Please enable JavaScript.
Coggle requires JavaScript to display documents.
Endocrine Disorder, Endocrine glands secrete chemical messengers (hormone)…
-
- Endocrine glands secrete chemical messengers (hormone) into bloodstream
- Many endocrine processes involve several tissues:
- hypothalamus: sends signals to pituitary gland
- anterior pituitary: receives hormonal signals from hypothalamus
- Posterior pituitary: release hormones synthesized by hypothalamus
- End organs: targets for pituitary hormones, may or may not secrete additional hormones
- Link between hypothalamus-pituitary-end organ
- Pituitary (hypophysis)
- Anterior pituitary (adenohypophysis):
-- blood vessel connection with hypothalamus (hypothalamus-hypophyseal portal system)
-- release tropic hormones
- Posterior pituitary (neurohypophysis)
-- neural connection with hypothalamus
-- hormones made by hypothalamus, stored & released by posterior pituitary
- Anterior
- growth hormone
- prolactin
- adrenocorticotropic
- thyroid-stimulating hormone
- Follicle-stimulating hormone
- Luteinizing hormone
- Posterior
- Antidiuretic hormone
-- AKA arginine vasopressin
- oxytocin
- Negative feedback mechanism
- end-product hormone negatively feeds back to prevent further stimulatory signals (eg. thyroid hormones suppress thyroid-stimulating hormone production)
- Receptor activity
- upregulation
-- increased receptor sensitivity and number
- downregulation
--decreased receptor sensitivity and number
- Hormone Deficiency
- gland destruction
-- autoimmune, infection, tumor
- Hormone excess
- tumor, autoimmune, genetic mutation
- Hormone resistance
- usually genetic (lack hormone receptor or ability to respond)
- Hypofunction
- inadequate amount of hormone
- Hyperfunction
- excessive amount of hormone
- three levels of dysfunction
- Primary
-- endocrine gland itself
- Secondary
-- abnormal pituitary activity
- tertiary
-- dysfunction of hypothalamic origin
- Autoimmune
- Antibodies target endocrine gland, may cause hypofunction or hyperfunction
- Neoplasia
- hypofunction or hyperfunction of gland itself or any endocrine tissue the gland affects
- some cancers: paraneoplastic disorders in which cancer cells secrete hormone-like substances
- Endocrine-disrupting compounds (EDCs)
- Chemical in environment that can alter endogenous hormone functions
- Current and past medical history
- Some endocrine disorders present with wide-ranging, multisystem signals and symptoms
- Endocrine dysfunction may affect mood and behavior, can be misinterpreted as psychological issues
- Immunoassays or blood levels of hormones most important
- Urinary hormone levels assessed in some instances
- Urinary collection over 24 hours
- Suppression/stimulation tests
- CT scan/MRI
- Ultrasound
- Hormone replacement therapy
- dosage schedules attempt to mimic physiological effects
- Glucocorticoids, thyroid hormones, sex steroids, ADH most common replacements
- Suppression of hormone overproduction
- medications, surgery, radiation
- One or more of pituitary hormones
- panhypopituitarism
-- complete loss of all pituitary hormones
-- rare
- Causes:
- pituitary tumor, brain surgery, radiation of brain tumor, congenital disorder
- trauma, ischemia, and infraction can cause sudden loss of pituitary function
-- Sheehan's syndrome (develops after childbirth with severe hemorrhage)
- Primary adenoma
- most common cause
- benign neoplasm
- with growth can compress pituitary gland in sella turcica (interfere with pituitary function)
- Craniopharyngioma
- benign neoplasm close to pituitary gland or pituitary stalk
- Pituitary apoplexy
- sudden destruction of the pituitary tissue due to infraction or hemorrhage into gland
- traumatic brain injury most common cause
- Depend on pituitary hormones suppressed
- most serious concerns are adrenal insufficiency, hypothyroidism, and diabetes insipidus
- Age of onset
- children with hypopituitarism will have different complications than adults
- if hypopituitarism is acute, rapid deterioration of patient
- Neonate & Infant
- Dwarfism
- developmental delay
- various visual and neurological symptoms
- seizure disorder
- congenital malformation
- Adults
- weakness
- weight loss/gain
- hypotension caused by adrenal insufficiency
- sluggishness
- depression
- excessive urination and dehydration
- Blood tests to assess hormone levels
- pituitary, hypothalamic, and end-organ levels may be needed
- Corticotropin stimulation test: Give ACTH
- cortisol levels should rise
-- if cortisol levels RISE with ACTH admin: Pituitary problem
-- if cortisol levels DO NOT RISE with ACTH admin: Adrenal gland problem
- MRI, CT scan
- Pituitary adenoma
- most common cause
- may produce ACTH, TSH, or GH
- prolactinoma most common form: secretes PRL
-- High PRL has antiestrogenic and antiandrogenic effects
- large tumors may cause headaches and visual disturbances (due to proximity to optic nerve)
- Children
- ACTH-producing adenoma
