PubMed Health⌕ Search

Biomedical subjects

Gregory A Kaltsas

Publications and source records attributed to Gregory A Kaltsas.

17 recordsLinked to original sources
PubMed2006

Ectopic ACTH syndrome.

Ectopic adrenocorticotropin secretion (EAS) accounts for 10-15% of cases of Cushing's syndrome and comprises a spectrum of tumours from undetectable isolated lesions to widespread metastatic and aggressive malignancies. EAS is often associated with severe hypercortisolaemia causing hypokalaemia, diabetes, generalized infections, hypertension and psychotic reactions. Surgical resection of the primary lesion, achievable with a curative intent in about 40% of patients with EAS, is associated with complete remission in up to 80% of such cases. It is therefore mandatory to localize the source of ectopic ACTH hypersecretion in order to stage the disease and adopt optimal treatment modalities. Modern cross-sectional imaging techniques can identify the majority of the ACTH secreting lesions, either initially or at follow-up reassessment. However, in approximately 10-20% of patients with EAS, the source of ACTH hypersecretion remains occult in spite of extensive investigation and prolonged followup. In such cases, control of the hypercortisolemia can be achieved with long-term adrenolytic medication. When conditions require a prompt and definitive resolution of the hypercortisolaemia (i.e. as in pregnancy), bilateral adrenalectomy remains an alternative option. This review focuses on the clinical features, diagnostic pitfalls, management and long-term followup of the EAS based on the extensive experience of major referral centres.

ACTH Syndrome, Ectopic↗
PubMed2005

The ectopic adrenocorticotropin syndrome: clinical features, diagnosis, management, and long-term follow-up.

CONTEXT: There are few large series of patients with ectopic, nonpituitary, corticotropin (ACTH) secretion (EAS). OBJECTIVE: The objective of this study was to analyze the clinical, biochemical, and radiological features, management, and treatment outcome of patients with EAS. DESIGN: This was a retrospective case-record study. SETTING: The setting for this study was a tertiary referral hospital center. PATIENTS: Forty patients with EAS were studied. MAIN OUTCOME MEASURES: Clinical, biochemical, and radiological features and response to therapy and survival were measured. RESULTS: The median follow-up was 5 yr (range, 2-30 yr). None of the dynamic tests achieved 100% accuracy, but bilateral inferior petrosal sinus sampling showed an absent central gradient in all but one case (one of 12). Imaging correctly identified the lesion at first investigation in 65% of cases. Bronchial carcinoid tumors were the most common cause of EAS (n = 12; 30%), followed by other neuroendocrine tumors (n = 13, 32.5%). In 12.5% of patients, the source of EAS was never found. Octreotide scintigraphy and whole-body venous sampling were of limited value. Surgical attempt at curative resection was successful in 83% (10 of 12) of patients with bronchial carcinoid tumors; others responded generally well to adrenolytic therapy or bilateral adrenalectomy. Tumor histology and the presence of distant metastases were the main predictors of overall survival (P < 0.05). CONCLUSIONS: A variety of tests and imaging studies are necessary for the correct diagnosis of the EAS, but even then, up to 20% of cases present a covert or occult EAS syndrome. These cases require a prolonged follow-up, review, and repetition of diagnostic tests and scans.

ACTH Syndrome, Ectopic↗
PubMed2005

Pregnancy following ovarian drilling in a woman with polycystic ovary syndrome and nine previous first trimester miscarriages.

CASE REPORT: We report a woman with a history of polycystic ovary syndrome (PCOS) and nine first-trimester miscarriages following ovulation induction and in vitro fertilization. The majority of these attempts were associated with ovarian hyperstimulation syndrome. No causes of recurrent miscarriages other than PCOS were found. Following laparoscopic ovarian drilling (LOD) she delivered a live neonate at 30 weeks of gestation. DISCUSSION: This case describes the difficulties associated with the management of patients with PCOS and recurrent abortions. We believe that LOD has helped prevent miscarriage in this patient. The early application of this technique in such patients needs to be formally assessed by a prospective study.

Abortion, Habitual↗
PubMed2005

Clinical and biochemical characteristics of adrenocorticotropin-secreting macroadenomas.

