Disorders of pituitary gland

PITUITARY GLANDSaddam Ansari

Tbilisi State Medical University

Disorders of Pituitary Gland

Causes of Disorder of Pituitary Gland

Mainly of 2 reasons:• Hyperactivity

• Hypoactivity

Disorders of Pituitary GlandParts involved Hyperactivity Hypoactivity Anterior Pituitary 1. Gigantism

2. Acromegaly3. Acromegalic

gigantism4. Cushing’s disease

1. Dwarfism2. Acromicria3. Simmond’s disease

Posterior Pituitary Syndrome of inappropriate hypersecretion of ADH (SIADH)

Diabetes insipidus

Anterior and Posterior Pituitary

……. Dystrophia adiposogenitalis






Diabetes insipidus



Gigantism

Pituitary disorder characterized by:• Excess growth of body• Average height is approximately 7 – 8 feet

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Causes of Gigantism• Hypersecretion of GH in childhood or in pre – adult

• Tumor of acidophilic cells of Anterior pituitary

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Signs and Symptoms• Huge stature : 7 or 8 feet height

• Hyperglycemia , develop glycosuria , pituitary diabetes mellitus

• Headache due to tumor of pituitary

Continued…

• Visual disturbances

• Gigantism ends in hypopituitarism (burning of cells of anterior pituitary )






Diabetes insipidus



Acromegaly

Anterior pituitary disorder characterized by:• Enlargement, thickening, and broadening of bones

• Particularly extremities of the body

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Causes of Acromegaly• Hypersecretion of GH after fusion of epiphysis with shaft

of bone• Adenomatous tumor of anterior pituitary involving the

acidophilic cells.

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Signs and symptomsStriking features are protrusion of :

• Supraorbital ridges• Broadening of nose • Thickening of lips• Thickening and wrinkles formation on forehead• Lower jaw (prognathism)

Face with these features called as acromegalic or guerilla face

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Signs and symptoms• Kyphosis : enlargement of hands and feet with bowing spine

• Scalp is thickened and thrown into folds

• Overgrowth of body hair

• Visceral organs are enlarged

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Signs and symptoms• Thyroid , parathyroid and adrenal glands shows hyperactivity

• Hyperglycemia and glucosuria• Hypertension• Headache• Visual disturbance – Bitemporal hemianopia






Diabetes insipidus



Acromegalic GigantismRare disorder

Due to hypersecretion of GH in children,before fusion of epiphysis with the shaft of bone results in Gigantism

If hyersecretion of GH is continued after the fusion of epiphysis the symptoms of Acromegaly also appear






Diabetes insipidus



Cushing’s Disease• Rare disease characterized by obesity

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Cause• Hypersecretion of glucocorticoids mainly cortisol• Either pituitary origin or adrenal origin

Cushing’s Cushing’s

disease syndrome

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Pituitary origin• Increased secretion of ACTH leads to hyperplasia of adrenal cortex therefore, hypersecretion of glucocorticoids takes place

• ACTH is increased by• Tumor in pituitary cells ( basophilic cells)• Malignant tumor of nonendocrine origin like cancer of

lungs or abdominal viscera• Hypothalamic disorder causing hypersecretion of

corticotropin releasing hormone

Continued…Signs and symptoms1. Disproportionate distribution of body fat results:

• Moon face : Fat accumulation and retention of water and salt

• Torso : Fat accumulation in chest and abdomen but slim legs and arms

• Buffalo hump : Fat deposit on the back of neck and shoulder

• Pot belly : Fat accumulation in upper abdomen

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2. Purple striae : Reddish purple stripes on abdomen due to mainly three reasons:

Stretching of abdominal wall by excess subcutaneous fat

Rupture of subdermal tissues due to stretching

Deficiency of collagen fibres due to protein depletion

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3. Thinning of extremities

4. Thinning of skin and subcutaneous tissues

5. Darkening of skin on neck (aconthosis)

6. Pigmentation of skin

7. Facial redness (facial plethora)

8. Weakening of muscle

Continued…9. Facial hair growth ( Hirsutism )

10. Bone resorption leads to osteoporosis

11. Hyperglycemia due to gluconeogeneis leads adrenal diabetes and glycosuria

12. Hypertension

13. Immunosuppression resulting in susceptibility for infection

14. Poor healing






Diabetes insipidus



Dwarfism

• Pituitary disorder in children characterized by stunted growth

Cause of Dwarfism• Reduction in the GH in infancy or early childhood• Occurs because of following reasons:

Deficiency of GH releasing hormone from hypothalamus

Deficiency of Somatomedin – C

Atrophy of acidophilic cells in the adenohypophysis

Tumor of chromophobes : nonfunctioning tumor , compresses and destroys the normal cells

Panhypopituitarism

Signs and Symptoms• Stunted skeletal growth

• Maximum height approximately 3 feet

• Head becomes slightly larger in relation of body

• Mental activity is normal without any deformity

• Reproductive system is not affected due to lack of GH but in Panhypopituitarism puberty is not obtained due to lack of gonadotropic hormone

