Endocrine Flashcards
What is the definition of precocious puberty for boys and girls ?
<8.5years girls
<9.5 years boys
What are the characteristics clinical/investigation features of GnRH dependent precocious puberty ?
Progressive pubertal clinical changes Advanced bone age Accelerated linear growth High FSH, LH High oestradiol girls / testosterone boys
What are 6 causes of central precocious puberty? What is the most common
Idiopathic 80% (almost always girls)
Hypothalamic hamartoma (most common CNS tumour)
International adoption
Other CNS tumours
Acquired CNS insults (radiation, hydrocephalus)
Neurofibromatosis type 1
What is the treatment for central precocious puberty?
Leuprolide (Lucrin)
GnRH analogue - overrides pulsatile endogenous GnRH
Monitor by measuring LH suppression
What is the triad defining McCune Albright syndrome ?
Cafe au lait spots (don’t cross midline, irregular Coast of Maine border, increase with age)
Peripheral precocious puberty
Polyostotic fibrous dysplasia
What is the inheritance of McCune Albright Syndrome ?
Somatic/post zygotic mutation
Ie not inherited
What investigation will differentiate central from peripheral precocious puberty ?
GnRH stimulation test
Name 4 syndromal causes of hypogonadotrophic hypogonadism
CHARGE
Prader Willi
Kallman
Bardet Biedl
Name a metabolic cause of hypergonadotrophic hypogonadism (girls)
Galactosaemia
(Deficiency in GALT)
Causes progressive ovarian failure - unclear mechanism
What is the half life of T4 (thyroxine) ?
7 days
What is the mechanism of action of carbimazole?
Inhibits thyroid peroxidase - inhibiting iodination of DIT and MIT
Thereby reducing production of T3 and T4
NB does not reduce T3/T4 release - takes weeks to have effect
What is the m:f for Neonatal graves ?
Males = females
What is the treatment for neonatal graves?
Lugol’s iodine - blocks T4 release, synthesis and uptake
Propranolol
Carbimazole
What should you suspect with a cause of hearing difficulties, goitre and learning difficulties ?
Pendred syndrome
What is the lifetime risk of T1DM for first degree relatives:
General pop
Paternal/ maternal offspring
Siblings
Twins
General pop 0.4% Parental offspring 8% Maternal offspring 3% Siblings 5% HLA identical siblings 16% Monozygotic twins 30-50%
Case of acidosis - can this be MODY?
No
What is the risk of coeliac disease associated with T1DM?
10% < 5 yo
3% > 10yo
What % of children with T1DM present with DKA?
25%
What % of children with T1DM have no family history?
95%
What age group for T1DM have the highest risk of DKA?
<2yo
And adolescents
What is the defn of DKA - mild/mod/severe?
Hyperglycaemia > 20
Or low bicarbonate < 15
pH
< 7.1 severe
< 7.2 mod
< 7.3 mild
Hyperthyroidism is a risk factor for DKA true or false ?
True
Increases basal metabolic rate
What effect does insulin have on glucagon ?
Inhibits
In regards to CFRD are macrovascular complications common?
No - almost never (fat malabsorption)
What should you suspect for small baby presenting with hyperglycaemia, gradually improves
Mum IVF
Transient neonatal diabetes
Transient neonatal diabetes confers an increased risk of IDDM in later life - true or false?
True - in second decade
Maternal IVF has no increased risk of genetic abnormalities - true or false
False - increased risk of methylation abnormalities / imprinting disorders
What should you suspect with diabetes, seizures, developmental delay and muscle weakness?
DEND syndrome
Developmental delay
Epilepsy
Neonatal diabetes
What is the gene mutation associated with MODY 3?
HNF1A
What is the gene mutation associated with MODY 1?
HNF 4A
What are the phenotypic features of MODY 1?
Present in adolescence
Progressive insulin secretory defect
Foetal macrosomia
Transient neonatal hypoglycaemia
What is the gene mutation associated with MODY 2?
And what is the usual presentation /phenotypic features?
GCK Present since birth Stable mild hyperglycaemia Often asymptomatic May have abnormal OGT/GDM/LBW Microvascular complications are rare
What is the gene mutation associated with MODY 3 and what is the phenotypic presentation ?
HMF 1A
Present in adolescence
Progressive insulin secretory defect
Renal glycosuria
What is the gene mutation associated with MODY 5? And what is the phenotypic presentation ?
HNF 1B Present in adolescence Progressive diabetes Pancreatic atrophy Exocrine dysfunction Renal/ urologic disease
What is the mutation responsible for the majority of permanent neonatal diabetes due to pancreatic beta cell mutations ?
KATP channel (SUR1 or Kir 6.2)
Mutation alters ability of channel to close
Usually sulfonurea responsive
What is DEND syndrome ?
Developmental delay
Epilepsy
Neonatal diabetes
Most severe type of Kir 6.2 mutations
(Channels also found in brain and muscle)
What investigation is essential for girls with Turner syndrome prior to commencing pubertal induction ?
FSH - need to confirm that she hasn’t gone into spontaneous puberty (30%) despite 90% having gonadal failure
Need to confirm FSH is elevated ie gonadal failure
What should you suspect from a presentation of precocious puberty and gelastic seizures ?
central cause
Hypothalamic hamartoma
Which cells secrete glucagon?
Alpha cells in pancreas
Which cells secrete somatostatin ?
Delta cells in pancreas
What has the most effect on peak bone mass ?
Genetic factors
What is the mechanism of action of fludrocortisone?
Synthetic analogue of aldosterone
Increases BP
