An Update on Subclinical Hypopituitarism Paula Andujar-Plata1, Eva Fernandez-Rodriguez1 and Felipe F
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ds & Ho roi rm te o S n f a l o S l c a i Journal of n e r n u c o e Andujar-Plata, et al., J Steroids Horm Sci 2016, 7:2 J 10.4172/2157-7536.1000175 ISSN: 2157-7536 Steroids & Hormonal Science DOI: Review Article Open Access An Update on Subclinical Hypopituitarism Paula Andujar-Plata1, Eva Fernandez-Rodriguez1 and Felipe F. Casanueva1,2,3* 1Endocrinology Division, Complejo Hospitalario Universitario de Ourense (CHUO), SERGAS, Ourense, 32005, Spain 2Departamento de Medicina, Universidad de Santiago de Compostela, Santiago de Compostela, 15706, Spain 3Centro de InvestigaciónBiomédicaen Red (CIBER) de FisiopatologíaObesidad y Nutrición, InstitutoSalud Carlos III, Santiago de Compostela, 15706, Spain *Corresponding author: Dr. Felipe F. Casanueva, Endocrinology Division, Hospital Clinico Universitario, Travesía da Choupana s/n. Santiago de Compostela, La Coruña, 15706, Spain, Tel: (+34) 981951245; Fax: (+34) 981951546; E-mail: [email protected] Received date: May 25, 2016; Accepted date: June 17, 2016; Published date: June 22, 2016 Copyright: © 2016 Andujar-Plata P, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Abstract Subclinical deficiency of pituitary hormones represents an intermediate situation among normal pituitary secretion and overt hypopituitarism. Clinical hypopituitarism is associated with impaired morbidity and mortality, but there are not many studies on these topics in the subclinical setting. Moreover, clinical manifestations and diagnosis criteria are not well defined, so this entity is probably an underdiagnosed disorder. Long-term controlled studies are needed to establish a correct definition of subclinical hypopituitarism and to know its clinical implications, optimal methods of diagnosis, and indications for substitutive treatment. This review will focus on the evidence related to epidemiology, clinical manifestations, diagnosis, and treatment of subclinical hypopituitarism. Keywords: Hypopituitarism; Subclinical hypopituitarism; Pituitary incidence of 2.07 cases per 100,000 inhabitants per year over a period insufficiency; Partial growth hormone deficiency; Partial of 10 years (2000-2009) [10]. adrenocorticotropic hormone deficiency Data about the epidemiology of subclinical hypopituitarism have not been reported in the general population, although there are studies Introduction evaluating subclinical pituitary deficiencies in some specific subgroups Hypopituitarism is the insufficient secretion of one or more of patients. For example, subclinical hypopituitarism was detected in pituitary hormones caused by pituitary and/or hypothalamic disorders 29% of patients evaluated after 6 to 9 months of a traumatic brain [1]. Hormonal deficiency can be isolated or multiple, with the injury and in 77% of patients treated with cerebral radiotherapy [11]. gonadotropic and somatotropic axes the most frequently affected. There are studies that evaluated some isolated subclinical deficiencies. Clinical manifestations associated to hypopituitarism are often Subclinical thyroid-stimulating hormone (TSH) deficiency was nonspecific and will depend on the underlying disease, age, rate of reported in 20.3% of patients who were previously irradiated because onset, and degree of hormonal defect. The clinical importance of of head and neck tumors [12] and in 38% of patients with type 2 hypopituitarism is its association with increased mortality compared diabetes [13], using the thyrotropic releasing hormone (TRH) test for with the general population and its association with increased diagnosis. morbidity [2-7]. In fact, changes in body composition, glucose As previously mentioned, subclinical hypopituitarism does not intolerance, hypertension, or altered lipid profile have been detected in produce symptoms that can be seen, and the methods for diagnosis are these patients [8,9]. not well established. These conditions probably make subclinical In clinical practice, we can observe intermediate situations between hypopituitarism an underdiagnosed disorder. established hormone deficiencies and normal pituitary function, which could be considered milder or subclinical forms of hypopituitarism. Causes of Subclinical Hypopituitarism These conditions, although theoretically would not cause clear The etiology of subclinical hypopituitarism is the same as that of symptoms, could be related to the mild impairment of morbidity and clinical hypopituitarism [14] (Table 1). In adults, the most common mortality as clinical hypopituitarism. However, there is no consensus cause is a pituitary adenoma or its treatment (surgery or radiotherapy). on the