol/L) ratio (41.20 vs. 55.74, p = 0.04) than those with mc. The remission (59% vs. 64%, p = 1.0) and relapse (53% vs. 37%, p = 0.26) rates after first-line surgery and remission rate after radiotherapy (RT) were comparable between the two cohorts, whereas time to remission after RT (27 vs. 13 months, p = 0.05) was longer in the MC group. A patient with MC had a pathogenic germline variant in CDH23.

CONCLUSION

In this large monocentric series of pediatric CD, frequent mass effect symptoms and short stature, higher BMI-SDS, less frequent livid striae, and hypokalemia with lower effective cortisol secretion characterize the MC cohort. The outcomes of surgery and RT were similar between the groups except for a longer time to remission after RT in the MC cohort. Germline variants are rare (4%) in pediatric MC.

Focus on adrenal and related causes of hypertension in childhood and adolescence: Rare or rarely recognized?

High blood pressure (BP) is not restricted to adults; children and adolescents may also be affected, albeit less frequently. Aside from unfavorable environmental factors, such as obesity and sedentary life leading to early-onset essential hypertension (HT), several secondary causes must be investigated in the occasional hypertensive child/adolescent. Endocrine causes are relevant and multiple, related to the pituitary, thyroid, parathyroid, gonads, insulin, and others, but generally are associated with adrenal disease. This common scenario has several vital components, such as aldosterone, deoxycorticosterone (DOC), cortisol, or catecholamines, but there are also monogenic disorders involving the kidney tubule that cause inappropriate salt retention and HT that simulate adrenal disease. Finally, a blood vessel disease was recently described that may also participate in this vast spectrum of pediatric hypertensive disease. This review will shed some light on the diagnosis and management of conditions, focusing on the most prevalent adrenal (or adrenal-like) disturbances causing HT.

Corticosteroid resistance in asthma: Cellular and molecular mechanisms

Inhaled glucocorticoids (GCs) are drugs widely used as treatment for asthma patients. They prevent the recruitment and activation of lung immune and inflammatory cells and, moreover, have profound effects on airway structural cells to reverse the effects of disease on airway inflammation. GCs bind to a specific receptor, the glucocorticoid receptor (GR), which is a member of the nuclear receptor superfamily and modulates pro- and anti-inflammatory gene transcription through a number of distinct and complementary mechanisms. Targets genes include many pro-inflammatory mediators such as chemokines, cytokines, growth factors and their receptors. Inhaled GCs are very effective for most asthma patients with little, if any, systemic side effects depending upon the dose. However, some patients show poor asthma control even after the administration of high doses of topical or even systemic GCs. Several mechanisms relating to inflammation have been considered to be responsible for the onset of the relative GC resistance observed in these patients. In these patients, the side-effect profile of GCs prevent continued use of high doses and new drugs are needed. Targeting the defective pathways associated with GC function in these patients may also reactivate GC responsiveness.

Utility of bilateral inferior petrosal sinus sampling for diagnosis and lateralization of Cushing's disease in the pediatric population: case series and review of the literature

OBJECTS

Cushing's disease (CD) is the most common cause of ACTH-dependent hypercortisolism in children age ≥ 7. The utility of bilateral inferior petrosal sinus sampling (BIPSS), an important test in adults, is less defined in children. We present a case series of children with ACTH-dependent hypercortisolemia and review the literature to assess the utility of BIPSS in the diagnosis and localization of CD.

METHODS

We performed an IRB-approved chart review of patients aged ≤ 18 with ACTH-dependent hypercortisolism at MGH between 2000 and 2019 and collected clinical, laboratory, radiographic, BIPSS, surgical, and outcomes data.

RESULTS

In our cohort (n = 21), BIPSS had a sensitivity of 93% and specificity of 100% for diagnosis of CD. Compared to surgery, successful BIPSS correctly predicted adenoma laterality in 69% of cases vs. 70% by MRI. Among patients with lesions ≥ 4 mm (n = 9), BIPSS correctly lateralized in 50% vs. 100% by MRI. In patients with subtle lesions (< 4 mm, n = 7), BIPSS correctly lateralized in 80% vs. 71% by MRI. In patients (n = 4) with CD and negative MRIs, BIPSS correctly lateralized in 75% cases. Surgical cure was achieved in 90% of patients and 95% of patients had long-term disease control.

CONCLUSIONS

In our cohort (n = 21; n = 20 CD, n = 1 ectopic ACTH secretion), BIPSS was sensitive and specific for the diagnosis of CD. Compared to MRI, BIPSS was not additionally helpful for lateralization in patients with lesions ≥ 4 mm on MRI. BIPSS was helpful in guiding surgical exploration and achieving immediate postoperative remission among patients with subtle and negative MRI findings.

Paediatric Cushing's disease: Epidemiology, pathogenesis, clinical management and outcome

Cushing's disease (CD) is rare in paediatric practice but requires prompt investigation, diagnosis and therapy to prevent long-term complications. Key presenting features are a change in facial appearance, weight gain, growth failure, virilization, disturbed puberty and psychological disturbance. Close consultation with an adult endocrinology department is recommended regarding diagnosis and therapy. The incidence of CD, a form of ACTH-dependent Cushing's syndrome (CS), is equal to approximately 5% of that seen in adults. The majority of ACTH-secreting adenomas are monoclonal and sporadic, although recent studies of pituitary tumours have shown links to several deubiquitination gene defects. Diagnosis requires confirmation of hypercortisolism followed by demonstration of ACTH-dependence. Identification of the corticotroph adenoma by pituitary MRI and/or bilateral inferior petrosal sampling for ACTH may contribute to localisation before pituitary surgery. Transsphenoidal surgery (TSS) with selective microadenomectomy is first-line therapy, followed by external pituitary irradiation if surgery is not curative. Medical therapy to suppress adrenal steroid synthesis is effective in the short-term and bilateral adrenalectomy should be considered in cases unfit for TSS or radiotherapy or when urgent remission is needed after unsuccessful surgery. TSS induces remission of hypercortisolism and improvement of symptoms in 70-100% of cases, particularly when performed by a surgeon with experience in children. Post-TSS complications include pituitary hormone deficiencies, sub-optimal catch-up growth, and persisting excess of BMI. Recurrence of hypercortisolism following remission is recognised but infrequent, being less common than in adult CD patients. With experienced specialist medical and surgical care, the overall prognosis is good. Early referral to an experienced endocrine centre is advised.

