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Endocrinology Board Review. September 24, 2010. Growth. Growth. After 18mos of age, growth curve should be followed closely Between 4y/o and adolescence, growth below 4-5cm/yr should be assessed Percentiles should not be crossed Pubertal growth spurt Girls early puberty
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Endocrinology Board Review September 24, 2010
Growth • After 18mos of age, growth curve should be followed closely • Between 4y/o and adolescence, growth below 4-5cm/yr should be assessed • Percentiles should not be crossed • Pubertal growth spurt • Girls early puberty • Boys midpuberty
Question 1 Choose the correct statement comparing “familial or genetically determined short stature” and “constitutional delay of growth,” in regards to bone age. A. Familial = delayed/ constitutional = advanced B. Familial = equivalent/ constitutional = delayed C. Familial = delayed/ constitutional = equivalent D. Both are delayed
Constitutional delay of growth • Variant of normal growth and pubertal development • Period of decreased linear growth within first 3yrs of life • Downward crossing of percentiles • Linear growth resumes at normal rate • Along lower growth percentiles • Family history of “Late Bloomers”
Constitutional Growth Delay: Note deceleration followed by normal growth rate
Question 2 The physical findings depicted below corresponds to which tanner stage? A. I B. II C. III D. IV E. V
Tanner Staging • Boys: Staged by genital development and pubic hair – starts at 9-14 • Testis volume >= 4mL is pubertal • Mark of pubertal onset • Girls: Staged by breast development and pubic hair – starts at 10 ½ • Stage II = breast buds • Mark of pubertal onset • Stage IV = Areola elevated above breast (secondary mound)
Hypothalamus • Neuroectodermal tissue • Inferior third ventricle • Pituitary stalk
Pituitary • Anterior • Upgrowth of ectodermal cells from Rathke’s pouch • Posterior • Downgrowth of neural tissue cells from the hypothalamus
Question 3 You are evaluating a patient in clinic and notice the abnormality pictured. Which of the following is most likely to be affected? A. Growth hormone levels B. Aldosteronelevels C. Catecholamine levels D. Insulin levels
Anterior Pituitary • Growth Hormone • Secretion • GH-releasing factor • Inhibition • Somatostatin • IGF-1, IGF-BP3
Anterior Pituitary • Growth Hormone • Deficiency • Normal birth weight • Normal growth pattern x 1 year • “Kewpie” doll appearance, “cherubic” • Short, excess subq fat, retarded body proportion changes and high-pitched voices • Diagnosed with stimulation test
Anterior Pituitary • ACTH • Secretion • CRF from hypothalamus • Inhibition • Cortisol from adrenals • Prolonged steroid use
Anterior Pituitary • Gonadotropins • Secretion • GnRH • Hypothalamus sends pulses • Increases during puberty • Inhibition • Inhibin • FSH • Aromatase (androgen to estrogen) • Spermatogenesis • LH • Testosterone • Androstenedione (estradiol)
Anterior Pituitary • TSH • Secretion • TRH • Inhibition • Thyroid Hormone • Actions • Increases iodide uptake, thyroglobulin synthesis and thyroid hormone
Anterior Pituitary • Prolactin • Acts directly on target organ • Initiation and maintenance of lactation • Inhibited by dopamine from hypothalamus • Hyperprolactinemia • Galactorrhea • Pituitary adenomas • Medication • Neuroleptics, antipsychotics, estrogens and anti-hypertensives
Question 4 You are on call in the PICU and following a very sick patient admitted with meningococcal meningitis. He has not had any urine output in the last 8 hours despite fluid administration. You order a BMP and his Na is 125. What is the most likely cause of the hyponatremia in this patient? A. Diabetes insipidus B. Psychogenic polydipsia C. Inappropriate fluid administration D. SIADH
Posterior Pituitary • Hormones synthesized in hypothalamus and stored in posterior pituitary • Vasopressin • AVP or ADH • Released in response to increased osmotic pressure in the blood • Water balance • Increased reabsorption of water in collecting ducts of kidneys • Arteriolar vasoconstriction – HTN • Increased thirst
Posterior Pituitary • Vasopressin • Overproduction • Head trauma, brain tumors, encephalitis, pneumonia • SIADH • HA, apathy, nausea, vomiting, impaired consciousness • Decreased plasma osmolarity • Underproduction • Central Diabetes Insipidus (DI) • Pituitary tumors, head trauma, infiltrative diseases, autoimmune or surgical • Increased plasma osmolarity
Posterior Pituitary • Vasopressin • Resistant • Nephrogenic DI • Tubules in kidney cannot respond • Genetic or acquired (lithium) • Oxytocin • Released in response to nerve stimulation • Contraction of the smooth muscle of the uterus and myoepithelial cells lining the ducts of mammary glands
