Endocrine Flashcards
The endocrine system consists of three components
- the cell, which sends a chemical message by means of a hormone
- the target cells, or end organs, which receive the chemical message
- the environment through which the chemical is transported (blood, lymph, extracellular fluids) from the site of synthesis to the sites of cellular action.
The endocrine system controls or regulates…
metabolic processes governing energy, production, growth, fluid and electrolyte balance, response to stress and sexual reproduction.
Endocrine Glands
Pituitary gland Thyroid gland Parathyroid glands Adrenal glands Ovaries Testes Islets of Langerhans
Structures sometimes considered endocrine glands; although they are not usually included
Pineal body
Thymus
GI glands
Placenta
Hormone
a complex chemical substance produced and secreted into body fluids by a cell or group of cells that exerts a physiologic controlling effect on other cells.
Local hormones
create their effect near the point of secretion
General hormones
produced in one organ or part of the body and are carried through the bloodstream to a distant part, or parts, of the body where they initiate or regulate physiologic activity of an organ or group of cells.
Regulation of hormonal secretion is based on:
Negative feedback.
Anterior pituitary
- Master gland
- the endocrine gland primarily responsible for stimulation and inhibition of target glandular secretions
Anterior pituitary hormones
GH –> muscles, bones, organs –> hyper = giantism –> hypo = small stature
Gonadotropin –> sex organs –> hyper = precocious puberty
ACTH –> adrenal cortex
Prolactin –> mammary; milk production –> hyper = too much milk –> hypo = no milk
TSH –> Thyroid –> hyper = overactive thyroid –> hypo = thyroid dysfunction
MSH –> skin
Posterior pituitary hormones
Oxytocin –> uterus; contractions & milk ejection –> hyper = premature ctx –> hypo = delayed/weak ctx
ADH –> kidney (distal tubules) –> hyper = SIADH –> hypo = DI
Thyroid
Thyroxine, T3, T4 –> widespread
Calcitonin –> skeleton –> stim osteoblasts –> hyper = decreased serum Ca –> hypo = weak bones
Parathyroid
PTH –> bone, kidney, GI tract –> stimulates osteoclasts –> hyper = increased serum CA, weak bones
Adrenal cortex
Glucocorticoid (wide spread), Mineral corticoids (kidney), sex hormones
Adrenal medulla
Catecholamines: 1. epinephrine, 2. norepinephrine
Pancrease
Glucagon and insulin
Gonads
Estrogen, progesterone, testosterone
Pituitary gland is controlled by:
either hormonal or neuronal signals from the hypothalamus. Hypothalamus secretes releasing hormones and inhibitory hormones.
Glandular hormones that are not under the control of the pituitary gland are:
glucagon, parathyroid hormone, antidiuretic hormone, aldosterone, and insulin
Two regulatory systems that maintain hemostasis are:
- the endocrine system
- autonomic nervous system
Collectively called neuroendocrine system
Endocrine dysfunction may result from an
intrinsic defect in the target gland (primary) or from a diminished or elevated level of tropic hormones (secondary).
An overproduction of the anterior pituitary hormones can result in:
gigantism (excess GH), hyperthyroidism hypercortisolism (Cushing syndrome), and precocious puberty (excess gonadotropins)
Panhypopituitarism
the loss of all anterior pituitary hormones, leaving only posterior pituitary function intact
**children with this condition should wear a medical bracelet.
Hypopituitarism
is defined as diminished or deficient secretion of pituitary hormones. The consequences of the condition depend on the degree of dysfunction:
Gonad. deficiency: abs./regr. of 2ndary sex charact.)
GH def: delayed somatic growth
TSH def: hypothyroidism
Corticotropin def: manifestations of adrenal hypofunction
The most common organic cause of pituitary undersecretion is
tumors in the pituitary or hypothalamic region, especially the craniopharyngiomas.
Clinical manifestations of panhypopituitarism
GH: short stature, delayed epiphyseal closure, increased insulin sensitivity
TSH: short stature, dry, coarse skin, pallor, cold intolerance, constipation
Gonad.: absence of sexual maturation
ACH: severe anorexia, weight loss, hypoglycemia, hypotension, hyponatremia, hyperkalemia, circulatory collapse
ADH: Polyuria, polydipsia, dehydration
MSH: decreased pigmentation
Familial short stature
refers to otherwise healthy children who have ancestors with adult height in the lower percentiles, and whose height during childhood is appropriate for genetic background.
Constitutional growth delay
individuals with delayed linear growth, generally beginning as a toddler, and skeletal and sexual maturation that is behind that of age-mates.
