Pituitary Disease Flashcards
Briefly describe endocrine diseases
- Dysfunction of hormone secreting glands
- Negative feedback regulation
- control failure (secondary)
- gland failure (primary) - Causes widespread, multi system effects
What tumours are present and associated with Multiple Endocrine Neoplasia 1 (MEN1)?
- Tumours
1. Parathyroid
2. Pancreatic Islets
3. Pituitary (anterior) - associated tumours
1. Adrenal cortex, carcinoid lipoma
What glands and tumours are associated with Multiple Endocrine Neoplasia 2a (MEN2a)?
- tumours
1. Parathyroid
2. medullary thyroid
3. Phaeochromocytoma
What tumours are associated with Multiple endocrine neoplasia 2b (MEN2b)?
- Medullary thyroid Carcinoma
- phaeochromocytoma
- Mucosal neuromas
What difference in control is there between the anterior and posterior pituitary gland?
The anterior pituitary can only be stimulated via vascular control whereas the posterior pituitary can be stimulated by vascular and neurological control
What complications can arise from head trauma that may affect the pituitary gland?
The stalk connecting the pituitary gland to the base of the brain can close off due to head trauma which will cause an infarction of the pituitary gland
What other anatomical feature could be affected by tumour growth around the pituitary gland?
Why is this?
What effects could this cause
- The optic chiasma
- put under pressure by tumour growth as any tumours will grow upwards due to pressure of the surrounding bone.
- this affects vision
What are the main functions of the pituitary gland?
- Control of many gland activities
- Hypothalamic control - releasing hormones:
- thyroid releasing hormone
- gonadotropin releasing hormone
- corticotropin releasing hormone - Hormones from the pituitary act directly on tissues to cause effect
- e.g thyroid, growth hormone
What hormones does the posterior pituitary associate itself with?
- Anti Diuretic Hormone
2. Oxytocin
What hormones are secreted from the anterior pituitary gland?
- TSH - thyroid stimulating hormone
- ACTH - adrenocorticotrophic hormone
- GH - growth hormone
- LH, FSH, Prolactin
What hormones are secretes by the posterior pituitary gland?
- ADH
2. Oxytocin
What condition can be caused by insufficient production of ADH?
Diabetes insipidus
What type of pituitary tumour usually causes dysfunction?
Adenomas
- functional
- non functional
What two types of functional adenomas are there and what do they cause?
- <40 years of age prolactin/ACTH
- amenorrhoea-Galctorrhoea syndrome
- Cushing’s disease - > 40 years of age growth hormone
- acromegaly
When do non functional adenomas appear and what do they cause?
- > 60 years of age
- cause mass effects
. Visual field defects, other hormone deficiencies
What is the most effective surgery for pituitary tumours?
Trans-sphenoidal surgery
- access is made through the sphenoid bone behind the nose, meaning the skull does not have to be opened
What complications can arise from insufficient growth hormone?
- Growth failure in children
- Metabolic changes in adults
- increased fat
- reduced vitality
How is secretion if growth hormone controlled?
- Growth hormone secretion is controlled by the hypothalamus
- Growth hormone releasing hormone (GHRH) released from the hypothalamus is essential to stimulate growth hormone release from the pituitary gland
- growth hormone acts on the body tissues to produce anabolic reactions
- insulin-like growth factor (IGF-1) is released from these tissues
- IGF-1 has a positive feedback on the tissues, but a negative feedback on the pituitary gland which helps control growth hormone secretion
What substance is most useful for measuring growth hormone levels due to the length of time it persists in the circulation?
insulin-like growth factor (IGF-1)
What complications can arise from excess growth hormone?
- ‘Giantism’ In children
- Acromegaly in adults
- growth plates have closed so only certain parts of the body can grow (e.g hands, feet, forehead and jaw)
Why is it important to be extra vigilant for signs of acromegaly?
- Insidious onset
- early changes are subtle and it takes time for them to be made evident
- if diagnosed late then changes are irreversible and patient will have an altered appearance
When is the peak incidence of acromegaly?
30-50 years of age
What are general presenting changes associated with acromegaly?
- Coarse features
- Enlarged supra-orbital ridges
- Broad nose, thickened lips and soft tissues
- Enlarged hands
- results in carpel tunnel syndrome due to pressure on the nerves = finger numbness - Type 2 diabetes mellitus
- due to resistance to insulin because of increased IGF-1 levels
What general cardiovascular Changes are associated with acromegaly?
- Cardiovascular disease
- ischaemic heart disease due to extra strain of supporting larger mass
- acromegalic cardiomyopathy die to the heart growing in size and becoming less efficient as a pump
What are intraoral changes that are associated with acromegaly?
- Enlarged tongue
- Interdental spacing
- ‘Shrunk’ dentures
- Reverse overbite
