Impairment of GH secretion in adults with primary empty sella

A Comprehensive Review of Empty Sella and Empty Sella Syndrome

OBJECTIVE

Incidental radiographic findings of an empty sella are prevalent in up to 35% of the general population. While empty sella was initially considered clinically insignificant, a subset of patients exhibits endocrine or neuro-ophthalmologic manifestations which are diagnostic of empty sella syndrome (ESS). Recent studies suggest that more patients are affected by ESS than previously recognized, necessitating a deeper understanding of this condition. This comprehensive review describes a practical approach to evaluating and managing ESS.

METHODS

Literature review was conducted on etiologies and risk factors associated with primary and secondary empty sella, the radiologic features that differentiate empty sella from other sellar lesions, and the role of clinical history and hormone testing in identifying patients with ESS, as well as treatment modalities.

RESULTS

Pituitary function testing for somatotroph, lactotroph, gonadotroph, corticotroph, and thyrotroph abnormalities is necessary when suspecting ESS. While an isolated empty sella finding does not require treatment, ESS may require pharmacologic or surgical interventions to address hormone deficits or intracranial hypertension. Targeted hormone replacement as directed by the endocrinologist should align with guidelines and patient-specific needs. Treatment may involve a multidisciplinary collaboration with neurology, neurosurgery, or ophthalmology to address patient symptoms.

CONCLUSION

This review underscores the evolving understanding of ESS, stressing the significance of accurate diagnosis and tailored management to mitigate potential neurologic and endocrine complications in affected individuals.

Management of a Growth Hormone-Secreting Pituitary Macroadenoma Associated With Idiopathic Intracranial Hypertension and an Empty Sella

Idiopathic intracranial hypertension (IIH) is a -condition associated with elevated intracranial pressure (ICP) and frequently presents with headaches, papilledema, and visual loss. Rarely, IIH has been reported in association with acromegaly. Although removal of the tumor may reverse this process, elevated ICP, especially in the setting of an otherwise empty sella, may result in a cerebrospinal fluid (CSF) leak that is exceedingly difficult to manage. We present the first case of a patient with a functional pituitary adenoma causing acromegaly associated with IIH and an otherwise empty sella and discuss our management paradigm for this rare condition.

Empty sella syndrome: Multiple endocrine disorders

Empty sella is a pituitary disorder characterized by the herniation of the subarachnoid space within the sella turcica. This is often associated with a variable degree of flattening of the pituitary gland. Empty sella has to be distinguished in primary and secondary forms. Primary empty sella (PES) excludes any history of previous pituitary pathologies such as previous surgical, pharmacologic, or radiotherapy treatment of the sellar region. PES is considered an idiopathic disease and may be associated with idiopathic intracranial hypertension. Secondary empty sella, however, may occur after the treatment of pituitary tumors through neurosurgery or drugs or radiotherapy, after spontaneous necrosis (ischemia or hemorrhage) of chiefly adenomas, after pituitary infectious processes, pituitary autoimmune diseases, or brain trauma. Empty sella, in the majority of cases, is only a neuroradiological finding, without any clinical implication. However, empty sella syndrome is defined in the presence of pituitary hormonal dysfunction (more frequently hypopituitarism) and/or neurological symptoms due to the possible coexisting of idiopathic intracranial hypertension. Empty sella syndrome represents a peculiar clinical entity, characterized by heterogeneity both in clinical manifestations and in hormonal alterations, sometimes reaching severe extremes. For a proper diagnosis, management, and follow-up of empty sella syndrome, a multidisciplinary approach with the integration of endocrine, neurological, and ophthalmological experts is strongly advocated.

Immune dyscrasia in adult growth hormone deficiency: Evaluation of hemolytic complement activity (CH50) and IgG subclasses

