Multiple thromboses in a late preterm infant present at birth

Background

This case presented with dramatic clinical signs immediately recognised at birth. It is a rare condition, especially when occurring spontaneously that requires prompt identification and a multidisciplinary approach.

Case presentation

A female infant was born overnight at 34 weeks’ gestation weighing 2940 gr by emergency caesarean section due to a poor cardiotocography trace (CTG) on a background of reduced fetal movements. There was a maternal history of type 1 diabetes and hypothyroidism. She was born in reasonable condition requiring a brief period of mask ventilation. It was noted immediately that her left arm (figure 1) was grossly oedematous, with necrotic patches surrounded by erythema. There was no palpable pulse, no spontaneous movement and no grasp or Moro reflex. There was an erythematous patch on her right forearm with no distal pulses, however this limb did have spontaneous movement. Of note, during stabilisation, there was a poor pulse oximetry signal on the right hand and absent on the left hand. She had skin to skin with mum before transfer to the neonatal unit for assessment. Over the next few hours, the erythema did not spread, no blisters developed and the perfusion remained poor. Apart from the appearance of the limbs, the remainder of the examination was normal and she was clinically well. She was referred to the plastic surgery team who promptly reviewed her within 3 hours of birth.

Investigations

The baby had a partial septic screen and was commenced on antibiotics. As well as a blood culture, a wound swab during the exploration was sent. An X-ray of the left arm was normal. A neonatal performed point of care ultrasound scan (USS) of the arm vessels demonstrated a colour Doppler pulse, however, we were unable to achieve a pulse wave measurement.

At this point, the plastic surgery team performed an exploration and fasciotomy which demonstrated necrotic tissues. Formal Doppler ultrasound of the left arm after the exploration demonstrated proximal brisk flow in the axillary artery (figure 2) and non-occlusive thrombus in the mid axillary artery extending to proximal brachial artery which was extremely tight in segments with barely detectable distal flow (figures 3 and 4). Ultrasound of the right arm demonstrated a non-occlusive thrombus distally just prior to the bifurcation again with negligible distal flow. Radiology commented that the thromboses was echogenic suggesting they had been present for days rather than hours.

A neonatal performed cranial ultrasound was performed prior to anticoagulation which demonstrated an echogenic area in the left parenchyma. A subsequent Magnetic Resonance Imaging (MRI) suggested this area was either a thrombus or a vascular malformation (figures 5 and 6).

In light of the differential diagnosis, an infection screen was performed. An initial full blood count demonstrated a haematocrit of 0.55, white cell count of 38 x10⁹/L and platelets of 49 x10⁹/L. A clotting screen was normal. In light of a possible inherited pro thrombotic condition, blood tests were taken from the infant and the parents. The paternal screen was normal. There was low maternal protein S (40%), however, this could be secondary to being post partum. The baby’s Protein S level was normal (64%) and the protein C level was low (19%) (lower limit normal 25%). It is unclear if this is clinically relevant.

An initial creatinine was high at 126 μmol/L, a renal USS including Doppler was normal and did not demonstrate any renal artery thrombosis.

Differential diagnosis

The initial presentation was an uncommon sight on the neonatal unit therefore the differential diagnosis was relatively broad. She was screened for infection for the possibility of a necrotising streptococcal infection. The absence of blistering made a diagnosis of epidermolysis bullosa less likely. The clinical findings pointed to a vascular insufficiency of the limbs guiding referral to plastic surgery and appropriate investigations.

Treatment

Intravenous benzylpenicillin and gentamicin were commenced which was changed to benzylpenicillin and cefotaxime when the severity of the necrosis became apparent. The plastic surgery team performed an exploration and fasciotomy under local anaesthetic at around 9 hours of age. This demonstrated some necrotic muscle and patchy infarction of skin. There was no evidence of compartment syndrome and the appearance of the tissues was not typical for necrotising fasciitis. Many multidisciplinary discussions followed at local, regional and national level including neonatology, plastic surgery, vascular surgery, haematology and interventional radiology. It was decided that endovascular options were not appropriate or safe in light of patient size and the size of available devices.

Prostacyclin was commenced for vasodilation as well as antiplatelet effect to buy time until intravenous unfractionated heparin reached therapeutic levels. The heparin was commenced 4 hours after a platelet transfusion. The first therapeutic level was achieved at 40 hours of life. The initial plan was for 2 weeks of unfractionated heparin before conversion, however, due to difficulty maintaining therapeutic levels she was transitioned to low molecular weight heparin on day 10.

She required paracetamol and morphine for initial pain management. Morphine had to be continued orally and was stopped on day 17.

She was reviewed regularly by the plastic surgery team with regular dressing changes and topical chloramphenicol ointment. The physiotherapy team developed soft-tissue massage and passive movements to be performed by parents.

Outcome and follow-up

After fasciotomy, perfusion to the distal limbs started to show improvement by 12 hours of age. A repeat Doppler ultrasound on day 4 demonstrated resolution of the thromboses and improved arterial flow.

Prior to discharge, the plastic surgery team performed a debridement and skin graft. She was discharged on low-molecular-weight heparin with regular monitoring. A repeat thrombophilia screen performed at this time was normal (protein C 36% (31–112) protein S 96% (80–116).

She continued on low-molecular-weight heparin with regular monitoring until 3 months of age where a repeat thrombophilia screen remained normal. Anticoagulation was stopped. She has been reviewed by plastic surgery and her arm has largely healed.

She was seen by the neurosurgical team and a repeat MRI has demonstrated a left developmental venous anomaly with no arterial connections.