The role of bilateral inferior petrosal sinus sampling in the diagnosis of Cushing's syndrome

Bilateral inferior petrosal sinus sampling in the differential diagnosis of ACTH-dependent Cushing's syndrome: A reappraisal

Cushing's syndrome (CS) is a rare disorder, once exogenous causes have been excluded. However, when diagnosed, the majority of cases are adrenocorticotropic hormone (ACTH)-dependent, of which a substantial minority are due to a source outside of the pituitary, ectopic ACTH syndrome (EAS). Differentiating among pituitary-dependent CS, Cushing's disease (CD) and an ectopic source can be problematic. Because non-invasive tests in the evaluation of CS patients often lack adequate sensitivity and specificity, bilateral inferior petrosal sinus sampling (BIPSS), a minimally invasive procedure performed during the investigation of ACTH-dependent CS, can be extremely helpful. BIPSS is considered to be the gold standard for differentiating CD from the EAS. Furthermore, although such differentiation may indeed be challenging, BIPSS is itself a complex investigation, especially in recent times due to the widespread withdrawal of corticotrophin-releasing hormone and its replacement by desmopressin. We review current published data on this investigation and, in the light of this and our own experience, discuss its appropriate use in diagnostic algorithms.

Pitfalls in Performing and Interpreting Inferior Petrosal Sinus Sampling: Personal Experience and Literature Review

CONTEXT

Inferior petrosal sinus sampling (IPSS) helps differentiate the source of ACTH-dependent hypercortisolism in patients with inconclusive biochemical testing and imaging, and is considered the gold standard for distinguishing Cushing disease (CD) from ectopic ACTH syndrome. We present a comprehensive approach to interpreting IPSS results by examining several real cases.

EVIDENCE ACQUISITION

We performed a comprehensive review of the IPSS literature using PubMed since IPSS was first described in 1977.

EVIDENCE SYNTHESIS

IPSS cannot be used to confirm the diagnosis of ACTH-dependent Cushing syndrome (CS). It is essential to establish ACTH-dependent hypercortisolism before the procedure. IPSS must be performed by an experienced interventional or neuroradiologist because successful sinus cannulation relies on operator experience. In patients with suspected cyclical CS, it is important to demonstrate the presence of hypercortisolism before IPSS. Concurrent measurement of IPS prolactin levels is useful to confirm adequate IPS venous efflux. This is essential in patients who lack an IPS-to-peripheral (IPS:P) ACTH gradient, suggesting an ectopic source. The prolactin-adjusted IPS:P ACTH ratio can improve differentiation between CD and ectopic ACTH syndrome when there is a lack of proper IPS venous efflux. In patients who have unilateral successful IPS cannulation, a contralateral source cannot be excluded. The value of the intersinus ACTH ratio to predict tumor lateralization may be improved using a prolactin-adjusted ACTH ratio, but this requires further evaluation.

CONCLUSION

A stepwise approach in performing and interpreting IPSS will provide clinicians with the best information from this important but delicate procedure.

Circulating Plasma microRNA to Differentiate Cushing's Disease From Ectopic ACTH Syndrome

