Week 4 - D - pathology of the pituitary and adrenal gland Flashcards
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/jpg/picture1-159185074130D1E4445.jpg
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/jpg/picture2-1591868C84610CACE69.jpg
What is the adenohypophysis and the neurohypophysis?
Adenohypophysis - anterior pituitary
Neurohypophysis - posterior pituitary
In embryogenesis, what is the evagination at the roof of the developing mouth in front of the buccopharyngeal membrane that gives rise to the anterior pituitary (adenohypophysis)?
Rathke’s pouch
What does the anterior pituitary secrete? Which hormones are trophic and non-trophic? What does the posterior pituitary secrete?
Anterior pituitary
- Trophic: TSH, ACTH, FSH, LH
- Non-trophic: GH and Prolactin
Posterior pituitary - ADH and oxytocin
What are the two terms to describe the cells on histology of the anterior pituitary?
Acidophils and basophils
Do the acidophils or basophils include the cells for trophic hormones?
Basophils include the cells which are for the trophic hormones
What is the rare syndrome that can cause hypopituitarism due to ischaemic necrosis of the pituitary gland during childbirth?
Sheehan syndrome
During pregnancy, an increased amount of the hormone oestrogen in the body causes an increase in the size of the pituitary gland and the volume of blood flowing through it.
This makes the pituitary gland more vulnerable to damage from loss of blood.
If heavy bleeding occurs during or immediately after childbirth, there will be a sudden decrease in the blood supply to the already vulnerable pituitary gland.
This can cause tissue death and subsequent loss of pituitary function.
Are pituitary adenomas derived from cells of the anterior or posterior pituitary?
Cells of the anterior pituitary
Pituitary adenomas arise from the cells of the anterior pituitary What can side effects of large adenomas be?
Visual defects
Infarction can lead to panhypopituitarism
What is the most common functional pituitary adenoma? What are common effects (women)?
Prolactinoma
Can cause infertility
Loss of sex drive
Amenorrhea
What is the second most common functional pituitary adenoma that causes increase in Insulin Like Growth Factors (IGF) ? What condition can this adneoma cause?
Growth Hormone Secreting adenoma
Can cause acromegaly
What inflammatory disorder can cause hypopituitarism?
Sarcoidosis
a type of brain tumor derived from pituitary gland embryonic tissue? Derived from remnants of Rathke’s pouch
Craniopharyngioma
What age groups are the ones affected (mostly) by craniopharyngiomas?
5-15years of age and 50-70
Excellent prognosis (especially if <5cm)
In craniopharyngiomas, following radiation, what can rarely develop?
A squamous cell carcinoma
What are the two types of diabetes insipidus?
- Central.
- Nephrogenic.
What is the difference between central and nephrogenic diabetes insipidus?
Central - ADH deficiency
Nephrogenic - Renal resistance to ADH effects
How many adrenal glands are there and what do they weigh?
Bilateral glands that weigh 4-5 grams each
Where do the adrenal glands sit in relation to the kidneys? What are the two regions of the adrenal glands?
They sit superiomedially to the kidneys
They have the outer cortex and the inner medulla
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/jpg/picture1-15918CB2F0F44AF927F.jpg
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/png/picture2jpg-15918CB842F736AA5E2.png
Adrenocortical (cortex) hyperplasia can occur due to congenital and acquired factors What acquired conitions can cause adrenocortical hyperplasia?
Endogenous ACTH production - Pituitary adenoma (Cushing’s disease)
Ectopic ACTH
Paraneoplastic syndrome (small cell lung carcinoma)
A deficiency in the enzyme that produces steroid hormones cortisol and aldosterone can cause congenital adrenocortical hyperplasia What is the enzyme name?
21-hydroxylase
What can a 21-hydroxylase deficiency cause other than a congenital adrenocortical hyperplasia? What does the loss of cortisol negative feedback on ACTH secretion cause? (seen in the babies)
Hypotension due to the decrease in production of aldosterone which is required for salt/water reabsorption
Causes excess androgen production which gives the baby ambiguous genitalia
Well circumscribed, encapsulated lesions Usually small – up to 2 to 3cm Yellow in colour What is this?
