Addison's Disease

Question 1

what is addison’s disease?

Answer 1

• involves a defective adrenal cortex, which manifests as an impairment in the synthesis and release of glucocorticoids and mineralocorticoids
• can present insidiously or acutely as an addisonian crisis requiring immediate medical attention

Question 2

what is the aetiology of addison’s disease?

Answer 2

• autoimmune (e.g. 21-hydroxylase Ab)
• infection (e.g. TB, CMV)
• vascular (e.g. adrenal haemorrhage)
• short-term steroid use
• trauma
• adrenal tumour
• surgery (e.g. adrenalectomy)
• congenital (e.g. CAH)
  medication (e.g. ketaconazole, rifampicin, phenytoin)

Question 3

what is the pathophysiology of addison’s disease?

Answer 3

• there is a lack of adrenal hormones (e.g. glucocorticoids, mineralocorticoids, androgens) due to a failure in the adrenal cortex’s three layers – the glomerulosa, fasciculata, and reticularis
• this decrease in steroid release will provide feedback to the pituitary within the hypothalamus-pituitary-adrenal axis, thus stimulating adrenocorticotrophic hormone (ACTH) release

Question 4

what are the risk factors for addison’s disease?

Answer 4

• female
• endocrine autoimmune disorders (e.g. autoimmune thyroid disease, T1DM, coeliac disease, vitiligo)
• presence of adrenocortical antibodies
• thromboembolic or hypercoagulable states (e.g. sepsis)

Question 5

what are the symptoms of addison’s disease?

Answer 5

• hypocortisolism (e.g. fatigue, weakness, weight loss, anorexia)
• hypoandrogenism (e.g. loss of libido, loss of sexual function)
• hypoaldosteronism (e.g. nausea, vomiting, salt craving, dizziness, abdominal pain)

Question 6

what are the signs of addison’s disease on examination?

Answer 6

• mucosal and cutaneous hyperpigmentation (e.g. due to increased ACTH causing increased melanocortin receptor activation)
• orthostatic hypertension (e.g. due to hypoaldosteronism)
• tachycardia (e.g. due to hypoaldosteronism)
• loss of axillary/pubic hair (e.g. due to hypoandrogenism)

Question 7

what is an addisonion crisis?

Answer 7

• an acute, severe presentation of addison’s disease
• typical symptoms include acute onset of severe weakness, syncope, severe abdominal pain, nausea and vomiting
• examination findings include abdominal tenderness and guarding, profound hypotension, reduced consciousness and/or delirium

Question 8

what are the investigations for addison’s disease?

Answer 8

• blood glucose (e.g. hypoglycaemia)
• ECG (e.g. hyperkalaemia)
• VBG (e.g. metabolic acidosis secondary to hyperkalaemia)
• FBC (e.g. anaemia, eosinophilia, lymphocytosis)
• U&Es (e.g. hyperkalaemia, hyponatraemia)
• morning serum cortisol ↓
• random serum cortisol
• plasma ACTH ↑
• ACTH stimulation test (e.g. Synacthen)
• autoimmune antibodies (e.g. 21-hydroxylase)
• adrenal CT/MRI

Question 9

what is the long-term management of addison’s disease?

Answer 9

• oral hydrocortisone
• oral fludrocortisone
• in times of ‘stress’ when a patient with addison’s disease is suffering from trauma, surgery, or infection, glucocorticoid doses must increase
• severe stressors like an acute illness or major trauma require a parenteral dose of hydrocortisone followed by fluid resuscitation and continuous hydrocortisone treatment for 24 hours

Question 10

what is the acute management of addison’s disease?

Answer 10

• ABCDE
• if a patient presents with shock, nausea, vomiting and acute abdomen symptoms, they should be immediately treated with IV hydrocortisone
• to treat the patient’s hypotension and fluid/electrolyte imbalance, 1L of saline should be administered immediately with further fluids in the next 24 hours
• 5% dextrose as a supplement to normal saline can be administered for a patient with hypoglycaemia

Question 11

what are the long-term complications associated with long-term treatment with exogenous glucocorticoids and mineralocorticoids in addison’s disease?

Answer 11

• cushing’s syndrome (e.g. due to exogenous glucocorticoid overreplacement)
• hypertension (e.g. due to exogenous mineralocorticoid overreplacement)
• hyperkalaemia (e.g. due to exogenous mineralocorticoid overreplacement)

Question 12

what is cushing’s syndrome?

Answer 12

CUSHINGOID

C - cataracts
U - ulcers
S - striae
H - hypertension/hirsutism/hyperglycaemia
I - infection
N - necrosis (e.g. of the head of the femur)
G - glucose elevation
O - osteoporosis/obesity
I - immunosuppression
D - depression/diabetes