Typically these children will reach normal adult height
Clinical manifestations of hypopituitarism
children generally grow normally during the 1st year and then follow a slowed growth curve that is below the 3rd percentile; emotional problems are not uncommon, especially as they near puberty.
GH levels are increased
20 minutes after strenuous exercise and 45 to 90 minutes after the onset of sleep.
Excess GH before the closure of the epiphyseal shafts results in
proportional overgrowth of the long bones. Individuals can reach a height of 8 feet (2.4m) or more.
If oversecretion of GH occurs after epiphyseal closure, growth is in the transverse direction, producing a condition known as
acromegaly
Precocious puberty
manifestations of sexual development before age 7 for girls and age 9 for boys.
Types of precocious puberty
Central: idiopathic or congenital anomalies or infection
Peripheral: male-limited; tumors
Incomplete: premature menarche, thelarche, adrenarche
Diabetes Insipidus
The primary disorder of posterior pituitary hypofunction.
Also known as neurogenic DI, resulting from undersecretion of ADH, or vasopressin.
uncontrolled diuresis
Primary cause of DI
familial or idiopathic; of all cases, approx. 45-50% are idiopathic
Secondary causes of DI
trauma, tumors, granulomatous disease, infections, vascular anomalies
Clinical manifestations of DI
Cardinal signs: polyuria and polydipsia
1st sign if frequently enuresis
Infant: irritability relieved with feedings of water only.
Vasopressin
Tx with DI
small brown particles, which indicate drug dispersion, must be seen in the suspension
Tx is lifelong
SIADH - Syndrome of inappropriate antidiuretic hormone
Oversecretion of the posterior pituitary hormone, or ADH.
- it occurs with increased frequency in a variety of conditions: infections, tumors, CNS disease/trauma
- the most common cause of hyponatremia in the pediatric population!
SIADH manifestations
- are directly related to fluid retention and hypotonicity
- excess ADH causes most of the filtered water to be reabsorbed from the kidneys back into central circulation.
- immediate management consists of restricting fluids
Nursing considerations with SIADH
- measure I&Os
- daily weight
- monitor for s/s of fluid overload
Secretion of thyroid hormones is controlled by
TSH from the anterior pituitary.
Hyperthyroidism/hypothyroidism may result from
a defect in the target gland or from a disturbance in the secretion of TSH or TRF.
The thyroid gland is the only endocrine gland capable of
storing excess amounts of hormones for release as needed.
The main physiologic action of TH is to
regulate the basal metabolic rate and thereby control the processes of growth and tissue differentiation.
Calcitonin
helps maintain blood calcium levels by decreasing the calcium concentration.
PTH
inhibits skeletal demineralization and promotes calcium deposition in the bone.
Hypothyroidism is
one of the most common endocrine problems of childhood.
Clinical manifestations of hypothyroidism
- depend on the extent of dysfunction and the child’s age at onset.
- low levels of circulating thyroid hormones and raised levels of TSH
- *if left untreated, congenital hypothyroidism causes decreased mental capacity.**
Presenting symptoms of hypothyroidism
-decelerated growth
-thyromegaly
-Myxedematous skin changes, dry skin, constipation, sleepiness, mental decline, growth failure, delayed puberty, excessive weight gain.
Tx: TH replacement (Synthorid)
Goiter
An enlargement or hypertrophy of the thyroid gland.
-can be congenital or acquired
Nursing alert for goiter:
- if an infant is born with a goiter, immediately begin precautions for emergency ventilation.
- have O2 and trach set nearby
- hyperextension of the neck often facilitates breathing
Lymphocytic Thyroiditis
- the most common cause of thyroid disease in children and adolescents
- accounts for the largest percentage of juvenile hypothyroidism (Hashimoto disease, juvenile autoimmune thyroiditis)
- occurs most frequently after age 6; reaches peak incidence during adolescence
- there’s evidence that the disease is self-limiting
- strong genetic predisposition
Clinical manifestations of lymphocytic thyroiditis
- enlarged thyroid gland
- symmetrical enlargement (may be asymmetrical), firm, freely movable, nontender
Therapeutic management of lymphocytic thyroiditis
- *surgery is contraindicated**
- in many cases the goiter is transient and asymptomatic and regresses spontaneously within a year or two.
