NEONATAL SOCIETY ABSTRACTS
Shoulder dystocia: Patterns of brain injury seen in term infants presenting with neurological signs
Presented at the Neonatal Society 2006 Summer Meeting (programme).
Ziprin J1, Rutherford M2, Cowan F1
1 Department of Paediatrics, Imperial College London, Hammersmith Hospital, London, UK
2 Robert Steiner MR Unit, Imaging Sciences Department, Imperial College London, Hammersmith Hospital, London, UK
Aim: There is little information regarding the outcome of infants with shoulder dystocia beyond the description of brachial plexus injuries. We present our perinatal data, brain MRI findings and outcome in such a group of babies.
Subjects/methods: Term infants with shoulder dystocia, neurological signs in the neonatal period and a subsequent brain MRI presenting between 1992-2005 were included in the study. Detailed data on family history, antenatal and perinatal events and neonatal parameters were collected as well as brain MRI findings (mean age 1st scan 7 days) and neurodevelopmental outcome. All scans had ethics approval from the HH NHS Trust and parental permission.
Results: 34 infants (20 male) fulfilled the criteria. Fifteen had stage II (Sarnat) encephalopathy, 12 stage III and 7 seizures alone. Seventeen mothers were primiparous, four had diabetes and one had glycosuria. Eight infants were delivered by ventouse, five by forceps, five had a failed attempt at ventouse and 22 had a non-instrumental delivery. Mean time of dystocia was 6.2mins (SD 3.3); 7 infants had a nuchal cord, 18 needed major resuscitation. Mean cord pH was 7.04 (SD 0.2) in severe and 7.23 (SD 0.07) in the normal/ mild outcome group. Mean GA 39.8 (SD 1.5), mean BW/centile 4.2kg (SD0.8)/86 (SD 18), mean HC/centile 35.8cm (SD 1.5)/77 (SD 22). Thirty infants had seizures, 3 transient hypoglycaemia and 9 an Erb`s palsy. Seizures (all day 1) were attributed to HIE (22), focal infarction (2), haemorrhage (4) uncertain (2).
MRI scans: Normal (3); severe basal ganglia (BG), thalamic and white matter (WM) injury (12), 7 of whom also had extracerebral haemorrhage. Mild abnormality in BG (2), WM (5) and BG+WM (3) and one infarction were also associated with haemorrhage; haemorrhage and infarction were isolated in 4 each. Ventouse use was associated with haemorrhage in 6 and infarction in a further 4 infants. Fetal distress was evident in 11/14 with a severe outcome.
Follow up: mean age 40m (SD 22). Seven infants died early: 5 had severe BGT/WM injury, one had a large subdural and one an infarction; all surviving severe BGT/WM infants and one with extensive infarction had severe neurological sequelae. Six infants had mild motor disorders, two with language delay; another two had a severe communication disorder and the rest (12) were normal.
Discussion: Infants with severe BGT injury had evidence of prior fetal distress and lesions that suggest more than a brief period of hypoxia; focal mild BGT injury was only seen in five infants. Most infants had haemorrhage and mild/moderate WM injury was common and these findings might be attributable to their large size (only 4 mothers were diabetic), to the mode of delivery (mainly complicated ventouse), the presence of a nuchal cord and/or to the dystocia itself; few of these infants were acidotic. The patterns of brain injury associated with shoulder dystocia are varied and not just those expected from a 3-10 minute period of hypoxia at delivery.