PEDIATRIC ENDOCRINE DISORDERS 1.1 (TB) Flashcards by Shiela Micah Gascon

What is hypopituitarism?

Underproduction of one or multiple pituitary hormones.

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What are the two primary sources of hypopituitarism?

Pathology of the hypothalamus and pathology within the pituitary gland.

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What is the incidence of congenital hypopituitarism?

1 in 4,000-10,000 live births.

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What percentage of isolated growth hormone deficiency (IGHD) cases are genetic?

0.13

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What percentage of multiple pituitary hormone deficiency (MPHD) cases are genetic?

0.2

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What are the forms of MPHD?

Genetic, congenital, and acquired.

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Which hormone deficiency is most commonly observed in hypopituitarism?

Growth hormone (GH) deficiency.

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Which transcription factors are mutated in MPHD and restricted to anterior pituitary?

PROP1 and POU1F1.

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Which genes involved in MPHD affect organs beyond the pituitary?

HESX1, LHX3, LHX4, OTX2, SOX3, PITX2.

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What syndrome is associated with GLI3 gene mutation?

Hall-Pallister syndrome.

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What anomalies are associated with an absence of the pituitary gland?

Hypothalamic hamartoma, polydactyly, nail dysplasia, bifid epiglottis, imperforate anus, anomalies of the heart, lungs, and kidneys.

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Which genes are linked to anophthalmia and hypothyroidism?

SIX6, SOX2, OTX2.

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What condition is associated with nystagmus and visual impairment?

Septo-optic dysplasia.

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What is the most common lesion causing acquired hypopituitarism?

Craniopharyngioma.

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What does GH insensitivity involve?

Abnormalities of the growth hormone receptor.

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What are some traumatic causes of acquired pituitary insufficiency?

Surgical resection, radiation damage, traumatic brain injury.

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Name an infiltrative cause of pituitary insufficiency.

Sarcoidosis.

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What fungal infections can cause pituitary insufficiency?

Histoplasmosis, aspergillosis.

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Which parasitic infection is listed under causes of pituitary insufficiency?

Toxoplasmosis.

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What is the criteria for short stature?

Height below the 1st percentile for age and sex or >2 SD below mid-parental height.

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What hormone must be checked before GH provocative testing?

Thyroid hormone.

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What defines low GH levels in provocative tests?

GH <10 ng/ml in each of 2 tests.

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What are some hormones to evaluate for other pituitary deficiencies?

TSH, free/total thyroxine, ACTH, cortisol, gonadotropins, gonadal steroids.

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What imaging shows suprasellar calcification in craniopharyngiomas?

CT scan.

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What radiologic triad is seen in severe early-onset MPHD?

Small anterior pituitary, attenuated stalk, ectopic posterior pituitary.

What test evaluates bone age in GH deficiency?

Hand X-ray.

What imaging can show lean mass and adiposity in GH deficiency?

Dual-photon X-ray absorptiometry.

What are clinical signs of GH deficiency in children?

Severe growth failure, hypoglycemia, micropenis, prolonged neonatal jaundice.

What sequence of hormone loss occurs in pituitary insufficiency?

GH > LH > FSH > TSH > ACTH.

What is the initial rhGH dose for GH deficiency?

0.16-0.24 mg/kg/week.

What is the treatment for ACTH deficiency?

Hydrocortisone 8-12 mg/m²/day.

What is the treatment for primary IGF-1 deficiency?

Recombinant IGF-1 (mecasermin), SQ 2x/day.

What hormone excess causes gigantism and acromegaly?

Growth hormone (GH).

What hormone excess causes prolactinoma?

Prolactin.

What condition results from GH excess before epiphyseal closure?

Gigantism.

What is the confirmatory test for GH excess?

Oral glucose suppression test.

What is the diagnostic cutoff for GH after glucose suppression?

<1 ng/mL.

What are signs of acromegaly?

Coarse facial features, enlarged jaw, broad nose, separation of teeth, kyphosis.

What is the treatment of choice for well-circumscribed pituitary adenomas?

Transsphenoidal surgery.

What drug is used for GH suppression?

Octreotide.

What is the first-line drug for hyperprolactinemia?

Cabergoline.

What are side effects of high-dose cabergoline?

Risk of cardiac valvular abnormalities.

What is the main cause of central diabetes insipidus?

