Case Report
A 26-year-old Caucasian primigravid woman presented at 38 weeks and 4
days after the onset of spontaneous labour. She did not have any medical
conditions and was not on regular medications prior to pregnancy. She
had an uneventful antenatal course, with well managed hypothyroidism and
iron deficiency anaemia. Ultrasound at the 34th week of gestation was
within reference ranges, with an estimated foetal weight of 2.8 kg
(85th percentile). She had no known drug allergies or
history of hay fever, asthma or eczema. However, had a strong family
history of atopy on her maternal side. Drug doses were administered as
per hospital guidelines.
After 2.5 hours of an uncomplicated first stage of labour, she required
10 units of intravenous (IV) Syntocinon (as per hospital protocol)
augmentation during the second stage of labour. Cardiotocography showed
a baseline foetal heart rate of 140 beats per minute, normal
variability, and recurrent variable decelerations. Eight minutes later,
she complained of facial oedema, the Syntocinon infusion was immediately
ceased. Over the next ten minutes, the facial swelling subsided with
stable vital signs. Due to prolonged foetal bradycardia down to 80 beats
per minute, mediolateral episiotomy and vacuum extraction was performed.
This was complicated by one minute of shoulder dystocia which was
managed using the McRoberts manoeuvre. An infant weighing 4.1 kg was
born in good condition, with Apgar scores of 8 and 9 at 1 and 5 minutes,
respectively. To augment delivery of the placenta, 10 units of
intramuscular (IM) Syntocinon was administered. However, postpartum
haemorrhage (PPH) developed shortly afterwards due to uterine atony and
a fourth-degree vaginal tear, with an estimated blood loss of 2 litres.
This was controlled with IV fluid resuscitation, 1g of IV tranexamic
acid, and 250mcg of IV and IM doses of ergometrine, with a plan to
repair the fourth-degree tear urgently in the operating theatre. Sixteen
minutes later, there was worsening throat discomfort and chest
tightness. The midwife noted facial oedema, patchy erythema on her back,
increased work of breathing, and dysphonia. No gastrointestinal symptoms
or urticaria were noted. Anaphylaxis was suspected and a rapid response
was initiated. Oxygen was administered through a non-rebreather mask at
15 litres/minute. Vital signs were stabilised with an oxygen saturation
of 100%, blood pressure of 140/84 mmHg (systolic blood
pressure/diastolic blood pressure), heart rate of 108 beats/min, and
respiratory rate of 16 breaths/minute. Electrocardiography (ECG)
demonstrated sinus tachycardia with no concerning features. Two 500mcg
doses of IM 1:1000 adrenaline and 200mg of IV Hydrocortisone were
administered, the airway was stabilised with endotracheal tube
intubation in the operating theatre. Of note, no laryngeal swelling was
visualised during intubation by the Anaesthesiologist.
The patient was transferred to the intensive care unit (ICU) after the
operation. She was extubated six hours later with a patent airway and no
increased work of breathing. The results of serial tryptase
measurements, absolute basophils, serum immunoglobulin-E (IgE), and
complement C3 and C4 levels post-surgery were all within normal limits
(Table 1). Serum electrolytes were normal throughout her admission.
Mobile chest x-ray immediately post-surgery demonstrated extensive
subcutaneous emphysema, but no other significant abnormalities. She
recovered well in ICU with 24 hours of 4mg IV dexamethasone three times
per day, and 2 units of packed red blood cells due to haemorrhage. She
was discharged from the hospital after a four-day admission.