Pituitary disease Flashcards
1) What is acromegaly?
2) What is the most common cause of acromegaly?
3) In 25-30% of cases of acromegaly, what is co-secreted?
1) The clinical manifestation of the presence/ production of excess growth hormone.
2) A pituitary adenoma which is hormone secreting.
3) Prolactin is co-secreted in 25-30% cases.
1) What is a rare cause of acromegaly?
2) Describe how a pituitary adenoma can affect a patient’s eyesight.
1) Rarely, acromegaly can be caused secondary to a cancer such as lung/ pancreatic cancer that secretes excessive GHRH or GH ectopic ally.
2) The optic chasm sits just above the pituitary gland. Pressure on the optic chasm from a pituitary tumour can cause bitemporal hemianopia.
1) How does growth hormone stimulate bone and soft tissue growth?
2) What causes gigantism?
1) GH stimulates bone and soft tissue growth through IGF-1.
2) Excess GH before epiphyseal growth plate fusion causes gigantism.
How do pituitary adenomas arise?
From the proliferation of single, mutated pituitary cells where genetic alterations promote cellular growth rate,
Name 3 things that patients may complain of when presenting with potential acromegaly.
Rings not fitting Old shoes not fitting Developing a wonky bite Developing curly hair Putting on weight
1) Describe the onset of acromegaly.
2) What 3 categories can presenting features of acromegaly fit into?
1) There is an insidious onset often resulting in diagnostic delay and signs can predate diagnosis by 4 years or more.
2) Signs/ symptoms of a space occupying lesion, tissue overgrowth or organ dysfunction.
State 4 signs or symptoms of a space occupying lesion which could be presenting features in patients with acromegaly.
Headaches
Bitemporal hemianopia
Cranial nerve palsies
Hypopituitarism (if pituitary stalk compression occurs)
State 5 possible signs or symptoms of tissue overgrowth which could be presenting features in patients with acromegaly.
Prominent forehead (frontal bossing) Large nose Large hands and feet Large tongue (macroglossia) Prominent, protruding jaw (prognathism) Decreased libido and alterations in sexual functioning Arthralgia/ arthritis Acanthosis ingrains Coarse skin and skin thickening
State the blood tests you might order for a patient with suspected acromegaly.
IGF-1 (elevated) Cortisol (may be low) Calcium/ phosphate (may be high) FBC U&Es Creatinine LFTs
Why can cortisol levels be low in acromegaly?
Because GH is an important regulator of conversion of cortisone to cortisol and its action is to inhibit this conversion, so excess GH = low cortisol levels.
What is the standard method used to diagnose acromegaly and how is the diagnosis made?
The oral glucose tolerance test is used if baseline IGF-1 values are abnormal. It is the standard method to confirm an acromegaly diagnosis.
If the lowest GH value during the OGTT is >1mcg/L then acromegaly is confirmed.
Why is the oral glucose tolerance test used to confirm acromegaly diagnosis?
Physiological GH secretion is inhibited by hyperglycaemia, but in acromegaly GH secretion is autonomous and does not suppress with hyperglycaemia and may paradoxically rise with hyperglycaemia.
Suggest 5 other investigations aside from blood tests or the oral glucose tolerance test which may be required in a patient with acromegaly.
CXR CT MRI of pituitary fossa ECG and ECHO Visual field testing
Describe the management aims for patients with acromegaly.
To control the symptoms caused by the local effects of the tumour and those due to the excess hormone production, and to normalise hormone levels.
No single treatment is effective on its own, so a combination of treatments (often a 3 part strategy) is usually required.
1) What is usually first line management for the treatment of acromegaly?
2) What are patients with residual disease after first line management offered?
1) Trans-sphenoidal surgery
2) Adjuvant drug treatment to reduce GH levels.
