Endocrine Flashcards
Deficiency of growth hormone with or without a deficiency of other pituitary hormones
Congenital or acquired
Clinical manifestations:
- of normal size and weight at birth
- atrophy of adrenal cortex, sensitivity to cold, absence of sweating
PE findings:
- tendency to hypoglycemia
- short and broad face, prominent frontal bone, depressed nasal bridge, underdeveloped mandible, short neck, high-pitched voice, well proportioned extremities but small hands and feet, delayed sexual maturity
LABORATORY findings
- diagnosis of classic type is suspected in cases of PROFOUND POSTNATAL GROWTH FAILURE (height >3 SD below the mean for age and gender)
- definitive diagnosis: ABSENT or LOW LEVELS OF GH in response to stimulation
- X-ray findings: destructive or space-occupying lesions: enlargement of the sella or erosions and calcifications within or above the sella turcica; delayed skeletal maturation
HYPOPITUITARISM
Normal range for height
Over time, it starts falling off the height curve
Pathologic short stature
Normal range for height
Normal final adult height is reached but the growth spurt and puberty are delayed
Constitutional short stature
Stay parallel to the growth curve
Familial short stature
Parallel to the growth curve but is much more marked
Prenatal short stature
Guidelines for growth hormone treatment
hGH 0.18.-0.3 mg/kg/wk SC in 6-7 divided doses
Criteria for stopping tx: growth rate 14 yrs in girls and >16 years in boys
Young persons with open epiphyses, overproduction of GH
Gigantism
Persons with closed epiphyses
Acromegaly
Cardinal clinical feature of gigantism
Longitudinal growth acceleration due to GH excess
Coarse facial features, enlarged hands and feet, broad noses, enlarged tongue, visual field defects
Hyperpituitarism
Diagnosis:
Serum somatomedin C (IGF-1) is uniformly increased in untreated cases
- more precise and cost-effective than serum GH because GH levels fluctuate and have short serum half-life (22 minutes)
Hyperpituitarism
Management of Hyperpituitarism
- if with well-circumscribed pituitary adenomas: transsphenoidal surgery (complete removal of the tumor)
- pituitary radiation and medical therapy
- somatostatin analog (Octreotide)
Cardinal features of diabetes insipidus
Polyuria and polydipsia
2 types of diabetes insipidus
- Vasopressin deficiency (central DI)
2. Vasopressin insensitivity (nephrogenic DI)
Pathogenesis of DIABETES INSIPIDUS
As plasma osmolality increases, pat it becomes thirsty and drinks fluids
Plasma is diluted before it reaches the higher set level to stimulate ADH release
Initiates cycle of polyuria and polydipsia
Congenital, trauma, tumors, autoimmune, infection, drugs (ethanol, phenytoin, etc)
Management:
- Fluid therapy
- Long-acting vasopressin analog dDAVP
Central diabetes insipidus
Congenital (more severe), hypercalcemia, hypokalemia, renal disease (PCKD, CRF), drugs (lithium, amophotericin, rifampicin, etc)
Management:
- Treat underlying disorder
- thiazides (decrease urine flow to DCT, induce formation of functional receptors)
Nephrogenic diabetes insipidus
What the hormone involved in Diabetes insipidus and what is its role?
VASOPRESSIN
- secreted from the posterior pituitary
Principal regulator of toxicity
Has both anitdiuretic and vascular pressor activity
Synthesized in the paracentricular and supraoptic nuclei of the hypothalamus
Onset of secondary sexual characteristics before 8 years old in girls and 9 years old in boys
Precocious puberty
Conditions causing precocious puberty
- Gonadotropin-dependent puberty (true precocious puberty) - increased sex hormone secretion
- Idiopathic
- Brain tumors, severe head trauma, hydrocephalus
- Prolonged and untreated hypothyroidism
- Ovarian tumors
Breast development in the first 2 years of life, regress after 2 years and rarely progressive
Premature thelarche
Pubic hair, early maturational event of adrenal androgen production
Premature adrenarche
Pertinent lab findings:
- Immunometric assay for LH (serum) - serial blood samples obtained during sleep and shows pulsatile LH secretion
- pelvic ultrasound - progressive enlargement of the ovaries and uterus
- Cranial CT scan/cranial MRI - physiologic enlargement of the pituitary gland; pedunculated mass attached to the tuber cinereum of the floor of the 3rd ventricle
Precocious puberty
Treatment of precocious puberty
Leuprolide acetate -0.25-0.3mg/kg IM once every 4 weeks (true precocious puberty)
If treatment is effective, serum sex hormones decrease to prepubertal levels (testosterone <1 IU/L
