Pathology: Glucocorticoidand mineralocorticoid deficiency due to failure of adrenal glands.
Aetiology: Autoimmune - 90% of cases
Infections - TB, HIV
Congenital - Congenital Adrenal Hyperplasia
Malignancy – Lymphoma, metastasis
Infiltration - Amyloidosis or sarcoidosis
Vascular – Haemorrhage, infarction, anticoagulants,meningococcal sepsis
(Waterhouse-Friderichsen Syndrome), antiphospholipidsyndrome.
Iatrogenic – Adrenalectomy
Drugs – Ketoconazole, busulfan, methadone
Symptoms: Fatigue, weight loss, nausea,poor appetite, dizziness
Addisonian Crisis: Fever, vomiting, abdominal pain, hypotension,tachycardia,
collapse, coma andhypovolaemic shock
Signs: Hyperpigmentation,postural hypotension, muscle wasting, vitiligo
Investigations: Bloods:Hyponatraemia, hyperkalaemia, hypoglycaemia, TFTs, Coeliac screen,
serum cortisol (low), serum ACTH (raised), short synacthentest
Imaging: Chest X-ray,CT adrenals, bone density scan to monitor osteoporosis
Treatment: Hydrocortisone 10-20mg/day individed doses – should be doubled when ill
Fludrocortisone 0.05-0.2 mg/day
Addisonian Crisis Treatment (5S’s)- Salt (saline), Sugar (Dextrose), Steroids,
Support, Search forprecipitating cause
Complications: Adrenal crisis at presentation/intercurrentillness, steroid over-replacement, other autoimmune conditions
Prognosis: Life expectancy reduced by10-20 years. Steroid over-replacement leads to increased morbidity
Synacthen Test
Underlying Pathology
Short
Long
Cortisol ↑
Cortisol ↑
No abnormalities.
Synacthen is an ACTH analogue so will increase normal Cortisol production
No change
Cortisol ↑
Secondary Hypoadrenalism
No change
No change
Primary Hypoadrenalism (Addison’s Disease)
Figure 5.6 SynacthenTest Results. Short and Long test can help differentiate between Primary
(Addison’s) or Secondary Hypoadrenalism
Pathology: ACTHdeficiency as part of hypopituitarism
Aetiology: Iatrogenic – Long term steroid therapyleading to hypothalamic-pituitary-
adrenal suppression
ACTH Disorder: Any pituitary or hypothalamicdisorder which causes a
reduction in ACTH
Symptoms: Fatigue, weight loss, nausea,poor appetite, dizziness
Signs: Posturalhypotension, muscle wasting, vitiligo
Investigations: Bloods:Hypoglycaemia, TFTs, serum cortisol (low), serum ACTH (low), short
and long synacthentest
Treatment: Hydrocortisone 10-20mg/day individed doses
Complications: Steroid over-replacement
Prognosis: If due to steroid overreplacement, then adrenal glands will recover following steroid withdrawal
