A 45-year-old male with a history of alcohol abuse has been intubated and ventilated following an out of hospital cardiac arrest. Forty-eight hours after admission the following results were obtained:

Parameter

Patient Value

Adult Normal Range

Sodium 

134 mmol/L*

135 – 145 

Potassium  

3.3 mmol/L*

3.5 – 5.0 

Chloride 

107 mmol/L*

95 – 105 

Bicarbonate 

19.0 mmol/L*

22.0 – 26.0 

Glucose 

6.7 mmol/L*

3.5 – 6.0 

Urea 

5.9  mmol/L

3.0 – 8.0 

Creatinine  

59  μmol/L

45 – 90   

Magnesium

0.79  mmol/L

0.75 – 0.95 

Albumin 

20 g/L*

35 – 50 

Protein 

54 g/L*

60 – 80 

Total bilirubin 

82 μmol/L* 

< 26 

Aspartate aminotransferase (AST)

249 U/L* 

< 35 

Alanine aminotransferase (ALT)

41 U/L* 

< 35 

Alkaline phosphatase (ALP)

124 U/L* 

30 – 110 

-Glutamyl transferase (GGT)

481 U/L* 

< 55 

Calcium corrected 

2.26  mmol/L

2.12 – 2.62 

Phosphate 

0.49 mmol/L* 

0.80 – 1.50 

Creatinine Kinase 

114  U/L

46 – 171 

Lipase

19 U/L

< 60 

        a) Give a rationale for the results observed.                                                                       (50% marks)

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College answer

Mild hyponatraemia and hypokalemia may be secondary to fluid therapy or diuretic treatment. Mild acidosis may be secondary to initial ischaemic insult, or hyperchloraemic in the setting of fluid resuscitation. 
Low phosphate and protein may indicate pre-existing malnutrition: risk of refeeding. 
Features of liver impairment or failure with elevated total bilirubin, GGT, AST and ALT.  
High AST to ALT ratio is associated with cirrhosis. rhabdomyolysis (unlikely as CK normal). 
In this context both ischaemic liver damage (from out of hospital cardiac arrest) and alcoholic liver damage should be considered. However, the normal renal function may make ischaemic liver damage less likely. The high AST may reflect AMI as a precipitating factor for the arrest. 
 

Discussion

"Rationale for the results observed" appears to be a request for an unordered list of abnormalities, judging by the college answer. Thus, they are presented here in the format of abnormality(rationale)

  • Trivial hyponatremia (liver disease, or fluids, or diuretics)
  • Trivial hypokalemia (fluids or diuretics)
  • Mild NAGMA -anion gap is 4.7 (saline resuscitation)
  • Low albumin (liver disease or malnutrition)
  • Raised bilirubin (liver disease)
  • Trivially deranged LFTs (liver disease)
  • Low phosphate (malnutrition)

It is unclear how this tests anything.

References