Bronchial Carcinoid Tumour as a Rare Cause of Cushing’s Syndrome in Children: A Case Report and Review of Literature

Cushing’s syndrome (CS) is rare in childhood and adolescence. The most common paediatric cause of CS is exogenous administration of glucocorticoids; either topical, inhaled or oral corticosteroids. Endogenous causes can be classified into adrenocorticotropic hormone (ACTH) independent and ACTH dependent causes. Herein, we report our experience of managing a 12 year old girl who presented with features of CS and was found to have an ectopic, ACTH-secreting bronchial carcinoid tumour, which was resected surgically. Our patient was managed successfully by multidisciplinary approach and has recovered from hypertension and Cushing’s habitus. The English language literature was searched from 2019 back, using PubMed, Google and Google Scholar. Keywords used for the search were; “Ectopic ACTH syndrome (EAS) in children”, “bronchial carcinoid in children” and “Cushing’s Syndrome in children”. Children with bronchial carcinoid tumours causing EAS were identified. Case variables such as age, sex, type of carcinoid, investigations, surgery, recurrences and outcome were reviewed. Fourteen cases of paediatric bronchial carcinoid producing ACTH were found with a mean age of 15.8 years and female preponderance. Most of the patients had a right lung lesion and histological appearance was typical of carcinoid tumour. Bronchial carcinoid is extremely rare in children and only 4% are associated with CS. The postoperative treatment of CS is challenging with a high prevalence of hypertension, increased body mass index and visceral fat mass, impaired cognitive function and decreased quality of life. A careful follow up is indispensable for monitoring recurrence of carcinoid and complete remission of CS.

Advances with glucocorticoids in the treatment of asthma: state of the art

INTRODUCTION

Asthma is one of the most frequent chronic diseases all over the world. Glucocorticoids (GCs), both inhaled (ICSs) and oral (OCSs), are the most effective treatment in asthma because they control symptoms and prevent exacerbations.

AREAS COVERED

The present article reviews the new therapeutic indications of GCs for the treatment of asthma and focuses on new molecules and safety issues.

EXPERT OPINION

Most patients with asthma benefit from corticosteroid-based treatments. Side effects are mainly due to prolonged use of oral GCs, while they are minor with inhaled GCs. Interesting insights come from the new ICSs, which are characterized by lower oral bioavailability and higher lipophilicity and are more effective with less side effects. Recent trials have shown the efficacy of early use of ICSs in mild asthma. Furthermore, the possibility to prescribe targeted therapies using specific biomarkers in steroid-sensitive asthma can reduce doses and duration of treatment, while biological agents should be reserved for non-responding patients. All this evidence confirm the need to continue on the path toward precision medicine, in which the treatments are based on clinical and molecular traits.

Treatment challenges in pediatric Cushing's disease: Review of the literature with particular emphasis on predictive factors for the disease recurrence

Cushing's disease (CD) is a rare endocrine condition caused by a corticotroph pituitary tumor that produces adrenocorticotropic hormone. The current state of knowledge of CD treatment is presented in this article including factors that can be helpful in predicting remission and/or recurrence of the disease. The primary goals in CD treatment are quick diagnosis and effective, prompt treatment as the persistent disease is associated with increased morbidity and mortality. Cooperation of a team consisting of experienced pediatrician/adult endocrinologist, neuroradiologist, transsphenoidal neurosurgeon and (if necessary) radiotherapist contribute to the best treatment effects.

Cyclic Cushing's Disease in the Prepubertal Period-A Case Report and Review of Literature

Background: Cyclic Cushing's disease (CD) has been described in about 15% of adult patients with CD. In the pediatric population, diagnosis of CD is rare and cyclic presentations of the disease are not adequately understood or described. Moreover, prepubertal patients usually do not present with the typical signs and symptoms of CD, which can obscure or delay diagnosis. In this paper, we report a case of cyclic CD in a prepubertal age girls whose etiology was a pituitary corticotropinoma. Case presentation: A Caucasian 7.8 year old girl was admitted to pediatric endocrinology for the evaluation of short stature and prior obesity. The patient remained overweight despite significant lifestyle modifications, resulting in 6 kg weight loss during the prior 6 months. The physical exam was notable for precocious adrenarche and thelarche, but difficult to differentiate from steatomastia. Hypothalamo-pituitary-adrenal axis diagnostics, including single diurnal excretion of urinary cortisol, morning ACTH, and serum cortisol levels, were all within normal limits, and MRI of the pituitary gland showed no deviations at this time. Because of the clinical suspicion of cyclic hypercortisolemia, she was referred to our outpatient clinic for follow-up. After 6 months, the patient returned with rapid weight gain, accompanied by nocturnal anxiety, exacerbation of depressive behavior, insomnia and excessive sweating, and was readmitted to the ward for testing. Standard diagnostics confirmed CD and repeat MRI at 8.6 years old showed a microadenoma of 3 × 4 mm in the right side of the anterior pituitary gland. Histopathologic examination described an atypical, densely-granulated pituitary corticotroph adenoma with Ki-67 expression above 3%. Conclusion: Cyclic presentations of CD in the prepubescent age group could cause difficulties in diagnosis because of atypical signs and symptoms, which can be absent in the remission phase. Decreases in height percentiles and velocities obtained from the growth chart, as well as fluctuations in weight, and signs of androgenization can allow the clinician to suspect cycling CD in prepubertal patients. Confirmation of cyclic CD diagnosis is only possible during periods of relapse (hypercortisolemic state) and should be investigated according to the current diagnostic standard.

Pediatric Cushing's Disease: Dichotomy in Lateralization between Imaging and Inferior Petrosal Sinus Sampling with Review of Literature

Inferior petrosal sinus sampling (IPSS) is a minimally invasive method done in adrenocorticotrophic hormone (ACTH)-dependent pituitary adenoma cases where magnetic resonance imaging (MRI) either gives equivocal results or fails to localize it. A 12-year-girl with cushingoid features and raised ACTH levels presented to us with two consecutive MRI’s done outside showing gross change in the morphology of a left-sided pituitary adenoma. Hence, a bilateral IPSS was done which showed a higher IPS/periphery ACTH ratio on the right side as compared to left. Transsphenoidal endoscopic excision of the left pituitary adenoma along with right hemihypophysectomy was performed. ACTH levels fell postoperatively. This case stands distinct in highlighting the discordance in lateralization of pituitary adenoma on MRI and IPSS. Review of literature tells us that while IPSS is more sensitive in accurately diagnosing Cushing’s disease, MRI provides better accuracy in lateralizing the site of adenoma.

