Endocrine Pathology Flashcards
How can you separate endocrine pathologies?
- Over/under production of hormones
- Mass lesions
Describe the pituitary gland
It has an anterior and posterior aspect
Anterior:
- Epithelial cells
- Blood supply by pituitary portal system
Posterior:
- Nervous cells
How is the anterior pituitary controlled? Name the hormones involved and their actions.
It is mainly controlled by the hypothalamus:
- Thyrotrophin releasing hormone STIMULTES Thyroid stimulating hormone
- Dopamine INHIBITS prolactin
- Corticotrophin releasing hormone STIMULATES ACTH
- Growth hormone releasing hormone STIMULATES growth hormones
- Gonadotrophin releasing hormone STIMULATES gonadotrophin
What are the causes of hyperpituitarism?
Usually, a result of a functional tumour
What are the different types of functional adenomas of the pituitary, and the epidemiology surrounding them.
- Prolactin cell (20-30%)
- ACTH (10-15%)
- Gonadotrophin (10-15%)
- Growth hormone (5%)
- TSH (1%)
Up to 20% of all pituitary adenomas are non functioning (cause hypopituitarism)
What are the clinical affects of the different functional adenomas of the pituitary?
Prolactin cell:
- Amenorrhoea
- Galactorrhoea
- Reduced libido
- Infertility
Growth hormone:
- Gigantism (if children) or Acromegaly (if adults)
- Diabetes mellitus, HTN and congestive cardiac failure
Corticotrophin:
- Cushing’s syndrome
What are the causes of hypopituitarism?
- Non functioning pituitary adenomas
- Ischaemic necrosis (Sheehan’s syndrome, DIC, Sickle cell)
- Ablation or radiation
What are the symptoms of hypopituitarism?
- Growth failure
- Amenorrhoea, infertility, reduced libido, impotence
- Hypothyroid, hypoadrenal
- No lactation (if breastfeeding)
What syndromes are associated with over/under regulation of the posterior pituitary?
Posterior pituitary produces:
- ADH
- Oxytocin
ADH is important:
- DI if under production
- SIADH if over production (brain trauma)
What local affects can a mass lesion have at the pituitary?
Optic chiasm compression:
- Bitemporal hemianopia
Signs of raised ICP:
- Papilloedema, headaches
Obstructive hydrocephalus:
- Brain stem compression
What is the thyroid gland’s main role? How is it controlled? What other roles does the thyroid have?
It produces thyroxine.
TSH from the pituitary stimulates the thyroid to take up iodine and it uses iodine to transform thyroglobulin to T3 and T4.
The thyroid also has parafollicular cells which produce calcitonin, which stimulate calcium reabsorption by bone.
What is goitre? What are the types?
This is an enlarged thyroid; it can be:
- Non-toxic
- Toxic
What are the causes of non-toxic goitre?
- Iodine deficiency
- Ingestion of substances which interfere with hormone syntheses (brassicas)
- Hereditary illnesses
- Female puberty
What is thyrotoxicosis? What are the causes of this?
It is a hyperthyroid state, causing a hypermetabolic state.
Primary causes:
- Grave’s disease
- Multinodular goitre
- Adenomas
- Thyroiditis
Secondary causes:
- TSH secreting pituitary adenoma
Non-thyroid:
- Ovarian teratoma (ectopic TSH)
- Factitious thyrotoxicosis
What is grave’s disease? What are the classical features? What is the epidemiology surrounding it? What are its associations?
It is an autoimmune disease mainly powered by antibodies to the TSH receptor on the thyroid, causing a hyperthyroid state.
It classically has a triad of thyrotoxicosis, exophthalmos (40%) and pretibial myxoedema.
It presents in younger adults, more commonly in females.
It is associated with other autoimmune conditions:
- SLE
- Pernicious anaemia
- T1DM
- Addison’s
Give causes of hypothyroidism
Primary:
- Post-ablative therapy
- Autoimmune (Hashimoto’s)
- Iodine deficiency
- Congenital
Secondary:
- Pituitary/hypothalamic insufficiency