A 35 year old female presents to your ED complaining of weakness and lethargy. She has had previous admissions for similar complaints.
vitals:
BP 124/80
PR 90/min
RR 24/min
Blood tests show:
pH 7.56 (7.36-7.44)
pCO2 54 (35-45 mmHg)
HCO3 50 (22-26 mmol/l)
BE 25 (0+/-2)
Sodium 133 (136-145 mmol/l)
Potassium 1.6 (3.5-5 mmol/l)
Chloride 75 (99-111 mmol/l)
Glucose 4.0 (4-6 mmol/l)
Lactate 2.9 (<2 mmol/l)
Magnesium 0.73 (0.7-1.2)
Urea 3.8 (3-8 mmol/l)
Creatinine 68 (30-100umol/l)
Describe at least 5 important abnormalities
Interpret the abnormalities
Give four reasonable differential diagnosis
What is the most likely cause of death if untreated
metabolic alkalosis
appropriately compensated resp acidosis (expected pCO2: 56)
severe hyperkalemia (1.6), even when correcting for pH (2.2)
magnesium just within normal limits: not the driver of hypokalemia
borderline hypoglycaemia
DDx: chronic vomiting (?occult/self-induced), diuretic abuse, milk alkali syndrome (but may expect high Ca or Mg). cortisol excess could explain low K and alkalosis but does not fit with hypoglycaemia and presenting history. The reverse is true for Addison’s.
hypokalemia is the immediate life threat.
Good work
Anything other conditions that might give you severe hypokalaemia, low chloride, low sodium and alkalosis?
Answer will be posted next week