Glucocorticoids

The most effective anti-inflammatory drugs used to treat patients with airways disease are topical glucocorticosteroids (GCs). These act on virtually all cells within the airway to suppress airway inflammation or prevent the recruitment of inflammatory cells into the airway. They also have profound effects on airway structural cells to reverse the effects of disease on their function. Glucorticosteroids act via specific receptors-the glucocorticosteroid receptor (GR)-which are a member of the nuclear receptor family. As such, many of the important actions of GCs are to modulate gene transcription through a number of distinct and complementary mechanisms. Targets genes include most inflammatory mediators such as chemokines, cytokines, growth factors and their receptors. GCs delivered by the inhaled route are very effective for most patients and have few systemic side effects. However, in some patients, even high doses of topical or even systemic GCs fail to control their disease. A number of mechanisms relating to inflammation have been reported to be responsible for the failure of these patients to respond correctly to GCs and these provide insight into GC actions within the airways. In these patients, the side-effect profile of GCs prevent continued use of high doses and new drugs are needed for these patients. Targeting the defective pathways associated with GC function in these patients may also reactivate GC responsiveness.

Cushing Syndrome: Diagnostic Workup and Imaging Features, With Clinical and Pathologic Correlation

OBJECTIVE

Cushing syndrome (CS) is a constellation of clinical signs and symptoms resulting from chronic exposure to excess cortisol, either exogenous or endogenous. Exogenous CS is most commonly caused by administration of glucocorticoids. Endogenous CS is subdivided into two types: adrenocorticotropic hormone (ACTH) dependent and ACTH independent.

CONCLUSION

Cushing disease, which is caused by a pituitary adenoma, is the most common cause of ACTH-dependent CS for which pituitary MRI can be diagnostic, with bilateral inferior petrosal sinus sampling useful in equivocal cases. In ectopic ACTH production, which is usually caused by a tumor in the thorax (e.g., small cell lung carcinoma, bronchial and thymic carcinoids, or medullary thyroid carcinoma) or abdomen (e.g., gastroenteropancreatic neuroendocrine tumors or pheochromocytoma), CT, MRI, and nuclear medicine tests are used for localizing the source of ACTH. In ACTH-independent CS, which is caused by various adrenal abnormalities, adrenal protocol CT or MRI is usually diagnostic.

Glucocorticoid-induced osteoporosis: pathophysiological role of GH/IGF-I and PTH/VITAMIN D axes, treatment options and guidelines

Glucocorticoid-induced osteoporosis is the most frequent form of secondary osteoporosis caused by chronic exposure to glucocorticoid excess. Pathogenesis of glucocorticoid-induced osteoporosis is multifactorial including direct effects of glucocorticoids on bone cells and indirect effects of glucocorticoids on several neuroendocrine and metabolic pathways. Fragility fractures occur early in glucocorticoid-induced osteoporosis and anti-osteoporotic drugs along with calcium and vitamin D should be started soon after exposure to glucocorticoid excess. This paper summarizes some of the main topics discussed during the 9th Glucocorticoid-Induced Osteoporosis Meeting (Rome, April 2016) with a specific focus on the role of growth hormone/insulin-like growth factor-1 and parathyroid hormone/vitamin D axes in the pathogenesis of glucocorticoid-induced osteoporosis and the controversial aspects concerning therapeutic approach to skeletal fragility in this clinical setting.

Management of Cushing syndrome in children and adolescents: experience of a single tertiary centre

The diagnosis and management of paediatric Cushing syndrome (CS) is highly challenging. This study aims to characterise its presentation, diagnosis, management and outcome by a retrospective case review of 30 patients (14 females) followed at a single tertiary paediatric endocrinology centre over a 30-year period. At presentation, median age was 8.9 years (0.2-15.5) and the commonest manifestations were weight gain (23/30), hirsutism (17/30), acne (15/30) and hypertension (15/30). Growth retardation was present in 11/30. Median body mass index (BMI) was +2.1 standard deviation score (SDS) (-6.5 to +4.6). Urinary free cortisol (UFC) was abnormal in 17/18 (94 %), midnight cortisol in 27/27 (100 %) and low-dose dexamethasone suppression (LDDS) test in 20/20 (100 %). High-dose dexamethasone suppression (HDDS) test was abnormal in 6/6 (100 %) of adrenal tumours, 1/10 (10 %) of Cushing disease (CD) and 1/2 (50 %) of ectopic tumours. Bilateral inferior petrosal sinus sampling (IPSS) identified five CD cases and one ectopic tumour. All patients underwent surgery and subsequently required cortisol replacement. Final diagnoses were 16 CD, 11 adrenal disease, 2 ectopic ACTH-secreting lesions and 1 case of unidentified aetiology. One year post-diagnosis, median BMI was 0.5 SDS (-2.5 to +3.7), hypertension was present in 4/14 (28 %), and 43 % (12/30) of individuals were off hydrocortisone.

CONCLUSION

The prevalence of the clinical manifestations differs from that reported in other series. Screening tests were highly sensitive, with UFC, midnight cortisol and LDDS performing well. One year post-treatment, BMI and BP normalised in the majority of patients and almost half of them were able to discontinue replacement hydrocortisone.

WHAT IS KNOWN

•Cushing syndrome is an extremely rare entity in the paediatric and adolescent age groups, so not many cohort studies have been published in this population. •Several tests can be employed to firstly diagnose hypercortisolaemia and secondly identify the source of origin of it. The efficacy and safety of these tests in children is still uncertain. What is New: •This study includes cases due to the different aetiologies of endogenous hypercortisolaemia (pituitary, adrenal and ectopic hypercortisolaemia) allowing us to compare the differences in presentation, diagnosis, management and long-term outcome between the groups. •There is a difference in the prevalence of Cushing syndrome symptoms and in the performance of the tests in our cohort compared to previously published studies in the literature.

Kidney Stones as an Underrecognized Clinical Sign in Pediatric Cushing Disease

OBJECTIVE

To investigate the prevalence of kidney stones in a population of children with Cushing disease (CD) and to compare it with the prevalence of kidney stones in healthy children.

STUDY DESIGN

Clinical and biochemical data from 139 pediatric patients with CD (68 females, 71 males) were analyzed retrospectively. Computed tomography scans were reviewed for kidney stones.