Thyroid • Location • Neck • Base of tongue • Mediastinum • Hormones • Thyroxine (T4) • Tri-iodothyronine (T3) • Need iodine for synthesis • Transported by TBG, albumin and transthyretin • Free hormone is active
Thyroid • Goiter • Hyper or hypo • Nodules • 70-80% benign or cystic • 1-1.5% of all childhood cancers • Neck irradiation, family history of medullary carcinoma, rapid growth, fixation to adjacent structures, enlarged lymph nodes
Question 5 A mother brings in her teenage daughter for hyperactivity and emotional lability. ROS is positive for diarrhea, weight loss and heat intolerance. On physical exam you notice tachycardia and a slight prominence of the eyes. A laboratory evaluation would most likely reveal: A. TSH, freeT4, + TSH receptor antibodies B. TSH, free T4, + antithyroperoxidase antibodies C. TSH, free T4, + TSH receptor antibodies D. TSH, free T4, + antithyroperoxidase antibodies
Thyroid • Hyperthyroid • Soft and fleshy gland • Tachycardia • Weight loss • Increased frequency of bowel movements • Heat intolerance • Nervousness • Widened pulse pressure • Tremor • Fatigue • Warm, moist skin • Fine, friable hair • Separation of distal margin of nail bed • Restlessness • Inability to sit still • Emotional lability • Short attention span • Excessive sweating
Thyroid • Hyperthyroidism • Graves Disease • Stimulating antibody to TSH receptor • Exopthalmos • Proptosis and lid lag • Large gland • Warm on palpation • Bruit • Labs • Increased T3 and T4 • Decreased TSH
Thyroid • Congenital Hypothyroidism • 1 in 4000 • Cretinism • Broad nasal bridge • Coarse facial features • Mental retardation • Short stature • Puffy hands • Protuberant tongue • Delayed skeletal maturation • Treatment within 3-4 weeks • Newborn Screening
Thyroid • Hypothyroid • Hypothalamic abnormalities • Pituitary abnormalities • Iodine deficiency • Chronic lymphocytic thyroiditis • Hashimoto thyroiditis • Anti-thyroid antibodies • Thyroglobulin • Thyroperoxidase • Positive FH • Increased TSH, decreased T4
Thyroid • Hypothyroid symptoms • Firm or bosselated gland • Congenital vs Acquired • Dry skin • Constipation • Hair loss • Fatigue • Cold intolerance • Apathy • Depressed or delayed relaxation
Acquired hypothyroidism: Note the sharp deceleration in growth before the onset of symptoms. Following initiation of therapy significant catch-up growth is seen.
PTH • Bone: • Increases release of Ca and Phos • Intestine: • Increased re-absorption of Ca and Phos • Kidney: • Increases excretion of Phos • Decreases excretion of Ca • Stimulates Synthesis of Vit D3
Vitamin D • Bone • Increases release of Ca • Increases release Ph • Intestine • Increases absorption of Ca • Increases absorption of Ph • Kidney • Improves reabsorption of Ca • Increases reabsorption of Ph
Calcitonin • Bone • Inhibits reabsorption of Ca • Inhibits reabsorption of Ph • Intestine (no specific effects) • Kidney • Decreases reabsorption of Ca • Decreases reabsorption of Ph
Hyperparathyroidism • Results in hypercalcemia • Manifestation of multiple endocrine neoplasia I (MEN 1) • Autosomal dominant • Islet cell tumors • Zollinger-Ellison syndrome • Pituitary tumors
Hypocalcemia Symptoms: Paresthesias Irritability Muscle Cramps Tetany Seizures
Question 6 A two day old infant experiences a prolonged seizure with respiratory arrest requiring intubation. BMP reveals hypocalcemia, and CXR demonstrates absent thymic shadow. Genetic testing is likely to reveal: A. Trisomy 21 B. Trisomy 18 C. Deletion of 22q11.2 D. Deletion of 15q13.3 E.DF508 Mutation
Hypoparathyroidism • Idiopathic (Autoimmune) • DiGeorge Syndrome • Dysmorphic features • Cardiac defects • Immune deficiency • Thymicaplasia • Low PTH • Deletion of 22q11.2 • May present with seizures secondary to hypocalcemia Ca low P high PTH low
Pseudohypoparathyroidism • PTH is elevated • Unresponsiveness to PTH (Bone/Kidney/Both) • Albright hereditary osteodystrophy • Suspect in short child with hypocalcemia Ca low P high PTH high
Vitamin D-Deficient Rickets • Vitamin D deficiency may result from • Inadequate sunlight exposure • Malabsorption • Drugs that affect Vit D • Phenytoin, phenobarb • Signs/Symptoms • Poor linear growth • Delayed walking • Muscle weakness • Bone pain • Hypotonia • Anorexia Ca NL/low P low PTH high AlkP high
Others • Vitamin D-Resistant Rickets • Resistance to Vit D, even when high amounts used • Findings in first months of life • Pseudovitamin D-Deficiency Rickets • AKA 1a-hydroxylase deficiency or Vit-D dependent rickets type I • Findings appear in early infancy • Autosomal recessive