Hypopituitarism

Question 1

What is hypopituitarism?

Answer 1

Inadequate production of one or more anterior pituitary hormones as a result of damage to the pituitary gland and/or hypothalamus

Question 2

What are the causes of hypopituitarism?

Answer 2

(Most common) Nonsecretory pituitary macroadenomas (≥ 10 mm in diameter)
(Pituitary apoplexy) Infarction of the pituitary gland as a result of ischemia and/or hemorrhage
Traumatic brain injury
Empty sella syndrome

Question 3

What are the clinical features of each type of hypopituitarism?

Answer 3

(GH deficiency)During childhood: short stature
During adulthood: usually asymptomatic
(Prolactin deficiency) Females: lactation failure following delivery
Males: asymptomatic
(FSH/LH deficiency) Females: primary amenorrhea (delayed puberty), secondary amenorrhea, irregular menstrual cycles, infertility
Males: delayed puberty, loss of libido, infertility, testicular atrophy, loss of facial, axillary and/or pubic hair, gynecomastia
(TSH deficiency) weight gain, cold intolerance, lethargy, constipation, dry skin
(ACTH deficiency) weight loss, weakness, hypotension, chronic hyponatremia, hypoglycemia (see adrenal insufficiency)
(ADH deficiency) Central diabetes insipidus: polyuria, polydipsia
(Pituitary apoplexy) Severe headache, Hypopituitarism, Bilateral hemianopia, Diplopia (due to damage to CN III)

Question 4

How is hypopituitarism diagnosed?

Answer 4

(GH deficiency) ↓ IGF-1 levels (insulin-like growth factor)
↓ GH levels (even after administering arginine and exogenous GHRH)
(FSH/LH deficiency) (Males) ↓ Or normal LH ↓Dehydroepiandrosterone, ↓ testosterone
(Females) ↓ FSH and ↓ LH ↓ Estradiol
(TSH deficiency) ↓ T3, ↓ T4, ↓ or normal TSH
(ACTH deficiency) Low cortisol levels, ↓ Serum ACTH

Question 5

What is the treatment for hypopituitarism?

Answer 5

(Treatment of underlying cause e.g. transphenoidal resection in macroadenomas)
(GH deficiency) Children: GH hormone replacement;
Adults: GH hormone replacement is usually not required
(TSH deficiency) administration of levothyroxine
(ACTH deficiency) glucocorticoid replacement therapy with increased dosage during periods of stress
(Gonadotropin deficiency)(Males + If fertility is desired) exogenous gonadotropins (e.g., hCG) should be administered (If fertility is not desired) testosterone replacement therapy
(Females) estrogen replacement therapy with/without progesterone
(Prolactin deficiency) no treatment is required
(Central diabetes insipidus) desmopressin
In addition to hormone replacement therapy