RESULTS

Among 139 patients, 27 with CD (19.4%) had either radiographic evidence and/or a history of kidney stones. Those with kidney stones had higher urine free cortisol (P = .008) and transsphenoidal surgery at an older age (P = .007). The average urinary calcium/creatinine ratio was elevated in patients with CD (0.22 ± 0.11). The prevalence of kidney stones was higher in children with CD than in normal children (19.42% vs 1.0%; P < .001).

CONCLUSION

Our results illustrate that kidney stones are an underestimated complication of pediatric CD, especially when compared with the prevalence of nephrolithiasis in the general pediatric population. Long-term consequences for kidney function are not known and need to be studied.

Residual manifestations of hypercortisolemia following surgical treatment in a patient with Cushing syndrome

Context

Cushing Syndrome is difficult to diagnose, and the comorbidities and persistent late effects of hypercortisolemia after treatment of the primary disease are challenging for the patient and the endocrinologist.

Objective

To report the case of a girl with obesity and hypertension, ultimately diagnosed with Cushing syndrome due to primary pigmented nodular adrenocortical disease. In this case, the complications of hypercortisolism persisted short term despite surgical intervention.

Patient

A 4 year old morbidly obese African-American girl with developmental delay presented with hypertensive emergency in the ER and 18-month history of progressive weight gain. Her previous history included premature adrenarche, hypertension, seizures and a random high cortisol with suppressed ACTH. She was subsequently stabilized, and a diagnostic work-up persistently demonstrated elevated cortisol and suppressed ACTH. An abdominal MRI showed bilateral adrenal multinodular disease, consistent with multinodular hyperplasia of the adrenal glands. Based on these findings the patient underwent a bilateral adrenalectomy, which confirmed primary pigmented nodular adrenocortical disease. The patient had a complicated, protracted post-operative course requiring adjustment of therapy for persistent hypertension. Two months after surgery, she was readmitted to the Emergency Department with hyperpyrexia and hypertension and succumbed to the complications of sepsis.

Conclusions and outcome

This case highlights the significant diagnostic and therapeutic challenges in treating children with Cushing syndrome. Resolution of the source of hypercortisolemia does not imply regression of hypertension or recovery of the immune system. Although the child underwent bilateral adrenalectomy, persistent consequences of prolonged severe hypercortisolism contributed to her death two months later.

MANAGEMENT OF ENDOCRINE DISEASE: Paediatric Cushing's disease

Cushing's disease (CD) is the commonest form of ACTH-dependent Cushing's syndrome and is a rare clinical diagnosis in paediatric and adolescent patients. CD is caused by an ACTH-secreting pituitary corticotroph adenoma and is associated with significant morbidity in children; therefore, early diagnosis and treatment are critical for optimal therapeutic outcome. This review highlights the key clinical and biochemical features of paediatric CD and appraises current practices in diagnosis and management. A close liaison with adult endocrinology colleagues, particularly, for interpretation of investigations and definition of therapeutic strategy is strongly advised.

A gender-dependent analysis of Cushing's disease in childhood: pre- and postoperative follow-up

OBJECTIVE

To analyse gender differences in the clinical presentation and recovery of paediatric patients with Cushing's disease (CD) after transsphenoidal surgery (TSS). Indeed, gender differences between paediatric patients with CD during presentation, after TSS and postoperative recovery have not been adequately studied.

DESIGN

Data were obtained and retrospectively analysed from clinical reports and biochemical tests at the time of presentation, 5-9 days after TSS and at the 6 and 12 months postoperative follow-up visits to determine hypothalamic-pituitary-adrenal axis (HPAA) recovery.

PATIENTS

Data from 102 paediatric patients (48 females, 54 males, mean age 12.9 ± 3.0) with CD who underwent TSS at the National Institute of Health (NIH) Clinical Center between 1997 and 2011.

RESULTS

There was equal distribution of paediatric CD between males and females (53% vs 47%; n = 102, P = 0.484). Males were more likely than females to present with higher mean BMI Z-scores (2.2 ± 0.7 vs 1.9 ± 0.6, P = 0.0079), lower mean height Z-scores (-1.2 ± 1.3 vs -0.7 ± 1.1, P = 0.0467) and higher median plasma ACTH (12.2 vs 8.5 pmol/l; P = 0.0495). Females did not present more frequently with any single sign or symptom. No significant differences were found between males and females for CD cure rates 5-9 days after TSS (87.0% males vs 87.5% females, P = 1.0), long-term cure rates (86.5% vs 93.7%; n = 69; P = 0.4374) and HPAA recovery time (11.2 ± 2.5 vs 11.7 ± 2.5 months; n = 47; P = 0.1992).

CONCLUSIONS

Paediatric CD is found to have equal distribution between males and females, but male patients present with elevated BMI and potentially shorter height and higher plasma ACTH. There is no significant difference in the cure rate or HPAA recovery time after TSS between males and females.

Pediatric Cushing's Disease and Pituitary Incidentaloma: Is This a Real Challenge?

Cushing's disease (CD) is the most common cause of endogenous Cushing's syndrome in children and adolescents and represents a rare cause of short stature. A 14-year-old boy came to our attention for progressive weight gain and short stature. At examination, height was 140 cm (3rd centile) and weight was 37.7 kg (10th centile). Tanner stage was G2, PH 3, testis 3 mL. Hypothyroidism and growth hormone deficiency were excluded. A marked increase of urinary free cortisol, a nonsuppressible serum cortisol after Liddle 1 test, and an elevated ACTH value confirmed the diagnosis of ACTH dependent Cushing's syndrome. Pituitary magnetic resonance imaging (MRI) showed a left microadenoma and a right focal area of lesser enhancement. Therefore, bilateral inferior petrosal sinus sampling (BIPSS) with CRH stimulation was performed to obtain an accurate preoperative localization of the adenoma: the interpetrosal sinus ACTH gradient indicated lateralization of ACTH secretion to the left side. The patient underwent transsphenoidal surgery with selective microadenomectomy, with an immediate ACTH decline in the postoperative phase. Histology confirmed the diagnosis of corticotrophic pituitary adenoma. Glucocorticoid replacement therapy was instituted. Clinical examination demonstrated a rapid catch-up growth (10th centile), with a normalization of body mass index and an adequate pubertal development.

