Pituitary Gland Disorders

Question 1

How is the pituitary gland supplied with blood

Answer 1

• short and long pituitary arteries
  -hypophyseal portal circulation that begins at the capillary plexus around the arc
  It has a dual blood supply

Question 2

What hormones are secreted by the anterior pituitary gland

Answer 2

• ACTH : regulation adrenal cortex
• TSH : thyroid hormone regulation
  -GH :growth hormone
  -LH/FSH: reproductive control
  -PRL:breast milk production

Question 3

What hormones are secreted by posterior pituitary gland

Answer 3

-oxytocin
-Adh

Question 4

Where is the pituitary gland found

Answer 4

-below brain in the sella turcica

Question 5

Three layers of the endocrine system

Answer 5

Primary layer - end organ
Secondary -pituitary gland.
Tertiary - hypothalamus

Question 6

3 factors to consider in pituitary tumours

Answer 6

-hormone hyper secretion
-space occupying lesion - lead to headaches , visual loss ,
-hormone deficiency states - interference with normal surrounding pituitary

Question 7

What is an excess of GH called

Answer 7

Acromegaly

Question 8

Excess of ACTH called?

Answer 8

Cushings disease

Question 9

Excess of TSH?

Answer 9

Secondary thyrotoxicosis

Question 10

Excess of FH/LSH

Answer 10

Non functioning pituatary tumour

Question 11

Excess PRL .

Answer 11

Prolactinoma

Question 12

What are some systemic effects growth hormone excess

Answer 12

• acral enlargement- hands and shoe size increase
  Macroglossia m- large tongue
  Carpal tunnel syndrome

-increased skin thickness
-increased sweating
-change in appearance
-insulin resistance
-diabetes mellitus
-increased triglycerides
-reduced total cholesterol
-increased nitrogen retention

Question 13

Consequences in the cardiovascular system from excess growth hormone

Answer 13

-cardiomyopathy
-hypertension
-bowel polyps
-colon cancer
-multinoduler goiter
-hypogonadism
-arthropathy
-

Question 14

What is prolactinomas

Answer 14

• high levels of prolactin which stimulates the production of breast milk
  Tonic release of dopamine inhibits PRL release
  Mechanical stimulation for nipple sends neural signal to the brain which stops dopamine production instantly , which leads to a large surge in prolactin to provide milk for the baby

Question 15

Role of prolactin

Answer 15

Inhibits production of LH and FSH so that all the energy is given to the baby that is being breast fed

Question 16

What drugs interfere with dopamine and prolactin

Answer 16

• antiemetics
• antipsychotic
  -OCP/HRT

Question 17

Features of PRL excess

Answer 17

-infertility
-reduced libido
-erectile dysfunction
-amenorrhoea
-oligoamenorrhoea

Question 18

Treatment for excess prolactin

Answer 18

Dopamine agonists
-bromocriptine
-cabergoline

Question 19

Non functioning pituitary tumours ; symptoms and treatment

Answer 19

30% of all pituitary tumours
Causes symptoms due to space occupation:
-headaches
-visual field defects
- nerve palsies

Treatement is surgery - radiotherapy

Question 20

Treatment of pituitary adenoma

Answer 20

• surgery through the nose
  -radiotherapy- slow
  Drugs - stop hormone release , and block hormone production

Question 21

Causes of pituitary failure

Answer 21

• tumour
  -trauma
  -infection
  -inflammation
  -Iatrogenic -illness caused by medical examinations

Question 22

Symptoms of lack of thyroid production

Answer 22

-bradycardia
-weight gain
-cold intolerance
-hypothermia
-constipation

Question 23

Symptoms when there is Lack of sex steriod

Answer 23

• oligomenorrhoea -period reduced
  -reduced libido- less sex drive
  Hot flushes
  Reduced body hair

Question 24

Symptoms of reduced cortisol

Answer 24

-tiredness
-weakness
-anorexia
-postural hypotension
-myalgia

Question 25

Symptoms of reduced GH

Answer 25

-tired
-central weight gain

Question 26

SIADH ( syndrome of inappropriate ADH)

Answer 26

excessive release of antidiuretic hormone (ADH) from the pituitary gland
Leads to brain infection /injury
-leads to water retention and dilutional hyponatremia
-sodium concentration in blood falls below normal

Question 27

Diabetes insipidus

Answer 27

-polydipsia
-polyuria
Body unable to regulate water balance due to insufficient production of ADH
Excessive thirst
Urination

Question 28

Two types of diabetes insipidus

Answer 28

CDI -deficiency or lack oc production of ADH , caused by damage to hypothalamus or pituitary gland

NDI- kindeys fail to respond to ADH even when ADH levels are normal or elevated , caused by inherited gene mutations , kidney disease , electrolyte imbalance

Question 29

Water deprivation test

Answer 29

-assess body ability t concentrate urine and regulate water balance
- differentiate between CDI and NDI by evaluating kidney response to dehydration and water restriction

Stimulate release of ADH
dehydration usually leads to release of ADH which leads to water reabsorption by kidneys

Preparation: Before the test, baseline measurements of body weight, urine volume, urine osmolality (concentration), and serum electrolytes are obtained. Blood tests may also be performed to assess ADH levels, serum osmolality, and electrolyte levels.
Fluid Restriction: The patient is instructed to restrict fluid intake for a specified period, typically overnight or for several hours. This step induces dehydration and stimulates the release of ADH.
Monitoring: Throughout the test, the patient’s weight, urine output, and urine osmolality are monitored at regular intervals, usually every hour or two. Blood samples may also be collected periodically to measure serum osmolality, electrolytes, and ADH levels if available.
Criteria for Test Termination: The test is typically terminated when certain criteria are met, such as a significant increase in urine osmolality (>50%) from baseline or a specified level of dehydration (e.g., 5-6% body weight loss). If the patient becomes severely dehydrated or experiences significant symptoms, the test may be stopped earlier, and fluids administered as needed.
Interpretation of Results:
Normal Response: In individuals with normal water balance and ADH function, dehydration leads to an increase in urine osmolality (>800 mOsm/kg), indicating concentrated urine, and minimal weight loss (<5-6%).
Central DI: In CDI, dehydration does not result in a significant increase in urine osmolality despite water restriction, indicating the inability to concentrate urine despite elevated ADH levels. ADH levels may be low or normal.
Nephrogenic DI: In NDI, dehydration may lead to a modest increase in urine osmolality, but it remains below normal levels (<300 mOsm/kg), indicating impaired kidney response to ADH. ADH levels may be elevated.