Hyperthyroidism
- largest percentage is caused by Graves disease
- enlarged thyroid gland & exophthalmos
- Graves occurs 6-15 years with peak at 12-14 years
- incidence is 5x higher in girls
- no cure for Graves disease
Clinical manifestation of hyperthyroidism
-excessive motion - irritability, hyperactivity, short attention span, tremors, insomnia, emotional lability, gradual weight loss despite a voracious appetite
Postoperative care (hyperthyroidism)
- positioning with the neck slightly flexed to keep strain off the sutures
- observe for bleeding and complications
Earliest indication of Hypoparathyroidism may be
-anxiety and depression, followed by paresthesia and evidence of heightened neuromuscular excitability, such as:
Chvostek sign: facial muscle spasm w/ tapping
Trousseau sign: carpal spasm
Tetany: carpopedal spasm, muscle twitching, cramps, stridor, seizures
Parathyroid glands
- secrete PTH
- main function of PTH, along with Vit D & calcitonin, is homeostasis of serum calcium concentration.
Principal effects of PTH on its target sites:
bones: increases osteoclastic activity, causing phosphate-producing bone demineralization
Kidneys: increases absorption of calcium and excretion of phosphate
GI tract: promotes calcium absorption
Hypoparathyroidism
a spectrum of disorders that result in deficient PTH
Clinical manifestations of hypoparathyroidism
- s/s may be none to significant morbidity
- mild deficiency dx through lab studies
- muscle cramps is an early symptom
- progressing numbness, stiffness, and tingling in the hands and feet
- convulsions with LOC may occur
- these episodes may be preceded by abdominal discomfort, tonic rigidity, head retraction, and cyanosis.
Therapeutic management of hypoparathyroidism
- maintain normal serum calcium & phosphate levels
- severe/acute tetany corrected with calcium gluconate
- longterm management is massive doses of Vit D and oral calcium supplementation.
Hyperparathyroidism
- rare in childhood but can be primary or secondary
- most common primary cause is adenoma of the gland
- most common secondary cause is chronic renal disease, renal osteodystrophy, and congenital anomalies of the urinary tract.
- common factor is hypercalcemia
Clinical manifestations of hyperparathyroidism
GI: N/V, abdominal pain, constipation
CNS: delusions, confusion, impaired memory, lack of interest, depression, varying LOC
Neuromuscular: weakness, easy fatigability, muscle atrophy, twitching of the tongue, paresthesias in extremities
Skeletal: vague bone pain, spontaneous fx, absence of lamina dura around teeth
Renal: polyuria, polydipsia, renal colic, HTN
Adrenal cortex
- secretes hormones, collectively called steroids, which are essential to life.
- glucocorticoids (sugar)
- mineralocorticoids (salt)
- sex steroids (sex)
- 3 S’
Adrenal medulla
secretes catecholamines, epinephrine and norepinephrine.
- hypothalamus controls the secretion of catecholamines.
- Pheochromocytoma is a tumor caused by hypersecretion of catecholamines; dangerously high systolic and diastolic pressures
- Surgical emergency!
Glucocorticoids
- most important is cortisol
- elevate serum glucose levels
- acts as an anti-inflammatory
- released under stressful situation
- fight or flight
- suppress growth hormone
Mineralcorticoids
- most important is aldosterone.
- It promotes sodium retention and postassium excretion in the renal tubules.
- circulating volume is conserved
- aldosterone synthesis is regulated primarily by the renin-angiotensin system of the kidney.
- aldosterone is released via activation of the JGA
Sex-steroids
-normally secreted in minimum amounts until adolescence
Chronic adrenocortical insufficiency (Addison disease)
- rare in children
- causes include infections, destructive lesions of the adrenal gland or neoplasms, and autoimmune processes, or the cause is idiopathic.
Cushing syndrome
- a characteristic group of manifestations caused by excessive circulating free cortisol.
- may be due to an adrenal tumor
- may also be caused by excessive or prolonged steroid therapy that produces a cushingoid appearance.
- this condition is reversible
S/S of Cushing syndrome
excessive hair growth, moon face, pendulous abdomen, poor wound healing, temporal fat, red cheeks, ecchymosis, red abdominal striae, bruises, weight gain
Diabetes Mellitus (DM)
- a chronic disorder of metabolism characterized by a partial or complete deficiency of the hormone insulin.
- most common metabolic disease
- age of presentation of type 1 DM peaks at 4-6 and 10-14
- inability to metabolize carbohydrates due to a deficiency or diminished effectiveness of insulin (usually absolute in childhood)
Type 1 DM
- destruction of pancreatic beta cells which produce insulin; usually leading to absolute insulin deficiency.
- 2 forms: immune-mediated DM and idiopathic type 1 - rare form of the disease with no known cause
Type 2 DM
usually arises because of insulin resistance; relative insulin deficiency.