CH50 is a screening assay for the activation of the classical complement pathway, the immunoglobulins-mediated one, activated in several inflammatory diseases. Adult growth hormone deficiency (aGHD) is recognized as a chronic inflammatory condition, although poorly evaluated under the profile of inflammatory biomarkers. The aim of this case-control observational study is to analyze CH50 and immunoglobulins G (IgG) subclasses production in aGHD, comparing this condition to healthy controls. 38 subjects were included and divided as follows: aGHD (n = 18, 6 females and 12 males); healthy controls (n = 20, 10 females and 10 males). GHD was diagnosed with dynamic test using Growth Hormone-Releasing Hormone (GHRH 50 μg i.v. + arginine 0,5 g/Kg), with a peak GH response < 9 μg/L when BMI was <30 kg/m² or < 4 μg/L when BMI was >30 kg/m². The two groups were evaluated for hormonal and metabolic parameters, CH50 and IgG subtypes. IgG1 and IgG2 were significantly higher in controls than in aGHD, while IgG3 and IgG4 showed a trend to higher levels in controls, although not significant. Furthermore, CH50 levels were significantly higher in aGHD. These data substantiate the hypothesis of a dyscrasia in IgG subclasses production in aGHD. As IgG levels decrease, CH50 levels do not.

Clinical presentation, evaluation and case management of primary empty sella syndrome: a retrospective analysis of 10-year single-center patient data

BACKGROUND

Primary Empty Sella (PES) syndrome is an increasingly common disorder, mostly diagnosed as an incidental finding during brain imaging scans. We intended to review the clinical management and hormonal profile of patients with PES.

METHODS

The study included ten-year retrospective analysis of registry containing PES cases in the period 2007 to 2017, from a single tertiary care center. The keyword 'primary empty sella' was used to retrieve patient details from the radiology unit. The clinical and biochemical profile of PES patients was analyzed. Case management of PES patients and their rate of referral to endocrinologists was explored.

RESULTS

The registry had 765 cases with a male: female ratio of 1:3.8 suggesting female predominance by almost four times. Although not significant, the onset of disease was earlier for males [Mean ± standard deviation (SD) (46.7 years ±17.3 vs 48.8 years±14.1), p = 0.110]. Almost 79% of the cases were found as an incidental finding during Magnetic Resonance Imaging. Of the total PES cases, only 20% were referred to the endocrinologists and the rest were handled by general physicians. Only 1-2.5% of the cases were evaluated for gonadal, growth and adrenal hormones by the general physicians. The hormonal evaluation by the endocrinologists was also found to be sub-optimal. Headache and visual disturbances were the most common presenting complaints followed by menstrual abnormalities. Endocrine abnormalities like thyroid dysfunction, hyperprolactinemia, hypogonadism and hypocortisolism were highly prevalent among those assessed.

CONCLUSION

There is a gross under-evaluation of hormonal assessment and minimal case-referral to Endocrinologists. PES is associated with varying degrees of hormonal dysfunction, and hence early assessment and management is needed. Establishing a standard protocol for diagnosis and case management is essential with the involvement of a multidisciplinary team consisting of endocrinologists, neurologists, primary care phys icians and ophthalmologists.

Case Report: Pituitary Morphology and Function Are Preserved in Female Patients With Idiopathic Intracranial Hypertension Under Pharmacological Treatment

Idiopathic Intracranial Hypertension is a neurological disorder primarily affecting overweight women of childbearing age. It is often characterized by radiologic evidence of empty sella (ES), which is in turn frequently associated with pituitary dysfunction, with the somatotropic axis most commonly affected. No recent evidence is available relative to the presence of pituitary hormone deficiencies in adult patients with Idiopathic Intracranial Hypertension (IIH) under pharmacological therapy. We therefore explored pituitary function and morphology in a small cohort of female patients with IIH treated with acetazolamide. Fifteen female patients aged 42 ± 13 years with IIH lasting between 12 and 18 months were evaluated. All patients were affected by recurrent headaches in addition to visual changes of variable severity. IIH diagnosis was made after exclusion of other causes of raised intracranial pressure, and a specific ophthalmological evaluation was conducted to assess for the presence of papilledema. No particular endocrinological disturbances were detected during the enrolment visits, except for a high obesity prevalence (87%, BMI 35.16 ± 8.21 kg/m²), one case of total thyroidectomy for papillary thyroid carcinoma and two patients with irregular menses and mild hirsutism. All the participants underwent a pituitary MRI with contrast, and two different operators performed pituitary measurements in coronal and sagittal scans for morphologic assessment. Blood samples for the anterior pituitary axis evaluation were collected, and the somatotropic axis was further evaluated with a GHRH + Arginine test; other dynamic tests were performed in case of suspected hormonal deficiency. Despite ES being found in 73% of the patients, pituitary volume was preserved, ranging from 213.85 to 642.27mm³ (389.20 ± 125.53mm³); mean coronal pituitary height was 4.53 ± 1.33 mm. Overall, baseline anterior pituitary hormones levels were within normal ranges, and none of the patients with ES had an altered response to the GHRH + arginine stimulation test. We found one patient suffering from iatrogenic hyperthyroidism and two diagnosed with subclinical primary hypothyroidism due to Hashimoto's thyroiditis. Two young patients were suspected of having polycystic ovary syndrome, and they were therefore further investigated. In conclusion, this case series shows that, despite the high prevalence of ES, the pituitary function of IIH patients treated with acetazolamide is preserved. To date, there is no evidence regarding the trend over time or upon treatment discontinuation in regard to the pituitary function of patients with IIH, and it is therefore not possible to infer whether our finding would be replicable in such settings. We therefore suggest an endocrine follow-up over time in order to monitor for potential pituitary dysfunction.