Adrenocortical adenoma
A rare, likely to be functional adrenal growth Can closely resemble an adrenocortical adenoma however 50% die within two years What is this?
Adrenocortical carcinoma
What are features suggestive of an adrenocortical carcinoma?
Large size (>50g, often >20cm)
Haemorrhage and necrosis
Frequent mitoses, atypical mitoses
Lack of clear cells
Capsular or vascular invasion
What disorder of aldosterone secretion is characterized by
• Increased total body sodium, ECF volume, plasma volume, BP, and pH; decreased potassium, renin and AT II activity; no edema?
Primary hyperaldosteronism (Conn syndrome) - due to an adrenal adenoma producing aldosterone
When is cushing’s syndrome known as cushing’s disease?
When the hypercortisolism is caused by an ACTH secreting pituitary adenoma
Primary adrenal insufficency can be acute or chronic, What syndrome can cause it acutely?
Waterhouse–Friderichsen syndrome (WFS)
Presents with: Adrenal hemorrhage, hypotension, DIC (disseminated intravascular coagulation) and meningitis
Waterhouse-Friderichsen syndrome (meningococcemia)
Waterhouse–Friderichsen syndrome (WFS) is defined as adrenal gland failure due to bleeding into the adrenal glands, commonly caused by severe bacterial infection.
The bacterial infection leads to massive bleeding into one or (usually) both adrenal glands.
Which bacteria typically causes waterhouse friderichson syndrome? What is the treatment of the disease?
Neisseria meningitidis
Typically IV ceftriaxone to treat the meningitis and IV hydrocortisone for addrenal support
Addison’s disease is an Insidious onset manifest once significant decreases in glucocorticoid and mineralocorticoid levels What happens to the glucose, potassium and sodium levels in the blood?
Hypoglycaemia
Hyperkalaemia
Hyponatraemia
What happens to a patients blood pressure in addison’s disease?
Due to decreased mineraloccorticoid causing decreased aldosterone an therefore decreased sdoium (and water) reabsorption, the ECF volume decreases and patient can become hypotensive
What are the two adrenal medullary tumours?
Pheochromocytoma and neuroblastoma
Usually diagnosed 18 months Cancer cells form in nerve tissue of the adrenal gland, neck, chest, or spinal cord What adrenal tumour is this?
Neuroblastoma
In neuroblastoma, the amplification of what proto-oncogene and the expression of which protein indicated a poor prognosis?
Amplification of N-myc & expression of telomerase predict a poor outcome
A neoplasm derived from chromaffin cells of the adrenal medulla that secretes catecholamines What is this and what can it cause?
Pheochromocytoma
Can cause hypertension, sweating and anxiety
What percentage of people with pheochromocytoma get hypertenison? What is the most appropriate initial test when suspecting pheochromocytoma?
90%
Tests 24 hr urinary collection of metanephrines (sensitivity 97%*) this has replaced a 24 hr urinary collection of catecholamines (sensitivity 86%)
What is the 10% rule in the pheochromocytoma?
10% are extra-adrenal
10% are bilateral
10% are biologically malignant
10% are NOT associated with hypertension
10% familial
10% found in kids
A certain labratory test can be carried out in which a chemical will turn tumour dark brown due to oxidation of catecholamines in tumour cells in a pheochromocytoma What is this chemical?
Potassium dichromate K₂Cr₂O₇
Phaeochromocytoma is a feature of multiple endocrine neoplasia (MEN2a and MEN2b) Does MEN2a or 2b involve parathyroid cancers and marfinoid habitus?
MENN2a has parathyroid cancers
MEN2b has people appear wth a marfinoid habitus
What are the three layers of the adrenal cortex?What do they produce? (mnemonic - Go Find Rex, Make Good, Sex)
- Zona Glomerulosa (outer Mineralocorticoids -> Aldosterone
- Zona Fasciculata – Glucocorticoids -> Cortisol
- Zona Reticularis – Sex Steroids + Glucocorticoids
(Go Find Rex= glomerulosa, fascicularis, reticularis Make Good Sex= mineralocorticoid, glucoortoicoid, sex)
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/png/picture2jpg-159193B4C907DA06F50.png
https://s3.amazonaws.com/classconnection/403/flashcards/11907403/png/picture1-159193B71307AA30453.png
