Endocrinology Flashcards
Hormones Produced by anterior pituitary
Prolactin, growth hormone, adrenocorticotropic hormone, luteinizing hormone, follicle stimulating hormone, and thyroid stimulating hormone
What is the weight of the pituitary gland?
About 600 mg
This is due to defective hypothalamic gonadotropin releasing hormone (GnRH) synthesis and is associated with anosmia, hypogonadism (males), and amenorrhea with failure to develop secondary sexual features (females)
Kallmann Syndrome
This developmental hypothalamic disorder is characterized by mental retardation, renal abnormalities, obesity, abnormal digits, and retinal degeneration.
Bardet-Biedl Syndrome
This is due to a deletion of the paternal copies of the imprinted SNRPN and NECDIN gene on chromosome 15q
Prader-Willi Syndrome
This characterized by hypogonadism, hyperphagia-obesity, muscle hypotonia, mental retardation, and adult onset diabetes mellitus.
Prader-Willi Syndrome
This is an endocrine emergency which is due to intrapituitary hemorrhage.
Pituitary Apoplexy
This is an autosomal dominant disorder characterized by a genetic predisposition to parathyroid, pancreatic islet, and pituitary adenoma
Multiple Endocrine Neoplasia 1 (MEN 1)
Multiple Endocrine Neoplasia (MEN 1) is due to a defect on what tumor suppressor gene and on what chromosome?
MENIN on chromosome 11q13
This syndrome is characterized by spotty skin pigmentation, myxoma, and endocrine tumors such as testicular, adrenal, and pituitary adenomas.
Carney Syndrome
This consists of polyostotic fibrous dysplasia, pigmented skin patches, and endocrine disorders (such as precocious puberty, autonomous ovarian function, acromegaly, and adrenal adenomas)
McCune-Albright Syndrome
These are benign suprasellar cystic masses that present with headache, visual field defects, and variable degrees of hypopituitarism.
Craniopharyngiomas
This disorder is characterized by diabetes insipidus, exothalmos, and punched out lyric bone lesions. It is also associated with granulamtos lesions.
Hand-Schüller-Christian Disease
About half of pituitary metastasis originate from _____
Breast Cancer
This syndrome is character end by harmatomas, craniofacial abnormalities, imperforate anus, cardiac, renal, lung, and pituitary failure. Mutation in GLI3 gene
Pallister-Hall Syndrome
Screening Test for Cushing’s Disease
24 hour urinary free cortisol, Dexamethasone Challenge, ACTH Assay
This hormone of the anterior pituitary is unique due to the central control mechanism is inhibitory rather than stimulatory.
Prolactin
What inhibits prolactin release?
Dopamine
What is the most common pituitary hormone hypersecretion syndrome in both men and women?
Hyperprolactinemia
What are the hallmarks of hyperprolactinemia in women?
Amenorrhea, galactorrhea, and infertility
Examples of oral dopamine agonist used for the treatment in prolactinomas.
Bromocriptine and Cabergoline
The most abundant anterior pituitary hormone is _____
Growth Hormone
Hypersecretion of growth hormone in adults leads to what condition?
Acromegaly
What is the most common cause of GHRH mediated acromegaly?
Chest or abdominal carcinoid tumor
Growth hormone hypersecretion before epiphyseal long bone closure is associated with the development of ______
Gigantism
What is the most common presenting feature of adult hypopituitarism?
Hypogonadism
The posterior pituitary are formed by axons that originate in the ______
Supraoptic and Paraventricular Nuclei of the Hypothalamus
What are the hormones produced by the posterior pituitary?
Arginine Vasooressin (Antidiurectic Hormone) and Oxytocin
A deficiency in vassopressin causes
Diabetes Insipidus
Vassopressin acts on what part of the nephron?
Medullary collecting ducts
What is the normal weight of the thyroid?
12-20 g
What cells of the thyroid produce calcitonin?
Medullary or C cells
What is the most useful marker of thyroid hormone action?
Thyroid Stimulating Hormone (TSH)
These glycoprotein hormones share a common alpha subunit.
LH, FSH, TSH, and hCG
What is the crucial first step in thyroid hormone synthesis?
Iodide uptake by the sodium iodide sum porter at basolateral membrane
What is the most common cause of preventable mental deficiency?
Iodine deficiency which leads to cretinism
What is the recommended daily intake of iodine in adults?
and children?
150-250 micrograms per day for adults
90-120 micrograms per day for children
Where are thyroid hormone receptors located?
At nuclear receptors (thyroid hormone receptors)
What is the method of choice in determining the size of the thyroid?
Ultrasound
A bruit over the thyroid glad indicates what?
Increased vascularity such as in hyperthyroidism
Venous distinction over the neck and difficulty breathing especially when arms are raised.
Pemberton’s sign
What is the most common cause of hypothyroidism worldwide?
Iodine deficiency
What is the weight of a single adrenal gland?
6-11 grams
From outer to inner name the layers of the adrenal glands.
Capsule, Zoma Glomerulosa, Zona Fasiculata, Zona Reticularis, Adrenal Medulla
The right supra renal vein drains into the _____ and the left supra renal vein drains into the ______.
Inferior Vena Cava
Left Renal Vein
What region of the hypothalamus will secrete corticotropin releasing hormon and subsequently cause the release of ACTH from the anterior pituitary.
Suprachiasmatic Nucleus
Peak levels of ACTH occur during what time of day?
Morning
Renin is produced by what cells?