DIAGNOSIS OF ENDOCRINE DISEASE: Primary empty sella: a comprehensive review

Primary empty sella (PES) is characterized by the herniation of the subarachnoid space within the sella, which is often associated with variable degrees of flattening of the pituitary gland in patients without previous pituitary pathologies. PES pathogenetic mechanisms are not well known but seem to be due to a sellar diaphragm incompetence, associated to the occurrence of upper sellar or pituitary factors, as intracranial hypertension and change of pituitary volume. As PES represents in a majority of cases, a neuroradiological findings without any clinical implication, the occurrence of endocrine, neurological and opthalmological symptoms, due to the above describes anatomical alteration, which delineates from the so called PES syndrome. Headache, irregular menses, overweight/obesity and visual disturbances compose the typical picture of PES syndrome and can be the manifestation of an intracranial hypertension, often associated with PES. Although hyperprolactinemia and growth hormone deficit represent the most common endocrine abnormalities, PES syndrome is characterized by heterogeneity both in clinical manifestation and hormonal alterations and can sometime reach severe extremes, as occurrence of papilledema, cerebrospinal fluid rhinorrhea and worsening of visual acuity. Consequently, a multidisciplinary approach, with the integration of endocrine, neurologic and ophthalmologic expertise, is strongly advocated and recommended for a properly diagnosis, management, treatment and follow-up of PES syndrome and all of the related abnormalities.

Central hypothyroidism and its role for cardiovascular risk factors in hypopituitary patients

Hypothyroidism is characterized by hypometabolism, and may be seen as a part of secondary failure due to pituitary insufficiency or tertiary due to hypothalamic disease. Secondary and tertiary failures are also referred to as central hypothyroidism. Whereas overt primary hypothyroidism has a well-known affection on the heart and cardiovascular system, and may result in cardiac failure, cardiovascular affection is less well recognized in central hypothyroidism. Studies on central hypothyroidism and cardiovascular outcome are few and given the rarity of the diseases often small. Further, there are several limitations given vast difficulties in diagnosing the condition correctly biochemically, and difficulties monitoring the treatment because normal thyroid-pituitary feedback interrelationships are disrupted. The present review summarizes available studies of central adult hypothyroidism and its possible influence on the cardiovascular system, describe differences from primary thyroid failure and seek evidence for performing guidelines for clinical management of this particular thyroid and hypothalamo-pituitary disorder.

Hypopituitarism in the elderly: a narrative review on clinical management of hypothalamic-pituitary-gonadal, hypothalamic-pituitary-thyroid and hypothalamic-pituitary-adrenal axes dysfunction

Hypopituitarism is an uncommon and under-investigated endocrine disorder in old age since signs and symptoms are unspecific and, at least in part, can be attributed to the physiological effects of aging and related co-morbidities. Clinical presentation is often insidious being characterized by non-specific manifestations, such as weight gain, fatigue, low muscle strength, bradipsychism, hypotension or intolerance to cold. In these circumstances, hypopituitarism is a rarely life-threatening condition, but evolution may be more dramatic as a result of pituitary apoplexy, or when a serious condition of adrenal insufficiency suddenly occurs. Clinical presentation depends on the effects that each pituitary deficit can cause, and on their mutual relationship, but also, inevitably, it depends on the severity and duration of the deficit itself, as well as on the general condition of the patient. Indeed, indications and methods of hormone replacement therapy must include the need to normalize the endocrine profile without contributing to the worsening of intercurrent diseases, such as those of glucose and bone metabolism, and the cardiovascular system, or to the increasing cancer risk. Hormonal requirements of elderly patients are reduced compared to young adults, but a prompt diagnosis and appropriate treatment of pituitary deficiencies are strongly recommended, also in this age range.

