Adrenal insufficiency (Addison disease)

E27.1/E27.2

DESCRIPTION

Primary adrenocortical insufficiency.

Clinical presentation

Acute crisis: (not all symptoms and signs may occur in a particular patient, so a high index of suspicion is needed).

  • hypotension
  • depressed mentation
  • fever
  • hypoglycaemia
  • GIT disturbances
  • hyponatraemia
  • dehydration
  • hyperkalaemia
  • weakness
  • acidosis

Chronic:

  • hyperpigmentation
  • GIT disturbances
  • weakness and fatigue
  • hypotension
  • loss of weight
  • hypoglycaemia
  • postural dizziness
  • arthralgia
  • hyponatraemia
  • hyperkalaemia

Always consider this diagnosis in a thin, hypotensive, hypoglycaemic patient, or during stress e.g. sepsis. The combination of hyponatraemia and hyperkalaemia should suggest possible primary adrenal insufficiency.

Note: Treatment of suspected acute adrenal failure should never be delayed to obtain results of diagnostic procedures.

Investigations

08h00 serum cortisol level (or at time of presentation in acute crisis):

  • >500 nmol/L: virtually excludes the diagnosis
  • with newer assays cortisol concentrations >450 nmol/L are acceptable to exclude hypoadrenalism
  • 100–450 nmol/L is indeterminate and may require an adrenocorticotropic hormone (ACTH) stimulation test:

  • ACTH depot, IM, 1 mg with blood sampling at 60 minutes.
    • Post ACTH, serum cortisol level normal value: >550 nmol/L or double the pre-test level.

LoEIII [1]

GENERAL MEASURES

All patients with confirmed hypoadrenalism.

Investigate for other causes such as sepsis and treat accordingly.

MEDICINE TREATMENT

Acute crisis

E27.2

Before administering hydrocortisone, ensure blood samples are taken for serum cortisol and plasma ACTH, if feasible.

  • Hydrocortisone, IV, 100 mg 6 hourly.
    • Change to oral maintenance therapy once stable.

LoEIII [2]

To maintain adequate intravascular volume guided by blood pressure:

  • Sodium chloride 0.9%, IV with regular glucose monitoring, and 50% dextrose boluses if required.
    • Beware of fluid overload if the combination of sodium chloride 0.9%/dextrose 5% is utilised.
    • The fluid deficit is often several litres.

LoEIII [3]

Monitor glucose levels closely and treat hypoglycaemia if present.

Note: All suspected cases should be referred for full evaluation, prior to chronic maintenance therapy.

Chronic

As maintenance therapy:

  • Hydrocortisone, oral.
    • Start with 10 mg in the morning and 5 mg at night.
    • Increase the dose according to clinical response up to 20 mg in the morning and 10 mg at night.
    • In patients requiring a midday dose, a suggested regimen is 10 mg in the morning, 5 mg at midday and 5 mg in the early evening.

LoEIII

OR

  • Corticosteroids (intermediate-acting) e.g.:
  • Prednisone, oral.
    • Start with 5 mg daily.
    • Increase to maximum of 7.5 mg daily, if necessary.

LoEIII [4]

For patients who have symptoms of mineralocorticoid deficiency:

  • Fludrocortisone, oral, 50–100 mcg daily may be required to normalise the potassium and to reduce postural hypotension in primary hypoadrenalism.
    • Titrate dose of fludrocortisone in consultation with a specialist.

LoEIII [5]

Monitor response to therapy with:

  • Symptoms: improvement in fatigue and GIT disturbances.
  • Blood pressure: normotensive and no postural drop.
  • Electrolytes: normal Na+ and K+.

During times of severe “stress” i.e. acute illness, surgery, trauma, etc.:

  • Hydrocortisone, IV, 100 mg 6 hourly.

LoEIII [6]

Minor stressors e.g.: Influenza, diarrhoeal illness, chest infections and dental procedures warrant doubling of the doses of hydrocortisone for the duration of illness and gradual tapering back to usual dose.

REFERRAL

All suspected cases, for full evaluation.