📚 Module Overview
Adrenal insufficiency is a life-threatening condition resulting from inadequate production of steroid hormones, primarily cortisol and aldosterone. Addison's disease, or primary adrenal insufficiency, is the rarest but most severe form. However, iatrogenic adrenal suppression from exogenous steroid use is far more common. Misdiagnosis is frequent, and an untreated adrenal crisis is fatal. This module provides the essential knowledge for pharmacists to recognise, manage, and counsel patients effectively.
On completion of this module, you will be able to:
- Differentiate between primary, secondary, and tertiary adrenal insufficiency.
- Recognise the key signs and symptoms of Addison's disease.
- Understand the diagnostic pathway, including the role of the 9am cortisol test.
- Identify the triggers and red flag symptoms of an adrenal crisis and the immediate actions required.
- Describe the principles of glucocorticoid and mineralocorticoid replacement therapy.
- Confidently explain "sick day rules" to patients on steroid replacement.
🔄 Causes of Adrenal Insufficiency
Understanding the origin of the problem is key to management. The issue can lie with the adrenal glands themselves, the pituitary gland, or the hypothalamus.
| Type | Site of Problem | Key Causes | Hormones Affected |
|---|---|---|---|
| Primary (Addison's Disease) | Adrenal Gland | Autoimmune destruction (most common in UK), TB (most common worldwide), adrenal haemorrhage, congenital adrenal hyperplasia. | Cortisol AND Aldosterone |
| Secondary | Pituitary Gland | Pituitary tumours, surgery, or radiation leading to deficient ACTH production. | Cortisol ONLY |
| Tertiary | Hypothalamus | Prolonged exogenous steroid use (most common cause overall), traumatic brain injury, hypothalamic tumours. | Cortisol ONLY |
🕵️ Presentation & Symptoms
The presentation of Addison's disease is often insidious, with non-specific symptoms that can be easily misattributed to other conditions like depression or chronic fatigue syndrome. The mnemonic 'ADDISONS' is a helpful tool.
- A - Always tired
- D - Dizzy on standing (postural hypotension)
- D - Drop in blood pressure
- I - Inexplicable weight loss
- S - Skin colour changes (hyperpigmentation)
- O - Only eating sparingly (anorexia), Nausea
- N - No strength (muscle weakness)
- S - Salt craving, Syncope
Note: Hyperpigmentation (a bronze tan on skin, especially in creases like knuckles and palms) and salt craving are specific to primary adrenal insufficiency (Addison's) due to high ACTH and aldosterone deficiency, respectively.
🔬 Diagnosis in Primary Care
If you suspect Addison's disease in a stable patient, the key investigation is a 9am cortisol blood test.
The 9am Cortisol Test
Cortisol levels follow a diurnal rhythm, peaking around 8-9am. A blood test at this time provides the most useful information.
| 9am Cortisol Result | Interpretation & Action |
|---|---|
| < 100 nmol/L | Diagnosis highly likely. Urgent same-day referral to endocrinology is required. This is a medical emergency. |
| 100 - 400 nmol/L | Adrenal insufficiency is possible. Refer to endocrinology for a short synacthen test (ACTH stimulation test). |
| > 400 nmol/L | Diagnosis unlikely. Consider other causes for symptoms. |
🚨 Adrenal Crisis: A Medical Emergency
An adrenal crisis is a state of acute adrenal insufficiency, triggered by physiological stress in a person with underlying insufficiency. It is life-threatening and requires immediate action.
Recognition and Immediate Action
Who is at risk? Anyone with known adrenal insufficiency or on long-term, high-dose steroids.
Triggers: Infection (especially gastroenteritis), surgery, trauma, severe emotional stress.
Red Flag Symptoms:- Profound weakness, severe dizziness or collapse
- Vomiting, diarrhoea, acute abdominal pain
- Fever, confusion, drowsiness
- Hypotension (e.g., systolic BP <100 mmHg) and hypoglycaemia
- CALL 999 for emergency ambulance transfer.
- Administer 100mg Hydrocortisone INTRAMUSCULARLY immediately. Do not delay transfer waiting for a line. Use hydrocortisone sodium succinate or phosphate (e.g., Solu-Cortef), NOT hydrocortisone acetate.
This single injection can be life-saving and will not harm the patient or prevent subsequent diagnosis.
💊 Pharmacological Management
Treatment involves replacing the missing hormones. This is initiated by specialists but managed long-term in primary care.
Standard Replacement Regimen for Addison's Disease
| Hormone Replaced | Drug | Typical Adult Dose & Regimen | Key Counselling Points |
|---|---|---|---|
| Glucocorticoid (Cortisol) | Hydrocortisone | 15-25mg daily, given in 2-3 divided doses. The largest dose is given on waking (e.g., 10mg), with smaller doses at lunchtime (5mg) and late afternoon (5mg) to mimic the natural rhythm. |
|
| Mineralocorticoid (Aldosterone) | Fludrocortisone | 50-200 micrograms ONCE daily. |
|
- Patients with Addison's disease are entitled to free prescriptions (via medical exemption certificate FP92A).