Ectopic Acromegaly Arising from a Pituitary Adenoma within the Bony Intersphenoid Septum of a Patient with Empty Sella Syndrome

Objective

 To describe the work-up and treatment of rare ectopic acromegaly caused by a biopsy-proven somatotroph pituitary adenoma located within the bony intersphenoid septum of a patient with empty sella syndrome (ESS).

Methods

 We report the presentation, clinical course, diagnostic work-up, and lesion localization and treatment challenges encountered in a 55-year-old patient, with a brief review of relevant literature.

Results

 A 55-year-old African-American man presented with acromegaly and ESS. Attempts to definitively localize the causative tumor were unsuccessful, though petrosal sinus sampling supported central growth hormone production and imaging suggested bone-enclosed subsellar pituitary tissue. Endoscopic endonasal transphenoidal exploration was undertaken with resection of a somatotroph pituitary microadenoma, and subsequent clinical improvement and biochemical remission. Retrospective review revealed the patient's pituitary to have been located ectopically within a unique bony intersphenoid septum.

Conclusion

 This report describes the first known case of an ectopic pituitary adenoma located within the midline bony intersphenoid septum, which we postulate to have resulted from anomalous embryological pituitary migration. Intra-intersphenoid septal tumors should be considered in cases of apparent central acromegaly with ESS or absence of tumor tissue within the paranasal sinuses or other peripheral locations.

Indexing

 Acromegaly, ESS, pituitary adenoma, sphenoid sinus septum.

Severe growth hormone deficiency and empty sella in obesity: a cross-sectional study

Obesity is associated with blunted growth hormone (GH) secretion. In some individuals, hypothalamic-pituitary (HP) structural lesions may contribute to GH deficiency (GHD). We explored pituitary morphology in obese patients with suspected GHD and its association with cardiovascular risk factors, body composition, and cardiac morphology. One hundred and eighty-four adults obese patients with symptoms and signs of GHD (147 females and 37 males; mean age 46.31 ± 12.11 years), out of 906 consecutive white obese outpatients, were evaluated. The main measures were anthropometric data, blood pressure, lipid profile, glycemic parameters, pituitary hormones, and insulin-like growth factor-1 values, echocardiography, magnetic resonance imaging (MRI) of the HP region, body composition, and growth hormone-releasing hormone plus arginine test. Seventy patients had GHD (GH peak values <4.2 μg/mL). GHD patients showed significantly higher body mass index and fat mass, lower lumbar bone mineral density, increased left ventricular mass index, and epicardial fat thickness. The MRI of the HP region showed empty sella (ES) in 69 and normal pituitary in one of the 70 GHD patients; the 114 patients with normal GH response had ES (n = 62, 54 %), normal pituitary (n = 37, 32 %), microadenomas (n = 10, 8 %), and other pituitary abnormalities (n = 5, 4 %). ES was a significant independent predictor of GH secretory capacity as determined by multiple regression analysis. The close relationship between ES and GH secretory capacity points out to the possibility of the organic nature of GHD in a portion of obese individuals and opens a new scenario with regard to the potential of GH treatment on metabolic consequences of obesity.

Role of pituitary dysfunction on cardiovascular risk in primary empty sella patients

OBJECTIVE

Primary empty sella (PES) is a frequent anatomical condition rarely causing pituitary dysfunction. We assessed cardiovascular risk in a cohort of PES patients referred to Endocrine Units.

DESIGN

The study was performed in three Italian tertiary referral centres. We evaluated pituitary function and cardiovascular risk, on the basis of lipid and glucose metabolism parameters and of Framingham score (FS), in 94 consecutive patients with PES diagnosis and in 94 gender, age and BMI matched controls.

PATIENTS

Pituitary function was normal in 30 patients (group A), whereas a single or multiple pituitary hormone deficiency was demonstrated in 64 (group B). Growth hormone deficiency (GHD) was diagnosed in 56, central hypothyroidism in 35, hypogonadotropic hypogonadism in 32 and central hypoadrenalism in 24 cases.

