Endocrine & Metabolic Flashcards Flashcards by Krista Ash-Robinson

Beckwith-Wiedemann Syndrome

Unknown cause
Autosomal dominant inheritance
Characteristics:
•	Macroglossia
•	Abdominal Wall Defect
•	Organomegaly
•	Including pancreas – dump insulin causing 
        hypoglycemia & islet cell hyperplasia
•	Hypoglycemia
•	Polycythemia

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Calcium Regulation processes:

• Maintenance of cell membrane permeability
• Activation of enzyme reactions for muscle
contraction
• Nerve transmission
• Blood Clotting
• Normal functioning & development of the skeletal
system

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Calcium Regulation & the Parathyroid Hormone (PTH)

Mobilizes calcium and phosphorous from bone

* Decreases renal excretion

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Calcium Regulation & 1,25 Dihyroxycholecalcerferol
Vitamin D (hormone)

• Required for PTH to work
• Increases absorption of Calcium and Phosphorous
from the gut

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Calcium Regulation & Calcitonin

Inhibits calcium mobilization from the bone
Increases calcium excretion
Decreases serum calcium

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Factors that Influence Calcium Levels

Acidosis increases Ca
Alkalosis decreases Ca
Phosphorous inhibits the absorption of Calcium

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A normal magnesium level is required for ? to work

• Parathyroid hormone

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Definition of Hypocalcemia

Total Ca of < 7.0 mg/dL

* Ionized Ca < 3 - 4.4 mg/dL or < 0.75 – 1.1 mmol/L

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Definition of Hypercalcemia

Total Ca of < 11.0 mg/dL

* Ionized Ca < 5.8 mg/dL

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Causes of Hypercalcemia

Iatrogenic
Hyperparathyroidism
Decreases phosphate (phosphorous inhibits Ca)
Familial Infantile Hypercalcemia

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Hypercalcemia Treatment

Hydrate
Promote excretion with Lasix
Decrease Ca and Vit D intake
Increase Phosphorous intake

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Causes of Hypomagnesemia

Low maternal level
Placental insufficiency
Prematurity or IUGR
Increased losses with renal or intestinal disorders
Hypoparathyroidism

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What does the Adrenal Medulla do?

• Secretes catecholamines (epinephrine &
norepinephrine)
• “Fight or Flight” response

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What does the Adrenal Cortex do?

Production of:
• Glucocorticoids
• Mineralcorticoids
• Androgens

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Actions of Cortisol (Glucocorticoid)

• Regulates blood sugar
• Important for growth
• Maintains cardiovascular function
• Releases in times of stress to increase glucose,
increase cardiac output, and maintain vascular tone.

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Actions of Aldosterone (Mineralcorticoid)

• Regulates fluid and electrolyte balance
• Stimulates the reabsorption of sodium and water in
the distal collecting tubules.
• Inhibits the secretion of potassium
• Important in maintaining blood pressure,
intravascular volume, cardiac function, and
electrolytes

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What is adrenal insufficiency?

• A transient phenomenon in the VLBW infant
• Related to the hypothalamic-pituitary-adrenal
immature (the pathway is immature)
• Levels of cortisol are decreased in the VLBW infant
• Levels do not increase during times of stress
• Cortisol suppression related to exogenous steroid
administration

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Clinical Manifestations of Adrenal Insufficiency

Glucose abnormalities
Refractory Hypotension
Decreased cardiac output, acidosis, and shock
Decreased urinary output
Infection
Hyponatremia, Hyperkalemia
Tachycardia

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What is the treatment for Adrenal insufficiency?

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Hydrocortisone therapy???
How much????

• Recover on own by 14 days of life

Thyroid excretes 2 hormones

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Thyroxine (T4)
Much of T4 is converted to T3

• Triiodothyronine (T3)

• 99% are bound to protein (not able to produce
effects)
• 1% is free (able to produce effects)

What does the pituitary secrete that stimulates the thyroid to release its hormones?