Deficiency in the production of ADH, often due to pituitary gland damage.

What are the clinical manifestations of diabetes insipidus?

Polyuria (excessive urination) and Polydipsia (excessive thirst).

What are the two main types of diabetes insipidus?

Central DI (vasopressin deficiency) and Nephrogenic DI (vasopressin insensitivity).

What is the inheritance pattern of congenital central diabetes insipidus?

Autosomal dominant.

Where is ADH synthesized?

In the paraventricular and supraoptic nuclei.

What gene is commonly mutated in hereditary central DI?

AVP gene.

What syndrome involves autosomal recessive inheritance of central DI?

Wolfram syndrome 1.

What gene is mutated in Wolfram syndrome 1?

WFS1 gene.

What causes X-linked nephrogenic diabetes insipidus?

Mutations in the V2 vasopressin receptors.

What causes autosomal recessive nephrogenic diabetes insipidus?

Mutations in the renal water channel.

What drugs can cause acquired nephrogenic DI?

Lithium and demeclocycline.

What metabolic disturbances can cause nephrogenic DI?

Hypercalcemia or hypokalemia.

What are congenital causes of central DI?

Genetic mutations, malformations.

What are acquired causes of central DI?

Drug or toxin exposure, granulomatous diseases, neoplastic conditions, infections, autoimmune conditions, trauma, vascular incidents.

What are congenital causes of nephrogenic DI?

Genetic mutations (AVP V2 receptor, aquaporin-2).

What are acquired causes of nephrogenic DI?

Drug-induced conditions, metabolic disturbances, infiltrative diseases, vascular conditions, mechanical obstructions, solute diuresis.

Which type of diabetes insipidus is more common?

Central DI.

What is the approximate prevalence of DI?

1:25,000.

Are males or females more affected by DI?

Both are equally affected.

What triggers ADH release in response to baroreceptor changes?

A 5-10% decrease in blood volume or a 5% decrease in mean arterial pressure.

What takes precedence in severe volume depletion?

Baroreceptor stimulation of ADH over osmoregulation.

What is the mechanism of central DI?

Deficiency in vasopressin (AVP) secretion.

What is the mechanism of nephrogenic DI?

Insensitivity to vasopressin.

What is a key diagnostic tool for DI?

Water Deprivation Test.

What are the urine and serum osmolarity values in DI?

Serum osmolarity >300 mOsm/kg, Urine osmolarity <300 mOsm/kg.

What is considered abnormal urine output in children with DI?

Exceeding 2L/m2/24 hr.

What are signs of DI in infants?

Irritability, failure to thrive, intermittent fever.

What is the mainstay treatment for central DI?

Desmopressin (DDAVP).

How is DDAVP usually administered?

Intranasal or tablet form, titrated every 8-12 hours.

What is the treatment approach for nephrogenic DI?

Treat the underlying disorder.

What medications can reduce polyuria in nephrogenic DI?

Thiazides, indomethacin, amiloride.

What is the main problem in SIADH?

Impaired water excretion due to inappropriate ADH secretion.

What is the typical sodium level in SIADH?

Hyponatremia.

Does SIADH present with peripheral edema?

No.

What are common causes of SIADH?

Primary brain injury, malignancy, drugs, infections, hypothyroidism.

What drugs mimic or increase vasopressin leading to SIADH?

Oxcarbazepine, carbamazepine, chlorpropamide.

What is a common iatrogenic cause of SIADH in children?

Excessive vasopressin administration.

How often is SIADH found postoperatively?

Up to 35% of patients 1 week after surgery.

What is the result of uninhibited ADH secretion in SIADH?

Water retention and dilutional hyponatremia.

What happens to sodium levels in SIADH?

They decrease due to dilution and increased excretion.

What is the serum osmolality in SIADH?

<275 mOsm/kg.

What is the urine osmolality in SIADH?

>100 mOsm/kg.

What is the urine sodium level in SIADH with normal dietary sodium?

>40 mmol/L.

What are early signs of SIADH?

Nausea, malaise, vomiting.

What are severe manifestations of SIADH?

Lethargy, obtundation, seizures, coma.

What is the main treatment for SIADH?

Fluid restriction with normal sodium intake.

What medication creates nephrogenic DI for SIADH treatment?

Demeclocycline.

What other options exist for chronic SIADH management?

Furosemide with Na supplementation, tolvaptan, oral urea.