RESULTS

Framingham score was higher and glucose and lipid profile were worse in PES patients than in controls. Cardiovascular risk parameters were not different between group A and B. In group B, increased cardiovascular risk was associated with hypothyroidism and hypogonadism, but not with GHD. In group A, cardiovascular risk was higher and FT3 and FT4 levels were lower than in controls. Moreover, PES patients stratified for BMI showed a worse glucose and lipid profile and (in the overweight subgroup) higher FS than matched controls.

CONCLUSIONS

Primary empty sella patients show increased cardiovascular risk, regardless of BMI. A worse lipid and glucose profile and higher FS were associated with secondary hypothyroidism, even subclinical, as well as hypogonadism.

Idiopathic adult growth hormone deficiency

GH secretion is controlled by hypothalamic as well as intrapituitary and peripheral signals, all of which converge upon the somatotroph, resulting in integrated GH synthesis and secretion. Enabling an accurate diagnosis of idiopathic adult GH deficiency (IAGHD) is challenged by the pulsatility of GH secretion, provocative test result variability, and suboptimal GH assay standardization. The spectrum between attenuated GH secretion associated with the normal aging process and with obesity and truly well-defined IAGHD is not distinct and may mislead the diagnosis. Adult-onset GHD is mainly caused by an acquired pituitary deficiency, commonly including prior head/neck irradiation, or an expanding pituitary mass causing functional somatotroph compression. To what extent rare cryptic causes account for those patients seemingly classified as IAGHD is unclear. About 15% of patients with adult GHD and receiving GH replacement in open-label surveillance studies are reported as being due to an idiopathic cause. These patients may also reflect a pool of subjects with an as yet to be determined occult defect, or those with unclear or incomplete medical histories (including forgotten past sports head injury or motor vehicle accident). Therefore, submaximal diagnostic evaluation likely leads to an inadvertent diagnosis of IAGHD. In these latter cases, adherence to rigorous biochemical diagnostic criteria and etiology exclusion may result in reclassification of a subset of these patients to a distinct known acquired etiology, or as GH-replete. Accordingly, rigorously verified IAGHD likely comprises less than 10% of adult GHD patients, an already rare disorder. Regardless of etiology, patients with adult GHD, including those with IAGHD, exhibit a well-defined clinical phenotype including increased fat mass, loss of lean muscle mass, decreased bone mass, and enhanced cardiac morbidity. Definition of unique efficacy and dosing parameters for GH replacement and resultant therapeutic efficacy markers in true IAGHD requires prospective study.

Primary empty sella (PES): a review of 175 cases

The term primary empty sella (PES) makes reference to the herniation of the subarachnoid space within the sella turcica in patients with no history of pituitary tumor, surgery or radiotherapy. To retrospectively assess clinical features, radiological findings and the biochemical endocrine function from the records of 175 patients with a diagnosis of PES. One hundred seventy-five patients (150 females) were studied. The mean age at diagnosis was 48.2 ± 14 year. Most diagnoses were made by magnetic resonance imaging (n = 172). In most patients, the pituitary function was assessed by basal pituitary hormones measurements. Pituitary scans were ordered for different reasons: headache (33.1 %), endocrine disorders (30.6 %), neurological symptoms (12.5 %), visual disturbances (8.75 %), abnormalities on sella turcica radiograph (8.75 %) and others (6.25 %). Multiple pregnancies were observed in 58.3 % of women; headaches, obesity, and hypertension were found in 59.4, 49.5, and 27.3 % of the studied population, respectively. Mild hyperprolactinemia (<50 ng/ml) was present in 11.6 % of women and 17.3 % of men. Twenty-eight percent of our patients had some degree of hypopituitarism. In the male population, hypopituitarism represented 64 % of cases, whereas it accounted for 22 % of all females. PES seems to be more commonly found in middle-aged women, with a history of multiple pregnancies. In most patients, PES was discovered as an incidental finding on imaging studies, while in almost a quarter of patients PES was found during the diagnostic evaluation of anterior pituitary deficiency, which was more common in men.