Types of Dwarfism

• Laron dwarfism• Psychogenic dwarfism• Dwarfism in dystrophia adiposogenitalis

Laron Dwarfism• Genetical disorder

• Called as GH insensitivity

• Occurs due to presence of abnormal GH secretagogue receptors in liver

• GHS becomes abnormal due to mutation in genes responsible for receptor

• Doesn’t depend on amount of GH secretion , hormone can’t stimulate the growth due to abnormal GHS

Psychogenic Dwarfism

• Due to extreme emotional deprivation or stress

• Deficiency of GH

• Also called as psychosocial dwarfism or Stress dwarfism

Dwarfism in Dystrophia adiposogenitalis

• Called as Frohlich syndrome• Rare childhood disorder• Characterized by :oObesityoGrowth retardationoRetarded development of genital organsoAssociated with tumors of hypothalamus – increased appetite and decrease in gonadotropin hormone






Diabetes insipidus



Acromicria • Rare disease in adults characterized by the atrophy of the

extremities of the body

Causes of Acromicria

• Deficiency of GH in adults• Secretion of GH decreases in the following conditions:Deficiency of GH releasing hormoneAtrophy of acidophilic cells in the anterior pituitary

Tumor of chromophobesPanhypopituitarism

Signs and Symptoms

• Atrophy and thinning of extremities ( major symptoms )

• Associated with hypothyroidism

• Hyposecretion of adrenocortical hormone

• Person becomes lethargic and obese

• Loss of sexual function






Diabetes insipidus



Simmond’s Disease

• Rare pituitary disease• Also called as cachexia• Occurs mostly in panhypopituitarism

Signs and Symptoms

• Developing senile decay

• Senile decay is due to deficiency of hormone from target glands of anterior pituitary e.g. thyroid gland, adrenal cortex and the gonads

• Loss of hair and loss of teeth

• The skin on face becomes dry and wrinkled. ( most common )

Summary…..Parts involved Hyperactivity Hypoactivity Anterior Pituitary 1. Gigantism





Diabetes insipidus








Diabetes insipidus



Syndrome of Inappropriate Hypersecretion of Antidiuretic hormone

• Disease characterized by loss of sodium through urine due to hypersecretion of ADH

Causes

• Due to cerebral tumors, lung tumors and lung cancers because the tumor cells secrete ADH

• Normal secretion of ADH makes the plasma hypotonic

• Hypotonic solution inhibits the ADH secretion and restoration of plasma osmolarity takes place

• But in SIADH ,secretion of ADH from tumor is not inhibited by hypotonic plasma

Signs and Symptoms

1. Loss of appetite

2. Weight loss

3. Nausea and vomiting

4. Headache

5. Muscle weakness , spasm and cramps

6. Fatigue

7. Restlessness and irritability

In severe conditions patient die because of coma and convulsions






Diabetes insipidus



Diabetes Insipidus• Posterior Pituitary disorder characterized by excess

excretion of water through urine

Causes

Develops due to the deficiency of ADH which occurs in the following conditions:

1. Lesion (injury) or degradation of supraoptic and paraventricular nuclei of hypothalamus

2. Lesion in hypothalamo-hypophyseal tract

3. Atrophy of posterior pituitary

4. Inability of renal tubules to give response to ADH hormone. Called as Nephrogenic diabetic insipidus.

Signs and Symptoms

1.Polyuria • Excretion of large quantity of dilute urine with

increased frequency of voiding is called polyuria

• Daily output is 4 to 12 liters.

• Due to absence of ADH ,the epithelial cells of distal convoluted tubule in the nephron and the collecting duct of the kidney becomes impermeable to water

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2.Polydipsia• Intake of excess water

• Because of polyuria ,thirst center in hypothalamus results in intake of large quantity of water

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3.Dehydration In some cases ,the thirst center in the hypothalamus is also affected by the lesion

Therefore water intake decreases in these patients and, the loss of water through urine is not compensated






Diabetes insipidus



Dystrophia Adiposogenitalis • Characterized by obesity and hypogonadism affecting

mainly adolescent boys

• Also known as Frohlich syndrome or hypothalamic eunuchism

Causes • Hypoactivity of both anterior and posterior pituitary

• Tumor in pituitary gland and hypothalamic regions concerned with food intake and gonadal development

• Injury or atrophy of pituitary gland

• Genetic inablility of hypothalamus to secrete luteinizing hormone

Symptoms • Obesity (common feature)

• Sexual infantilism (failure to develop secondary sexual characters)

• Dwarfism occurs if disease starts in growing age

• Called as infantile or prepubertal type of Frohlich syndrome (in children)

and adult type of Frohlich’s syndrome (in adults)

• Other features are loss of vision and diabetes

Education

Disorders of pituitary gland