CONTEXT: Cushing's disease as a result of a pituitary macroadenoma is an uncommon cause of Cushing's syndrome, and reports in the published literature are few and of limited size. OBJECTIVE: Our objective was to establish the clinical and biochemical characteristics of macroadenomas associated with Cushing's disease compared with a large cohort of microadenomas and to assess their response to therapy. DESIGN: We conducted a retrospective case-records study for the years 1964-2001. SETTING: The study occurred at a tertiary referral hospital center. PATIENTS: Patients had Cushing's disease presenting with a pituitary macroadenoma, in comparison with a large group of microadenoma patients. INTERVENTIONS: Interventions included therapy with surgery and radiotherapy. MAIN OUTCOME MEASURES: Outcome measures included basal and dynamically responsive plasma ACTH and cortisol levels and response to treatment. RESULTS: We identified 18 patients with Cushing's disease secondary to a macroadenoma; basal 0900 h plasma ACTH was 135.8 +/- 32.5 and 45.0 +/- 4.3 ng/liter (mean +/- SEM), respectively, in macroadenomas and microadenomas (P = 0.013). Mean 0900 h serum cortisol was significantly increased in the macroadenomas (27.5 +/- 3.0 microg/dl, 759.6 +/- 82.6 nmol/liter, vs. 22.6 +/- 0.6 microg/dl, 624.7 +/- 16.4 nmol/liter) (P = 0.021). Testing with high-dose dexamethasone showed less suppression in the macroadenomas (57.6 +/- 8.7% vs. 74.4 +/- 2.1%; P = 0.02) and an attenuated ACTH response to CRH. For all biochemical variables there was considerable overlap between the two groups. Few patients with macroadenomas were cured by surgery. CONCLUSIONS: Pituitary macroadenomas causing Cushing's disease have biochemical features largely distinct from patients harboring microadenomas but represent one end of a continuum.

Adenoma↗
PubMed2005

Clinical review: Diagnosis and management of pituitary carcinomas.

Pituitary carcinomas are rare, making up some 0.2% of all pituitary tumors, but represent a particular challenge to clinical practice. The diagnosis of a pituitary carcinoma requires evidence of metastatic disease, either outside the central nervous system (CNS) or as separate noncontiguous foci within the CNS. They may present as typical pituitary adenomas, which reveal their malignant character only as time progresses, or as peculiarly aggressive tumors ab initio. Recent changes in histopathological classification have clarified many of the features of such tumors, including immunohistochemical staining for Ki-67 and p53, but to date none has been found to be pathognomonic. The majority of carcinomas are secretory, usually arising from corticotroph tumors or prolactinomas, but all histological types and secretory patterns are represented. Treatment is by surgery, transsphenoidal wherever possible, and conventional and stereotactic radiotherapy, but ultimately, a plethora of therapies may be required, including various attempts at medical therapy. Chemotherapy in some instances probably prolongs survival, but, in general, their progress from the diagnosis of carcinomatous changes is progressive and inexorable. However, we do not believe there will be any real prospect of long-term survival until the development and use of therapies targeted at specific molecular abnormalities.

Adrenocorticotropic Hormone↗
PubMed2005

Spontaneous gonadotrophin deficiency recovery in an adult patient with Langerhans cell histiocytosis (LCH).

Langerhans cell histocytosis (LCH) is a rare disease which exhibits a particular predilection for pituitary involvement leading to diabetes insipidus (DI) and other anterior pituitary hormonal deficiencies that are usually permanent and unresponsive to treatment. We report a 35 year old woman with a 10 year history of multisystemic LCH who developed DI, mild hyperprolactinemia, gonadotrophin and partial growth hormone deficiency following a normal delivery that was accompanied with infundibular thickening on pituitary magnetic resonance imaging (MRI). Following several courses of glucocorticoid administration, that were not associated with any substantial improvement, the patient was started on estrogen replacement therapy and cabergoline. After a three year period free of further relapses she developed irregular uterine bleeding. Following estrogen and cabergoline discontinuation she resumed normal menstruation while a repeated MRI of the pituitary showed an almost normal infundibulum. Endocrine investigation revealed normal gonadotrophin axis and prolactin levels, while the patient continues to menstruate, every 30-40 days, ten months after the resumption of her menstrual cycle. This case demonstrates for the first time that LCH induced pituitary deficiencies can run a variable clinical course and even spontaneously recover.

Adult↗
PubMed2004

Secondary forms of polycystic ovary syndrome.

Hyperandrogenism and chronic anovulation are the most common endocrine disorders of premenopausal women. Most patients have polycystic ovary syndrome (PCOS), which is essentially benign, but might be associated with increased cardiovascular morbidity; PCOS is associated with specific endocrine and ultrasonographic features. Some patients exhibiting similar features to PCOS might have other underlying diagnoses, such as adrenal and ovarian steroidogenic deficiencies, adrenal and ovarian androgen-secreting tumours, other medical or endocrine disorders, and/or be on medications thought to cause PCOS, such as anti-epileptics. Unlike PCOS, some of these conditions can occasionally be life threatening and require prompt diagnosis and treatment. Here, we focus on these disorders, including their pathogenesis, and attempt to define the clinical and biochemical features that distinguish them from PCOS.

