Endocrine Flashcards
Growth rate that suggests no underlying pathologic disorder?
5 cm per year between age 3 and puberty
Normal variant short stature versus pathologic short stature?
Height below 3rd percentile with normal growth velocity
versus
below 3rd percentile with sub optimal growth velocity (less than 2 inches per year)
Height estimate?
(Mothers height + father’s height +/-5 inches)/2
+/-4
Normal upper-to-lower body segment ratios?
Birth: 1.7
3 years: 1.3
>7: 1.0
Types of normal variant short stature?
- Familial – 2 SDs below mean but with normal bone age, normal onset of puberty, and minimal growth of 2 inches per year
- Constitutional – 2 SDs below mean and minimal growth of 2 inches per year but with: delayed puberty in parents, delayed bone age, late onset puberty
Proportionate versus disproportionate pathologic short stature?
Normal U/L ratio versus increased U/L ratio
Causes of prenatal onset proportionate short stature? Postnatal onset proportionate short stature?
- Environmental exposures (tobacco/alcohol in utero)
- Chromosome disorders (down/Turner)
- Genetic syndromes (Russell-silver, Prader-Willie)
- Borrow infections in early pregnancy (CMV, rubella)
- Malnutrition
- Psychosocial (neglect, child abuse)
- Organ system diseases (IBD, congenital heart disease, renal failure, cystic fibrosis, hypothyroid, GH deficiency, Cushing’s)
Causes of disproportionate short stature?
- Ricketts
2. Skeletal dysplasias
Laboratory studies to conduct with pathologic short stature? Radiographic studies?
- Common labs - CBC, ESR, T4, calcium, phosphorus, creatinine
- IGF- indirect test for growth hormone
- Chromosome analysis and girls (Turner)
- Bone age (AP of left hand and wrist)
- AP and lateral skull radiographs (for pituitary Island, craniopharyngioma)
Ddx if bone age equals chronologic age?
If bone age <chronological age?
- Familial short stature,
- Intrauterine growth retardation
- Turner
- Skeletal dysplasia
- Constitutional short stature
- Hypothyroid
- Hypercortisolisn
- Growth Hormone deficiency
- Chronic diseases
Growth hormone deficiency – clinical features? Causes? Evaluation? Management?
- Prolonged neonatal jaundice
- Cherubic facies, central obesity
- Microphallus, cryptorchidism
- Hypoglycemia
- Poor growth velocity
- Single central maxillary incisors or cleft palate
- Craniopharyngioma
- CNS irradiation, vascular malformations
- Autoimmune
- MRI of head
- IGF-1 levels, poor response to GH stimulation (glucagon, clonidine)
Daily subcutaneous injections of GH
Sexual precocity associated with?
Obesity
Precocious puberty? Causes?
Development before nine years
- premature thelarche
- Premature adrenarche
- Isosexual precocious puberty or central precocious puberty
- Peripheral precocious puberty or heterosexual gonadotropin-independent puberty
Premature Thelarche – definition, epidemiology, etiology, work up/treatment?
Breast tissue only, without other sexual secondary sex characteristics (Normal growth pattern, no pubic hair)
Common and benign, usually begins the first two years of life
Premature activation of HPGA, resulting in the release of low levels of estrogen
No workout/treatment unless pubic hair or rapid growth
Premature adrenarche – definition? Epidemiology? Classic presentation? Tx?
Early-onset pubic/axillary hair without development of breast/testing
More common in girls
Girl over 5 presents with pubic hair growth and a print order. No breast tissue/no clitorimegaly/normal growth
No Treatment
Isosexual precocious puberty or central precocious puberty – Definition? Epidemiology? Clinical features? Causes?
Are the activation of the hypothalamus
Higher incidence in girls
breast/testes development, pubic hair, rapid growth
Idiopathic in girls
Organic in boys – get MRI
1 CNS causes- Hydrocephalus, infection, cerebral palsy, hamartomas, astrocytomas/gliomas
2. Hypothyroidism – unlike other causes, poor growth and delayed bone age
Evaluation of a patient with suspected central precocious puberty?
- FSH, LH, sex steroids should be elevated into pubertal range
- GnRH stimulation test (measure LH/FSH response)
- Head MRI in males
Peripheral precocious puberty or heterosexual gonadotropin-independent puberty – definition? Features? Evaluation?
Precocious puberty that is independent of the HPGA (peripheral production of sex steroids and no increase in FSG/LH)
- Boys – present with feminization or premature pubic hair – no increase in FSH so no testicular enlargement
- Girls – virilization or breast development
- Boys – serum FSH, LH, testosterone, B-HCG
- Girls – serum FSH, LH, estradiol
- CNS imaging
Causes of peripheral precocious puberty?
Girls – adrenal tumors, virilizing ovarian tumors, feminizing ovarian tumors, nonclassical CAH, McCune-Albright syndrome
Boys – typically no teaticulat enlargement (no FSH): adrenal tumors, leydig cell tumors, nonclassical CAH, B-HCG tumors
Males with testicular enlargement:
- McCune-Albright syndrome (bony changes, café au lait spots endocrinopathy)
- Testicular toxicosis – testes enlarged but independent of HPGP
- B-hCG secreting tumors – chest, pineal gland, gonad, hepatoblastoma (B-HCG cross reacts with LH receptors, stimulating leydig cells)
Delayed puberty – definition? Classification? Evaluation?
No testicular enlargement by 14 or no breast tissue by each 13 or no menarche by age 14
- Hypogonadotropic hypogonadism – inactivity of hypothalamus and pituitary gland, causing low hormones and flat GnRH stimulation test
- Hypergonadotrophic hypogonadism – gonadal failure resulting in high FSH and LH with low testosterone/estradiol
CBC, ESR, T4, testosterone, estradiol, FSH, LH, prolactin level, bone age
Causes of hypogonadotrophic hypogonadism?
- Constitutional delay of puberty
- Chronic disease
- Hypopituitarism (brain tumors)
- Primary hypothyroidism
- Prolactinoma
- Genetic syndromes (Kallmann syndrome, Prader-Willi, Lawrence-Moon-Biedl)