Histo: Endocrine disease Pt.3 Flashcards
What is the most common cause of secondary hyperparathyroidism?
Renal failure
- Parathyroid can be enlarged
- Leads bone disease as with primary disease
Can be caused by any condition with chronic calcium depression
List some causes of hypoparathyroidism.
- Surgical ablation
- Congenital absence
- Autoimmune
List some clinical features of hypoparathyroidism.
- Neuromuscular irritability - paresthesia, muscle spasm, tetany
- Cardiac arrhythmias
- Seizures
- Cataracts
CATs go numb
Which cell types constitute the cortex and medulla of the adrenal gland?
Cortex = epithelial
Medulla = neural
What are the layers of the adrenal cortex and which hormones do they produce?
- Glomerulosa - aldosterone
- Fasciculata - glucocorticoids
- Reticularis - sex steroids
Which conditions causes adrenal hyperfunction?
- Cushing’s syndrome - excess glucocorticoids
- Hyperaldosteronism (Conn’s)
- Virilising syndrome - excess androgens
What is the most common cause of Cushing’s syndrome?
Iatrogenic - administration of exogenous corticosteroids (leads to adrenal atrophy)
What happens to the adrenal glands in Cushing’s disease?
Undergo nodular hyperplasia of the cortex
List 4 endogenous causes of Cushing’s syndrome.
- Cushing’s disease - ACTH producing pituitary adenoma (> 50%)
- Adrenal adenoma/carcinoma
- Adrenal hyperplasia
- Ecotopic ACTH production - small cell lung cancer
What are the clinical features of Cushing’s syndrome?
- Hypertension
- Weight gain
- Truncal obesity
- Moon face
- Buffalo hump
- Cutaneous striae
What are the causes of hyperaldosteronism?
- 35% adenoma (Conn’s syndrome)
- 60% bilateral adrenal hyperplasia
List the two main clinical features of hyperaldosteronism.
- Hypertension
- Hypokalaemia
What causes virilising syndromes?
- Neoplasms (more commonly carcinoma than adenoma)
- Congenital adrenal hyperplasia
Describe the pathophysiology of congenital adrenal hyperplasia.
- Autosomal recessive
- Hereditary defect in an enzyme involved in cortisol synthesis leads to cortisol deficiency
- This leads to increased ACTH release from the pituitary gland
- ACTH stimulates adrenal hyperplasia and androgen synthesis
What is the most common cause of CAH?
21-hydroxylase deficiency
List three causes of acute primary adrenal failure.
- Sudden withdrawal of corticosteroid treatment
- Haemorrhage (neonates)
- DIC associated with sepsis (Waterhouse-Friderichson syndrome)
List some causes of chronic primary adrenal failure. (UK)
- Autoimmune (90%)
- TB
- HIV
- Metastatic tumour (lung and breast)
- Amyloid, fungal infection, haemochromatosis, sarcoid (very rare)
What are some secondary causes of adrenal insufficiency?
- Non-functional pituitary adenoma
- Pituitary/hypothalamic lesions including infarction
What are the two types of adrenocortical neoplasm?
- Adenomas - mostly functional, may be associated with Cushing’s syndrome or Conn’s syndrome
- Carcinomas - rare, more commonly associated with virilisng syndromes than adenomas
What are the two types of tumours of the adrenal medulla?
- Phaeochromocytoma
- Neuroblastoma
What is the rule of 10s regarding phaeochromocytomas?
- 10% associated with a familial syndrome (MEN)
- 10% bilateral
- 10% malignant
- 10% oustide the adrenal gland (paraganglioma)
Secrete catecholamine and causes a surgically correctable form of hypertension
Define multiple endocrine neoplasia and its inheritance.
A group of autosomal dominant conditions resulting in proliferative lesions (hyperplasia, adenoma, carcinoma) of multiple endocrine organs
Outline the characteristics of tumours in MEN.
- Tend to occur at a younger age
- Tend to arise in multiple endocrine organs or may be multifocal within one organ
- Often preceded by hyperplasia
- Usually more aggressive than sporadic tumours
What are the different types of MEN and the tumours associated with them?