Corticotropinomas and adrenocorticotropic hormone (ACTH)-secreting neuroendocrine tumors exhibit differential levels of some microRNAs (miRs) compared to normal tissue. Because miRs can be released from tissues into circulation, they offer promise as novel disease biomarkers. Objective: To evaluate whether miRs are differentially detected in plasma samples of patients with ACTH-dependent Cushing's syndrome (CS). Design: Case-control study. Methods: Morning fasting plasma samples were collected from 41 consecutive patients with confirmed ACTH-dependent CS and 11 healthy subjects and stored at -80°C. Twenty-one miRs previously reported to be differentially expressed in ACTH-secreting tumors vs. healthy tissue samples were quantified in plasma by qPCR. Results: Among enrolled subjects, 28 were confirmed to have Cushing's disease (CD), 13 had ectopic ACTH secretion (EAS) and 11 were healthy controls. We found statistically significant differences in the circulating levels of miR-16-5p [45.04 (95% CI 28.77-61.31) in CD vs. 5.26 (2.65-7.87) in EAS, P < 0.001; q = 0.001], miR-145-5p [0.097 (0.027-0.167) in CD vs. undetectable levels in EAS, P = 0.008; q = 0.087] and differences in miR-7g-5p [1.842 (1.283-2.400) in CD vs. 0.847 (0.187-1.507) in EAS, P = 0.02; q = 0.14]. The area under the receiver-operator (ROC) curve was 0.879 (95% CI 0.770-0.987), p < 0.001, when using miR-16-5p to distinguish between CD and EAS. Circulating levels of miR-16-5p in the healthy control group differed from that of both the CD and EAS groups. Conclusions: Plasma miR levels differ in patients with CD and EAS. In particular, miR-16-5p, miR-145-5p and miR-7g-5p are promising biomarkers for further research to differentiate ACTH-dependent CS.

Hypokalaemic metabolic alkalosis, hypertension and diabetes: what is the link

Two years after diagnosis of a metastatic neuroendocrine gastrin-secreting tumour and after several cycles of chemotherapy and peptide receptor radionuclide therapy, a 56-year-old woman presented with hypokalaemic metabolic alkalosis, hypertension, leg oedema and new-onset diabetes mellitus. Further investigations revealed renal potassium loss confirmed by a transtubular potassium gradient of 16, fully suppressed serum aldosterone, but instead highly elevated blood levels of morning cortisol and adrenocorticotropic hormone as well as increased urinary excretion of glucocorticoid and mineralocorticoid metabolites. Ruling out other causes, paraneoplastic hypercortisolism was diagnosed. Pharmacological inhibition of the steroid 11β-hydroxylase with metyrapone resulted in complete resolution of metabolic alkalosis, hypokalaemia, hypertension, hyperglycaemia and leg oedema within 1 week.

Bilateral inferior petrosal sinus sampling

Simultaneous bilateral inferior petrosal sinus sampling (BIPSS) plays a crucial role in the diagnostic work-up of Cushing's syndrome. It is the most accurate procedure in the differential diagnosis of hypercortisolism of pituitary or ectopic origin, as compared with clinical, biochemical and imaging analyses, with a sensitivity and specificity of 88-100% and 67-100%, respectively. In the setting of hypercortisolemia, ACTH levels obtained from venous drainage of the pituitary are expected to be higher than the levels of peripheral blood, thus suggesting pituitary ACTH excess as the cause of hypercortisolism. Direct stimulation of the pituitary corticotroph with corticotrophin-releasing hormone enhances the sensitivity of the procedure. The procedure must be undertaken in the presence of hypercortisolemia, which suppresses both the basal and stimulated secretory activity of normal corticotrophic cells: ACTH measured in the sinus is, therefore, the result of the secretory activity of the tumor tissue. The poor accuracy in lateralization of BIPSS (positive predictive value of 50-70%) makes interpetrosal ACTH gradient alone not sufficient for the localization of the tumor. An accurate exploration of the gland is recommended if a tumor is not found in the predicted area. Despite the fact that BIPSS is an invasive procedure, the occurrence of adverse events is extremely rare, particularly if it is performed by experienced operators in referral centres.

Recommendations of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism for the diagnosis of Cushing's disease in Brazil