Juxtaglomerular Cells Kidney
What cleaves angiotensinogen to angiotensinogen I?
Renin
What cleaves angiotensin I to angiotensin II
Angiotensin Converting Enzyme
Mineralocorticoid synthesis occurs in what layer of the adrenal gland?
Zona Glomerulosa
Glucocorticoids are produced in what layer of the adrenal gland?
Zona Fasciculata
In what layer will primarily produce adrenal androgens?
Zona Reticularis
Most frequent cause you Cushing’s Syndrome
ACTH Producing Pituitary Adenoma
Most common source of ectopic ACTH production
Occult Carcinoid Tumor Most Frequently in the Lung
Lung cancer that may produce ectopic ATCH
Small Cell Lung Cancer
Aldosterone producing adrenal adenoma causing hypertension and hypokalemia
Conn’s Syndrome
Most common cause of primary adrenal insufficiency?
Autoimmune Adrenalitis
What is the characteristic biochemical feature of patients with adrenal insufficiency?
Hyponatremia
The diagnosis of adrenal insufficiency is established by what test?
Cosyntropin Test
Referred to as the “master gland”
Anterior Pituitary
What are the “rule of tens” in pheochromocytoma?
10% bilateral, 10% extraadrenal, 10% malignant
Classic triad of pheochromocytoma
Palpitations, Headaches, and Profuse Sweating
Dominant sign of pheochromocytoma
Hypertension
Examples of catecholamines
Epinephrine, norepinephrine, and dopamine
Vanillylmadelic acid, and metanephrines are commonly used for initial testing of what disorder? Which is more sensitive?
Pheochromocytoma, and metanephrines are more sensitive
This autosomal dominant disorder is characterized by medullary thyroid carcinoma, pheochromocytoma, and hyperparathryroidism
MEN 2A
This autosomal dominant disorder is characterized by medullary thyroid carcinoma, pheochromocytoma, as well as multiple mucosal neuromas, and marfanoid habitus.
MEN 2B
What is the leading cause of end stage renal disease?
Diabetes mellitus
Diagnosis of Diabetes Mellitus
- Fasting Plasma Glucose > or = 7 mmol/L (126 mg/dL)
- 2 Hour Plasma Glucose Challenge > or = 11.1 mmol/L (200 mg/dL)
- HbA1C > or = 6.5%
Diagnosis for impaired fasting glucose
- Fasting Plasma Glucose > or = 5.6-6.9 mmol/L (100-125 mg/dL)
- 2 Hour Plasma Glucose Challenge > or = 7.8-11 mmol/L (140-199 mg/dL)
- HbA1C > or = 5.7-6.4%
Recommended screening for DM
At age 45 and every 3 years thereafter. May start earlier if overweight or with risk factors
What cell produce insulin?
Beta cells of the pancreatic islets
This is a useful marker in insulin secretion and allows discrimination between endogenous and exogenous sources of insulin.
C Peptide
What is the key regulator of insulin secretion? At what level will it stimulate secretion?
Glucose
It will stimulate insulin if levels > 3.9 mmol/L (70mg/dL)
What is the rate limiting step that controls glucose regulated insulin secretion?
Glucokinase
Glucagon is secreted by what cell?
Alpha Cells of the Pancreatic Islets
Delta cells of the pancreatic islet secrets ______
Somatostatin
Diabetic Ketoacidosis is more common in Type 1 or Type 2 Diabetes Mellitus
Type 1 DM
Kussmaul Respiration, fruity odor on breath, abdominal pain, and nausea and vomiting.
Diabetic Ketoacidosis
The basic patholophysology of diabetic ketoacidosis
Relative or absolute insulin deficiency combined with counter regulatory hormone excess
Case: An elderly patient with Type 2 DM with several week history of polyuria, weight loss, and diminished oral intake is noticed to be in mental confusion and then progressed to lethargy.
Hyperosmotic Hyperosmolar State
What are the microvascular complications of DM?
Retinopathy, Neuropathy, and Nephropathy?
What are the macrovascular complications of DM?
Coronary Artery Disease, Peripheral Atrial Disease, and Cerebrovasular Disease
What is the leading cUse of blindness in patients aged 20-74 in the U.S.
Diabetic Retinopathy
What is the blood pressure goals of diabetic individuals based on Harrison’s
What is the most common pattern of dyslipidemia in patients with DM
Hypertriglyceridemia and reduced HDL
HbA1C goal for patients with DM
Goal for preprandial capillary plasma glucose
3.9-7.2 mmol/L (70-130 mg/dL)
Goal for peak postprandial capillary plasma glucose
Goal for Triglycerides in Patients with DM
Examples of short acting insulin
Aspart, Glulisine, Lispro, Regular
Examples of long acting insulin
Detemir and Glargine
Example of Biguanides
Metformin
Mechanism of action of Metformin
Decrease Hepatic Glucose Production
Examples of Insulin Secretagogues - Sulfonylureas
Glimepiride, Glipizide, Glyburide
Mechanism of action of insulin secretagogues such as the sulfonylureas and nonsulfonylureas
Stimulates insulin secretion by interacting with the ATP sensitive potassium channel in the beta cell
Examples of “incretins”
Exenatide and Liraglutide
Examples of Dipeptide Peptidase-4 Inhibitors which result in inhibiting the degradation of native GLP-1
Saxagliptin, Sitagliptin, and Vildagliptin
Examples of Alpha Glucosodase Inhibitors and their mechanism of action
Acarbose and Miglitol which reduces post prandial hyperglycemia by delaying glucose absorption