Adrenal disorders and the paediatric brain: pathophysiological considerations and clinical implications

Various neurological and psychiatric manifestations have been recorded in children with adrenal disorders. Based on literature review and on personal case-studies and case-series we focused on the pathophysiological and clinical implications of glucocorticoid-related, mineralcorticoid-related, and catecholamine-related paediatric nervous system involvement. Childhood Cushing syndrome can be associated with long-lasting cognitive deficits and abnormal behaviour, even after resolution of the hypercortisolism. Exposure to excessive replacement of exogenous glucocorticoids in the paediatric age group (e.g., during treatments for adrenal insufficiency) has been reported with neurological and magnetic resonance imaging (MRI) abnormalities (e.g., delayed myelination and brain atrophy) due to potential corticosteroid-related myelin damage in the developing brain and the possible impairment of limbic system ontogenesis. Idiopathic intracranial hypertension (IIH), a disorder of unclear pathophysiology characterised by increased cerebrospinal fluid (CSF) pressure, has been described in children with hypercortisolism, adrenal insufficiency, and hyperaldosteronism, reflecting the potential underlying involvement of the adrenal-brain axis in the regulation of CSF pressure homeostasis. Arterial hypertension caused by paediatric adenomas or tumours of the adrenal cortex or medulla has been associated with various hypertension-related neurological manifestations. The development and maturation of the central nervous system (CNS) through childhood is tightly regulated by intrinsic, paracrine, endocrine, and external modulators, and perturbations in any of these factors, including those related to adrenal hormone imbalance, could result in consequences that affect the structure and function of the paediatric brain. Animal experiments and clinical studies demonstrated that the developing (i.e., paediatric) CNS seems to be particularly vulnerable to alterations induced by adrenal disorders and/or supraphysiological doses of corticosteroids. Physicians should be aware of potential neurological manifestations in children with adrenal dysfunction to achieve better prevention and timely diagnosis and treatment of these disorders. Further studies are needed to explore the potential neurological, cognitive, and psychiatric long-term consequences of high doses of prolonged corticosteroid administration in childhood.

Long-term follow-up on Cushing disease patient after transsphenoidal surgery

Cushing disease is caused by excessive adrenocorticotropic hormone (ACTH) production by the pituitary adenoma. Transsphenoidal surgery is its first-line treatment. The incidence of Cushing disease in children and adolescents is so rare that long-term prognoses have yet to be made in most cases. We followed-up on a 16-year-old male Cushing disease patient who presented with rapid weight gain and growth retardation. The laboratory findings showed increased 24-hour urine free cortisol and lack of overnight cortisol suppression by low-dose dexamethasone test. The serum cortisol and 24-hour urine free cortisol, by high-dose dexamethasone test, also showed a lack of suppression, and a bilateral inferior petrosal sinus sampling suggested lateralization of ACTH secretion from the right-side pituitary gland. However, after a right hemihypophysectomy by the transsphenoidal approach, the 24-hour urine free cortisol levels were persistently high. Thus the patient underwent a total hypophysectomy, since which time he has been treated with hydrocortisone, levothyroxine, recombinant human growth hormone, and testosterone enanthate. Intravenous bisphosphonate for osteoporosis had been administered for three years. At his current age of 26 years, his final height had attained the target level range; his bone mineral density was normal, and his pubic hair was Tanner stage 4. This report describes the long-term treatment course of a Cushing disease patient according to growth profile, pubertal status, and responses to hormone replacement therapy. The clinical results serve to emphasize the importance of growth optimization, puberty, and bone health in the treatment management of Cushing disease patients who have undergone transsphenoidal surgery.

A rare case of familial Cushing's syndrome with a common presentation of weight gain due to a mutation of the PRKAR1A gene causing isolated primary pigmented nodular adrenocortical disease

BACKGROUND

Cushing's syndrome (CS) is uncommon in childhood and adolescence. Variable presentation with subtle symptoms and signs can make diagnosis difficult.

CASE REPORT

We report the case of a 17-year-old girl referred for acne and progressive weight gain with an adrenocorticotropic hormone-independent CS. A computed tomography scan of the adrenals showed normal-sized adrenal glands with discrete bilateral shape irregularity. Bilateral adrenalectomy was performed and the histopathological findings were characteristic of primary pigmented nodular adrenocortical disease (PPNAD). Genetic analysis confirmed a germline mutation of the PRKAR1A gene. The same mutation was found in her sister, mother, and maternal grandfather. Endocrine tests showed that the sister of our patient also presented PPNAD requiring bilateral adrenalectomy and a similar histopathological pattern was observed. No other features of Carney complex was found among all affected members of the family.

CONCLUSION

It is exceptional for PPNAD to be an isolated phenomenon as well as being revealed by progressive weight gain in adolescence.

Cushing syndrome

Cushing syndrome is the constellation of signs and symptoms caused by protracted exposure to glucocorticoids. The most common cause of Cushing syndrome in children and adolescents is exogenous administration of glucocorticoids. Presenting features commonly include weight gain, growth retardation, hirsutism, obesity, striae, acne and hypertension. Almost invariably, linear growth is severely diminished, a factor which may be useful in differentiating between childhood obesity and Cushing syndrome. Diagnostic approaches are based on distinguishing between adrenocorticotropic hormone (ACTH)-dependent and ACTH-independent etiologies, and consideration of the most likely diagnosis by age. Treatment modality is dependent upon etiology. After cure, important components of care include attention to linear growth, pubertal progression and body composition.

A pediatric patient with Cushing syndrome caused by ectopic ACTH syndrome and concomitant pituitary incidentalomas

Ectopic ACTH syndrome is a rare but important cause of pediatric Cushing syndrome, for which management by a multidisciplinary team is required. Although diagnostic evaluation is similar to that in adults, the variation in epidemiology may sway investigations, leading to inappropriate and/or incomplete diagnostic interventions. We present a case of 15-year-old girl with symptoms of severe ACTH-dependent Cushing syndrome and two pituitary adenomas. The ectopic source of ACTH production was confirmed after petrosal venous sampling was performed. Diagnostics and perioperative management of a pulmonary carcinoid tumor producing ectopic ACTH is reviewed. In pediatric patients, as in adult patients, a pituitary lesion <6 mm on MRI is not sufficient confirmation of Cushing's disease, and appropriate diagnostic work-up should be performed to assess the source of the ACTH overproduction.

Cushing syndrome related to leukemic infiltration of the central nervous system: a case report and a possible role of LIF

BACKGROUND

Adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome (CS) in the presence of leukemic central nervous system infiltration is very rare.

