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46 Cards in this Set

  • Front
  • Back
Are most of the effects mediated by GH direct or indirect?
Indirect (via IGF)
IGF are small protein hormones also known as...?
Somatomedins
What is the most important regulator of postnatal growth?
IGF-1
How do IGF-1 and GH levels in the blood differ throughout the day?
IGF-1 levels are constant throughout the day
GH levels are variable with peaks and valleys
Besides hormones, what physical factors regulate GH?
1. Stress
2. Exercise
3. Nutrition
4. Sleep
What are the primary controllers of GH release?
1. GHRH (stimulatory)
2. Somatostatin (inhibitory)
Somatostatin regulates GH in response to which stimulatory factors?
1. GHRH
2. Low blood glucose
How do high levels of IGF-1 affect GH?
Inhibits GH directly by suppressing its secretion and indirectly by stimulating somatostatin secretion
(negative feedback loop)
What is the effect of high levels of IGF-1 on somatostatin secretion?
Stimulation
Which hormones inhibit GH secretion?
1. Somatostatin
2. High levels of IGF-1
3. High levels of GH (autocrine)
Are basal concentrations of GH in blood high or low?
Very low
When is the most intense period of GH release in children and young adults?
Shortly after the onset of deep sleep
If a child had a normal birth weight, and now has normal bone age and normal age of puberty, but has a target height below the 3rd percentile, what variant of normal growth is this?
Familial short stature
What is the effect of a thyroid deficiency on mature height?

What is the effect of excess thyroid on mature height?
Deficiency --> Reduced height

Excess --> No effect (normal height)
How do thyroid deficiencies and excess thyroid affect growth rate and bone maturation?
Deficiency --> very slow growth rate, very slow bone maturation

Excess --> mild acceleration of both
Short stature is defined as height below what percentile?
3rd percentile (or -2SDs)
(most often not pathological)
Is growing at a slow rate (crossing percentiles) usually non-pathological or should it be a concern that needs evaluation?
Slow growth rate (growth failure) warrants evaluation
Failure to thrive is usually caused by..?
Malnutrition
GH insensitivity results in what syndrome?
Laron syndrome
Which gene is affected in Laron syndrome?
GHR
(GH deficiency)
Which condition results in immune deficiency, high GH production, and low IGF-1, IGFBP-3?
STAT5b deficiency
What is the result of an IGF-1 gene mutation on Prenatal and postnatal growth?
Both are decreased
What is the effect of a GH insensitivity on prenatal and postnatal growth?
Prenatal --> not affected
Postnatal --> decreased
What is the effect of IGF-1 gene mutation on GH, IGF-1, and IGFBP-3?
GH--> increased
IGF-1 --> decreased
IGFBP-3 --> not affected
Which condition results from an IGF2 gene mutation?
Russel-silver syndromE
Which condition results in deafness, microcephaly, and CHO intolerance?
IGF-1 mutation
What is the effect of Russel Silver syndrome on prenatal and postnatal growth?
(IFG2 abnormality)

*Both are decreased
Which gene is affected in IGF resistance?
IGF1R
What is the effect of IGF resistance on prenatal and postnatal growth?
Both are decreased
Will birth weight be normal or abnormal with a GH deficiency?
Normal
Will birth weight be normal or abnormal with an IGF1 gene mutation?
Abnormal--> low birth weight
Will birth weight be normal or abnormal with an IGF1R mutation?
Abnormal--> low birth weight
Describe the clinical features seen with a GH deficiency?
(birth weight, growth rate, height, bone age, weight)
1. Normal birth weight
2. Failure to grow in first 6 months
3. Short stature
4. Delayed bone age
5. Normal weight for height
Describe the laboratory diagnosis for GH deficiency?
1. Low IGF-1 and IGFBP-3
2. Increased GH level after simulation (i.e. clonidine, arginine, usually <7ng/ mL)
List 3 general causes for a congenital GH deficiency.
1. GH axis gene mutations (GH1, GHRH)
2. Abnormal CNS/ hypothalamic development
3. Idiopathic
List 4 general causes for an acquired GH deficiency.
1. Craniopharyngioma
2. CNS Dysgerminoma
3. Glioma
4. Langerhans cell histiocytosis
Which condition is a congenital malformation syndrome characterized by optic nerve hypoplasia and absence of the septum pellucidum?
Septo-optic dysplasia
(Morsier syndrome)
Septo-optic dysplasia is also known as which syndrome?
Morsier syndrome
List 5 intracranial malformations seen in septo-optic dysplasia.
1. Hypoplasia of Optic N
2. Absence of septum pellucidum
3. Schizencephaly (gray matter malformation)
4. Lobar holoprosencephaly (forebrain fails to develop into 2 hemispheres)
5. Hypopituitarism
Craniopharyngiomas can result with what type of visual deficit?
Bilateral hemianopsia
(tumor may compress on optic chiasm)
What is the most common location of an intracranial germinoma?
On or near the midline-- often in the pineal or suprasellar areas. Common in hypothalamic regions.
Langerhans cell histiocytosis affects which organs?
Can affect almost any organ
What type of individuals are more susceptible to developing Langerhans cell histiocytosis?
Children
Multifocal unisystem LCH (Langerhans cell histiocytosis) is characterized by what signs and symptoms?
1. Fever
2. Bone lesions
3. Diffuse eruptions (scalp and in the ear canals)
4. ~50% of cases involve the pituitary stalk --> Diabetes insipidus
What is the Hand-Shuller-Christian triad?
1. Diabetes insipidus
2. Exopthalmos
3. Lytic bone lesions
What is the treatment for GH deficiency?
1. Replacement with recombinant human GH
2. Replace any associated deficiencies (i.e. thyroxine, cortisol)