Specimen Name Result Units Range
Plasma Sodium 144 mmol/L (135-145)
Potassium 1.7 mmol/L (3.5-5.5)
Chloride 85 mmol/L (100-109)
Bicarbonate 40 mmol/L (22-32)
Urea 3.4 mmol/L (2.7-7.2)
Creatinine 80 μmol/L (60-110)
ABG pH 7.56 (7.36-7.44)
PaO2 68 mmHg (70-100)
PaCO2 44 mmHg (35-45)
HCO3- 38 mmol/L (21-26)
Urine Sodium 22 mmol/L (> 20)
Chloride 84 mmol/L
Creatinine 71 μmol/L

Adult patient with persistent hypertension.
Primary Hyperaldosteronism
  • pH : alkalaemia
  • HCO3- : metabolic origin
  • PO2 : marginal hypoxaemia, depending upon age / FiO2
  • PCO2 : inadequate compensation / combined respiratory alkalosis
    • should be >48 mmHg with respiratory compensation
  • PO2 + 1.25*PCO2 → AaDO2 > 27 mmHg if on RA

 

Conn's Syndrome

- benign adenoma of the zona glomerulosa of the adrenal cortex
- rarely due to bilateral hyperplasia or carcinoma
  1. Hypertension - mild diastolic ± headaches
  2. Hypokalaemia
    • may be severe
    • weakness ± paralysis
    • polyuria 2° nephrogenic DI
    • U waves, PVC's, arrhythmias
  3. Metabolic alkalosis
  4. Polyuria - hypokalaemic nephrogenic DI ± polydipsia
  5. Biochemistry
    • hypokalaemic metabolic alkalosis
    • hypernatraemia - Na+ retention + water loss (DI)
    • low plasma renin activity - ie. not 2° hyperaldosteronism
  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