Endocrinology Flashcards
causes linear and soft tissue growth increase bone thickness protein synthesis fatty acid release from adipose tissue insulin resistance increase blood glucose
Growth hormone
milk production
prolactin
stimulates release of thyroxine (T4) and triiodothyronine (T3)
TSH
stimulates cortisol synthesis and secretion from adrenal cortex
Adrenocorticotropic hormone (ACTH)
promotes luteinization of the ovary and Leydig cell function of the testis
LH
stimulates follicular devt in the ovary and gametogenesis in the testis
FSH
increases water reabsorption via insertion of aquaporin 2 in the renal collecting duct
ADH
milk secretion
stimulates uterine contractions during labor and delivery
oxytocin
severe growth failure, tendency for hypoglycemia, micropenis, prolonged neonatal jaundice
HYPOpituitarism
short and broad face, prominent frontal bone, depressed nasal bridge, saddle shaped nose, underdeveloped mandible, short neck, high pitched voice, well proportioned extremities but small hands and feet, delayed or absent sexual maturity
hypopituitarism
atrophy of adrenal cortex thyroid and gonads result in weight loss asthenia sensitivity to cold absence of sweating
hypopituitarism
- height is initially w/in normal range that starts falling off the height curve over time
- delay bone age
pathologic short stature
prenatal onset (infection, undernutrition, chromosome defect) postnatal (nutritional defcy, chronic systemic dse, psychosocial deprivation)
- ht is sustatined at lower percentiles during childhood
- eventual normal final adult ht
- often with history of similar growth pattern w/ family members
- delayed bone age (chronologic > bone age)
constitutional growth delay
hallmark: delayed pubertal growth spurt
- stays parallel to to the growth curve
- significant number of family members are short
- bone age is not delayed (chronologic = bone age)
familial short stature
ht <1st percentile for age and sex
ht >2sd below sex-adjusted mid-parental ht
severe post natal growth failure
radiologic findings of hypopituitarism
- delayed skeletal maturation/ bone age
- small anterior pituitary gland
- suprasellar calcification (if assoc w/ craniopharyngioma)
criteria for stopping hGH treatment
- decision of patient that he/she is tall enough
- growth rate <1in /year
- bone age >14 years in girls and >16 years in boys
overproduction of GH that leads to Gigantism and Acromegaly
HYPERpituitarism
- longitudinal growth acceleration (Cardinal feature)
- coarse facial feature
- enlarged hands and feet
- behavioral problems
- visual field defects, loss of visual acuity
- headache
- visceromegaly
gigantism
- coarse facial feature
- increase skull circumference
- broad nose
- enlarged tongue and jaw
- separation of teeth
- enlargement of distal parts of the body
- visual field defects
- dorsal kyphosis
acromegaly
Screening for GH excess
elevated insulin like growth factor binding protein 3 (IGFBP-3) of IGF-1 (serum somatomedin C)
confirmatory for GH excess
oral glucose suppression test: serum GH levels are not suppressed by glucose load
management for well circumscribed pituitary adenoma
transsphenoidal surgery (complete removal of tumor)
somatostatin analog for GH suppression
Octreotide
GH receptor antagonist for treatment of GH excess
Pegvisomant
mgt for local invasion and involvement of optic chiasm/ nerve or unsuccessful surgery
pituitary irradiation
result from vasopressin deficiency
central DI
vasopressin receptor insensitivity
nephrogenic DI
principal regulator of tonicity (secreted in the posterior pituitary gland) which has both antidiuretic & vascular pressor activity
vasopressin
cardinal feature of Diabetes insipidus
polyuria and polydipsia (exceeding 2L/m2/24hr
mgt of SIADH
limit OFI
mgt for CSW
NaCl & H2O replacement
mgt for Central DI
fluid therapy
long acting vasopressin analog DDAVP
acute onset after neurosurgery: vasopressin w/ total fluid intake limited to 1L/m2/day during antidiuresis
mgt for Nephrogenic DI
- Thiazide (dec overall urine output by enhancing Na excretion at the expense of water and by causing decrease in GFR)
- indomethacin or amiloride +/- thiazide to further reduce polyuria
- ensure intake of adequate calories for growth and to avoid severe dehydration
onset of secondary sexual characteristics before 8 years old in girls and 9 yo in boys
precocious puberty
treatment for Central precocious puberty
GnRH agonist
treatment for peripheral precocious puberty
Aromatase inhibitor: letrozole, testolactone
Anti-estrogen: tamoxifen
Anti-androgen: spironolactone, fluramide, bicalutamide
inhibitor of testosterone synthesis: ketoconazole