Systemic hypertension counteracts potential benefits of growth hormone replacement therapy on left ventricular remodeling in adults with growth hormone deficiency

BACKGROUND

Systemic Hypertension (SH) is the main cause of left ventricular (LV) hypertrophy in the general population, but only scanty data are available on LV geometric remodeling (LVGR) in hypertensive patients with GH deficiency (GHD).

AIM

We investigated hypertensive LVGR in adult-onset GHD patients, before (T0) and after 55±16 months (T1) of individualized GH replacement therapy (GHRT).

SUBJECTS

Fifty-one patients, aged 45±15 yr, 29 women, were enrolled. Fifteen patients met criteria for SH (group A) whereas 36 were normotensive (group B).

METHODS

An echocardiogram was performed on all patients, at least twice (at T0 and T1). LV geometric remodeling as a relationship between LV mass (LVM) index and relative wall thickness (RWT), LV volumes, and ejection fraction were measured.

RESULTS

At T0, group A showed higher LV mass and LVM index values than group B; LV hypertrophy was found in 40% and 22% of patients, respectively (p=0.06). At T1, IGF-I levels had increased significantly in both groups. LV hypertrophy rate consistently increased in group A (from 40 to 60%, p<0.05), whereas slightly decreased in group B (from 22 to 19%, ns). Body surface area (p<0.001), age (p<0.05), and systolic blood pressure (p<0.05) were main determinants of LVM at multivariate analysis.

CONCLUSIONS

Along with body surface area and age, SH was significantly related to abnormal LVGR (LV hypertrophy) in GHD patients. As a result, blood pressure management and caloric intake restrictions are deemed necessary for this subset of patients.

Pituitary autoimmunity is associated with hypopituitarism in patients with primary empty sella

OBJECTIVE

Some evidence suggests that late stage autoimmune hypophysitis (AH) may result in empty sella (ES). Aim of the study was to assess the prevalence of serum pituitary antibodies (PitAb) and their correlation with pituitary function in patients with ES.

DESIGN

In this casecontrol study 85 patients with primary ES, 16 patients with ES secondary to head trauma, 214 healthy controls, and 16 AH were enrolled in a tertiary referral center.

METHODS

PitAb were assessed in all cases and controls. Endocrine function was assessed by basal hormone measurement and dynamic testing in all ES cases.

RESULTS

PitAb prevalence was higher in primary ES (6%) than in healthy subjects (0.5% p=0.003) and lower than in AH patients (50%, p<0.0001). PitAb were not found in patients with secondary ES. Hypopituitarism was found in 49% of primary ES and in 62% of secondary ES (p=0.34). A positive correlation between the presence of PitAb and hypopituitarism was found in primary ES (p=0.02).

CONCLUSIONS

The significant association between pituitary autoimmunity and hypopituitarism suggests that ES, in selected cases, could be the final result of AH.

Diagnosis of adult GH deficiency

The current guidelines for the diagnosis of adult GHD are mainly based on the statements from the GH Research Society Consensus from Port Stevens in 1997. It is stated that diagnosis of adult GHD must be shown biochemically by provocative tests within the appropriate clinical context. The insulin tolerance test (ITT) was indicated as that of choice and severe GHD defined by a GH peak lower than 3 microg/L. The need to rely on provocative tests is based on evidence that that the measurement of IGF-I as well as of IGFBP-3 levels does not distinguish between normal and GHD subjects. Hypoglycemia may be contraindicated; thus, alternative provocative tests were considered, provided they are used with appropriate cut-off limits. Among classical provocative tests, arginine and glucagon alone were indicated as alternative tests, although less discriminatory than ITT. Testing with the combined administration of GHRH plus arginine was recommended as an alternative to ITT, mostly taking into account its marked specificity. Based on data in the literature in the last decade, the GRS Consensus Statements should be appropriately amended. Regarding the appropriate clinical context for the suspicion of adult GHD, one should evaluate patients with hypothalamic or pituitary disease or a history of cranial irradiation, as well as those with childhood-onset GHD are at obvious risk as adults for severe GHD. Brain injuries (trauma, subarachnoid hemorrage, tumours of the central nervous system) very often cause acquired hypopituitarism, including severe GHD. Given the epidemiology of brain injuries, the important role of the endocrinologist in providing major clinical benefit to brain injured patients who are still undiagnosed should be underscored. From the biochemical point of view, although normal IGF-I levels do not rule out severe GHD, very low IGF-I levels in patients highly suspected for GHD (i.e. patients with childhood-onset, severe GHD or with multiple hypopituitarism acquired in adulthood) can be considered as definitive evidence for severe GHD; thus, these patients would skip provocative tests. Patients suspected for adult GHD with normal IGF-I levels must be investigated by provocative tests. ITT remains a test of reference but it should be recognized that other tests are as reliable as ITT. Glucagon as classical test and, particularly, new maximal tests such as GHRH in combination with arginine or GH secretagogues (GHS) (i.e. GHRP-6) have well defined cut-off limits, are reproducible, able to distinguish between normal and GHD subjects. Overweight and obesity have confounding effect on the interpretation of the GH response to provocative tests. In adults cut-off levels of GH response below which severe GHD is demonstrated must be appropriate to lean, overweight and obese subjects to avoid false positive diagnosis in obese adults and false negative diagnosis in lean GHD patients. Finally, normative values of GH response to provocative tests may depend on age, particularly in the transitional age; the normative cut-off levels of GH response to ITT in this phase of life are now available.

