Question 9.2

Created on Wed, 09/13/2017 - 18:53
Last updated on Thu, 12/07/2017 - 08:04
Pass rate: 59.2%
Highest mark: 9.5

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A 45-year-old male was admitted with life threatening shock after being involved in a motor vehicle accident, requiring emergency surgery with large volume blood loss. Post-operatively following return to ICU, he was noted to become hypotensive, febrile and oozy from various drip and operative sites. Red urine was noted. 

The following blood results were obtained: 

Parameter               Patient Value         Adult Normal Range
Haemoglobin             87 g/L*             120 - 160
White Cell Count             18.9 x 109/L*           4.0 - 11.0  
Platelet count             132 x 109/L*          150 - 350  
                                           
Sodium               138 mmol/L           135 - 145  
Potassium               4.3 mmol/L           3.5 - 5.0    
Chloride               102 mmol/L           95 - 105    
Bicarbonate             20.0 mmol/L*           22.0 - 26.0  
Glucose               5.3 mmol/L       .       3.5 - 6.0    
Urea               15.2 mmol/L*           3.0 - 8.0    
Creatinine               80 µmol/L           45 - 90    
Creatinine Kinase             2000 U/L*           55 - 170    

Urine Myoglobin: trace

Urine Haemoglobin: ++

Based on his clinical history and the lab report (shown on page 7), what is the likely cause of his post-operative deterioration? How will you confirm your diagnosis?          

(30% marks)


 

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College answer

Mismatched transfusion.

Check patient’s and donor groups and re check cross match.

Discussion

A systematic discussion of the results:

  • There is anaemia
  • The WCC is raised, consistent with ..something going on.
  • There is thrombocytopenia, which is not particularly severe
  • The electrolyte biochemistry is relatively normal, albeit with a mild acidosis
  • The urea is slightly deranged, which may be accounted for by the hypercatabolic response to trauma or dehydration intraoperatively
  • The CK is raised appropriately, given that there has been extensive muscle damage; however this level would not support the diagnosis of rhabdoimyolysis
  • The urinary myoglobin is low, which also suggests that there is no rhabdomyolysis
  • The urinary haemoglobin is high, which may demonstrate that there is intravascular haemolysis. Depending on the type of testing, this sort of result could also be produced by haematuria (i.e. the test may not discriminate between intact red cells and liberated haemoglobin)

Overall everything points to an acute haemolytic transfusion reaction. It would have been nice for the college to offer a picture; the urine of haemoglobinuria is classically bright red but translucent, in contrast to the muddy clot-filled haematuria which might result from some sort of renal trauma. 

To confirm the diagnosis, the Australian Red Cross recommends the following steps:

  • Confirm haemolysis:
    • Serum haptoglobin
    • Blood film looking for fragmented cells
  • Confirm that it is autoimmune  
    • Perform Direct Antiglobulin Test (DAT) and Indirect Antiglobulin Test (IAT),
  • Check transfusion records and document the blood products the patient had received
  • Repeat patient ABO grouping and antibody screen in both pre- and post-transfusion samples.

References