A person sustains head trauma leading to transaction of pituitary stalk. All can be consequence of this, except: (AIIMS Nov 2011)
In hypopituitarism hormone are affected in the following order: GH, FSH and LH, prolactin (PrL), TSH, and ACTH. (MCQ)
Causesare from 3 levels
1). Hypothalamus: Kallmann’s syndrome , tumor, inflammation, infection (eg meningitis, TB), ischemia.
2). Pituitary stalk: Trauma, craniopharyngioma, meningioma.
3). Pituitary: Tumour, irradiation, inflammation, infiltration (hemochromatosis, amyloidosis, metastatic ca), ischemia (pituitary apoplexy, Sheehan's syndrome).
Pituitary apoplexy occur in pregnancy, DM, HT, Sickle cell anemia. (AIIMS May 09) It does not occur in. hyperthyroidism. (H-18th ed. Pg- 2879)
Features are due to
B. Mass effect
1). GH deficiency
2). Gonadotrophin deficiency (FSH; LH) oligomenorrhea or amenorrhea
3). Thyroid deficiency: As for hypothyroidism .
4). Corticotrophin deficiency: As for adrenal insufficiency . (MCQ: No hyper pigmentation as ACTH is reduced)
5). Prolactin deficiency: failure of lactation.
1).DI is not a feature of hypopituitarism i.e. transection of pituitary stalk does not lead to diabetes insipidus)
2). Insulin is a pancreatic hormone and is not under the control of pituitary.
3). Transection of the pituitary stalk does not lead to diabetes mellitus.
B. Mass effect: eg pituitary tumour, causing mass effect, (Headache, Bitemporal hemianopia)
Insulin tolerance test: In this test I/V insulin is given to induce hypoglycemia causing stress to ↑cortisol and GH secretion.
Treatmentinvolves hormone replacement and treatment of underlying cause.
1). Hydrocortisone for secondary adrenal failure.
2). Thyroxine if hypothyroid.
3). Hypogonadism (for symptoms and to prevent osteoporosis).
a. Sheehan’s syndrome is post-partum infarction of the pituitary, leading to hypopituitarism.
b. Treatment consists of hormone replacement therapy including Glucocorticoids, thyroid hormone, sex steroids, growth hormone, vasopressin.
c. Thus multiple hormones must be replaced, but cortisol replacement is most important & should be the first to be replaced.
d. Steroids are given before thyroxine, otherwise thyroxine may precipitate an adrenal crisis, because of sudden increase in metabolic rate.