Question 23

College answer

Syllabus topic/section:

2.1.12 Obstetric Intensive Care / Special considerations when managing the obstetric patient: L1
2.1.12 Obstetric Intensive Care / Amniotic fluid embolism: L1
2.1.5 Respiratory Intensive Care / Pulmonary embolism: L1

Discussion:  

This was a core intensive care topic where some candidates achieved the standard required to a very high degree. Answers were rewarded for demonstrating depth of understanding of assessment for a differential diagnosis. Many candidates could have improved marks by articulating helpful Echo and CXR findings which are highly discriminatory investigations.
Precise terminology gained marks, for example, describing echo findings such as LVEF parameters for peripartum cardiomyopathy, as well as typical patterns on ECGs for amniotic fluid/ pulmonary embolism. Some answers were clearly rushed; candidates are reminded to proportion their time wisely.

Discussion

a) Six most likely differentials? for a postpartum patient immediately following delivery?

• Postpartum haemorrhage would have to be at the top of the list
• PE would have to be next
• Amniotic fluid embolism 
• Peripartum cardiomyopathy
• Sepsis 
• Complication of pre-existing rheumatic heart disease (MR, TR)

Other possibilities, some of which offer only patchy coverage of the clinical features from the stem, could include:

• Pre-existing unrecognized congenital heart disease
• Pre-existing idiopathic dilated cardiomyopathy (IDC) unmasked by pregnancy
• Pregnancy-associated myocardial infarction
• Complication of tocolytic therapy or of the spinal/epidural
• Air embolism from the uterine veins
• Anaphylaxis
• Transfusion reaction
• Aspiration pneumonia

b):

What if you didn't tabulate your answers? Surely that would still make it possible to "achieve the standard required to a very high degree."  Especially if you listed the ECG changes associated with AFE and PE. How much to write, of course, becomes the limiting factor, if one does in fact possess all the detailed knowledge required. The suggestion that specific LVEF parameters may need to be quoted to score maximum marks may seem somewhat farfetched, but in fact there is historical precedent for this: Question 28 from the first paper of 2017 asked specifically for diagnostic criteria of peripartum cardiomyopathy. In case everyone forgot, those were LV ejection fraction < 45% and/or fractional shortening < 30%. But there are seven marks and six differentials to cover, which means writing, on average, no more than 23 words on each. What follows is a crazed attempt to fit within this limited wordcount:

• Postpartum haemorrhage
  • Clinical features:
    • PV blood loss, abdominal distension, clinical features of hypovolaemia
  • Investigations:
    • ABG for lactate and Hb, FBC, G&H, c​​​​​​oags, TEG
• PE:
  • Clinical features:
    • Leg swelling (DVT), RV heave, split S2, raised JVP,  normal lung auscultation, TR murmur
  • Investigations:
    • Troponin, CTPA, CXR (NAD), TTE (RV dilation), ECG pattern: S1Q3T3 and RBBB
• Amniotic fluid embolism 
  • ​​​​​​​​​​​​​​Clinical features:
    • Petechial rash, creps on auscultation, seizures
  • Investigations:
    • Coags (DIC), CTPA (no PE),  CXR (looks like ARDS), TTE (RV dilation), ECG pattern: S1Q3T3 and RBBB
• Peripartum cardiomyopathy
  • ​​​​​​​​​​​​​​Clinical features:
    • Coarse creps, apex beat displaced, raised JVP, no murmur usually
  • Investigations:
    • ​​​​​​​Troponin, proBNP, TTE (EF<45%), APO on CXR
• Sepsis 
  • ​​​​​​​​​​​​​​Clinical features:
    • Fever, wide pulse pressure, hyperdynamic circulation, discharge/sputum/malodorous urine/ infected cannula
  • Investigations:
    • ​​​​​​​Raised inflammatory markers, positive blood cultures, normal-looking TTE
• Rheumatic heart disease (MR, TR)
  • ​​​​​​​​​​​​​​Clinical features:
    • Raised JVP, murmur, may or may not have creps
  • Investigations:
    • ​​​​​​​​​​​​​​Troponin, proBNP, TTE (MR or MS are the usual culprits)