Lab case 94

A 35 year old female presents to your ED complaining of weakness and lethargy. She has had previous admissions for similar complaints.


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


2 thoughts on “Lab case 94

  1. 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

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