Endocrine System Diseases↗
PubMed2004

The diagnosis and medical management of advanced neuroendocrine tumors.

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms that originate from endocrine glands such as the pituitary, the parathyroids, and the (neuroendocrine) adrenal, as well as endocrine islets within glandular tissue (thyroid or pancreatic) and cells dispersed between exocrine cells, such as endocrine cells of the digestive (gastroenteropancreatic) and respiratory tracts. Conventionally, NETs may present with a wide variety of functional or nonfunctional endocrine syndromes and may be familial and have other associated tumors. Assessment of specific or general tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogs and metaiodobenzylguanidine. Successful treatment of disseminated NETs requires a multimodal approach; radical tumor surgery may be curative but is rarely possible. Well-differentiated and slow-growing gastroenteropancreatic tumors should be treated with somatostatin analogs or alpha-interferon, with chemotherapy being reserved for poorly differentiated and progressive tumors. Therapy with radionuclides may be used for tumors exhibiting uptake to a diagnostic scan, either after surgery to eradicate microscopic residual disease or later if conventional treatment or biotherapy fails. Maintenance of the quality of life should be a priority, particularly because patients with disseminated disease may experience prolonged survival.

Adrenal Gland Neoplasms↗
PubMed2003

The value of the low-dose dexamethasone suppression test in the differential diagnosis of hyperandrogenism in women.

We studied 211 hyperandrogenic women with respect to clinical presentation, basal androgen levels, and the degree of cortisol and androgen suppression during a 48-h low-dose (2 mg) dexamethasone-suppression test (LDDST) to exclude ovarian and adrenal tumors. In 42 women with elevated testosterone levels, 21 of whom failed to suppress testosterone during the LDDST, the response of serum androgen levels during a 4-wk administration of 7.5 mg prednisolone in a reverse circadian regimen was also assessed. These results were compared with an additional 17 patients with histologically proven androgen-secreting tumors. Clinical presentation alone was suggestive of a virilizing tumor in 70% of patients with tumors. Serum testosterone, although occasionally only marginally elevated, was the sole androgen that was elevated in every patient with a tumor. After the LDDST, none of the patients with tumors obtained either a greater than 40% reduction or normalization of the previously elevated testosterone levels, whereas 88% of patients with nontumorous hyperandrogenism showed either normalization or suppression of more than 40%. With one exception, all of the patients with nontumorous hyperandrogenism who showed inadequate suppression of testosterone during the LDDST, and were treated with prednisolone, normalized the previously elevated androgens after 1 month of administration. In summary, in women presenting with hyperandrogenism, lack of testosterone suppression during the LDDST is associated with 100% sensitivity and 88% specificity in distinguishing patients with ovarian and adrenal androgen-secreting tumors from patients with nontumorous hyperandrogenism in this small series. The LDDST is an easy to perform screening test that can also identify causes of hyperandrogenism due to altered glucocorticoid secretion.

Adolescent↗
PubMed2003

Identification of adrenocorticotropin receptor messenger ribonucleic acid in the human pituitary and its loss of expression in pituitary adenomas.

The ACTH receptor (ACTH-R) is the second member of the melanocortin (MC-2) receptor family that includes five seven-transmembrane G protein-coupled receptors and has been shown to be predominantly expressed in the adrenal cortex. It has been postulated that ACTH may regulate its own secretion through ultra-short-loop feedback within the pituitary. ACTH-secreting adenomas are characterized by resistance to glucocorticoid feedback, and they may have dysregulated ACTH feedback. We therefore investigated the ACTH-R in normal and adenomatous human pituitary tissue. We report here the identification of ACTH-R mRNA in the human pituitary gland, which was confirmed by direct sequencing. We studied the expression of the ACTH-R in 23 normal pituitary specimens and 53 pituitary adenomas (22 ACTH-secreting, nine GH-secreting, eight prolactin-secreting, one TSH-secreting, one FSH-secreting, 10 nonfunctioning, and two silent corticotroph adenomas), using the sensitive technique of real-time quantitative PCR. Contamination of ACTH-secreting adenomas and nonfunctioning pituitary adenomas with nonadenomatous tissue was excluded by lack of Pit-1 expression. ACTH-R mRNA was detected in all normal pituitary specimens, and in situ hybridization colocalized expression to ACTH staining cells only. However, ACTH-R mRNA levels were undetectable in 16 of 22 ACTH-secreting tumors and in both silent corticotroph tumors. Diagnostic preoperative plasma ACTH levels were significantly lower in the ACTH-R positive ACTH-secreting tumors, compared with those who were ACTH-R negative (P = 0.0006). Direct sequencing of the coding region of the ACTH-R in cDNA from three ACTH-secreting tumors positively expressing the receptor showed no mutations, as did sequencing of genomic DNA in three receptor negative ACTH-secreting tumors and the two silent corticotrophs. These results provide further evidence compatible with an ACTH feedback loop in the pituitary and suggest that loss of expression of the ACTH-R in corticotroph adenomas of patients with Cushing's disease may play a role in the resistance to feedback of the pituitary-adrenal axis seen in these patients.

