Hypopituitarism Flashcards Preview

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Flashcards in Hypopituitarism Deck (18):
1

Definition

Decreased secretion of anterior pituitary hormones

2

Order of affected hormones

Growth hormone
FSH/LH
PRL
TSH
ACTH

3

Cause of pan-hypopituitarism

Irradiation
Surgery
Pituitary tumor

4

Etiology

Neoplastic:
Pituitary adenoma (most common cause)
Craniopharyngomas
Rathke's cyst
Other space occupying->sellar meningiomas, metastases, plasmacytomas, germ cell, astrocytomas
Pituitary metastasis

Vascular:
Pituitary apoplexy
Sheehans
Intrasellar aneurysms

Inflammatory/infiltrative:
Lymphocytic hypophysitis
Immunotherapy
Haemachromatosis
Sarcoid
TB

Infection:
Abscess
Fungal
Tuberculomas

Congenital
Radiotherapy
Surgery
Traumatic brain injury
Empty sella syndrome

5

Classification of microadenoma and macroadenoma

Micro 10mm

6

How to remember which hormones are lost first

The hormones essential for life (ACTH and TSH) lost last

7

How does pituitary adenoma lead to hypopituitarism

Impaired blood flow
Compression
Interference of hormone delivery

8

Presentation

Due to hormone lack and cause
presence of risk factors
FHx of pituitary hormone deficiencies
headaches
failure to thrive or short stature
infertility
hypoglycaemia
amenorrhoea/oligomenorrhoea
galactorrhoea
delayed puberty
hypotension
visual field defects
ophthalmoplegia
Other diagnostic factors
cardiovascular events
cold intolerance
weight gain
hypoactive sexual desire
hot flushes
erectile dysfunction and reduced libido
nausea
vomiting
fatigue
weakness
dizziness
constipation
nocturia and polyuria
breast atrophy
reduced bone and muscle mass
loss of axillary and pubic hair
dry skin
delayed relaxation of reflexes

9

Clinical features based on the hormone deficient

GH->central obesity, atherosclerosis, reduced strength/exercise, cardiac output, hypoglycemia, osteoporosis
FSH/LH: libido loss, oligo/amenorrhea, -ve fertility, ED, hypogonadism
ACTH->adrenal insufficiency, anorexia, wt loss, nausea, myalgias, pallor, hypotension
TSH->hypothyroid
DI-> nocturia, polyuria, polydipsia (suggests hypothalmic/hypothalmic/pituitary stalk cause)

10

Investigations

serum electrolytes->low sodium (ACTH -ve), +sodium (DI_
8 a.m. cortisol and ACTH->low cortisol and inappropriately low ACTH
TFT
8 a.m. testosterone, FSH, and LH in men
estradiol, FSH, and LH in women
prolactin->slightly elevated
insulin-like growth factor-1 (IGF-1)
cosyntropin/tetracosactide stimulation test

Other test to consider;
Insulin tolerance test
Water deprivation and desmopressive response test
MRI pituitar

11

What is the cosyntropin stimulation test

250 micrograms of cosyntropin (synthetic ACTH 1-24) is administered intramuscularly or intravenously; serum cortisol levels are measured at 30 and 60 minutes.

Serum cortisol concentration ≥498 nmol/L (18 micrograms/dL) is considered a normal response.

12

What is the insulin tolerance test

0.05 to 0.15 units of insulin/kg is administered intravenously and serum glucose, cortisol, and GH are measured before and after 15, 30, 60, 90, and 120 minutes of injection.

In normal subjects, serum cortisol increases to ≥498 nmol/L (18 micrograms/dL) if the serum glucose falls to 5 micrograms/L in the setting of hypoglycaemia (glucose

13

What is the water deprivation and desmopressin response test

Deprived of fluids for 8 hours
Measure osmolarity every 4 hours, urine volume and osmolarity every 2 hours
Then given desmopressin IM, measurements over next 4 hours
If central DI->kidneys response and develop concentrated urine

In hypo: low paired urine and plasma osmolalities; low urinary sodium; low urine specific gravity (3 L/24h)

14

Management

Address underlying cause
Other than GH and ADH->replacement is the target hormones of the pituitary produced

ACTH deficiency-> maintenance hydrocortisone or prednisolone + IV/IM for stress events. Have emergency bracelet
Thyroid->levothyroxine after adrenal (ACTH replacement)
GnRH deficient:
Female X fertility desired->transdermal estrogen + progesterone
Female +fertility desire->gonadotropins
Male Xfertility->testosterone
Male +fertility->gonadotropins
GH-> somatropin (recombinant human growth hormone)
ADH->desmopressin

Anti-CTLA-4 antibody therapy with hypophysitis-> high dose glucocorticoid

15

Why must ACTH deficiency be diagnosed and treated prior to thyroid replacement

Levothyroxine may provoke addisonian crisis due to +cortisol clearance

16

Follow up

Long term f/u with endocrinologist to monitor hormone replacement, response, management of underlying etiology

17

Patient instructions

Need ++education, about life threatening nature
Medical alert bracelet
Knowledge of sick day adjustments of hydrocortisone

18

Contraindications to somatropin

Pregnancy
Malignancy
Renal transplant