Although it is a rare condition, the accurate diagnosis and treatment of Cushing's disease is important due to its higher morbidity and mortality compared to the general population, which is attributed to cardiovascular diseases, diabetes mellitus and infections. Screening for hypercortisolism is recommended for patients who present multiple and progressive clinical signs and symptoms, especially those who are considered to be more specific to Cushing's syndrome, abnormal findings relative to age (e.g., spinal osteoporosis and high blood pressure in young patients), weight gain associated with reduced growth rate in the pediatric population and for those with adrenal incidentalomas. Routine screening is not recommended for other groups of patients, such as those with obesity or diabetes mellitus. Magnetic resonance imaging (MRI) of the pituitary, the corticotropin-releasing hormone (CRH) test and the high-dose dexamethasone suppression test are the main tests for the differential diagnosis of ACTH-dependent Cushing's syndrome. Bilateral and simultaneous petrosal sinus sampling is the gold standard method and is performed when the triad of initial tests is inconclusive, doubtful or conflicting. The aim of this article is to provide information on the early detection and establishment of a proper diagnosis of Cushing's disease, recommending follow-up of these patients at experienced referral centers. Arch Endocrinol Metab. 2016;60(3):267-86.

Bilateral inferior petrosal sinus sampling using vasopressin

CONTEXT

Anatomical localization of pituitary adenoma can be challenging in adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome, and bilateral inferior petrosal sinus sampling (BIPSS) is considered gold standard in this regard. Stimulation using corticotrophin-releasing hormone (CRH) improves the sensitivity of BIPSS, however, same is not easily available in India. Therefore, we undertook this study of BIPPS using vasopressin as agent for stimulation owing to its ability to stimulate V3 receptors present on corticotrophs.

AIMS

To study the tumor localization and lateralization in difficult to localize cases of ACTH-dependent Cushing's syndrome by bilateral inferior petrosal sinus sampling using vasopressin for corticotroph stimulation.

SETTINGS AND DESIGN

Prospective observational study.

SUBJECTS AND METHODS

Six patients (5 females) meeting inclusion criteria underwent BIPSS using vasopressin for stimulation.

RESULTS

All six patients had nonsuppressible overnight and low dose dexamethasone suppression test with elevated plasma ACTH levels suggestive of ACTH-dependent Cushing's syndrome. High dose dexamethasone suppression test showed suppressible cortisol in two cases, and microadenoma was seen in two patients on magnetic resonance imaging pituitary. Contrast enhanced computed tomography of the abdomen showed left adrenal hyperplasia in one case and anterior mediastinal mass with bilateral adrenal hyperplasia another. Using BIPSS four patients were classified as having Cushing's disease that was confirmed histopathologically following surgery. Of the remaining two, one had primary pigmented nodular adrenocortical disease, and another had thymic carcinoid with ectopic ACTH production as the cause of Cushing's syndrome. No serious adverse events were noted.

CONCLUSIONS

Vasopressin may be used instead of CRH and desmopressin for stimulation in BIPSS.

Role of bilateral inferior petrosal sinus sampling (BIPSS) in the diagnosis of Cushing's disease in a patient with double superior vena cava

Cushing's syndrome is known to have a wide spectrum of clinical presentation with debilitating consequences and morbidity if not diagnosed and treated in time. Sometimes the diagnosis of Cushing's syndrome can be challenging to the endocrinologist, especially when the usual battery of biochemical tests and advanced cross-sectional imaging is negative or inconclusive. We described a case in which the use of bilateral inferior petrosal sinus sampling (BIPSS) was conclusive albeit being technically challenging (due to a rare incidental finding of double superior vena cava) and invasive in nature.

Cushing’s disease: the clinical features, diagnostics, differential diagnostics, and methods of treatment

The present guidelines on diagnostics, differential diagnostics, and methods of treatment of Cushing’s disease have been developed by a group of Russian specialists.

[Technical and functional aspects of catheterization of inferior petrosal sinuses in ACTH dependent Cushing's syndrome]

OBJECTIVE

To describe and analyze technique for bilateral catheterization of inferior petrosal sinus in our service, discussing the difficulties and success rates found.

SUBJECTS AND METHODS

Fourteen patients with suspected Cushing's syndrome underwent bilateral inferior petrosal sinuses (IPS) catheterization between 2009 and 2012. The technique for catheterization and for hormone analysis were described.