Adenoma↗
PubMed2003

Discriminatory value of the low-dose dexamethasone suppression test in establishing the diagnosis and differential diagnosis of Cushing's syndrome.

Cushing's syndrome requires a screening test of high sensitivity, followed by biochemical evaluation of the source of the tumor when the cause is ACTH dependent. The high-dose dexamethasone suppression test is still in common use as an aid in differential diagnosis, although its value has been queried. We have routinely used the low-dose dexamethasone suppression test for many years in the diagnosis of Cushing's syndrome but noticed that patients with pituitary-dependent Cushing's syndrome or Cushing's disease, usually showed some degree of suppression of their serum cortisol, compared to those with the ectopic ACTH syndrome. We therefore analyzed retrospectively the serum cortisol responses during the low-dose dexamethasone suppression test and the high-dose dexamethasone suppression test in 245 patients with ACTH-dependent Cushing's syndrome and compared the diagnostic utility of each test either alone or in combination with a standard test using CRH. Evaluation of the serum cortisol response at 24 and 48 h during the low-dose dexamethasone suppression test correctly identified 98% of patients with ACTH-dependent Cushing's syndrome and distinguished between pituitary and ectopic causes with a sensitivity of 82% and a specificity of 79%. In the same patients, the serum cortisol response to the high-dose dexamethasone suppression test had a slightly higher sensitivity (91%) and specificity (80%). However, the combined criteria of a more than 30% suppression of serum cortisol during the low-dose dexamethasone suppression test and/or a more than 20% increase in the CRH test had a significantly higher sensitivity (97%) and specificity (94%) than either the high-dose dexamethasone or the CRH tests alone in the differential diagnosis of ACTH-dependent Cushing's syndrome. It produced equivalent information to that when high-dose and CRH test results were combined. We therefore conclude that in our patient series, the serum cortisol response during the low-dose dexamethasone suppression test is highly sensitive in diagnosing Cushing's syndrome and, combined with the results of the serum cortisol response to the CRH test, offered a safe and cost-effective test in the differential diagnosis of ACTH-dependent Cushing's syndrome. There does not appear to be any necessity for retaining the high-dose dexamethasone suppression test in this diagnostic work-up.

Adrenocorticotropic Hormone↗
PubMed2002

Sequence analysis of the PRKAR1A gene in sporadic somatotroph and other pituitary tumours.

OBJECTIVE: Carney complex (CNC) is an autosomal dominant multiple neoplasia syndrome featuring cardiac, endocrine, cutaneous and neural tumours, as well as a variety of pigmented lesions of the skin and mucosa. Pituitary GH-secreting tumours are found in approximately 10% of patients with CNC. One of the genes responsible for CNC, the PRKAR1A gene located on human chromosome 17q22-24, has recently been cloned. This represents a putative tumour suppressor gene, coding for the type 1alpha regulatory subunit of protein kinase A (PKA), which is found to be mutated in approximately half of the patients with CNC. However, it is currently unclear as to whether similar mutations occur in sporadic pituitary tumours. We have therefore investigated a series of GH-secreting and other pituitary tumours for sequence abnormalities in the PRKAR1A gene. The mRNA produced by the PRKAR1A undergoes decay if it codes for a truncated protein; we therefore also determined PRKAR1A mRNA levels in the tumours, and compared them with known mutant PRKAR1A-carrying lymphocyte samples. METHODS: We extracted RNA from a series of pituitary tumours, reverse transcribed it to cDNA, and directly sequenced the PRKAR1A coding sequence in 17 GH-secreting, three prolactin-secreting, three ACTH-secreting, one FSH-secreting and 10 nonfunctioning pituitary tumours. Lymphocyte and tumour tissue RNA from two patients with CNC was used as positive controls. Using duplex polymerase chain reaction (PCR) with the PRKAR1A and the "housekeeping" gene GAPDH, we determined the relative expression of the PRKAR1A gene in the unknown as well as in the positive control samples. RESULTS AND CONCLUSION: No mutations were found in any of the exons sequenced. Relative mRNA expression was not decreased in any of the sporadic pituitary tumour samples. The present data thus do not suggest a major role for the PRKAR1A tumour suppressor gene in sporadic GH-secreting or other pituitary tumours.

