Worthy of consideration: pericardial effusion – a differential diagnosis in maternal collapse

Pericardial effusions are the most common form of pericardial disease in pregnancy, most often presenting in the third trimester, but can be seen at any gestation.1 In 52 low risk women, effusions were seen in 15.3% in the first, 19.2% in the second and 44.2% in the third trimester, all resolved spontaneously by 6 weeks postpartum.2 Although large effusions can be well tolerated in pregnancy,1 small rapidly developing effusions ( A patient was a 35-year-old nullipara who had a normal ECHO at 23 weeks to exclude valvular dysfunction. Her pregnancy was unremarkable. She went into spontaneous labour at 40 weeks, required augmentation, but her labour arrested at 5 cm dilatation in the presence of suspected fetal distress and caesarean section advised. 20 min following an epidural top-up in theatre she became profoundly hypotensive, tachycardic, hypoxic and remained cardiovascularly unstable despite phenylephrine boluses. Her heart rate was 150/min and heart sounds clear with no murmurs or added sounds. She was peripherally vasoconstricted and her JVP could not be assessed as she was lying flat. An ECHO performed in theatre revealed RA and RV diastolic collapse and a sinusoidal contractile pattern. A 0.5–1 cm pericardial effusion was seen around RA/RV and apex. LV function and size were normal. Ultrasound guided pericardiocentesis removed 100 ml of straw coloured fluid and there was immediate cardiovascular improvement. Pericardial effusions should be considered as differential for acute cardiovascular instability in pregnancy.