RESULTS

The procedure was well tolerated by all patients, and adequate catheterization was achieved in 92.85% of cases. The diagnosis of Cushing's disease was confirmed in 10 cases. The result of IPS catheterization after CRH infusion was coherent in all cases, without false negatives.

CONCLUSION

The catheterization of IPS, despite being an invasive technique, is a safe procedure. The objectives can be done properly in most cases. When well indicated, this procedure remains the gold standard in distinguishing the ectopic form to pituitary source in Cushing's syndrome.

Adrenocorticotropin responsiveness to acute octreotide administration is not affected by mifepristone premedication in patients with Cushing's disease

Octreotide (OCT) is ineffective in patients with Cushing's disease (CD) due to the cortisol-induced down-regulation of somatostatin receptor subtype 2 which was shown to be reversible in vitro by using anti-glucocorticoid mifepristone. This study aimed to verify, in vivo, if mifepristone can modulate response to acute OCT administration in patients with CD. Three men and two postmenopausal women (age 52.5 ± 2 years) with CD were enrolled in the study. OCT (100 μg, s.c.) was administered alone on the first day (OCT-only), and it was then given after mifepristone administration (2 × 200 mg, p.os, 12 and 1 h before OCT), 3 days later (OCT-mif). ACTH and cortisol levels were measured before OCT administration and every 60 min thereafter for 6 h. Baseline ACTH and cortisol values, nadir values and percentage decrements (Δn) were compared during both tests. Mean ACTH-Δn did not differ significantly during the two tests. Both tests induced a <30 % decrease in plasma ACTH in three patients (#1, 2 and 3) and a >50 % decrease in the other two cases (#4 and 5). Cortisol decreased in patients #4 and 5, during both tests. ACTH-Δn did not correlate with morning cortisol nor with urinary free cortisol values. Patients #4 and 5 with the highest ACTH-Δn had the lowest cortisol values after 1 mg of dexamethasone. Brief mifepristone pre-treatment does not modify ACTH and cortisol response to acute OCT administration in CD. However, OCT seems to be more effective in patients with partially preserved cortisol inhibitory feedback.

Intraoperative multiple-staged resection and tumor tissue identification using frozen sections provide the best result for the accurate localization and complete resection of tumors in Cushing's disease

The treatment of choice in Cushing's disease (CD) is surgical removal; however, most tumors are too small to be detected. The objective was to establish a method to achieve the complete removal of tumors on the basis of the results of high-resolution magnetic resonance imaging (MRI), inferior petrosal sinus sampling (IPSS), and a surgical resection technique using frozen biopsy. Eighteen patients who underwent transsphenoidal surgery from 2004 to 2010 were included. High-resolution MRI and IPSS, multiple-staged resection, and tumor tissue identification in frozen sections (surgical and histological identification, SHI) were performed. All patients achieved surgical remission, as confirmed by 24 h urinary free cortisol excretion tests. Visible microlesions were identified on the initial MRI in 11 patients (61%). The SHI findings agreed with the MRI findings in 10 of the 11 patients (90.9%) and with IPSS lateralization in 6 of the 11 patients (54.5%). In the 7 patients whose lesions were not visible on the initial MRI, only 1 (14.3%) showed an agreement between IPSS and SHI. In 3 of the 7 patients, the microlesions were identified by additional MRI. The rate of concordance with SHI was 77.8% for the overall MRI and 38.9% for IPSS. High-resolution MRI is better than IPSS for localizing corticotroph adenomas. In patients with lesions not visible on the initial MRI, additional MRI should be performed using a different protocol. Although high-resolution MRI is better for localizing tumors, SHI remains an important approach for removing the tumors completely.

Bilateral inferior petrosal sinus sampling by unilateral femoral venous approach

Purpose

Bilateral inferior petrosal sinus sampling (IPSS) is a direct method of distinguishing between pituitary and ectopic ACTH secretion. We present unilateral femoral route technique avoiding bilateral femoral venous puncture using two 4F catheters into both sides of IPSS in these obese patients.

