Specimen Name Result Units Range
Plasma Sodium 141 mmol/L (135-145)
Potassium 2.9 mmol/L (3.5-5.5)
Chloride 92 mmol/L (100-109)
Bicarbonate 35 mmol/L (22-32)
Glucose 7.6 mmol/L (3.8-5.5)
Urea 4.8 mmol/L (2.7-7.2)
Creatinine 90 μmol/L (60-110)

18yo female with gradual onset lethargy weakness.
Conn's Syndrome
  • hypokalaemic metabolic alkalosis
  • normal urea/creat → hypovolaemia unlikely
  • normal Na+ consistent with hyperaldosteronism ∝ renal 'escape'

 

Conn's Syndrome

  • benign adenoma of the zona glomerulosa of the adrenal cortex
  • rarely due to bilateral hyperplasia or carcinoma
  1. hypertension - mild diastolic hypertension ± headaches
  2. hypokalaemia
    • often severe
    • weakness ± paralysis
    • polyuria 2° nephrogenic DI
    • ECG : U-waves, PVCs, arrhythmias
  3. metabolic alkalosis
  4. polyuria ∝ hypokalaemic nephrogenic DI ± polydipsia
  5. biochemistry
    • hypokalaemic metabolic alkalosis
    • hypernatraemia : often normal /mild Na+-retention / renal DI
    • low plasma renin-activity
  6. oedema → classically absent
    • exhibit intrinsic renal "escape" from mineralocorticoid
    • may occur in longstanding cases 2° to CCF & azotaemia

 

Hypokalaemic Metabolic Alkalosis
Diuretics (esp. loop agents) - low Na+, Cl- / high urea
Mineralocorticoid excess - normal-high Na+, Cl- / normal urea
Vomiting / Gastric outlet obs. - very low Cl- / low-normal Na+ / high urea
Diarrhoea / laxatives - low Cl- / normal Na+ / high urea
Post massive transfusion - citrate metabolism & acidosis correction