Endocrinology Flashcards
What hormones are in the anterior pituitary and which are in the posterior pituitary?
anterior: growth hormone, prolactin, TSH, FSH, LH, ACTH
posterior: ADH, oxytocin
What defects can occur with congenital hypopituitarism
usually growth hormone deficiency and one or more of the other 5 hormones made in the anterior pituitary
What is septo optic dysplasia
abnormality of the optic nerve or chiasm (absence or hypoplasia) children are often blind or have very little vision
agenesis of the septum pellucidum and/or corpus callosum
hypothalamic insufficiency affecting both the anterior and posterior pituitary
What is associated with midface anomalies particularly a solitary maxillary central incisor
growth hormone deficiency
What is the most common tumor in children that affects the pituitary
crainiopharyngioma
What are the effects of an ectopic posterior pituitary gland
failure of the posterior pituitary to migrate toward the anterior pituitary and form the infundibulum causes problems with the portal vessels and communication between the hypothalamus and the anterior pituitary:
thus leads to anterior pituitary problems: growth hormone deficiency to panhypopituitariam
What is an indicator of the degree of problems in those with an ectopic posterior pituitary gland?
presence of pituitary stalk
if present: isolated growth hormone deficiency
if abnormal: multiple hormone deficiencies
What are some clinical manifestations of growth hormone deficiency
normal size at birth
fall off of growth curve by more than 4 SD by 1 year of age
microphallus in males
hypoglycemia and direct hyperbilirubinemia in neonate
characteristic facies over time: round head, short broad face with prominent frontal bone and depressed saddle shaped nose
high pitched voice
small gonads, sparse secondary hair
normal intelligence
How is growth hormone deficiency diagnosed
suspect when there is post natal growth failure (more than 3 SD below the curve by age 3)
Serum IGF-1 and IGH BP-3: if in the upper range of normal GH deficiency is ruled out
definitive diagnosis with lack of response to stimulation of GH production (exercise, insulin, glucagon, L-dopa, arginine, clonidine)
What is idiopathic short stature?
more than 2.25 SD below the mean
with normal GH levels
unlikely to reach a normal adult height
can now be treated with GH
What is Laron syndrome
short stature with normal GH levels
problem is at the receptor
low levels of IGF-1
treated with IGF-1
What is seen in constitutional growth delay
variant of normal growth, with slower growth rate, but after age 3 normal growth velocity
bone age is delayed
family history of growth delay is common
often have delayed puberty
will reach normal adult height with no intervention
What is seen in familial short stature
normal growth velocity
normal bone age
family history of short stature
What is seen in hormone deficiency
decrease in growth velocity
delayed bone age
sometimes family history
How is mid parental height calculated?
boys: {mom height + dad height + 13 cm }/2
girls {mom height + dad height-13 cm} /2
What are some other causes of short stature
hypothyroidism
psychosocial dwarfism
Silver-Russell: short stature, SGA, frontal bossing, triangular facies, short and incurved 5th digits and asymmetry
What are some of the side effects to growth hormone
SCFE, pseudotumor cerebri, transient carbohydrate intolerance, transient hypothyroidism, scoliosis
What causes diabetes insipidus
ADH deficiency from the posterior pituitary
or kidney unresponsive to ADH
ADH works on kidney to conserve water and make urine hyperosmolar
What causes increase in ADH
elevated osmolality, hypervolemia sodium is the strongest stimulus thirst begins with osmolality is > 295 nausea is a potent stimulus angiotensin II, insulin-induced hypoglycemia, acute hypoxia and acute hypercapnia
What are some causes of central DI
primary inherited (rare): AD wolfram syndrome and septooptic dysplasia Acquired: tumors (craniopharyngioma, optic glioma, germinomas) head injury Systemic disease: sarcoidosis, encephalitis, histiocytosis, tuberculosis
What causes nephrogenic DI
x linked inherited form lithium polycystic kidney disorder sickle cell anemia chronic pyelonephritis sarcoidosis, amyloidosis
What are the clinic findings of diabetes insipidus
polyuria and polydipsia
infants: poor feeding, poor growth, irritability, high fevers
new onset enuresis in older children
What is the diagnosis and treatment of diabetes insipidus
hyperosmolar serum dilute urine low or absent ADH suggests central DI give desmopressin DDAVP: if central DI: urine will become more concentrated and osmolality will decrease if nephrogenic: no change
Central DI: DDAVP
nephrogenic DI: low sodium with adequate protein and lots of water ) 300-400 ml/kg/day, can use thiazide, indomethacin
What are the symptoms of SIADH
hyponatremia, low serum osmolality
high urine osmolality
fluid overload with low urine output