hypothalamo-pituitary axis basics

Question 1

what is released from anterior pitiutary 6

Answer 1

TSH

ACT

LH,FSH

Growth hormone

Prolactin

Question 2

what is released from posterior pituitary 1

Answer 2

ADH

Question 3

important point regarding low GH levels

Answer 3

if child is short even after stimulation low GH levels are common and not synonymous with a true GH deficiency

Question 4

overview of true GH deficiencys

Answer 4

rare -may be isolated or part of multiple pituitary deficienceis

can be congenital - ie hereditary GH deficeincy
or
acquired- tumours like craniopharyngioma

Question 5

what isoften associated with GH insufficiency (transiently low GH levels)

Answer 5

constitutional delay

Question 6

delayed puberty and gonadal axis

Answer 6

usually people have an intact axis and the delayed puberty is due to constitiutional elay, ill health or anoreexia

Question 7

causes of true central deficeinces in gonadal axis 2

Answer 7

as part of a panhypopituitrasim

or

isolated pnenomenon eg Kallmanns syndrome

Question 8

when can primary overian failure be seen 2

Answer 8

turners syndrome

or following total body irradiation prior to a bone marrow transplantation for leukaemia

Question 9

when can primary testicular failure be seen 3

Answer 9

following srugery for cryptorchidism

klinefelters syndrome

or following total body irradiation prior to a bone marrow transplantation for leukaemia

Question 10

what will be elevated in primary gonadal failure 2

Answer 10

FSH and LH

Question 11

primary hypothyrdoisim in children

Answer 11

congenital (due to thyroid dysgenesis or
dyshormonogenesis)

or acquired (Hashimoto’s thyroiditis).

Question 12

how can primary hypothyrodism. be screen for in children

Answer 12

TSH is elevated and this is used for newborn screening usuing capillary blood spots on the Guthrie card

Question 13

overview of hyperthrydoism in children

Answer 13

usually due to Graves’ disease. Graves’ disease is rare in
childhood and adolescence, but more severe and less likely to remit than in adults.
TSH is suppressed, and T4 and T3 elevated in hyperthyroidism.

Question 14

causes of thryoid goitre 3

Answer 14

hypothyroid (most commonly Hashimoto’s),

hyperthyroid,

or euthyroid (usually Hashimoto’s, occasionally carcinoma)

Question 15

posterior pitutitary axis overview

Answer 15

The hormones ADH and oxytocin are synthesised in the hypothalamus but stored in
the posterior pituitary.

· Most polyuria and polydipsia in preschool children is due to habit drinking and can
be resolved by banning flavoured drinks.
·

Question 16

split of diabetes insipidus and explination 2

Answer 16

Congenital diabetes insipidus is due to a dominantly inherited ADH defect and can
take a year after birth to manifest itself.
· Acquired DI is usually caused by a tumour (e.g. craniopharyngioma) and is an
indication for serial MRI scanning if no lesion is found initially