Primary "empty sella" in adults: endocrine findings

Increasing evidence of impaired pituitary function in many subjects with primary empty sella (PES) has been reported. We conducted a retrospective analysis of our patients with PES, in order to ascertain presenting symptoms and endocrine status on diagnosis and during follow-up. Magnetic resonance imaging (MRI) of the pituitary leading to the diagnosis of PES was performed in 8 patients (5 F and 3 M, age: 60.1 +/- 3.3 years, M +/- SE; group 1) after the diagnosis of global anterior hypopituitarism (H), and in 20 patients (F, age 56.9 +/- 2.2 years, group 2) for other clinical reasons. Baseline determinations of pituitary and target gland hormones and of IGF-I were performed. GH response to GHRH plus arginine stimulation was also evaluated. Ten age- and BMI-matched subjects (7 F, 3 M, age: 53.0 +/- 4.0 years) with normal pituitary function served as controls (C). In group 1, the presenting symptoms leading to the diagnosis of H were consciousness disturbances, hyponatremia and chronic fatigue. The GH response to stimulation was absent (peak:1.0 +/- 0.3 ng/ml) and IGF-I levels (60.1 +/- 9.3 ng/ml) were significantly lower (p<0.001) than in C and group 2 PES patients. Among group 2 PES patients, the main presenting symptoms were headache and visual alterations. Baseline hormone levels proved normal in 17 subjects, while slight hyperprolactinemia was observed in 2 and hypogonadotropic hypogonadism in one. The GH response to stimulation (12.9 +/- 3.4 ng/ml) and IGF-I levels (141.7 +/- 12.0 ng/ml) were lower (p<0.05) than in C (GH: 33.4 +/- 8.8 ng/ml, IGF-I: 193.1 +/- 20.3 ng/ml). PES is a heterogeneous condition that ranges from hypopituitarism to various degrees of isolated GH deficiency, and which needs careful endocrine assessment, treatment and follow-up.

Insulin-Like Growth Factor I Levels and the Diagnosis of Adult Growth Hormone Deficiency

The current guidelines state that, within the appropriate clinical context, the diagnosis of adult growth hormone (GH) deficiency must be made biochemically using provocative tests. Measurement of insulin-like growth factor I (IGF-I) and binding protein 3 (IGFBP-3) levels cannot always distinguish between healthy and GH-deficient individuals. In particular, IGFBP-3 as a marker of GH status is clearly less sensitive than IGF-I and there is general agreement that its measurement does not provide useful diagnostic information. However, the diagnostic value of measuring IGF-I levels has been revisited recently. It has been confirmed that normal IGF-I levels do not rule out severe GH deficiency (GHD) in adults, in whom the diagnosis has therefore to be based on the demonstration of severe impairment of the peak GH response to provocative tests. It has also been emphasized that very low IGF-I levels in patients with high suspicion of GHD could be considered to be definite evidence for severe GHD. This assumption particularly applies to patients with childhood-onset, severe GHD or with multiple hypopituitary deficiencies acquired in adulthood. In addition, the use of IGF-I levels to monitor the efficacy and adequacy of recombinant human GH replacement remains widely accepted.