Specimen Name Result Units Range
Plasma Sodium 145 mmol/L (135-145)
Potassium 2.2 mmol/L (3.5-5.5)
Chloride 109 mmol/L (100-109)
Bicarbonate 27 mmol/L (22-32)
Anion Gap 11 mmol/L (7-17)
Glucose 5.4 mmol/L (3.8-5.5)
Urea 6.0 mmol/L (2.7-7.2)

23yo female with weakness following acute appendicectomy.
Familial Periodic Paralysis

NB : 3 types based upon plasma [K+]

  1. Hypokalaemic : < 3.0 mmol/L
    • inherited - familial periodic paralysis
    • acquired
    • precipitated by:
      • large meals
      • post-exercise
      • glucose/insulin infusion
      • catecholamines
    • *most common form
  2. Normokalaemic : ≈ 3.0-5.5 mmol/L
    • precipitated by alcohol, exercise and stress
  3. Hyperkalaemic : > 5.5 mmol/L
    • precipitated by:
      • exercise (? release of K+ from muscle)
      • K+ infusions
      • hypothermia (decreased activity of Na+/K+ pump)
    • usually localized to tongue and eyelids

 

Causes of Episodic Paralysis

  • myasthenia gravis
  • myasthenic syndrome
  • thyrotoxicosis
  • hyperaldosteronism
  • antibiotics
  • botulinism
  • multiple sclerosis
  • familial periodic paralysis
  • TIA, RIND
  • hysterical