CASE

A 3.8-year-old girl who had been treated for B-cell acute lymphoblastic leukemia (ALL) for 1.5 years was admitted to our hospital with excessive weight gain and depression for the last 2 months. Prior to her admission, she was on maintenance with the ALL-BFM95 study protocol for 10 months that does not contain corticosteroids. On physical examination, central obesity and moon face appearance were determined. Laboratory tests revealed high morning ACTH, cortisol level, and 24-h urinary free cortisol level. Morning cortisol level was 33.94 nmol/L after a 2-day (4 × 0.5 mg) dexamethasone suppression test. A lumbar puncture revealed leukemic cells in the cerebrospinal fluid. No pituitary adenoma was detected on magnetic resonance imaging. We diagnosed the patient with ACTH-dependent CS related to leukemic infiltration of the central nervous system.

CONCLUSION

Central nervous system infiltration should be considered in leukemic patients who have developed CS. We believe increased leukemia inhibitory factor levels may be a factor for CS in our patient with ALL.

Cushing syndrome in pediatrics

Cushing syndrome is characterized by truncal obesity, growth deceleration, skin changes, muscle weakness, and hypertension. Cushing syndrome in childhood usually results from the exogenous administration of glucocorticoids. This article presents the causes and discusses the treatment of endogenous Cushing syndrome. It also discusses the clinical and molecular genetics of inherited forms of this syndrome. Cushing syndrome needs to be diagnosed and treated properly when first recognized; improper treatment can turn this otherwise completely curable disorder into a chronic ailment. Barriers to optimal care of a pediatric patient with Cushing syndrome are discussed.

Cushing's disease in children: report of three cases

Cushing's disease is rare in children and adolescents. We report the clinical presentations of three children with Cushing's disease. All three exhibited the typical symptoms and signs of weight gain and growth retardation. Tw o also demonstrated personality changes, hypertension and hypokalemia, the last of these being rarely reported in patients with Cushing's disease. Lack of diurnal changes in serum cortisol levels was the most common biochemical finding. Serum cortisol levels were suppressed by low-dose dexamethasone in one patient, which is not typical for patients with Cushing's disease. Imaging studies are essential for localizing the tumor. Transsphenoidal surgery remains the treatment of choice, and pituitary irradiation should be considered for those patients whose tumors cannot be totally removed. Careful follow-up of these patients with awareness of the possibilities of relapse and the complications of hypopituitarism is indicated.

Surgical management of pediatric Cushing's disease: an analysis of 15 consecutive cases at a specialized neurosurgical center

OBJECTIVE: The aim of this study was to review the results of surgery for pediatric patients with Cushing's disease who were less than 18 years old and underwent transsphenoidal surgery in a specialized center during a 25-year period. SUBJECTS AND METHODS: Retrospective study, in which the medical records, histology and pituitary imaging of 15 consecutive pediatric patients with Cushing's disease (mean age: 13 years) were evaluated by the same team of endocrinologists and a neurosurgeon from 1982 to 2006. Patients were considered cured when there was clinical adrenal insufficiency and serum cortisol levels were below 1. 8 µg/dL or 50 nmol/L after one, two, three, or seven days following surgery; they therefore required cortisone replacement therapy. Follow-up was for a median time of 11.5 years (range: 2 to 25 years). RESULTS: Clinical and biochemical cure was achieved in 9/15 patients (60%) exclusively after transsphenoidal surgery. Hypopituitarism was observed in four patients; growth hormone deficiency, in two; permanent diabetes insipidus, in one case. CONCLUSIONS: Cushing's disease is rare in children and adolescents. Transsphenoidal surgery is an effective and safe treatment in most of these patients. Plasma cortisol level < 1. 8 µg/dL following surgery is the treatment goal and is a good predictive factor for long-term cure of Cushing's disease.

Diagnosis of diseases of steroid hormone production, metabolism and action

Biochemical tests have been the basis for investigations of disorders affecting steroid hormones. In recent years it has been possible however to study the genes that determine functional enzymes, cofactors, receptors, transcription factors and signaling systems that are involved in the process. Analyses of mutations are available as a diagnostic service for only a few of these genes although research laboratories may be able to provide a service. Both biochemical and genetic research have brought to light new disorders. Some genes for transcription factors involved in the development of the endocrine organs have also been identified and patients with defects in these processes have been found. This paper will review general aspects of adrenal disorders with emphasis on clinical and laboratory findings. As with all endocrine investigations there are few single measurements that provide a definitive answer to a diagnosis. Timing of samples in relation to age, gender and time of day needs to be considered.

Work-up and management of paediatric Cushing's syndrome

PURPOSE OF REVIEW

Paediatric Cushing's syndrome presents a diagnostic and therapeutic challenge. Most paediatric endocrinologists have limited experience in managing children or adolescents with Cushing's syndrome and thus benefit from close consultation with adult colleagues. A protocol for investigation of the child with suspected Cushing's syndrome is presented followed by principles of management.

RECENT FINDINGS

Cushing's syndrome is rare in childhood, but causes serious morbidity. Investigations have evolved and now include new genetic and imaging techniques as well as classical endocrine studies. In Cushing's disease trans-sphenoidal surgery has transformed management, although only a few surgeons have experience in children. Pituitary radiotherapy is effective second-line therapy.

SUMMARY

Early diagnosis and treatment of Cushing's syndrome is vital for long-term outcome. The overall prognosis for Cushing's syndrome is good but challenges remain to ensure normal postcure growth and body composition.

Operative management of Cushing syndrome secondary to micronodular adrenal hyperplasia

BACKGROUND

We reviewed our experience with micronodular adrenal hyperplasia (MAH), its pigmented variant primary pigmented nodular adrenocortical disease (PPNAD), and the association with Carney's complex (CNC) to better characterize these disorders.

METHODS

This retrospective study analyzes clinical data and operative reports of 34 patients identified with MAH and/or PPNAD who underwent resection between 1969 and 2006 at the Clinical Research Center, an inpatient research hospital at the National Institutes of Health. Symptoms and anthropometric and biochemical data were used to evaluate effect of resection.

RESULTS

Fifteen patients (44%) presented as adults and 19 (56%) as children. Twenty-five patients (74%) presented with noncyclic Cushing syndrome and 9 patients (26%) presented with cyclic Cushing syndrome. Thirty-one patients underwent bilateral resection; this was curative biochemically in 30 patients. Fourteen operations were performed laparoscopically (41%), and 20 were performed as open resections (59%). There was 1 postoperative complication in the laparoscopic group (7%) and 6 complications in the open group (30%; P = .20). Follow-up was available for 25 patients (74%). Statistically significant improvements in anthropometrics were observed for both adults and children. The most frequent manifestation of CNC requiring additional operation was cardiac myxoma, which was associated strongly with an atypical (cyclic) presentation of Cushing syndrome (P = .009).