- Corticotropinomas (common before puberty)
- Cushing-like symptoms
- GH-secretion adenoma
- Children
-- gigantism
- adults
-- acromegaly
Diagnosis:
- serum hormone levels
- urine hormone levels may also be assessed
- dexamethasone suppression test to assess ACTH response
Treatment:
- depends on elevated hormone
- prolactinoma (bromocriptine)
- transsphenoidal surgery
- adrenal enzyme inhibitors
- GH inhibitors
- Excessive ADH
- causes: brain injury or neurosurgery
- paraneoplastic disorder
- Causes fluid retention
- concentrated urine, dilute plasma, hypervolemia
- treatment
- fluid restriction
- slow correction of hyponatremia
- ADH receptors antagonists may be used
- Triiodothyronine (T3) and thyroxine (T4)
- Iodine required for synthesis
- thyroxine (regulate the metabolism)
- Thyroid disorder more common in women
- primary thyroid disorders most common
- enlarged thyroid can indicate hypo or hyperfunction
- Hashimoto's thyroiditis
- autoimmune disorder
- anti-thyroglobulin antibody and anti-thyroperoxidase antibody
- other causes:
- drugs
- genetics
- thyroiditis (postpartum period especially high incidence)
- congenital hypothyroidism: cretinism
Signs & Symptoms:
- cold intolerance
- weight gain
- fatigue
- memory deficit
- muscle cramps
- hair loss
- brittle nails
Diagnosis:
- Primary: High TSH, low free T3 & T4
- Secondary: Low TSH, free T3 & T4
- Hashimoto's thyroiditis antibodies
- antithyroglobulin (anti-Tg)
- Antithyroperoxidase (anti-TPO)
- ultrasound
- Elevated free T3 and free T4
- Grave's disease
- most common cause
- autoimmune stimulation of the thyroid gland
- Other causes:
- subacute thyroiditis
- thyroid adenoma
- excessive TSH
- excessive iodine ingestion
Treatment:
- Antithyroid hormone medication propylthiouracil (PTU)
- Radioactive iodine treatment
- Surgery
- if gland removed, replacement thyroid hormone (levothyroxine) needed for life
- Four pea-sized glands on posterior thyroid
- secrete PTH (parathyroid hormone)
- release when blood calcium low
- activate bone resorption, intestinal calcium absorption by kidneys
- Rare
- Inadvertent damage with thyroid surgery, genetic disorders
- presentation due to hypocalcemia
- trousseau's sign, chvostek's sign
- muscle cramps, tetany
- convulsion
- Treatment
- replacement PTH, normalize serum calcium
- Usually due to parathyroid adenoma
- Primary
- Secondary
- elevated PTH, low normal calcium
- Presentation due to excess calcium
- muscle weakness
- poor concentration
- neuropathies
- kidney stones
- osteopenia
- Treatment
- surgery
- reduce serum calcium
- Hypoadrenalism can also be due to exogenous glucocorticoids
- prolonged glucocorticoid use, CRF-ACTH signals to adrenal cortex suppressed
- adrenal gland down regulates receptors
- steroid usage should NOT be abruptly stopped
-- individual may be unable to respond to stressor
- Smallest dosage of steroid needed should be given to patient to lessen adrenal atrophy
Symptoms:
- weakness
- hypotension
- easy fatigue
- anorexia
- electrolyte imbalance
-- hyponatremia
-- hyperkalemia
- tanned appearance due to melanocyte-stimulating hormone (MSH)
- ACTH and MSH arise from same precursor molecule
- Diagnosis:
- rapid ACTH test
-- with rapid test, cortisol should rise within 30 min
-- no cortisol rise: adrenal cortex insufficiency
- Treatment:
- daily replacement of glucocorticoid and mineralocorticoid
- parental steroid coverage in times of major stress, trauma, or surgery
- Cushing's disease
- elevated ACTH tumor in pituitary
- Cushing's syndrome
- elevated cortisol, hyperfunction of adrenal cortex
- Exogenous steroids most common cause of Cushing's syndrome
- Causes:
- pituitary adenoma
-- Cushing's disease
- Cushing's syndrome
-- adrenal hyperplasia, adrenal neoplasm
-- carney complex (genetic disorder)
- McCune-Albright syndrome (Cushing's syndrome & precocious puberty)
- Secretion of ACTH from tumors
Signs and Symptoms:
- weight gain
- redistribution of body fat to the face, trunk, and abdomen
- puffy face ("moon facies")
- extra subcutaneous fat in the cervicothoracic area
- striae
Diagnosis:
- serum levels
- elevated WBCs, hyperglycemia, hypokalemia
- Salivary levels of cortisol, 24-hour urine cortisol
- dexamethasone suppression test
- administer dexamethasone
- serum cortisol should be suppressed
- Cushing's syndrome: no cortisol suppression with dexamethasone
- MRI, CT scan
- Block the action of insulin
- glucose intolerance and hyperglycemia
- inhibit bone formation and accelerates bone reabsorption
- suppress immune response
- hypertension
-
- Adrenal medulla tumor
- secrete norepinephrine and epinephrine
- excessive sympathetic stimulation
- Hypertension, tremors, increased cardiac contractility, cardiac arrhythmias, tachycardia
- diagnosis
- 24-hour urine for catecholamine metabolites
- Produces melatonin with the phases of light-dark cycle
- tumor may place pressure on adjacent brain structures
- symptoms include headache, seizures, memory disturbances and visual changes