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Best Practice & Research. Clinical... Mar 2017Hypothyroidism may occur in association with congenital parathyroid disorders determining parathyroid hormone insufficiency, which is characterized by hypocalcemia and... (Review)
Review
Hypothyroidism may occur in association with congenital parathyroid disorders determining parathyroid hormone insufficiency, which is characterized by hypocalcemia and concomitant inappropriately low secretion of parathormone (PTH). The association is often due to loss of function of genes common to thyroid and parathyroid glands embryonic development. Hypothyroidism associated with hypoparathyroidism is generally mild and not associated with goiter; moreover, it is usually part of a multisystemic involvement not restricted to endocrine function as occurs in patients with 22q11 microdeletion/DiGeorge syndrome, the most frequent disorders. Hypothyroidism and hypoparathyroidism may also follow endocrine glands' damages due to autoimmunity or chronic iron overload in thalassemic disorders, both genetically determined conditions. Finally, besides PTH deficiency, hypocalcemia can be due to PTH resistance in pseudohypoparathyroidism; when hormone resistance is generalized, patients can suffer from hypothyroidism due to TSH resistance. In evaluating patients with hypothyroidism and hypocalcemia, physical examination and clinical history are essential to drive the diagnostic process, while routine genetic screening is not recommended.
Topics: Autoimmunity; Calcium; Female; Goiter; Humans; Hypocalcemia; Hypoparathyroidism; Hypothyroidism; Male; Parathyroid Diseases; Parathyroid Glands; Parathyroid Hormone; Thyroid Hormone Resistance Syndrome
PubMed: 28648505
DOI: 10.1016/j.beem.2017.04.004 -
The Journal of the Association of... Mar 2023Awareness regarding the etiological spectrum of tetany is poor among physicians. Because of poor awareness, tetany is underdiagnosed and undertreated.
INTRODUCTION
Awareness regarding the etiological spectrum of tetany is poor among physicians. Because of poor awareness, tetany is underdiagnosed and undertreated.
MATERIALS AND METHODS
Databases like PubMed, PubMed Central, Scopus, and Google Scholar are searched to identify peer-reviewed articles on tetany. Case reports, case series, and original articles are analyzed to identify different causes of tetany prevalent in the community. Different causes found are analyzed and tabulated, and finally, a flowchart is made on the approach for diagnosing different underlying pathologies of tetany.
RESULTS
Both metabolic and respiratory alkalosis are important causes of tetany because of reduced ionized calcium levels. Gitelman syndrome (GS) is associated with metabolic alkalosis, hypokalemia, hypomagnesemia and hypocalciuria, and frequently causes normocalcemic tetany. Recurrent vomiting and primary hyperaldosteronism also cause tetany due to metabolic alkalosis. Hyperventilation syndrome (HVS) leads to respiratory alkalosis and is a frequent cause of tetany. Hyperventilation-induced tetany is also seen after spinal anesthesia and in respiratory disorders like asthma. Vitamin D deficiency (VDD), primary hypoparathyroidism, and pseudohypoparathyroidism (PHP) (1a, 1b, and 2) cause hypocalcemic tetany. Hypomagnesemia causes hypocalcemia and tetany due to peripheral parathyroid hormone resistance and impaired parathyroid hormone secretion. Drugs causing tetany include bisphosphonates, denosumab, cisplatin, antiepileptics, aminoglycosides, diuretics, etc. Tetany is also seen in acute pancreatitis, dengue, falciparum malaria, hyperemesis gravidarum, tumor lysis syndrome (TLS), massive blood transfusion, etc. Conclusion: The spectrum of disorders associated with tetany is diverse. Awareness of different causes will help early and proper diagnosis of tetany.
Topics: Humans; Tetany; Alkalosis, Respiratory; Hyperventilation; Acute Disease; Pancreatitis; Hypocalcemia; Alkalosis; Magnesium; Parathyroid Hormone; Calcium
PubMed: 37354510
DOI: 10.5005/japi-11001-0203 -
Annales D'endocrinologie Jun 2021PTH is a metabolic active hormone primarily regulating calcium and phosphate homeostasis in a very tight and short term-manner. Parathyroid disorders in adult patients... (Review)
Review
PTH is a metabolic active hormone primarily regulating calcium and phosphate homeostasis in a very tight and short term-manner. Parathyroid disorders in adult patients reflect a variety of different conditions related either to the parathyroid glands itself or to the effects of the secreted hormone. The clinical spectrum varies from the common disease primary hyperparathyroidism (PHPT) to the orphan conditions pseudohypoparathyroidism (Ps-HypoPT) and chronic hypoparathyroidism (HypoPT). The purpose of this review is to describe the consequences of disturbances in levels or action of PTH for cardiac function and cardiovascular risk in adult patients with these disorders. Most patients with PHPT achieve the diagnose by chance and have minor or no specific symptoms. Still, these patients with mild PHPT do possess cardiovascular (CV) morbidity, however so far not proven ameliorated by surgery in controlled trials. In severe cases, the CV risk is increased and with a potential reversibility by treatment. Patients with Ps-HypoPT have resistance to PTH action, but not necessarily total resistance in all tissues. So far, no clear CV morbidity or risk has been demonstrated, but there are several aspects of interest for further studies. Most patients with HypoPT do get their hormonal deficiency syndrome following neck surgery. These patients do experience multiple symptoms and do have an increased CV-risk before the primary surgery. Based on existing data, their CV mortality do not deviate from the expected when adjusting for the preexisting increased risk. Patients with nonsurgical (NS-) HypoPT do demonstrate increased CV-risk also associated with exposure time. Endocrine disorders with alterations in PTH function have major impact on the cardiovascular system of importance for morbidity and mortality, wherefore management of these specific diseases should be optimized currently, as new data become available, however also avoiding over-treating asymptomatic patients.