CONCLUSION

Cushing syndrome due to MAH and PPNAD may be cured by bilateral adrenal resection. All patients should be screened for manifestations of CNC at the time of adrenal diagnosis with particular attention to cardiac disease.

Altered amygdala and hippocampus function in adolescents with hypercortisolemia: a functional magnetic resonance imaging study of Cushing syndrome

Chronic elevations of endogenous cortisol levels have been shown to alter medial temporal cortical structures and to be accompanied by declarative memory impairments and depressive symptoms in human adults. These effects of elevated endogenous levels of cortisol have not been directly studied in adolescents. Because adolescents with Cushing syndrome show endogenous elevations in cortisol, they represent a unique natural model to study the effects of prolonged hypercortisolemia on brain function, and memory and affective processes during this developmental stage. Using functional magnetic resonance imaging (fMRI), we compared 12 adolescents with Cushing syndrome with 22 healthy control adolescents on amygdala and anterior hippocampus activation during an emotional faces encoding task. None of these adolescents manifested depressive symptoms. Encoding success was assessed using a memory recognition test performed after the scan. The fMRI analyses followed an event-related design and were conducted using the SPM99 platform. Compared to healthy adolescents, patients with Cushing syndrome showed greater left amygdala and right anterior hippocampus activation during successful face encoding. Memory performance for faces recognition did not differ between groups. This first study of cerebral function in adolescents with chronic endogenous hypercortisolemia due to Cushing syndrome demonstrates the presence of functional alterations in amygdala and hippocampus, which are not associated with affective or memory impairments. Such findings need to be followed by work examining the role of age and related brain maturational stage on these effects, as well as the identification of possible protective factors conferring resilience to affective and cognitive consequences in this disease and/or during this stage of cerebral development.

Pediatric Cushing's syndrome: clinical features, diagnosis, and treatment

Cushing's syndrome (CS) results from prolonged exposure to supraphysiological levels of circulating glucocorticoids, endogenously or exogenously derived. Although rare in childhood, CS remains a difficult condition to diagnose and treat. A multidisciplinary approach and close collaboration with adult colleagues is adopted at most large centres that manage pediatric CS patients. Although pediatric protocols are derived from adult data, significant differences exist between adult and childhood CS. Furthermore, long term outcome parameters including final height, bone mineral density, reproductive function, body composition and psychological health pose challenges for pediatric care. This article will aim to provide an overall view of pediatric CS highlighting some of the differences between adult and pediatric CS.

Abnormal puberty in paediatric Cushing's disease: relationship with adrenal androgen, sex hormone binding globulin and gonadotrophin concentrations

OBJECTIVE

Paediatric Cushing's disease is frequently associated with abnormal puberty. We addressed the hypothesis that prepubertal patients show excessive virilization and pubertal patients show suppression of LH and FSH secretion.

DESIGN AND MEASUREMENTS

Serum androstenedione (A4), dehydroepiandrosterone sulphate (DHEAS), testosterone (T), and sex hormone binding globulin (SHBG) were determined at diagnosis and converted to standard deviation scores. LH, FSH concentrations were also determined. Severity of CD was assessed from the sleeping midnight cortisol concentration. Puberty was staged and excessive virilization defined as advance in pubic hair stage for breast stage or testicular volume (TV).

PATIENTS

Twenty-seven CD patients (17 male, 10 female), median age 13.4 years (range 5.9-17.8) were studied.

RESULTS

In the CD group as a whole, A4, DHEAS, T standard deviation scores (SDS) values were normal. SHBG SDS values (n = 19) were low (median -1.93, -4.32-0.86) correlating with BMI (r = -0.49). A4, DHEAS, T, SHBG, LH and FSH did not correlate with midnight cortisol, but A4 and T SDS correlated with ACTH at 09.00 h (both r = 0.51). Thirteen patients (11 male, 2 female) had excessive virilization with increased A4 (P = 0.033), DHEAS (P = 0.008), testosterone (P = 0.033) and decreased SHBG (P = 0.004) compared with subjects without excessive virilization. Pubertal boys (TV > or = 4 ml) (n = 7) and girls (breasts > or = stage 2) (n = 8) had low median LH and FSH. Boys had an LH concentration of 1.2 mU/l (0.3-3.5), FSH, 0.9 mU/l (0.2-6.4) and median T SDS, -1.95 (-3.8-4.65), while girls had an LH concentration of 1 mU/l (0.3-7.4).

CONCLUSIONS

Many patients had abnormal puberty and excessive virilization associated with increased adrenal androgens and decreased SHBG. Pubertal patients had low LH and FSH suggesting impaired pituitary-gonadal axis function.

Use of desmopressin as an alternative to corticotropin-releasing hormone during inferior petrosal sinus sampling in a child with Cushing's disease

Cushing's syndrome (CS) is rare in children. Information on bilateral inferior petrosal sinus sampling (BIPSS) in children with CS is limited. In the procedure CRH is always used to stimulate ACTH values. In addition, growth failure is the main complication of pediatric CS, mainly due to a profound GH suppression that persists for a few months after cure of the disease. Early treatment with recombinant GH after CS cure may partly reverse this phenomenon. We report herein a case of Cushing's disease (CD) in a 7-yr-old child, presenting with severe growth failure. No pituitary adenoma was shown on magnetic resonance imaging and a BIPSS using desmopressin allowed the identification of a central to peripheral (C/P) gradient; however transphenoidal surgery (TSS) did not cure the disease thus requiring the performance of bilateral adrenalectomy. After cure of the disease, a partial catch up of the growth delay occurred without any GH treatment. Our case reinforces the fact that BIPSS can be performed safely in very young children with CD. It also suggests for the first time that the use of desmopressin during the procedure gives the same information as CRH, as well as confirming the fact that the success of TSS is poor in very young children. Finally, it suggests that growth failure in children with CS can be partially reversed after surgical cure of the disease without any GH treatment and that the high IGF-I observed during corticosteroid replacement therapy is due to a state of IGF-I resistance.