methods of diagnosis and treatment in these subclinical cases. Benign pituitary adenomas, which are the most frequent pituitary In this article, we review the epidemiology, clinical manifestations, masses, and particularly macroadenomas (≥ 1 cm) are commonly diagnosis, and treatment of subclinical hormone pituitary deficiencies. associated with hormone deficiencies. Probable mechanisms include the compression of normal pituitary tissue, compression of the blood Epidemiology of Subclinical Hypopituitarism flow, and interruption of hypothalamic–pituitary communication. There are few data available about the prevalence and incidence of Although pituitary surgery is sometimes associated with some hypopituitarism in the general population. In a well-defined degree of recovery in pituitary function, it can be a cause of hormone population in the northwest of Spain, our group reported a prevalence deficit [15]. Tumor size, tumor infiltration, or surgeon experience are of hypopituitarism of 37.5 cases per 100,000 inhabitants and an some factors involved in the development of hypopituitarism. Radiotherapy is another cause of hypopituitarism, and its effect is dose-dependent. Newer methods of irradiation can lower the J Steroids Horm Sci Volume 7 • Issue 2 • 1000175 ISSN:2157-7536 JSHS, an open access journal Citation: Andujar-Plata P, Fernandez-Rodriguez E, Casanueva FF (2016) An Update on Subclinical Hypopituitarism. J Steroids Horm Sci 7: 175. doi:10.4172/2157-7536.1000175 Page 2 of 5 prevalence of subclinical hypopituitarism, although there is still risk Clinical Manifestations of Subclinical Hypopituitarism involved [16]. Other possible causes of subclinical hypopituitarism include traumatic brain injury, Sheehan’s syndrome, infiltrative and Subclinical growth hormone deficiency immunological diseases, and genetic disorders. Clinical manifestations of subclinical hypopituitarism varied based Pituitary tumours on the age of onset, although the clinical course is usually insidious - Adenomas and without specific symptoms, especially in adults. In children, the main feature of growth hormone deficiency (GHD) - Other pituitary tumours is decreased growth velocity and short height. However, in adulthood, Parasellar tumours this deficiency can be unrecognized, because the symptoms can be nonspecific. Adults with severe GHD can show changes in body - Craniopharyngiomas composition with increased fat mass and decreased muscle mass, - Chordomas reduced bone mineral density, metabolic changes (glucose intolerance and altered lipid profile), cardiac changes with premature - Germinomas atherosclerosis and low energy, and reduced quality of life [17-21]. - Meningiomas Patients with subclinical GHD could present some of the clinical manifestations of severe GHD but with less intensity. It has been - Gliomas shown that patients with intermediate values in stimulation tests - Metastases present changes in body composition at an intermediate degree between healthy subjects and patients with severe GHD. Studies of - Others body composition have demonstrated that subjects with subclinical Brain injury GHD have increased fat mass, reduced lean body mass, and increased skin-fold thickness [22]. This intermediate state has been also - Neurosurgery associated with impaired insulin sensitivity, impaired lipid profile, and carotid intima-media thickness [23,24]. These changes seem to be - Radiotherapy related to IGF-I levels. - Traumatic brain injury Another study found that, compared with healthy people, patients Vascular disease who were insufficient in growth hormone (GH) had higher levels of plasminogen activator inhibitor type-I (PAI-I), suggesting an increased - Pituitary apoplexy cardiovascular risk [25]. A more recent study showed a correlation among the GH axis, the visceral adiposity index, and cardiometabolic - Sheehan’s syndrome risk; thus, apparently healthy patients could have some degree of - Subarachnoid haemorrhage visceral adipose dysfunction associated with GH and IGF-I levels, but without overt GHD [26]. However, more investigations are needed to - Stroke support the association between subclinical GHD and increased Infiltrative and immunological disease cardiovascular risk. - Sarcoidosis Subclinical gonadotropin deficiency - Tuberculosis Symptoms of follicle stimulating hormone/luteinizing hormone - Histiocytosis (FSH/LH) deficiency depend on the age at onset. Before the age of puberty, males with FSH/LH deficiency have small penises and testes, - Haemochromatosis and women with FSH/LH deficiency have primary amenorrhea with the absence of breast development. In adulthood, males show impaired - Lymphocytic hypophysitis sexual function, reduction of testicular size, infertility, and weakness, Infections