Body Surface Area (BSA) is calculated from height and weight, using a validated formula. An online calculator can be found here. If height is not available, then an approximate BSA can be found via the British Society for Paediatric Endocinology and Diabetes Adrenal Insufficiency guidelines.

Physiological requirement

Physiological cortisol production is equivalent to approximately 10 mg/m²/day Hydrocortisone.

All pharmacological doses of oral steroids used in clinical practice are greater than an individual's physiological requirement. The exception to this is when a child is taking hydrocortisone for known adrenal suppression, where doses are designed to mimic normal endogenous production.

Assessing Risk

Children treated with higher than physiological dose of steroid (>10 mg/m²/day hydrocortisone, or equivalent) are at risk of secondary adrenal suppression.

Risk increases with duration of therapy: >4 weeks therapy may cause secondary adrenal suppression. Children receiving >6 months therapy should be assumed to have secondary adrenal suppression until proven otherwise.

Concurrent treatment with other forms of steroid e.g. intra-articular, inhaled, topical, nasal, eye drops will increase the risk. The absence of cushingoid appearance does not mean that the patient is not at risk of adrenal suppression. However, if a child has cushingoid appearance, he/she should be assumed to have adrenal suppression.

Children who have receive >= 6 months of steroid therapy should be assumed to have secondary adrenal insufficiency until proven otherwise.

Symptoms of adrenal insufficiency

• Significantly tired/lethargy
• Weight gain/weight loss
• Multiple and increased frequency of intercurrent illnesses (taking longer to recover)
• Adrenal crisis when unwell - hypoglycaemia, hypotension, vomiting.

All children on oral steroids and who are likely to remain on treatment for >6 months should be provided with an emergency plan for use during intercurrent illness, especially when unable to tolerate steroids due to vomiting. Note that this emergency plan should be modified during weaning process (see "Discontinuing steroids").

If a child is taking supraphysiological doses of Hydrocortisone (i.e. >30mg/m²/d) or equivalent (see "determine risk" for steroid conversions) and are tolerating oral medication, they should be advised to continue taking their normal dose of steroids. If on pulsed steroid therapy, they should continue/restart their normal dose.

If a child is taking the equivalent of <30mg/m²/d Hydrocortisone, then they should follow the British Society for Paediatric Endocrinology and Diabetes (BSPED) guidance for sick day rules during times of:

• Minor illness
• Moderate or severe illness
• Surgical and dental procedures

If any child with presumed adrenal insufficiency is:

• acutely unwell requiring hospital admission OR
• is unable to take oral mediction OR
• is receiving a surgical intervention,

then refer to the BSPED guidance on:

• Emergency management of adrenal crisis in the community
• Emergency management of adrenal crisis in hospital
• Peri- and post-operative management - major surgery
• Peri and post-operative management - minor procedures

The British Society for Paediatric Endocrinology and Diabetes (BSPED) Adrenal Insufficiency website contains a number of useful resources to ensure adequate provision of information to families. These include:

• Checklist for information education and training

• Patient information on when to give additional steroids

• Paediatric steroid care plan/adrenal insufficiency card

Normal endogenous cortisol secretion resumes in 6-8 weeks in most cases although normal secretion may not resume for 6-12 months, especially in those following prolonged periods of oral steroid treatment (i.e. >12 months) and/or those who have had concurrent treatment with other forms of steroid (eg topical, inhaled or intra-articular etc).

Nearly half of children who discontinue long term oral steroid therapy have an abnormal response to synacthen test despite a weaning regime. There are no known clinical or biochemical factors that predict those with an abnormal response - assume adrenal insufficiency until proven otherwise.

Steps to discontinuing long term steroids:

1. Wean steroid dose down to a physiological dose* (e.g. 2.5 mg/m²/day Prednisolone or equivalent) in the duration that symptoms of the underlying condition permits (or at least 4-6 weeks).
2. Convert prednisolone to hydrocortisone 10 mg/m²/day in 3 divided doses. Hydrocortisone has a shorter half-life and aids in the recovery of adrenal function.
3. Update emergency plan in accordance with BSPED guidance on sick day rules.
4. Wean HC over an 8 to 12 week period, ensuring biggest dose is given in the morning^.

* If steroid regimen involves non-daily dosing (e.g. alternate days or 10 days on/off), then wean until average dose over cycle is equivalent to physiological dose. For example, if currently on alternate day prednisolone, then wean to 5mg/m²/dose before converting to daily hydrocortisone (step 2).

^ Hydrocortisone weaning

Oral Hydrocortisone is available in a variety of forms. These include:

• 20mg tablets
• 10mg tablets
• 2.5mg mucco-adhesive buccal tablets ("Corlan" pellets)
• 2mg/1mg and 0.5mg granules in capsules ("Alkindi").

Granules are only available on a named patient basis. The most practical choice for weaning for children who are on low doses and unable to take tablets is to dissolve 10mg HC in a known quantity of water - discuss with pharmacy.

HC decrements will depend on Starting Dose (SD). The following is a suggested regimen, with example of SD 20mg HC/day given (in brackets):

Adrenal function should be assessed via a synacthen test approximately 8 weeks after discontinuing hydrocortisone.

Assume adrenal insufficiency until proven otherwise - children should have an emergency plan in accordance with BSPED guidance until normal adrenal function is demonstrated.

The synacthen test can be completed sooner i.e. after 8 weeks of weaning hydrocortisone. If doing so, omit hydrocortisone the night before and morning of the synacthen test before recommencing hydrocortisone until synacthen results are available.

Alternatively, a random early morning cortisol can be used to guide decision making. If doing so, omit hydrocortisone for 24 hours prior to the test. Early morning cortisol <40nmol/l is strongly suggestive of ongoing adrenal insufficiency, whilst cortisol >250nmol/l is suggestive of normal adrenal function.