Addisons’s disease (adrenal insufficiency)

• Rare
• Destruction of the adrenal cortex leads to glucocorticoid (cortisol) and mineralocorticoid (aldosterone) insufficiency
• Causes;
  • Autoimmune
  • TB (most common cause world wide)
  • Adrenal metastases (lung, breast and renal cancer)
  • Opportunistic infections in HIV
  • Adrenal haemorrhage – Waterhouse-Friederichsen syndrome
  • Congenital – late onset congenital adrenal hyperplasia

Symptoms

• Fatigue, weakness, anorexia, weight loss, dizziness, fainting, myalgia, athralgia, depressed mood and psychosis, nausea, vomiting, abdo pain, diarrhoea or constipation

Signs

• Hyperpigmentation due to increased ACTH look at palmer creases and buccal mucosa
• Postural hypotension

Tests

• Na low, K+ high, glucose reduced due to decreased cortisol
• Also uraemia, raised calcium, eosinophilia, anaemia

Diagnosis

• Short ACTH stimulation test;
  • Give Synacthen 250?g and measure cortisol levels before and 30mins after
  • If the second value is >550nmol/L then exclude Addison’s
  • Pregnancy and OCP increase cortisol binding globulin leading to reassuring high cortisol levels
• ACTH measurement
  • It Addison’s the 9am ACTH measurement is high
  • It is low in secondary cases
• Can also measure;
  • 21-hydroxylase adrenal autoantibodies
  • Plasma renin and aldosterone
  • AXR and CXR to look for signs of TB or calcified adrenals

Treatment

• Replace steroids – 15-25mg hydrocortisone daily in 2/3 doses – avoid giving late in the day as it causes insomnia
• Mineralocorticoid replacement may be required if N+ is low, K+ high or postural hypotension – give fludrocortisone

Steroids

• Warn against abruptly stopping steroids
• Give steroid card and bracelet declaring steroid use
• Add 5-10mg hydrocortisone to daily intake before strenuous exercise
• Double steroids in febrile illness, injury or stress
• Patients should be given syringes with hydrocortisone in and taught to administer IM themselves in case vomiting prevents oral intake
• If vomiting take hydrocortisone 100mg IM and seek medical help
• Admit for IV fluids if dehydrated

Secondary adrenal insufficiency

• The commonest cause is iatrogenic due to long term steroids leading to suppression of the pituitary-adrenal axis
• Other causes are rare and include;
  • Hypothalamic-pituitary disease leading to decreased ACTH
  • Mineralocorticoid production remains intake and there is no hyperpigmentation as ACTH is reduced

Emergency management of an Addisonian crisis

Signs and symptoms

• Patient may be in shock (tachycardia, peripheral vasoconstriction, postural hypotension, oligouria, weak, confused, comatosed
• Typically seen in a patient with known Addison’s disease or someone on long term steroids who has forgotten to take then
• Can also present with hypoglycaemia

Precipitating factors;

• Trauma, infection, surgery

Management

• If suspected treat before the biochemistry comes back
• Take blood for cortisol and ACTH if possible
• Give 100mg hydrocortisone sodium succinate IV stat
• IVI use a plasma expander first for resuscitation then 0.9% saline
• Monitor BM – there is a danger of hypoglycaemia
• Blood, urine, sputum for culture
• Give antibiotics e.g. cefuroxime 1.5g/8hr

Continuing treatment

• Glucose IV may be needed if hypoglycaemic
• Continue IV fluids more slowly
• Continue hydrocortisone sodium succinate 100mg IV/IM every 6hr
• Change to oral steroids after 72hr is the patients condition is good
• Fludrocortisone is only needed if hydrocortisone dose is <50mg/24hr and the condition is due to adrenal disease