Paediatric Cushing's syndrome: epidemiology, investigation and therapeutic advances

Cushing's syndrome (CS), which is caused by excessive circulating glucocorticoid concentrations, is rare in the paediatric age range but presents a diagnostic and therapeutic challenge. Most paediatric endocrinologists have limited experience of managing children or adolescents with CS and thus benefit from close consultation with colleagues who treat adult patients. A protocol for investigation is required that broadly follows the model for adult patients. Here, the epidemiology and diagnosis of different causes of CS are discussed according to typical age of presentation. Treatment strategies for adrenocorticotrophic hormone (ACTH)-independent and ACTH-dependent CS are described and critically appraised. The management of paediatric CS patients after cure also presents challenges for optimizing growth, bone health, reproduction and body composition from childhood into and during adult life.

Diagnosis and treatment of pediatric Cushing's disease

Cushing's disease (CD) is rare in the pediatric age range, but may present a diagnostic and therapeutic challenge. Most pediatric endocrinologists have limited experience managing children or adolescents with CD and thus benefit from close consultation with adult colleagues. A diagnostic protocol for investigation is required which broadly follows the model for adult patients. Treatment strategies for CD are described and critically appraised. The management of pediatric CD patients after cure also presents challenges for optimizing growth, bone health, reproduction and body composition from childhood into and during adult life.

Update on glucocorticoid action and resistance

Extensive development of inhaled and oral glucocorticoids has resulted in highly potent molecules that have been optimized to target activity to the lung and minimize systemic exposure. These have proved highly effective for most asthmatic subjects, but despite these developments, there are a number of subjects with asthma who fail to respond to even high doses of inhaled or even oral glucocorticoids. Advances in delineating the fundamental mechanisms of glucocorticoid pharmacology, especially the concepts of transactivation and transrepression and cofactor recruitment, have resulted in better understanding of the molecular mechanisms whereby glucocorticoids suppress inflammation. The existence of multiple mechanisms underlying glucocorticoid insensitivity raises the possibility that this might indeed reflect different diseases with a common phenotype, and studies examining the efficacy of potential new agents should be targeted toward subgroups of patients with severe corticosteroid-resistant asthma who clearly require effective new drugs and other approaches to improved asthma control.

The discriminatory value of the low-dose dexamethasone suppression test in the investigation of paediatric Cushing's syndrome

BACKGROUND

Low- and high-dose dexamethasone suppression tests (LDDST, HDDST) are used in the investigation of Cushing's syndrome (CS). In adults with Cushing's disease (CD), cortisol suppression during LDDST predicts suppression during the HDDST.

METHODS

We reviewed the results of the LDDST (0.5 mg 6 hourly x 48 h), HDDST (2.0 mg 6 hourly x 48 h) and corticotrophin-releasing hormone (CRH) test in 32 paediatric patients with CS: 24 had CD, 1 ectopic ACTH syndrome, 5 nodular adrenal hyperplasia and 2 adrenocortical tumours.

RESULTS

In CD, LDDST suppressed cortisol from 590.7 +/- 168.8 (mean +/- SD) to 333.7 +/- 104.0 nmol/l after 48 h (0 vs. 48 h, p < 0.05; mean suppression, 45.1%; CI (30.8, 59.4%); 16/24 (66%) suppressed >30%; mean suppression 68.1%, CI (58.1, 77.9%)). The HDDST suppressed cortisol from 596.3 +/- 174.5 to 47.1 +/- 94.8 nmol/l after 48 h (0 vs. 48 h, p < 0.05; mean suppression, 93.5%; CI (88.2, 98.8%) with 17/24 (71%) suppressing to <50 nmol/l and 100% to <50% of baseline). In the LDDST, suppression correlated with that during the HDDST (r = +0.45, p < 0.05) with >30% suppression predicting that in the HDDST and hence CD. CRH increased cortisol by +100.3% (CI 62, 138.5%), 22/24 (91.7%) showing a >20% increase. In the other CS pathologies (n = 8) the LDDST induced no significant decrease in cortisol.

CONCLUSION

The LDDST was of diagnostic value by discriminating between CD and other CS aetiologies. In our view the HDDST is redundant in the investigation of paediatric CS.

Cushing's disease

Cushing's disease, i.e., pituitary ACTH-secreting adenoma causing excess glucocorticoid secretion, is a rare disease with significant mortality and morbidity. Timely diagnosis and appropriate treatment can alter the course of the disease and are therefore mandatory. First step of the diagnostic work-up is the endogenous glucocorticoid excess by measurement of urinary free cortisol, cortisol circadian rhythmicity or suppression by low doses of dexamethasone. In patients with equivocal results, second line tests, such as the dexamethasone-suppressed CRH test and desmopressin stimulation, usually enable the diagnosis to be confirmed. Measurement of plasma ACTH then allows the distinction between ACTH-dependent (e.g., pituitary or extrapituitary neuroendocrine tumors) and ACTH-independent causes (e.g., adrenal tumors). The last step in the diagnostic algorithm is often the most fraught with problems as the distinction between Cushing's disease and ectopic ACTH secretion relies on judicious interpretation of several diagnostic procedures. Positive responses to stimulation with CRH and inhibition by high doses of dexamethasone, if concurrent, enable a pituitary origin to be established whereas conflicting results call for inferior petrosal sinus sampling, the latter to be performed in experienced centres only. Visualisation of the tumor at pituitary imaging is helpful but not required for the diagnosis, as microadenomas often remain undectected by MRI and/or CT scan and, on the other hand, visualisation of a non-secreting incidentaloma may be misleading. Surgical removal of the pituitary tumor is the optimal treatment choice and should be attempted in every patient. Surgical failures as well as relapses can be treated by radiotherapy, medical therapy or, if necessary, bilateral adrenalectomy. Finally, patients cured of Cushing's disease require long-term monitoring given the risk of relapse and clinical burden of associated ailments.

The biochemical investigation of Cushing syndrome

Cushing syndrome is an insidious illness that warrants an early diagnosis to avoid the effects of prolonged hyper-cortisolism. The variability in the clinical features of the disease and the occasional inconsistencies between different biochemical tests performed to identify it render the diagnosis challenging. In this paper the author discusses the various biochemical tests that are useful for the diagnoses of Cushing syndrome and Cushing disease, with an emphasis on the respective sensitivities and specificities of these tests. The measurement of evening salivary cortisol and the combined low-dose dexamethasone–corticotropin-releasing hormone stimulation test have improved overall sensitivity and specificity in the evaluation of Cushing syndrome and Cushing disease.