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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.
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Pituitary and hypothalamic diseases Dr.Malith Kumarasinghe MBBS( Colombo)
Overview • Anatomy and physiology • Pituitary disorders • Hypothalamic disorders
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
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
Pituitary disorders • Tumors primary -benign -non functional -adenomas-macroadenoma/microadenoma -malignant secondary
Infections • Infiltrative diseases-TB • Vascular disorders-Sheehans syndrome
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
Prolactin • TSH • Cortisol • Testosterone/Estradiol • LH, FSH • IGF-1, GH • Water deprivation test (assess ant pituitary hormones first)
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
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
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