Cardinal symptoms of DM
polyphagia, polydipsia, polyuria
Rapid-acting insulin
- Lispro
- 15 minutes to blood
- peaks at 30 to 90 minutes
- lasts up to 5 hours
Short-acting insulin
- regular
- 30 minutes to blood
- peaks at 2 to 4 hours
- lasts for 4 to 8 hours
Intermediate-acting insulin
- NPH and Lente
- 2 to 6 hours to blood
- peaks at 4 to 14 hours
- lasts 14 to 20 hours
Long-acting insulin
- Ultralente
- 6 to 14 hours to blood
- has no peak or a very small one at 10 - 16 hours
- lasts 20 to 24 hours
Insulin is packaged
in the strength of 100 units/mL
human insulin analogs are
Lispro-H (Humalog) Insulin aspart (NovoLog)
Insulin drug alert
human insulin from various manufacturers may be interchangeable, but human insulin and pork insulin or pure pork insulin should never be substituted for one another.
Regular insulin is best administered
30 minutes before meal time
Insulin pump needles are changed
every 48 to 72 hours
Normal glucose ranges
80-120 mg/dl
Hypoglycemia
- episodes most commonly occur before meals, or when the insulin effect is peaking
- S/S: nervousness, pallor, palpitations, sweating, hunger, weakness, dizziness, headache, irritability, loss of coordination, seizures, and coma.
Pituitary dysfunction is manifested primarily by
growth disturbance
Five categories of Cushing syndrome are:
Pituitary Adrenal Ectopic Iatrogenic Food dependent
Management of CAH includes
assignment of a sex according to genotype, administration of cortisone, and possibly, reconstructive surgery
The focus of DM type 1 is:
insulin replacement
diet
exercise
Which of the following statements best described hypopituitarism?
skeletal proportions are normal for age
Which of the following should the nurse include when discussing a child’s precocious puberty with the parents?
Dress and activities should be appropriate to chronologic age.
Which of the following is the primary clinical manifestation of DI?
Polyuria, polydipsia
A 13 y/o girl is brought to the clinic with the complaint of insomnia and hyperactivity. Other symptoms include gradual weight loss despite a good appetite; warm, flushed, and moist skin; and unusually fine hair. These manifestations are most suggestive of which of the following?
Hyperthyroidism
The nurse is caring for a child hospitalized with acute adrenocortical insufficiency. Because of the sudden, severe nature of the disease the family needs a great deal of emotional support. The most appropriate nursing action is which of the following?
Prepare the family for each procedure.
Which of the following statements best describes Cushing syndrome?
It is caused by excessive production of cortisol.
The parent of a 10 y/o child with diabetes asks the nurse why home blood glucose monitoring is being recommended. The nurse should base the explanation on which of the following?
Children have a greater sense of control over the diabetes.
A school-age child recently diagnosed with type 1 DM asks the nurse if he can still play soccer, play baseball, and swim. The nurse’s response should be based on knowledge that:
exercise is not restricted unless indicated by other health conditions.
The nurse should recognize that when a child develops diabetic ketoacidosis, this is which of the following?
Life-threatening
Endocrine function
- maintain homeostasis by producing and secreting hormones
- controls and regulates those processes that govern energy, growth, f&e balance, stress, sexual reproduction
Endocrine
directly into circulation; tissues bathed
Exocrine
excreted into ducts
Anabolism
building phase of metabolism
catabolism
destructive phase of metabolism
tropin
stimulating
Glycogen
intracellular glucose
Gluconeogenesis
development of glucose form protein & fat
Glyconeogenesis
formation of glycogen from protein & fat
Posterior pituitary secretes
ADH, oxytocin
Anterior pituitary secretes
G2APTM: GH, gonadotropins, prolactin, TSH, MSH
Thyroid storm
- crisis
- uncontrolled hyperthyroidism
- precip. events: infection, stress, surgery
- S/S: increased temp, tachycardia, resp. distress, HF, coma
Calcitonin
- stimulates osteoblasts
- increased calcitonin = decreased calcium
Hyposecretion of ADH is
DI…increased urine output!
DI S/S
polyuria polydipsia nocturia dilutional hypernatremia decreased specific gravity decreased BP rapid dehydration
Blood sugar ranges
0-6 y/o = 100-200
6 - Tanner II = 80-180
Tanner II - Tanner V = 80-150
Glycosylated hemoglobin
- HgB A1C
- 6.5-8% is desired
- control for past 2-3 months
- RBC dies every 120 days
Urine ketones with DM
test during illness and when blood glucose is greater than 240
test q 3 hrs
Ketoacidosis
- emergency necessitating ICU admission
- rehydrate with 0.9% NaCl cautiously
- may start 5% dextrose when BS 250-300
- start regular insulin infusion at 0.1 unit/kg/hr
- metabolic acidosis
DM complications
retinopathy
nephropathy
neuropathy
