Endocrinology Flashcards
What is primary adrenal insufficiency commonly known as?
Addison’s disease
Addison’s disease is characterized by destruction of the adrenal cortex, leading to deficiencies in cortisol and aldosterone.
What leads to the hyperpigmentation seen in Addison’s disease?
Increased CRH and ACTH production due to reduced cortisol levels
The feedback mechanism causes elevated levels of ACTH, which can stimulate melanin production.
What is the incidence of Addison’s disease?
3-4 million per year
The prevalence of Addison’s disease is estimated to be between 40-60 million per year.
What is the most common cause of primary adrenal insufficiency in the western world?
Autoimmune destruction of the adrenal cortex
This condition is more common in women, with autoantibodies targeting steroid biosynthesis enzymes.
Name three causes of primary adrenal insufficiency.
- Autoimmune destruction
- Tuberculosis
- Rare causes (e.g., adrenal hemorrhage, malignant metastasis)
Autoimmune destruction is the leading cause in the western world.
What are the clinical features of Addison’s disease?
- Weight loss
- Malaise
- Weakness
- Nausea and vomiting
- Abdominal pain
- Confusion
- Fainting
Symptoms can vary widely, leading to late diagnosis.
What is an Addisonian crisis?
A life-threatening presentation of Addison’s disease
It often occurs due to the sudden withdrawal of exogenous steroids.
What are common symptoms of an Addisonian crisis?
- Hypotension
- Dehydration
- Confusion
- Hyponatraemia
- Hypoglycaemia
These symptoms are critical and require immediate medical attention.
What are some signs of chronic Addison’s disease?
- Loss of weight
- General wasting
- Pigmentation (palmar creases, buccal mucosa)
- Postural hypotension
- Dehydration
Signs can be very subtle and may overlap with other conditions.
What blood test results may indicate adrenal insufficiency?
- Hyponatraemia
- Hyperkalaemia
- Elevated urea and creatinine
These abnormalities occur due to mineralocorticoid deficiency.
What is the purpose of the Synacthen test?
To assess adrenal function by measuring cortisol response to synthetic ACTH
A lack of cortisol response can indicate primary adrenal insufficiency.
What is the management for adrenal insufficiency?
- Mineralocorticoid replacement (fludrocortisone)
- Glucocorticoid replacement (hydrocortisone)
- IV hydrocortisone and fluid rehydration during Addisonian crisis
Hormone replacement is crucial for managing adrenal insufficiency.
What is secondary adrenal insufficiency primarily caused by?
Iatrogenic causes from long-term steroid therapy
This leads to suppression of the pituitary-adrenal axis.
True or False: Secondary adrenal insufficiency results in hyperpigmentation.
False
In secondary adrenal insufficiency, ACTH is not produced, hence no hyperpigmentation occurs.
What is the definition of Cushing’s syndrome?
Chronic glucocorticoid excess + loss of the normal feedback mechanisms of the HPA axis and loss of circadian rhythm of cortisol secretion.
What is the most common cause of Cushing’s syndrome?
Exogenous administration of steroids.
What are the rare endogenous causes of Cushing’s syndrome?
Endogenous causes are rare.
What is the annual epidemiology rate of Cushing’s syndrome?
3 million per year.
What are the two classifications of Cushing’s syndrome?
- ACTH-dependent
- ACTH-independent
What is Cushing’s disease?
A pituitary adenoma resulting in corticotrophs releasing excess ACTH.
What is ectopic ACTH production?
It manifests as a paraneoplastic syndrome in a number of malignancies such as small-cell lung cancer.
What are the primary causes of ACTH-independent Cushing’s syndrome?
- Primary cortisol secreting adrenal tumours (adenomas and carcinomas)
- Hyperplasia
What are common symptoms of Cushing’s syndrome?
- Tiredness
- Depression
- Weight gain (central)
- Easy bruising
- Back pain
- Amenorrhoea
- Reduced libido
What are the signs of Cushing’s syndrome?
- Acne
- Moon face (cushingoid facies)
- ‘Buffalo hump’
- Central obesity
- Hyperpigmentation (in ACTH dependent)
- Proximal muscle wasting
