Specimen Name Result Units Range
Plasma Sodium 118 mmol/L (135-145)
Potassium 5.7 mmol/L (3.5-5.5)
Chloride 91 mmol/L (100-109)
Bicarbonate 21 mmol/L (22-32)
Glucose 5.5 mmol/L (3.8-5.5)
Urea 16.0 mmol/L (2.7-7.2)
Creatinine 140 μmol/L (60-110)

52yo female with abdominal pain weakness and confusion.
Addison's Disease / Crisis

Electrolyte changes:

  • Hyponatraemia > 90%
  • Hyperkalaemia > 70%
  • Hypo-osmolality
  • Hypoglycaemia
  • Mild uraemia
  • Mild metabolic acidosis 2° to AKI
    (normal or mild raised AG>

General Features:

  • Weakness / fatigue - 100%
  • Hyperpigmentation > 90%
  • Hypotension > 90%
  • Hypovolaemia
  • Vomiting, diarrhoea, abmoninal pain > 60%

Aetiology:

  1. Primary adrenal insufficiency
    • Autoimmune - Addison's disease
    • Surgical removal - e.g. breast Ca
    • Infection
      • TB
      • over-whelming sepsis
      • histoplasmosis, cryptococcus, coccidioidomycosis
      • viral - esp. in AIDS
    • Haemorrhagic/coagulopathic necrosis
      • Waterhouse-Friderichsen syndrome
      • Pseudomonas, menningococcus (esp. children)
      • peripartum
      • anticoagulant Rx
    • Rare causes
      • bilateral metastatic Ca
      • amyloidosis
      • sarcoidosis
  2. Secondary adrenal insufficiency
    • Hypopituitary syndromes
    • Pituitary suppression
      • exogenous steroids (*most common)
      • steroid secreting tumours
  3. Interference with hormone synthesis
    • Congenital hypoplasia - C21, C11, C17
      • C21-hydroxylase - adrenal virulization & hypoaldosteronism
      • C11-hydroxylase - adrenal virulization & hypertension
    • Enzyme inhibitors
      • metyrapone, mitotane
      • aminoglutethamide
      • ketoconazole
    • Cytotoxics

Causes of hyponatraemia & hyperkalaemia (Na+:K+ ratio < 25:1):

  • Addison's - hypo-osmolar, mild uraemia
  • K+-sparing diuretics
  • DKA - hyper-osmolar, hyperglycaemia
  • Renal failure - esp. salt-losing nephritis, hypo-osmolar & uraemia
  • ACE Inhibitors (rarely) - **Entresto®