Materials and Methods

Unilateral femoral puncture using 9F guiding catheter allowed two 4F catheters which can be introduced in each side of inferior petrosal sinus. To reduce bleeding in the gap between 2 catheters at the diaphragm of the 9F femoral sheath, we introduced a short guidewire provided along with femoral sheath. After removing the 9F sheath after procedure, we applied manual compression as usual. We evaluated any technical difficulty and other complications including the presence of hematoma at the puncture site 1 day and 30 days later.

Results

Bilateral IPSS by using two 4F catheters in both inferior petrosal sinuses was possible via unilateral femoral route via 9F sheath. There was no technical difficulty introducing 4F catheters into each IPS of both sides. After removing 9F femoral sheath, there was no other complication and no hematoma at the puncture site at 1 day and 30 days later.

Conclusion

Unilateral femoral venous approach with a 9-French sheath can be used in IPSS. This technique allowed to pass two 4F catheters for IPSS at both sides and could avoid unnecessary bilateral femoral puncture in these obese patients without any hematoma formation after the procedure.

The role of interventional venous sampling in localising neuroendocrine tumours

PURPOSE OF REVIEW

This review focuses on the role of interventional venous sampling in the diagnosis and localization of neuroendocrine tumours (NETs), and its role in relation to conventional and novel imaging techniques.

RECENT FINDINGS

Imaging of NETs has evolved together with advances in imaging technology. Imaging localization plays an important role in the subsequent management of these tumours. This article provides an overview of the application of venous sampling in the localization of NETs, presented with current evidence to support its continued role in the diagnostic work-up of pituitary, parathyroid, pancreatic, adrenal and ovarian endocrine disease.

SUMMARY

Interventional venous sampling continues to be a highly sensitive modality in the localization of NETs. Although significant advances in noninvasive anatomic and functional imaging modalities have reduced the reliance of this well established technique, the latest literature continues to support its important role in the diagnostic armament of these unique and rare tumours.

Psychosomatic aspects of Cushing's syndrome

There has been growing interest in the psychosocial aspects of Cushing's syndrome, such as the role of life stress as a pathogenetic factor, the association with affective disorders, and the presence of residual symptoms after treatment. Interestingly, a temporal relationship between stressful life events and disease onset is relevant only to pituitary-dependent Cushing's disease, and not to the pituitary-independent forms. A number of psychiatric and psychological disturbances may be associated with the active hypercortisolemic state, regardless of its etiology. Within the high frequency of mood disorders (about 60%), major depression is the most common complication. Other psychopathological aspects include mania, anxiety disorders, psychological symptoms (demoralization, irritable mood, somatization) and cognitive impairment. Cognitive symptoms are associated with brain abnormalities (mainly loss of brain volume). Quality of life may be seriously compromised during both active and post-treatment phases. Long-standing hypercortisolism may imply a degree of irreversibility of the pathological process. Recovery, thus, may be delayed and be influenced by highly individualized affective responses. Outcomes of Cushing's syndrome treatment are not fully satisfactory. Within its great complexity, a conceptual shift from a merely biomedical care to a psychosomatic consideration of the person and his/her quality of life appears to be necessary to improve effectiveness. It is time to translate the research evidence that has accumulated into clinical practice initiatives. To patients who show persistence or even worsening of psychological distress upon adequate endocrine treatment psychiatric/psychological interventions should be readily available. Applying interdisciplinary expertise and addressing the needs for rehabilitation would markedly improve final outcome.

