Question 21.3

College answer

Syllabus topic/section:

2.1.6 Gastrointestinal Intensive Care / Acute hepatic failure: L1
2.1.5 Renal Intensive Care / Acid base and electrolyte disorders: L1
2.1.11 Haematological and Obstetric Intensive Care / Anaemia: L1
2.1.12 Obstetric Intensive Care: / Physiological change related to pregnancy: L1

Discussion:  

This was a repeat data interpretation question. Surprisingly the pass rate was low for this question. Lower scores were associated with not being specific about causes of hyperammonemia, but rather listed causes of hepatic dysfunction. A lack of synthesis of findings was also a feature of the answers failing to reach the standard required.

Discussion

This was a repeat of  Question 9.3 from the first paper of 2017. Note that these days the examiners would never ask the trainees to "indicate the change you would anticipate"; this question would have a appeared as an "outline" or "list" instead. The college answer in 2017 was:
 

a) Platelet count: Decrease

b) Factors V, VII, IX, X level: Increase

c) Fibrinogen level: Increase

d) Protein S level: Decrease

The overall trend in pregnancy is towards hypercoagulability. In the third trimester, coagulation activity is about double that of normal. The best source to read further is probably the 2003 article by Katarina Bremme.

In brief:

• Platelet count decreases, particularly in late pregnancy
  • Normal pregnancy is associated with a degree of enhanced platelet destruction which is compensated for by increased production
  • The destruction takes place in the uteroplacental circulation
• Factors VII, VIII, IX, X, XII and von Willebrand factor increase significantly; Factor VII may increase as much as tenfold.
• Factor XI decreases down to 60–70% of the non-pregnant value
• Factors II and V do not change in pregnancy
• Fibrinogen levels increase throughout pregnancy
• Protein S levels decrease progressively during pregnancy
• Protein C activity is unaffected by pregnancy
• Plasma fibrinolytic activity decreases throughout pregnancy, but returns to normal within one hour of delivery. This is due to synthesis of plasminogen activator inhibitor-1 and -2 by the placenta