Disorders of Pituitary gland

a. Hypersecretion of anterior pituitary hormones:- This condition usually occurs due to excess secretion of growth hormone releasing hormone(GHRH) by the hypothalamus. As the tumor increases in size, all the nearby structure are compressed; which results in hyposecretion of other hormones from pituitary gland. This can damage the optic nerve, and can cause visual disturbance; excessive growth of bones; enlargement of internal organs; raised BP etc. the three main disorders under this category include:-

• Gigantism:- this occurs in children, when the GH is in excess and the epiphyseal cartilages are still growing.
• Acromegaly:– this occurs in adults when the GH is in excess; the bones become abnormally thick and also leads to thickening of soft tissues
• Hyperprolactinemia:- This is caused by a tumor that secretes excess of prolactin. This results in- inappropriate milk secretion, sterility in women etc.

Causes:- prolonged secretion of growth hormone and prolactin.

Treatment:– dopamine agonist, receptor agonist

b. Hyposecretion of anterior pituitary hormones:- During this condition, the number of hormones involved for the disorder and the depth of hyposecretion is not constant. The condition where there is complete absence of all anterior pituitary hormones is known as panhypopituitarism. It includes:-

• Ischaemic necrosis:– It is also known as Simmond’s disease. During this disease, there is low stimulation of target glands, mild functioning of some or all the hormones of anterior pituitary. When this condition associates with severe blood loss, it is known as postpartum necrosis.
• Pituitary dwarfism:– It is caused by severe deficiency of GH and other hormones during childhood.

Causes:- tumors of hypothalamus, trauma (usually caused by broken base of skull), ionising radiations, infection etc.

c. Diabetes insipidus:- This is a disorder of posterior pituitary.  This occurs when the renal tubules are unable to respond to ADH. Water reabsorption is lost and the results in excessive secretion of diluted urine; hence causes dehydration.

Causes:- hyposecretion of ADH, damage to hypothalamus, trauma, tumor in hypothalamus, encephalitis.

Treatment:–  vasoconstrictors and

Disorders of Thyroid Gland

a. Hyperthyroidism:- also known as thyrotoxicosis . This condition arises due to the excessive secretion of T3 and T4. Its effects includes- weight loss, hair loss, warm sweaty skin etc. It may lead to cardiac failure.

Causes:– 1. Graves’ disease- it is a autoimmune disorder in which an antibody that acts like TSH is produced.

2. adenoma- It is a benign tumor.

3. toxic nodular goitre- one or two nodules of gland that is already affected by goitre; becomes active and leads to excess of T3 and T4.

Treatment:-  anti-thyroid medication, beta-blockers

b. Hypothyroidism:- this disorder mainly occurs in adults. deficiency of T3 and T4 leads to low metabolic rates, obesity, constipation, dry skin etc.

Causes:-  1. Autoimmune thyroiditis:- the autoantibodies react with thyroglobulin and thyroid gland cells develop and prevents the synthesis of thyroid hormones. Other causes for hypothyroidism includes iron deficiency, goiter, anti-thyroid drugs etc.

Treatment:- synthetic thyroid hormone levothyroxine

c. Simple goiter:- This is enlargement of thyroid gland. sometimes, the extra thyroid tissue are able to maintain the normal hormone secretion; but if not, it causes hypothyroidism. The enlarged gland may cause pressure damage to the adjacent tissue; most affected is the oesophagus which causes dysphagia.

Causes:- iodine deficiency, genetic abnormality which affects the synthesis of T3 and T4, anti-thyroid drugs.

Treatment:- thyroid drugs, radioactive iodine

Disorders of Adrenal Glands

a. Hypersecretion of glucocorticoid:– When the main glucocorticoid, that is cortisol is secreted in excess, this disorder is caused. Hypersecretion of cortisol influences several physiological effects like-

• disturb protein synthesis
• formation of renal calculi(stone in kidney)
• menstrual disturbance
• fractures dur to to calcium loss from bones etc.

