Surgical causes of acute abdominal pain in pregnancy

M R C O G PA R T 2 · S O S P O C K E T C A R D · K N O W L E D G E A R E A 5 – A N T E N ATA L C A R E

Surgical Causes of Acute Abdominal Pain in Pregnancy Woodhead N et al. Surgical causes of acute abdominal pain in pregnancy. TOG 2019;21:27–35. doi:10.1111/tog.12536

1:500–635 1:800–1500 ~3/yr INCIDENCE OF ACUTE ABDOMEN IN APPENDICITIS IN PREGNANCY UK MATERNAL DEATHS FROM INTRA- PREGNANCY ABDOMINAL PATHOLOGY

DO N' T-M IS S FA C TS

  1. Fall in blood pressure is a late sign of hypovolaemic shock in pregnancy – earliest signs are mild tachycardia, tachypnoea, narrowed pulse pressure, agitation

  2. Normal pregnancy hydronephrosis: up to 5 mm (left) / 15 mm (right) pelvicalyceal diameter; ureteric dilatation up to 2 cm in 3rd trimester

  3. Aneurysm rupture: incidence rate ratio 4.0 (95% CI 2.0–8.2) in pregnancy; manage with permissive hypotension, prefer open repair; splenic artery aneurysm commonest (up to 95% present in pregnancy)

  4. Appendicitis MRI: sensitivity 91%, specificity 98%; peaks 2nd trimester, perforation more common 3rd trimester

  5. CT abdo/pelvis fetal dose up to 30–50 mGy; organogenesis window 5–15 weeks most radiosensitive; MRI preferred (no ionising radiation)

  6. Antenatal corticosteroids 24–34+6 weeks before surgery; left lateral tilt after 20 weeks; anti-D if RhD-negative and uterine manipulation

  7. Avoid NSAIDs for analgesia; surgery risks: miscarriage 0.7%, preterm labour 3.2%

  8. Lactate >4 mmol/l = severe sepsis; CRP normal upper limit in pregnancy 20 mg/l

CONDITION FREQUENCY AT A GLANCE

Appendicitis 1:800–1500 Cholecystitis 1–6:1000 Bowel obstruction ~1:1500 Pancreatitis 3:10,000

ABBREVIATION KEY

ABCDE — airway, breathing, circulation, disability, exposure CT — computed tomography

MI — myocardial infarction MRI — magnetic resonance imaging

GORD — gastro-oesophageal reflux disease CBD — common bile duct

ECG — electrocardiogram ERCP — endoscopic retrograde cholangiopancreatography

CRP — C-reactive protein VTE — venous thromboembolism

GFR — glomerular filtration rate CI — confidence interval

ABG — arterial blood gas DKA — diabetic ketoacidosis

mGy — milligray HELLP — haemolysis, elevated liver enzymes, low platelets

Source: The Obstetrician & Gynaecologist (TOG), RCOG journal — Woodhead N et al. Surgical causes of acute abdominal pain in pregnancy. TOG 2019;21:27–35. doi:10.1111/tog.12536

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