Hypersecretion of Anterior pituitary gland Flashcards
What is the ususal cause of hyperpituitarism?
Usually: isolated pituitary tumor
But can also be ectopic (i.e. from non-endocrine tissue)
What are the symptoms/results of hyperpituitarism?
Always dependant on the excess hormone
Can be accompined by bitermporal hemianopa (usually late stage)
What is a micoradenoma?
What is a macroadenoma?
Microadenoma:
- Maximal diameter <10mm
Macroadenoma
- Maximal diameter > 10mm
In which physiological states is a prolactinaemia normal?
In
- pregnancy
- and breastfeeding
What are the characteristics of a prolactinoma?
- often microadenomas
- it is the most common functioning pituitary tumor
What are the symptoms of hyperprolactinaemia due to a pituitary adenoma in women?
Explain them
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)
What are the symptoms of a hyperprolactinaemia due to a pituitary adenoma in men?
Explain them
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
What is the usual treatment for a hyperprolactinaemia?
Dopmaine D2 agonist (prolactine is supressed by dopamine)
- decreases prolactin secretion
- reduces tumor size
Names:
- Bromocriptine
- Cabergoline
What are side effects of dopaminergic receptor agonists (used in reatment of prolactinoma)?
- Nausea and Vomiting
- Postural hypotension
- Dyskinesia ( movement disorders that are characterized by involuntary muscle movements)
- Depression
- Pathological gambling/risk taking etc.
–> Due to role of dopamine in reward system (depression, gambling), nausea, and movement controll
What is the usual cause and effect of excess growth Hormone secretion in childhood and adulthood?
Usually due to benigsn GH secretion tumor
In Childhood it results in
- Gigantism
In Adulthood it results in
- Acromegaly
What is gigantism?
A condition due to excess growth hormone in childhood leading to abnormal growth
What is acromegaly?
Hypersecretion of Growth hormone in adulthood leading to growth of soft tissue and cartilage
What are the main causes of death/symptoms of acromegaly?
- Cardiovascular disease 60%
- Respiratory complications 25%
- Cancer 15%
What grows in acromegaly?
- Periostal bone
- cartilage
- fibrous tissue
- connective tissue
- internal organs
- cardiomegaly
- splenomegaly
- hepatomegaly etc.
What are the signs and symptoms of acromegaly?
How might patients describe them?
- 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
Explain the formation of Diabetes in Acromegaly
Excessive GH
–> increases Blood glucose levels
–> Hypersecretion of insulin
–> Insulin desentivity –> DM2
What are the main complications in acromegaly?
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
Which other condition is common in patients with acromegaly?
Hyperprolactinaemia
- ofter tumor co-secretes prolactin
- –> Symptoms of GnRH supression
How can you diagnose Acromegaly?
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
How could you treat Acromegaly?
- Trans-sphenoidal surgery (removal of tumor)
- 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
- Somatostatin analogues (Octreotide)
- Radiotherapy (if no access to tumor surgically)
What is octreotide?
A somatostatin analogue (used e.g. in treatment of acromegaly)
What is Cabergoline?
A D2 Dopaminergic agonist
used e.g. in treatment of prolactinma, acromegaly
What are the side effects of octreotide?
What is it used for?
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.