Causes:– hormone secreting adrenal tumors, hypersecretion of ACTH by anterior pituitary, bronchial and pancreatic tumors, prolonged therapeutic use of systemic ACTH.

b. Hyposecretion of glucocorticoid:- inadequate secretion of cortisol leads to diminish of gluconeogenesis, low blood glucose level, muscle weakness and body turns pale.

Causes:- due to disease of adrenal cortex, deficiency of ACTH, hyposecretion of aldosterone.

Treatment:– depressants, stimulants, opiates

c. Tumors:- This is a disorder of adrenal medulla. Hormone secreting tumors are very common problems. The effects of hypersecretion of epinephrine and non epinephrine are hypertension, weight loss, anxiety, headache, constipation, hyperglycemia , excessive sweating. There are two types of tumors:-

• Pheochromocytoma:– This is a benign tumor that occurs in both the glands. It results in constant elevation in secretion of hormone and also raises the intra-abdominal pressure.
• Neuroblastoma:– This is a malignant tumor which occurs mainly in children.

Causes:- cushing syndrome( too much release of adrenaline), hypoxia, hypertension and congenital heart diseases

Treatment:- adrenal gland blockers

d. Chronic adrenocortical insufficiency (Addison’s disease):- This is due to the destruction of adrenal cortex; which results in hyposecretion of glucocorticoid and mineralocorticoid. Autoimmune disease of other lands can be associated with Addison’s disease, for example diabetes, thyrotoxicosis and hypothyroidism. Its effects are:-

• muscle weakness
• GIT disturbances
• tiredness
• hypoglycemia
• confusion
• menstrual disturbances.

Causes:- development of antibodies to cortical cell, metastasis(secondary tumors) and infection.

Multiple choice questions(MCQs)

1. What is gigantism?
A. when growth hormone is in excess and epiphyseal cartilage is growing
B. renal tubules are unable to respond to ADH
C. low stimulation of target glands
D. excess of prolactin hormone

2. Which of the following is not the treatment of hyperthyroidism?
A. anti-thyroid drugs B. beta blockers
C. synthetic thyroid hormone D. none of the above

3. Which of the following is the cause of goiter?
A. genetic abnormality B. iodine deficiency
C. anti-thyroid drugs D. all of the above

4. Match the following treatment with its disorder-
a. hyperthyroidism 1. Adrenal gland blockers
b. hypothyroidism 2. Iron rich drugs
c. goiter 3. levothyroxine
d. adrenal tumors 4. Beta blockers

5. What happens during simmond’s disease?
A. when growth hormone is in excess and epiphyseal cartilage is growing
B. renal tubules are unable to respond to ADH
C. low stimulation of target glands
D. excess of prolactin hormone

6. Which of the following comes under tumors?
A. gigantism B. acromegaly
C. hyperprolactinemia D. none of the above

7. Which of the following is not the effect of addison’s disease?
A. muscle weakness B. tiredness
C. hyperglycemia D. menstrual disturbance

8. Which of the following statement is true?
A. acromegaly is a disorder of pituitary gland
B. addsion’s disease is one of the thyroid gland disorder
C. hypothyroidism is low level of T3 and T4
D. simmond’s disease is a adrenal gland disorder

9. What happens during Diabetes insipidus?
A. when growth hormone is in excess and epiphyseal cartilage is growing
B. renal tubules are unable to respond to ADH
C. low stimulation of target glands
D. excess of prolactin hormone

10. Which of the following disease is caused by adenoma?
A. hyperthyroidism B. hypothyroidism
C. adrenal tumors D. acromegaly

ANSWERS:-

1. when growth hormone is in excess and epiphyseal cartilage is growing
2. synthetic thyroid hormone
3. all of the above
4. a – 4 b – 3 c – 2 d – 1
5. low stimulation of target glands
6. none of the above
7. hyperglycemia
8. acromegaly is a disorder of pituitary gland
9. renal tubules unable to respond ADH
10. hyperthyroidism

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REFERENCE:-

Ross and Wilson-Anatomy and physiology in health and illness;  12^th edition; page no.-: 230-235.