Pituitary and hypothalamic diseases

Dr.Malith Kumarasinghe MBBS( Colombo)

Overview Anatomy and physiology Pituitary disorders Hypothalamic disorders

Pitutary gland

Location Sella turcica Floor of the brain

Parts of the Pituitary Gland

Anterior Pituitary Posterior Pituitary

Anterior Lobe Hormones

Growth Hormone Prolactin Thyroid Stimulating Hormone - TSH AdrenoCorticoTrophic Hormone - ACTH Follicle Stimulating Hormone Lutenizing Hormone

Posterior pituitary hormones Oxytocin

Milk ejection mechanism Uterine Contraction

Vasopressin or ADH

Hypothalamus

Lies superior to the pituitary at the base of the brain

Hypothalamic functions

homeostasis. controls the autonomic nervous system, regulates eating and drinking, controls

body temperature controls pituitary gland secretions.

Hypothalamic actions on the pituitary

Posterior pituitary 

The hypothalamic nuclei produce ADH and oxytocin. These move down the axon and are stored in the posterior pituitary. Following stimulation of the hypothalamus these hormones are then released into the bloodstream.

Anterior pituitary

the hypothalamus is linked to the anterior pituitary by a network of microcapillaries - Control is maintained by release of hypothalamic hormones, some of which stimulate release and others inhibit release of pituitary hormones

Hypothamo pituitary axis

Pituitary disorders Tumorsprimary-benign -non functional

-adenomas-macroadenoma/microadenoma

-malignantsecondary

Infections Infiltrative diseases-TB Vascular disorders-Sheehans

syndrome

Pituitary tumors-features

Pituitary tumors-features Pituitary tumors may produce one

or more hormones causing endocrine dysfunction

Some pituitary tumors compress rest of the gland causing deficiency of hormones

Pituitary tumors-features

Symptoms caused by pressure from a larger pituitary tumor

Headache Visual changes

Double vision Visual field loss

Hypopituitarism-deficiency of pituitary hormones Causes

Pituitary tumour Sheehan’s syndrome TB,sarcoidosis

GH deficiency High body fat content fracture risk Fatigue, muscle weakness

Gonadotrophin deficiency Male

testicular volume Loss of facial & body hair sexual function and libido

Female Amenorrhoea Vaginal dryness

ACTH deficiency Weakness, tiredness Hypotension Vomiting Hypoglycaemia Hyponatraemia Myalgia

TSH deficiency Features of hypothyroidism

Investigation of hypopituitarism

Prolactin TSH Cortisol Testosterone/Estradiol LH, FSH IGF-1, GH Water deprivation test (assess ant

pituitary hormones first)

Treatment of hypopituitarism

Growth hormone defficiency-Recombinant GH S-C injections

ACTH Deficiency- Hydrocortisone-IV/oral TSH Deficiency-Thyroxin Gonadotrophin Deficiency

- Female estrogen /progesterone

-Male Testsosterone: injection

Diabetes insipidus Absence/defficincy of ADH 30-50% idiopathic Trauma, tumours Clinical features

Polyuria: urine output > 3 litres/day

Investigation, treatment

Water deprivation test Normal: urine osmolality rises in water

deprivation DI: Urine fails to concentrate ADH deficiency: urine osmolality with

desmopressin Nephrogenic DI: no response to desmopressin

Treatment Desmopressin

Nasal fluid/aerosol, tablet

Pituitary hormone excess

GH excess Causes

Pituitary tumour causing high growth hormone secretion

gigantism

Excessive GH Production during childhood causes increased height

acromegaly

When growth hormone excess occurs in adulthood

Clinical features Enlargement of hands, altered shoe and

ring size sweating Thyroid enlargement Sleep apnoea Diabetes, hypertension Colonic polyps, GI malignancies

Prior

Early Onset

Full Development

Treatment Surgery: Usually transsphenoidal Radiotherapy Somatostatin analogues

Octreotide/Lanreotide:

Hyperprolactinaemia Can occur due to-prolactin secreting pituitary

tumour(prolactinoma)-disconnection hyperperolactinemia-commonly

due to non functioning pituitary tumors

Hyperprolactinaemia: Reproductive function Nipple discharge

Treatment Dopamine agonists:

Bromocriptine

Surgery

Cushing’s disease Due to high ACTH Usually microadenoma

Central obesity Proximal weakness Osteopenia hypertension Purple striae

Treatment Pituitary surgery

Radiotherapy

Hypothalamic disorders Causes-trauma-malignancy-malnutrition-anorrexia nervosa

Features Endocrine dysfunction Eating disorders Problems related to autonomic

control

Questions ….