Adenoma↗
PubMedDate not supplied

GH deficiency in adults.

Until the last decade, the diagnosis of GH deficiency (GHD) in adults was only considered as a marker of hypothalamo-pituitary disease. GHD in adults is now recognized as a specific clinical syndrome associated with a cluster of cardiovascular risk factors such as altered body composition with increased body fat, insulin resistance, adverse lipid profile, reduced physical performance, reduced bone mineral density and impaired quality of life. Several randomized placebo controlled trials have now established that GH replacement can reverse some of these biological changes and improve the overall health status in GHD adults; as a consequence, GH replacement therapy has now been approved in many countries in such patients. With the advent of recombinant technology, there is a virtually unlimited, safe supply of recombinant human GH. Although GH replacement is not administered as commonly as steroid, thyroid and sex hormones in hypopituitary patients, a six-month trial of GH replacement with re-evaluation of well-being, body composition and lipid profile is currently recommended. However, there is marked individual variability in the response to GH replacement, with IGF-I being the most sensitive serum marker of GH action. Questions yet remaining to be answered relate to the role of GH replacement in cases of partial GHD and its use in the elderly population. The safety of long term replacement therapy remains an important issue, particularly in relation to the cardio-vascular system, the incidence of de novo malignant tumours and the recurrence rate of pituitary tumours. In the context of safety, it remains essential to monitor patients by means of longitudinal surveillance databases.

Journal Article↗
PubMedDate not supplied

The diagnosis and differential diagnosis of endogenous Cushing's syndrome.

Cushing's syndrome (CS) is a physically and psychologically disabling disease associated with high morbidity resulting from inappropriate elevation of circulating free cortisol levels. The main features of CS are disturbance of the normal circadian rhythm of cortisol secretion, impairment of the normal feedback of the hypothalamo-pituitary-adrenal (HPA)-axis, and excessive integrated 24 hours cortisol secretion. All biochemical tests used for the diagnosis of CS rely upon the ascertainment of a disturbance of these features. However, the diagnosis of CS (endogenous hypercortisolism) still remains a challenge, although the evolution of several diagnostic tests has allowed diagnosis at an earlier stage. In the initial investigation of CS, tests of high sensitivity are required to identify patients at risk, which are followed by tests of high specificity to confirm the diagnosis and establish the precise aetiology. This review will discuss the various causes of endogenous CS and focus on established and evolving diagnostic procedures used for its diagnosis, as several studies with large number of patients have recently appeared in the literature validating current practice and proposing improved diagnostic algorithms.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Treatment of advanced neuroendocrine tumours with the radiolabelled somatostatin analogue octreotide.

Neuroendocrine tumours (NET) have a particular tendency to express functional receptors and/or uptake mechanisms. Radionuclides, such as (111)In-pentetreotide, a somatostatin analogue, which bind to somatostatin receptors, present an imaging modality that has been used for both the diagnosis and staging of NET. Scintigraphy with (111)In-pentetreotide can identify lesions beyond the diagnostic sensitivity of conventional imaging modalities. In addition, NET that demonstrate positive uptake to a diagnostic (111)In-pentetreotide can, in theory, be treated with these radionuclides, thus presenting a novel and evolving therapeutic modality in addition to other traditional therapeutic approaches. Although experience with (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide therapy is still limited, preliminary studies have demonstrated useful activity in a variety of NET with limited side-effects. Large phase II clinical trials using (90)Y-DOTA-D-Phe(1)-Tyr(3)-octreotide therapy are still on-going and the results are expected to be presented soon. In order to improve the response rates obtained, newer somatostatin analogues are being developed and the combination with other beta-emitting particles in addition to (90)Y is being considered.

Journal Article↗
PubMedDate not supplied

Hypoglycaemia secondary to the secretion of pro-insulin like growth factor II by a metastatic neuroendocrine tumour with sarcomatous differentiation.

A patient presented with frequent episodes of spontaneous hypoglycaemia due to a disseminated neuroendocrine tumour with sarcomatous differentiation, secreting incompletely processed pro-insulin-like growth factor II (pro-IGF-II). Although the combination of GH and glucocorticoid therapy initially controlled the hypoglycaemia, there was a later escape necessitating frequent re-admissions to hospital. The patient deceased two weeks following her latest admission.

Journal Article↗