Imaging study of the long extracranial extension of the inferior petrosal sinus with MSCT

The aim of this study was to explore the anatomic route of Long-Inferior Petrosal Sinuses (IPS) with multi-slice spiral computed tomography, and to provide referenced evidence for the interventional preoperative evaluation for the diagnosis and treatment of skull base and sellar lesions. The route of Long-IPS and its confluence with the internal jugular vein (IJV) and the connection level of 12 IPS were shown with multi-planar reconstruction and curved multi-planar reconstruction, and the IPS length was determined. Combining the results of continuous multi-slice scanning, the diameters of the IPS at the initial segment in the jugular foreman and middle segment and the confluence segment of the IPS-IJV junction level were determined. The mean length of the Long-IPS was 66.2 +/- 17.5 mm, and the length was over 60 mm on eight sides and its peak value 100 mm. The mean diameters of the IPS were 2.4 mm +/- 0.7 mm, 2.1 mm +/- 0.4 mm, and 2.1 mm +/- 0.5 mm at the initial, middle, and confluent segments, respectively. Their diameters were equal to or greater than 2 mm at the connection level on eight sides. Furthermore, the diameter was greater than 1.6 mm at the middle and initial segments. The Long-IPS might be used as a route to the intra-cranial IPS. MSCT is helpful for showing the route and variation of the IPS and could be an effective method for preoperative evaluation of the IPS.

[Diagnosis and differential diagnosis of Cushing's syndrome]

Because of the variability in the clinical expression of Cushing's syndrome, different biochemical tests and imaging techniques must be used for effective diagnosis and treatment. The clinical history is important to assess the general impact of hypercortisolism on organs and systems, as well as to guide suspicion toward more aggressive entities such as overt ectopic ACTH syndrome or to detect an iatrogenic etiology of Cushing's syndrome. The screening phase relies on tests that are sensitive but not specific, such as urinary free cortisol, nocturnal salivary cortisol and 1 mg dexamethasone suppression, which still require established assessment criteria. Confirmation can be obtained by repeating urinary cortisol, 2 mg/day dexamethasone suppression, both alone and combined with corticotropin releasing hormone (CRH), to exclude pseudoCushing states. ACTH dependency can be easily explored by ACTH measurements, but the differential diagnosis between pituitary and ectopic Cushing's disease is difficult and may require invasive procedures such as inferior petrosal sinus sampling. Sophisticated imaging and isotopic techniques play a significant role in locating the source of ACTH in ectopic syndromes but are not always effective. In general, biochemical and imaging tests should be combined in order to assess different mechanisms and perspectives of the syndrome. Rigorous methodology is essential to obtain accurate results, allowing a correct diagnosis and improving therapeutic performance in this devastating disease.

Cyclic Cushing syndrome due to an ectopic pituitary adenoma

BACKGROUND

A 39-year-old man was referred to an endocrinology clinic for evaluation of his Cushing syndrome. He had gained 20 kg over 5 years and complained of intermittent headaches and easy bruisability. His medical history included a left foot fracture associated with minimal trauma 2 years earlier, hypertension, and stable Crohn disease with no use of exogenous glucocorticoids for at least 10 years.

INVESTIGATIONS

Measurements of plasma adrenocorticotropic hormone, 24 h urine free cortisol excretion, late-night salivary cortisol, serum cortisol levels before and after corticotropin-releasing hormone administration during a dexamethasone suppression/corticotropin-releasing hormone-stimulation test, pituitary MRI, and inferior petrosal sinus sampling.

DIAGNOSIS

Cyclic Cushing syndrome secondary to an ectopic pituitary adenoma.

MANAGEMENT

The cyclic nature of Cushing syndrome was suggested by the absence of hypercortisolemia during inferior petrosal sinus sampling, and was confirmed by multiple 24 h urine free cortisol measurements. The patient underwent transsphenoidal surgery, during which a 5 mm firm, round, midline sphenoid sinus lesion was identified and resected. In preoperative imaging studies, this lesion had been interpreted as being a mucosal polyp. At microscopic examination, the lesion was found to be a pituitary adenoma, which stained diffusely with antiadrenocorticotropic-hormone antibodies. Explorations of the sella and pituitary did not reveal any abnormalities. Postoperatively, the patient became hypocortisolemic and his cushingoid features resolved. His adrenal function normalized 3 months after surgery. At 18 months, the patient continued to be symptom-free with normal levels of urinary-free cortisol and midnight salivary cortisol.