Addison's disease Flashcards
Addison’s disease: primary hypoadrenalism
In Addison’s disease there is destruction of the entire adrenal cortex. Therefore the production of glucocorticoid, mineralocorticoid and sex steroids are all reduced.
The adrenal cortex usually secretes cortisol (hydrocortisone) which has glucocorticoid activity and weak mineralocorticoid activity. Aldosterone which is a mineralocorticoid is also secreted.
Causes
- autoimmune disease
- tuberculosis
- haemorrhage/infarction
- infiltration
- Schilder’s disease
- surgical removal of adrenal gland
Clinical features
Symptomatology is often vague and non-specific, with symptoms similar to many other diseases. Initial symptoms may include weight loss (unintentional), malaise, muscle weakness, depression / low mood, increased thirst, and increased increased urination.
Further signs can include postural hypotension, nausea and vomiting, muscle cramps and pigmentation especially of new scars and palmar creases.
If left untreated and hormone levels continue to fall, symptoms can worsen and may lead to an Addisonian crisis which is life threatening. In an Addisonian crisis, patients will present with severe symptoms which have developed quickly. The symptoms of a crisis include; dehydration, pale and clammy skin, sweating, severe vomiting and diarrhoea, severe muscle cramping and weakness.
Diagnosis
When a patient presents acutely, the diagnosis must be made quickly and treatment initiated. Diagnosis is made taking into account the clinical features and results from tests. These include: • Biochemical abnormalities • Serum cortisol • Short tetracosactrin test • Other tests / investigations for cause
Treatment
-Maintenance treatment is with long-term corticosteroid replacement therapy. It is important to replace both the glucocorticoid and mineralocorticoid- cortisol and
aldosterone.
-Giving hydrocortisone alone does not provide sufficient mineralocorticoid activity and therefore fludrocortisone is given as well to ensure complete replacement.
-Hydrocortisone is often given in two divided doses, the larger in the morning and the smaller in the evening, mimicking the normal diurnal rhythm of cortisol secretion.
-Dehydroepiandrosterone (DHEA) replacement has also
been used as treatment but results from studies have been conflicting.
-Acute hypoadrenalism needs urgent emergency treatment; patients will be admitted to hospital and administered intravenous fluids and intravenous hydrocortisone.
-In some cases patients and members of their family may be trained to administer hydrocortisone injections at home in the event of an emergency.
Patient advice and counselling
- Carry a steroid card
- Advise on how to take steroid replacement therapy
- Wear a warning/alert bracelet
- Know how to increase your steroid replacement dose if suffering intercurrent illness
- Keep an emergency supply of hydrocortisone injection
Glucocorticoid replacement
Hydrocortisone is usually used, but longer-acting glucocorticoids, such as prednisolone and dexamethasone, are sometimes used to avoid the peaks and troughs which may occur with hydrocortisone.
The daily adult dosage of hydrocortisone is usually 15–30 mg in divided doses. Dosage depends on body weight, metabolism, and absorption.
Ideally glucocorticoid replacement should resemble the natural cycle of corticosteroid release. Three divided doses are usually given (for example 10 mg on waking, 5 mg at noon, and 5 mg in the early evening), as this aims to provide even levels of glucocorticoid throughout the day.
- Dosages in children are usually in the region of 8–10 mg/m2 daily in three divided doses, although the total daily dose may be divided into a larger morning dose and a smaller evening dose
Mineralocorticoid replacement
Fludrocortisone, which has 125 times the mineralocorticoid action of hydrocortisone, is usually used.
The daily adult dosage of fludrocortisone is usually 50–300 micrograms. Dosage depends on metabolism and exercise levels.
Androgen replacement
Dehydroepiandrosterone (DHEA) is an androgen made in the adrenal cortex; therefore, levels are decreased in Addison’s disease. DHEA replacement (unlicensed) may be prescribed by some specialists.
How should I manage a suspected adrenal crisis?
If an adrenal crisis is suspected, arrange emergency admission to hospital. Do not delay admission by doing diagnostic tests.
Give the person hydrocortisone intramuscularly or intravenously (if not already self-administered) and stabilise with an intravenous saline infusion (if available) before transfer to hospital.
The preferred formulations of hydrocortisone are:
- Hydrocortisone sodium phosphate (Efcortesol®). This is licensed for the treatment of adrenal crisis and may be more suitable for self-injection kits because it is a solution and does not require reconstitution. However, there is a risk of pain and paraesthesia on intravenous injection and it is not recommended for use in children.
- Hydrocortisone sodium succinate (Solu-Cortef®). This is licensed for treating adrenal crisis, but it is in powder form requiring reconstitution and so may be less suitable
The dose of hydrocortisone depends on the person’s age.
-Adults: 100 mg.
-Children 6 years of age or older: 50 mg to 100 mg (use clinical judgement depending on the age and size of the child).
-Children 1–5 years of age: 50 mg.
Infants up to 1 year of age: 25 mg.
Emergency administration of fludrocortisone is not required because high-dose hydrocortisone has a mineralocorticoid effect.
What should not be used to treat adrenal crisis
Do not use hydrocortisone acetate injection
How should I advise a person with Addison’s disease who is to undergo a dental procedure?
- Dental surgery without general anaesthetic (for example root canal work with local anaesthetic). The glucocorticoid dose should be doubled (up to 20 mg hydrocortisone) 1 hour before surgery. After the procedure, the dose of oral medication should be doubled for 24 hours, then returned to the normal dose.
- Minor dental procedures (for example replacement filling) — extra glucocorticoid is not usually needed. An extra dose is only needed after the procedure if the person experiences hypoadrenal symptoms.
How should the corticosteroid dose be adjusted during intercurrent illness or exercise to prevent adrenal crisis?
- The person should double the normal dose of hydrocortisone (or alternative glucocorticoid) if they have a fever or are prescribed antibiotics for an infection until they are recovered.
- The person should take 20 mg hydrocortisone orally and sip oral rehydration solution (such as Dioralyte®) if they experience severe nausea (often with headache). If they are taking an alternative glucocorticoid (such as dexamethasone or prednisolone), consult their care plan, or seek advice from an endocrinologist regarding the dose.
- If the person has vomited, they should use their emergency hydrocortisone injection and seek immediate medical advice, emphasizing that it is an Addison’s disease emergency — early self-administration of hydrocortisone intramuscularly will often stabilize an episode of vomiting or diarrhoea.
- After major injury, the person should take 20 mg hydrocortisone orally. If they are taking an alternative glucocorticoid (such as dexamethasone or prednisolone), consult their care plan, or seek advice from an endocrinologist regarding the dose.
- If the person has diarrhoea, seek specialist advice from their endocrinologist as to whether the glucocorticoid dose needs to be adjusted.
- If the person is undertaking strenuous exercise (such as a marathon), they will need to increase their medication. Up to double the normal dose of glucocorticoid and mineralocorticoid and increasing fluid intake is suggested.
- If a less strenuous activity (such as hiking) is being undertaken, the person should add 5 mg to 10 mg hydrocortisone to their normal regimen shortly before the activity. If they are taking an alternative glucocorticoid (such as dexamethasone or prednisolone), consult their care plan, or seek advice from an endocrinologist regarding the dose.
