16 - Pituitary Disorders Flashcards

1
Q

What can non functioning pituitary tumours do to the pituitary gland?

A
  • Inadequate production of pituitary hormones due to pressure from tumour growing on glandular tissue
  • Pressure on surrounding structures of the tumour causing symptoms such as headaches
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2
Q

What are some symptoms of a non-functioning pituitary tumour?

A
  • Headaches
  • Visual problems due to compression of optic nerve
  • Vomiting
  • Nausea
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3
Q

What are symptoms of hyper secreting (functional) pituitary tumours?

A
  • Rare but problems due to overproduction of one or more of the pituitary hormones
  • Symptoms due to systemic effect of the hormone being over produced but may not be seen due to negative feedback
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4
Q

How do you investigate a suspected pituitary tumour?

A
  1. Look at the anatomy, size and topographical location of the mass by MRI
  2. Assessment of visual field defects
  3. Assessment of endocrine function to determine if hormone excess or deficiency
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5
Q

How do you measure hormone levels in the blood to test for a hypersecreting pituitary tumour?

A
  • Staining sections from biopsy of the tumour with antibody for the hormone
  • Measure blood levels
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6
Q

What are causes of hypopituitarism?

A
  • Mainly pituitary adenoma causing secondary effect
  • Radiation therapy
  • Inflammatory Disease
  • Head injury
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7
Q

What are the first hormones to be affect in hypopituitarism?

A
  • Progressive loss of anterior pituitary gland function
  • Starts with GH and LH/FSH
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8
Q

What is it called when all the hormones from the anterior pituitary gland are deficient?

A

Panhypopituitarism

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9
Q

When does hypopituitarism affect the posterior pituitary gland?

A

Only when the tumour affects hypothalamic function or inflammatory process involved

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10
Q

What are some symptoms of growth hormone deficiency in adults?

A
  • Subtle
  • Decrease in tolerance to exercise
  • Decreased muscle strength
  • Increased body fat
  • Reduced sense of “well being”
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11
Q

How do you investigate GH deficiency?

A

Difficult as secretion is pulsatile, need lots of direct and indirect measurements, look at IGFs

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12
Q

What are the causes of GH deficiency?

A

- Adults: usually due to mass effect of pituitary adenoma

- Children: idiopathic but gene mutations and autoimmune inflammation could be a cause

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13
Q

What effect does GH deficiency have on children?

A

- Fetal: no effect on growth unless severe which can result in hypoglycaemia and jaundice

- 1 year to mid teens: poor growth and short stature

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14
Q

How can you treat GH deficiency?

A

Recombinant GH therapy

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15
Q

What are the symptoms and causes of gonadotropin deficiency?

A
  • Hypogonadism due to mass effects of pituitary adenoma

- Women: lack of libido, infertility, oligomenorrhea or amenorrhea

- Men: lack of libido and impotence

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16
Q

What causes TSH and ACTH deficiency?

A

Mainly pituitary adenoma

17
Q

What can cause ADH deficiency?

A
  • Hypothalamic tumour
  • Pituitary tumour extending into hypothalamus
  • Cranial radiotherapy
  • Pituitary surgery
  • Autoimmune infiltration
  • Infections like meningitis
18
Q

What are some symptoms of ADH deficiency and what condition does it cause?

A

- Diabetes Insipidus

  • Dehydration
  • Polydipsia
  • Polyuria
19
Q

What are the three main conditions in hyperpituitarism?

A
  • Prolactin excess
  • GH excess
  • ACTH excess

All caused by hypersecreting pituitary adenoma

20
Q

What symptoms can hyperprolactinaenia present with?

A
  • Galactorrhea
  • Gynecomastia
  • Hypogonadism
  • Amenorrhea
  • Erectile dysfunction
21
Q

Why does hyperprolactinaemia lead to symptoms like erectile dysfunction?

A
  • Leads to hypogonadism due to higher levels of dopamine in the hypothalamus
  • Dopamine inhibits GnRH from hypothalamus so FSH and LH not secreted
22
Q

What are the causes of hyperprolactinaemia?

A
  • Prolactinoma
  • Pregnancy and suckling
  • Stress and exercise
  • Antipsychotics (haloperidol as dopamine antagonist) -
  • Antidepressants
23
Q

Why do antipsychotics leads to hyperprolactinaemia?

A

They inhibit dopamine secretion which is the inhibitor of prolactin

24
Q

Who does hyperprolactinaemia present in first and why?

A

Women as they get their periods early whereas men tend to be sexually active later

25
Q

How is hyperprolactinaemia treated?

A

- Cabergoline (dopamine agonist) is first line

  • Trans-sphenoidal surgery (rare)
  • Radiotherapy

MEASURE PROLACTIN LEVELS BEFORE SURGERY ON PITUITARY GLAND

26
Q

What is one of the causes of Cushing’s syndrome related to the pituitary gland?

A

ACTH excess

27
Q

What are the symptoms of growth hormone excess in adults?

A

- Headache, visual field defects and other cranial nerve pulsies as secreting adenomas tend to be large

- Takes several years (around 6) to manifest with:

broad noses, coarse facial features, thick lips, prominent supraorbital ridge, enlargement of hands and feet, greasy skin due to excess sweating, deep voice due to hypertrophy of soft tissues in air ways

28
Q

What are the symptoms of growth hormone excess in children?

A

- Gigantism not acromegaly

  • Growth in long bones where epiphyseal growth plates not fused
29
Q

What other disorders can be caused from a growth hormone excess?

A
  • Diabetes mellitus (GH antagonises insulin actions)
  • Increase IGF-1 associated with cancer
30
Q

What are the treatment options for acromegaly?

A
  1. Surgery to remove adenoma
  2. Radiation therapy
  3. Drug therapy with dopamine receptor agonists
31
Q

What drugs are used to treat acromegaly?

A

- GH receptor antagonists like Pegvisomant are main drug

  • Not somatostatin as short half life but analogs with long half like produced
  • High dose dopamine receptor agonist
32
Q

What is diabetes insipidus?

A
33
Q

What is pituitary apoplexy?

A
  • Sudden vascular event in a pituitary tumour
  • Sudden onset headache, double vision, cranial nerve palsy, visual field loss and hypopituitarism (cortisol deficiency is the most dangerous). Apoplexy needs prompt diagnosis and treatment
34
Q

Why do patients with diabetes insipidus get hypertranemia?

A
  • High sodium in blood as cannot reabsorb water in kidneys to balance it out
35
Q

What is the normal pattern of plasma cortisol concentration?

A

Plasma cortisol reaches its peak at around 7:00 to 8:00 AM and then gradually declines throughout the day to a lowest levels at around midnight before gradually increasing again through the night. For this reason it is essential to always record the time a blood sample for cortisol measurement was taken and to take repeated samples the same timne of day. Typically cortisol is measured in the morning

36
Q

Name the type of surgical procedure that can be used to remove a pituitary tumor by inserting an endoscope and/or surgical instruments through the nose.

A

Transsphenoidal surgery can go through sphenoid sinus