Growth & endocrine Flashcards
What’s the most common cause of congenital hypothyroidism in:
- the world
- the UK
- a consanguineous pedigree?
World: iodine deficiency
UK: thyroid dysgenesis
Consanguineous: Dyshormonogenesis
What’s the difference between thyroid dysgenesis and dyshormonogenesis?
Thyroid dysgenesis is when the thyroid has not developed properly so can’t produce hormones properly
Dyshormonogenesis is when the thyroid is normal but doesn’t produce hormones
Treatment of hypothyroidism in children?
Levothyroxine
What is congenital adrenal hyperplasia?
Genetic mutation leading to an enzyme deficiency
With the most common enzyme deficiency there is no synthesis of cortisol
Body recognises the lack of cortisol and stimulates the adrenals to produce more, they can’t so produce excess precursor hormones, which are androgens similar to testosterone.
What are the two parts of the adrenal glands? And what do they each do?
Medulla (inner section): produces adrenaline
Cortex (outer section): produces aldosterone, cortisol and androgens
What’s the most common enzyme deficiency causing CAH?
21-hydroxylase deficiency
What’s the inheritance of CAH?
Autosomal recessive
How do babies with CAH present?
Due to lack of cortisol, they get adrenal crisis
They’re in shock
Hyperkalaemia Hypercalcaemia Hypoglycaemia Hypotension Convulsions Fever V+D, dehydration
If they’re female they get ambiguous genitalia due to high levels of male hormones
Can CAH be treated pre-natally?
Yes, give the mother dexamethasone
How would you classify the causes of faltering growth? Give a couple of causes for each category.
Inadequate intake:
- impaired suck-swallow
- cleft palate
- not enough milk/food
Inadequate retention
- GORD
- vomiting
Malabsorption
- coeliac
- intolerance of some sort
- short gut syndrome
Failure to utilise nutrients
- syndromes
- prematurity
- metabolic disorders
Increased requirements
- CF
- thyrotoxicosis
- malignancy
How is precocious puberty defined?
When puberty starts too early
Before 8 yrs in females and 9 yrs in males
There are two categories of causes of precocious puberty, what are they? Describe the difference between the categories.
Gonadotropin-dependent
The pituitary gland is producing too much LH and FSH, causing puberty to start
Gonadotropin-independent
Oestrogen or testosterone is produced by gonads or an extra-gonadal source, causing puberty to start
Give some gonadotropin-dependent causes of precocious puberty?
Idiopathic, familial
CNS abnormalities: post-irradiation, infection, surgery, hydrocephalus
Hypothyroidism
Give some gonadotropin-independent causes of precocious puberty?
Adrenal disorders: CAH
Ovarian or testicular tumour
Exogenous sex steroids
What are gonadotropins?
Family of hormones including FSH and LH
Describe the hormone axis of the thyroid?
Hypothalamus releases TRH
Which causes anterior pituitary to release TSH
Which causes thyroid to release T3 and T4
Describe the hormone axis of growth hormone?
Hypothalamus releases GHRH
Which causes anterior pituitary to release GH
Which causes liver to release IGF-1
Which raises blood glucose and stimulates bone, tissue and cartilage growth
Describe the adrenal hormone axis?
Hypothalamus releases CRH (corticotropin releasing hormone)
Which causes a. pituitary to release ACTH (adrenocorticotropic hormone)
Which causes adrenal cortex to release cortisol
What are some causes of short stature?
Familial short stature
Severe intra-uterine growth restriction
Endocrine: GH deficiency, hypothyroid, excess steroids
Syndromes: Turner
Skeletal dysplasia
What are some causes of tall stature?
Familial tall stature
Obesity: as puberty is advanced
Hyperthyroidism
Precocious puberty
Gigantism (excess GH)
Syndromes: Marfan’s, Klinefelter
What’s the first sign of puberty in girls and boys?
Breast development in girls
Testicular growth in boys
What are the symptoms of hypernatraemia?
Jittery movements
Hypertonia
Hyperreflexia
Convulsions