- They should be issued with a Steroid Emergency Card.
- They should be encouraged to wear a MedicAlert bracelet/necklace.
- They must have an emergency injection kit (100mg hydrocortisone for IM injection) at home.
🤒 Sick Day Rules
This is one of the most critical areas for pharmacist counselling. Failure to increase steroid doses during illness is a major cause of adrenal crises.
The Double Dose Rule
The core principle is simple: if the patient is unwell with a fever or infection, they must double their daily hydrocortisone dose until they have recovered.
| Situation | Action Required |
|---|---|
| Minor illness (e.g., cold, no fever) | Continue usual hydrocortisone dose. Monitor closely. |
| Moderate illness (Fever >38°C, infection requiring antibiotics) | DOUBLE the usual daily hydrocortisone dose. (e.g., if on 10/5/5, take 20/10/10). Continue for at least 48h or until fully recovered. |
| Vomiting or Diarrhoea | If a dose is vomited within 30 mins, retake it. If vomiting persists for more than one episode or the patient cannot tolerate oral medication: Use emergency IM hydrocortisone injection (100mg) and seek immediate medical help. |
| Severe illness / Trauma / Surgery | Use emergency IM hydrocortisone injection (100mg) and go to A&E immediately. Hospital admission is required for IV steroids and fluids. |
Note: Fludrocortisone dose is NOT changed during illness.
🎯 OSCE Preparation
Counselling on Sick Day Rules
Scenario: A patient newly diagnosed with Addison's disease collects their first prescription for hydrocortisone, fludrocortisone, and an emergency injection kit. Counsel them on what to do if they get sick.
Key Communication & Counselling Steps:- Check Understanding & Set Context: "I can see you're starting new medication for Addison's. It's really important we talk about what to do when you're unwell. Your body can't make extra steroid hormone like other people's can when it's under stress from an illness."
- Explain the Core Rule Simply: "The main rule is simple: if you get ill with a fever, you need to double your daily dose of hydrocortisone. So if you normally take 20mg a day, you'll take 40mg a day, spread out as usual, until you're better."
- Address Vomiting (The Big Red Flag): "The most dangerous situation is if you are vomiting and can't keep your tablets down. This is when you must use your emergency injection. Have you been shown how to use it?"
- Demonstrate/Explain the Injection: "This kit contains a 100mg hydrocortisone injection. You (or a family member) would inject the full amount into the large muscle of your thigh. As soon as you've done that, you must call 999 or go straight to A&E. This injection is a life-saving bridge to get you to hospital safely."
- Reinforce Key Points: "So, to recap: Fever? Double your hydrocortisone. Can't keep tablets down? Inject and go to hospital. Your fludrocortisone dose always stays the same."
- Safety Netting & Teach-Back: "It's also vital you carry your new Steroid Emergency Card and wear a MedicAlert bracelet. To make sure I've explained that clearly, can you tell me what you would do if you got the flu and had a high temperature?"
⭐ Bonus: Clinical Pharmacist Case Study
The Patient: The "Tired All The Time" Consult
Patient Profile: Mrs. Evans, a 42-year-old woman, presents to the pharmacy looking tired. She mentions she's been to the GP multiple times for fatigue over the last year. She was diagnosed with depression and started on sertraline, but it hasn't helped. She looks tanned despite it being winter.
On questioning, she reveals: She feels very dizzy when she stands up, has gone off her food, and has been adding lots of salt to everything. Her blood pressure at the pharmacy kiosk is 95/60 mmHg.
Pharmacist's Thought Process & Plan
- Subjective: Chronic fatigue, dizziness, anorexia, salt craving. Unresponsive to antidepressants.
- Objective: Hypotension (95/60). Hyperpigmentation ("tan").
- Assessment:
- The constellation of chronic fatigue, postural symptoms (dizziness), hypotension, weight loss (inferred from anorexia), salt craving, and hyperpigmentation is classic for undiagnosed Addison's disease.
- The previous diagnosis of depression is a common misdiagnosis for early Addison's.
- This patient is at high risk of precipitating into an adrenal crisis. This requires urgent investigation.
- Plan:
- Action: This is not a "wait and see" situation. The pharmacist should advise the patient to see her GP the same day for an urgent assessment.
- Communication to GP (by phone or secure message): "I have seen your patient Mrs. Evans today. I am concerned she has clinical features highly suggestive of primary adrenal insufficiency. She has postural hypotension, salt craving, and marked hyperpigmentation. I have advised her to contact you for a same-day appointment for assessment and an urgent 9am cortisol test."
- Patient Counselling & Safety Netting: "Mrs. Evans, the combination of your symptoms makes me concerned about a specific hormone problem that can be treated. It's very important you see your GP today to get a specific blood test. If you suddenly feel much worse, start vomiting, or feel like you might collapse, you must call 999."