Hypersecretion of Anterior pituitary gland Flashcards

1
Q

What is the ususal cause of hyperpituitarism?

A

Usually: isolated pituitary tumor

But can also be ectopic (i.e. from non-endocrine tissue)

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2
Q

What are the symptoms/results of hyperpituitarism?

A

Always dependant on the excess hormone

Can be accompined by bitermporal hemianopa (usually late stage)

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3
Q

What is a micoradenoma?

What is a macroadenoma?

A

Microadenoma:

  • Maximal diameter <10mm

Macroadenoma

  • Maximal diameter > 10mm
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4
Q

In which physiological states is a prolactinaemia normal?

A

In

  • pregnancy
  • and breastfeeding
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5
Q

What are the characteristics of a prolactinoma?

A
  • often microadenomas
  • it is the most common functioning pituitary tumor
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6
Q

What are the symptoms of hyperprolactinaemia due to a pituitary adenoma in women?

Explain them

A

galactorrhoea (milk production)

–> what prolactin is meant to do

  • secondary amenorrhoea (or oligomenorrhoea)
  • loss of libido
  • Infertility

–> Prolactin supresses pulsatile release of GnRH (no LH/FSH, no cycle)

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7
Q

What are the symptoms of a hyperprolactinaemia due to a pituitary adenoma in men?

Explain them

A

Symptoms in Men

  • galactorrhoea uncommon (since appropriate steroid background usually inadequate + supresses it) but possible
  • loss of libido
  • erectile dysfunction
  • infertility

Supressing of GnRH –> supressing of LH/FSH –> reduced testosterone levels

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8
Q

What is the usual treatment for a hyperprolactinaemia?

A

Dopmaine D2 agonist (prolactine is supressed by dopamine)

  • decreases prolactin secretion
  • reduces tumor size

Names:

  • Bromocriptine
  • Cabergoline
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9
Q

What are side effects of dopaminergic receptor agonists (used in reatment of prolactinoma)?

A
  1. Nausea and Vomiting
  2. Postural hypotension
  3. Dyskinesia ( movement disorders that are characterized by involuntary muscle movements)
  4. Depression
  5. Pathological gambling/risk taking etc.

–> Due to role of dopamine in reward system (depression, gambling), nausea, and movement controll

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10
Q

What is the usual cause and effect of excess growth Hormone secretion in childhood and adulthood?

A

Usually due to benigsn GH secretion tumor

In Childhood it results in

  • Gigantism

In Adulthood it results in

  • Acromegaly
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11
Q

What is gigantism?

A

A condition due to excess growth hormone in childhood leading to abnormal growth

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12
Q

What is acromegaly?

A

Hypersecretion of Growth hormone in adulthood leading to growth of soft tissue and cartilage

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13
Q

What are the main causes of death/symptoms of acromegaly?

A
  • Cardiovascular disease 60%
  • Respiratory complications 25%
  • Cancer 15%
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14
Q

What grows in acromegaly?

A
  • Periostal bone
  • cartilage
  • fibrous tissue
  • connective tissue
  • internal organs
    • cardiomegaly
    • splenomegaly
    • hepatomegaly etc.
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15
Q

What are the signs and symptoms of acromegaly?

How might patients describe them?

A
  • excessive sweating (hyperhidrosis)
  • headache
  • enlargement of supraorbital ridges, nose, hands and feet, thickening of lips and general coarseness of features –> face looks different, rings/shoes don’t fit anymore
  • enlarged tongue (macroglossia) –> problems speaking, biting the side of the toung
  • mandible grows causing protrusion of lower jaw (prognathism), face lookds different
  • carpal tunnel syndrome (median nerve compression) –> tingeling in fingers
  • barrel chest, kyphosis
  • Diabeties mellitus
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16
Q

Explain the formation of Diabetes in Acromegaly

A

Excessive GH

–> increases Blood glucose levels

–> Hypersecretion of insulin

–> Insulin desentivity –> DM2

17
Q

What are the main complications in acromegaly?

A

Obstructive sleep anoea

  • enlargement of tounge and soft tissue in upper airway

Hypertension

  • Direct effects of GH &/or IGF-1 on vascular tree
  • GH mediated renal sodium reabsorption

Cardiomiopathy

  • Hypertension, DM, direct toxic effects of excess GH on myocardium

Increased risk of cancer

  • Colonic polyps, regular screening with colonoscopy
18
Q

Which other condition is common in patients with acromegaly?

A

Hyperprolactinaemia

  • ofter tumor co-secretes prolactin
  • –> Symptoms of GnRH supression
19
Q

How can you diagnose Acromegaly?

A

Paradox reaction to increased blood glucose levels

  • in healthy people: GH levels should fall after increase in serum glucose levels
  • In Acromegaly: GH levels rise in response to it

Elevated serum IGF-1 (rather than normally pulsatile GH)

Pituitary MRI

20
Q

How could you treat Acromegaly?

A
  1. Trans-sphenoidal surgery (removal of tumor)
  2. Medical intervention
    • Somatostatin analogues (Octreotide)
      • Until surgery, reduces hormone levels and shrinks tumor
    • Dopaminergic agonists (Cabergoline)
      • for prolactinaemia, and also tumors regularly express D2 receptors
  3. Radiotherapy (if no access to tumor surgically)
21
Q

What is octreotide?

A

A somatostatin analogue (used e.g. in treatment of acromegaly)

22
Q

What is Cabergoline?

A

A D2 Dopaminergic agonist

used e.g. in treatment of prolactinma, acromegaly

23
Q

What are the side effects of octreotide?

What is it used for?

A

SS analogue: used for treatment of Acromegaly

Can be given as depot or injection (short lasting)

  • Normally GI side effects e.g.
  • nausea, gallstones, diarreah etc.