GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY

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GLUCOSE-6-PHOSPHATE DEHYDROGENASE DEFICIENCY

• Practical IBL

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• CASE HISTORY
• A 14 years old boy was admitted to King Abdulaziz
  University Hospital complaining of headache,
  anorexia, nausea, and a severe backache. He had
  bouts of shivering, a temperature of 40.6?C.
  Malaria was suspected and confirmed by
  identification of the parasite in blood smear.
  The patient was treated by primaquine. Three days
  later the patient said that the urine was dark,
  and the following day it was almost black. He
  complained of weakness and abdominal and back
  pain. His sclerae were yellow. The treating
  doctor requested the following laboratory
  investigations on admission and 10 days later

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On admission 10 days later Normal range
Hemoglobin, g/dl 9.2 14.5 14 - 18
Red blood cells ? 1012/l 3.5 5 5
Reticulocytes, 12 4 0.5 - 1.5
Bilirubin, mol/l 340 23 2 - 14
Red cell glucose-6-phosphate dehydrogenase, units per gram hemoglobin ? ? 13 - 19
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• QUESTIONS
• Determine red cell glucose-6-phosphate
  dehydrogenase activity in units/gm Hb.
• What is the cause of changes in the laboratory
  findings?
• What is your diagnosis for such a case?
• What are the functions of glucose-6-phosphate
  dehydrogenase in different tissues?
• What are the chemical characteristics of drugs
  which would be expected to bring on a hemolytic
  crisis?
• From your knowledge in vitamins how could you
  treat this case?

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(No Transcript)
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• Glucose-6-phosphate dehydrogenase deficiency
• The disorder is X-linked and women are affected
  only if homozygous for the condition.
• G6PD deficiency does not cause any symptoms
  unless the patient takes one of a number of
  drugs, such as the anti-malarial primaquine. The
  administration of one of these grugs causes rapid
  and often severe hemolysis and jaundice.

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• Glucose-6-phosphate dehydrogenase deficiency
  (cont..,)
• In G6PD deficiency the red cells are not
  completely lacking in the enzyme younger cells
  contain some 6 of the normal amount. This is
  sufficient to provide reducing power for every
  day needs
• When, however, a drug such as primaquine is given
  the limited reducing power is overwhelmed,
  oxidation of intracellular proteins takes place
  and hemolysis, particularly of the older red
  cells, follows

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Measurement of G6PD activity
SAMPLE Blood collected in heparin, citrate or
EDTA, Avoid hemolysis
T1 (on admission) T10 (at 10 days)
Reagent 1 (buffer) 1 ml 1 ml
Reagent 2 (coenzyme) 2.5 ml 2.5 ml
Hemolysate (sample) 1 ml 1 ml
Reagent 3 (substrate) 1 ml 1 ml
Mix incubate for 10 min. at 37 0C Read the absorbance (A) of each tube at 710 nm against water Mix incubate for 10 min. at 37 0C Read the absorbance (A) of each tube at 710 nm against water Mix incubate for 10 min. at 37 0C Read the absorbance (A) of each tube at 710 nm against water
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• CALCULATION
• G6PD U/g Hb on admission (T1)
• Absorbance of T1 X 1015.9 X 1 X 1
  
• 
  9.2 10
  
• 
  (Hb) (incubation
• 
  time)
• G6PD U/g Hb at 10 days (T10)
• Absorbance of T10 X 1015.9 X 1 X 1
  
• 
  14.5 10
  
• 
  (Hb) (incubation
• 
  time)

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• Normal level of G6PD 13-19 U/g Hb
• Your result on admission U/g Hb
• Your result at 10 days U/g Hb
• Comment on your results G6PD deficiency