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• Thyroid Stimulating Hormone (TSH)

Congenital Hypothyroidism: Causes

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• Dysgenic or absent thyroid gland
• Deficient synthesis of thyroid hormones
• Maldevelopment or absence of the anterior
pituitary

Congenital Hypothyroidism: Clinical Manifestations

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•	Often asymptomatic
•	Symptoms are often subtle and nonspecific
•	May be associated with chromosomal defects (. 
         Downs)
•	Post dates / LGA
•	Defective skeletal maturation & growth
•	Hypotonia
•	Large tongue
•	Umbilical hernia
•	Temperature instability
•	Poor feeding

Congenital Hypothyroidism: Diagnosis

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• State metabolic screen

T4 is low
TSH is elevated

• Anterior pituitary sees the low T4 and cranks out
the
• TSH to stimulate the thyroid

Congenital Hypothyroidism: Treatment

* L-thyroxine (a synthetic T4) * Monitor levels * Irreversible mental retardation if not treated

Hypothyroxinemia of Prematurity What is it?

* A transient phenomena due to immaturity * Fetal thyroid hormones not made until 30 weeks * Severity is dependent on gestational age * Persists for 4-6 weeks * No proven benefit with treatment. * Low T4 * Normal TSH

Hyperthyroidism Neonatal Thyrotoxicosis

• Thyroid gland secretes excessive thyroid hormone • 90% are due to Maternal Graves disease • Transplacental transfer of thyroid stimulating immunoglobulins (Mom has thyroid stimulating immunoglobulins that cross the placenta and stimulate the babies thyroid) • May be transient or prolonged • Considered a medical emergency

Hyperthyroidism: Clinical Manifestations

* IUGR * Irritability * Tachycardia & tachypnea * Cardiac failure * Hyperthermia * Vomiting & diarrhea (due to overeating) * Failure to thrive * Goiter

What is the best position to exam the neonatal thyroid?

• Sitting up

Hyperthyroidism: Diagnosis

• High T4 • Because the maternal immunoglobulins are stimulate the infants thyroid • Low TSH • Because the anterior pituitary sees the high T4 level and is trying not to stimulate the thyroid anymore.

Hyperthyroidism: Treatment

Acute treatment: • PTU (Prophlthiouracil) – blocks the thyroid from making hormones Chronic treatment: • Lugol’s solution – iodine solution

Osteopenia of Prematurity: What is it?

* Thinning and undermineralization of the bone * Occurs in 50% of infants < 1000 grams * Peaks in 2-3 months of age

Osteopenia of Prematurity and Prematurity

• 80% of bone mineralization occurs during 3rd trimester • Intrauterine mineral accretion is much greater than extrauterine • Inadequate postnatal bone mineralization

Osteopenia of Prematurity: Causes

• Inadequate calcium, phosphorus, & Vit D intake • Feeding intolerance • Lasix • Increases renal calcium loss • Stimulates calcium reabsorption from bone • Aminophylline – calcium excretion in urine • Phenobarbital & Dilantin – enhanced Vit D metabolism

What do you need to make bones?

``` Vitamin D o 1,25 dihyroxyvitamin D o Stimulates absorption of calcium & phosphorous from the intestines Phosphorous o Stimulates bone formation o Inhibits reabsorption of bone Calcium ```

Clinical Manifestations of Osteopenia of Prematurity

* Normal calcium levels * Normal to low phosphorous (< 3.5 mg/dL) * Increased alkaline phosphate (> 499) * Enzyme released due to bone breakdown * Cupping & fraying of the metaphysic * Decreased bone density * Fractures of the long bones & ribs

Osteopenia of Prematurity: Treatment

* Prevention! * Adequate amounts of calcium & phosphorous * Adequate kcal & protein * 400 IU of vitamin D * Fortify breastmilk / use of premature formulas

Osteopenia of Prematurity: Prognosis

* Self-resolving | * Increased incidence of BPD

When are the gonads formed?

6 – 7 weeks gestation

When is testosterone first released?

6 – 7 weeks gestation

When is sexual differentiation?

8 – 9 weeks gestation

Klinefelter’s Syndrome

* 47xxy * hypogonadism * dysgenesis of the seminiferous tubules * Not generally diagnosed in the neonatal period

Hermaphrodite

* 46xx or 46xy mosaic | * Both ovaries and testes in one individual

What is an inborn error in metabolism?

• Autosomal recessive genetic defect • Due to the absence of an enzyme, cofactor, or transport • protein which either degrades or converts one substance into another. • This absence results in either a toxic accumulation of the substrate or the deficiency itself can be toxic

Inborn Error of Metabolism (Pathway)

• The lack of the enzyme leads to an excess (elevation) of the precursor and a deficiency (decrease) in the substrate.

Endocrine & Metabolic Flashcards

(45 cards)