Topics: Adult; Aging; Cardiovascular Diseases; Cardiovascular System; Humans; Parathyroid Diseases
PubMed: 32192790
DOI: 10.1016/j.ando.2020.02.003 -
QJM : Monthly Journal of the... Dec 2020
Topics: Humans; Parathyroid Hormone; Pseudohypoparathyroidism
PubMed: 32196109
DOI: 10.1093/qjmed/hcaa102 -
Clinical Calcium 2017It is often difficult for terrestrial animals to take enough calcium. To maintain serum or extracellular calcium levels is very important for muscle and nerve function.... (Review)
Review
It is often difficult for terrestrial animals to take enough calcium. To maintain serum or extracellular calcium levels is very important for muscle and nerve function. Two major regulators to increase the serum calcium levels are parathyroid hormone(PTH)and vitamin D. PTH binds to the G protein coupling receptor, PTH1R, and increases intracellular cAMP levels. Impirement in the PTH signalling causes many diseases such as pseudohypoparathyroidism and acrodysostosis with hormone resistance. Vitamin D is activated to 1,25-dihydroxyvitamin D[1,25(OH)2D]by two steps of hydroxylation which occurs in the Liver and Kidney. Then, 1,25(OH)2D binds to vitamin D receptor(VDR), which works as a ligand-dependent transcription factor. Hypocalcemia and hypercalcemia are caused by various disorders including abnormal regulation of PTH and vitamin D production and their signal transduction.
Topics: Animals; Calcitriol; Calcium; Humans; Parathyroid Hormone; Phosphorylation; Receptors, Calcium-Sensing; Signal Transduction
PubMed: 28336823
DOI: No ID Found -
Bone Apr 2018GNAS is a complex imprinted gene encoding the alpha-subunit of the stimulatory heterotrimeric G protein (Gsα). GNAS gives rise to additional gene products that exhibit... (Review)
Review
GNAS is a complex imprinted gene encoding the alpha-subunit of the stimulatory heterotrimeric G protein (Gsα). GNAS gives rise to additional gene products that exhibit exclusively maternal or paternal expression, such as XLαs, a large variant of Gsα that shows exclusively paternal expression and is partly identical to the latter. Gsα itself is expressed biallelically in most tissues, although the expression occurs predominantly from the maternal allele in a small set of tissues, such as renal proximal tubules. Inactivating mutations in Gsα-coding GNAS exons are responsible for Albright's hereditary osteodystrophy (AHO), which refers to a constellation of physical and developmental disorders including obesity, short stature, brachydactyly, cognitive impairment, and heterotopic ossification. Patients with Gsα mutations can present with AHO in the presence or absence of end-organ resistance to multiple hormones including parathyroid hormone. Maternal Gsα mutations lead to AHO with hormone resistance (i.e. pseudohypoparathyroidism type-Ia), whereas paternal mutations cause AHO alone (i.e. pseudo-pseudohypoparathyroidism). Heterotopic ossification associated with AHO develops through intramembranous bone formation and is limited to dermis and subcutis. In rare cases carrying Gsα mutations, however, ossifications progress into deep connective tissue and skeletal muscle, a disorder termed progressive osseous heteroplasia (POH). Here I briefly review the genetic, clinical, and molecular aspects of these disorders caused by inactivating GNAS mutations, with particular emphasis on heterotopic ossification.
Topics: Animals; Chromogranins; Cyclic AMP; GTP-Binding Protein alpha Subunits, Gs; Humans; Mutation; Ossification, Heterotopic
PubMed: 28889026
DOI: 10.1016/j.bone.2017.09.002 -
Journal of Cataract and Refractive... Jul 2016A 22-year-old white man presented with photopsia of 3-year duration despite a corrected distance visual acuity of 20/20 in both eyes. Ophthalmic examination revealed...
UNLABELLED
A 22-year-old white man presented with photopsia of 3-year duration despite a corrected distance visual acuity of 20/20 in both eyes. Ophthalmic examination revealed multiple irregularly shaped white cortical opacifications of the lens in both eyes but no other significant ocular findings. One year after the photopsia onset, the patient experienced an episode of seizures with generalized tonic-clonic movements. Neurological follow-up examination demonstrated extensive brain calcification in the basal ganglia and frontal lobes, leading to a diagnosis of pseudohypoparathyroidism. Pseudohypoparathyroidism is a rare condition, and there are few reports of ocular findings with this underlying pathology. Our findings clearly demonstrate that even relatively unremarkable ocular signs can lead to diagnosis of severe systemic diseases. Therefore, the cataract surgeon should be aware of these conditions before removing the lens.
FINANCIAL DISCLOSURE
None of the authors has a financial or proprietary interest in any material or method mentioned.
Topics: Adult; Cataract; Cataract Extraction; Humans; Lens Implantation, Intraocular; Lens, Crystalline; Male; Pseudohypoparathyroidism; Visual Acuity; Young Adult
PubMed: 27492110
DOI: 10.1016/j.jcrs.2016.06.007 -
Endocrinologia, Diabetes Y Nutricion Oct 2018
Topics: Consensus Development Conferences as Topic; Humans; International Cooperation; Pseudohypoparathyroidism
PubMed: 30243379
DOI: 10.1016/j.endinu.2018.08.002 -
Mayo Clinic Proceedings Sep 2021
Topics: Adult; Brachydactyly; Female; Fingers; Humans; Metatarsal Bones; Pseudohypoparathyroidism
PubMed: 34481595
DOI: 10.1016/j.mayocp.2021.05.009