Clinical History
A premature neonate with sepsis, coagulopathy and seizures.
Imaging Findings
The 34-week gestation neonate was transferred to the paediatric intensive care unit after he collapsed during a feed. He was noted to be poorly perfused, and the nursing staff described his extremities as being “black”. An AXR (not presented) showed multiple dilated loops of bowel, extensive pneumatosis coli and free air. A diagnosis of necrotising enterocolitis complicated by bowel perforation was made, and he underwent a laparotomy and surgical resection of the terminal ileum. He remained septic following his surgery. In the days that followed, he developed a coagulopathy and had several seizures.
A brain ultrasound (Figure 1) and subsequently a CT scan of brain (Figure2) were requested.
The ultrasound revealed bilateral intraventricular haemorrhages, and mixed echogenicity soft tissue masses in the left temporo-parietal lobe and right frontal lobe, which appeared to be cavitating. Extensive subdural fluid was also seen. The cavitating mass lesions were interpreted as representing haemorrhagic infarctions. The differential diagnosis included cerebral abscess formation, given the patient’s continued sepsis. For this reason, further evaluation with a brain CT was recommended.
The brain CT confirmed the ultrasound interpretation of cerebral infarctions. In addition, CT defined a right subdural haematoma over the frontal lobe, a left Sylvian fissure subarachnoid haemorrhage, with extension to the overlying subdural space and subdural blood extending over the left temporal lobe and into the temporal parenchyma. Subdural blood was also seen over the left cerebellar hemisphere.
Following the CT scan, and after discussion of the findings and prognosis with the infant’s parents, a decision was made to withdraw ventilatory support. Our patient died a few hours later, in his parents’ arms.
Discussion
Intracranial haemorrhage is a common cause of neonatal morbidity which can be diagnosed by cranial ultrasound. The incidence of intracranial haemorrhage in premature infants of less than 35 weeks gestational age is approximately 30-55%. Most of the haemorrhages occur in the germinal matrix. This is highly vascular subependymal tissue that is situated adjacent to the lateral ventricles. At 26 weeks gestation it has its largest volume and it involutes by 32-34 weeks gestation. Risk factors for intracranial haemorrhage include prematurity, low birth weight, multiple gestations, trauma at delivery, prolonged labour, and deranged coagulation.
The pathogenesis of germinal matrix haemorrhage is thought to be due to the fact that the blood vessels supplying the matrix are fragile and unable to auto-regulate cerebral blood flow. Therefore factors that cause fluctuation or an increase in cerebral blood flow can precipitate haemorrhage. These include respiratory distress in premature infants, systemic hypertension, rapid expansion of blood volume, hypercarbia, decrease in cerebral blood flow with systemic hypotension followed by reperfusion and coagulation disturbance.
Germinal matrix haemorrhage can be described according to the Papile classification, using ultrasound. In neonates the anterior fontanelle is used as the imaging window, however the posterior and mastoid fontanelles can also be used to gain supplementary views of the posterior fossa.
Grade 1 is haemorrhage confirmed to the germinal matrix. With US an echogenic mass at the level of the head or body of the caudate nucleus or the caudothalamic groove is identified. Over time the lesion may regress and decease in size and echogenicity and not infrequently a subependymal cyst can form.
Grade 2 is haemorrhage within a non-distended ventricular system (as was the case in our patient), and may represent an extension of a type 1 GMH. A clot within the occipital horn of the lateral ventricle or a blood/CSF level in a dependent part of the ventricular system may be the only indication of a grade 2 haemorrhage. US identifies echogenic material within the lateral ventricles. The haemorrhage should be distinguished from the normal echogenic choroid plexus which does not extend anterior to the foramen of Monro or into the occipital horns of the lateral ventricles. An associated ventriculitis (echogenic ventricular lining) is common.
Grade 3 is intraventricular haemorrhage with ventricular enlargement. Initially the haemorrhage itself can distend the ventricle but subsequently obstructive hydrocephalus can occur. A grade 3 haemorrhage may represent an extension of a grade 2 IVH.
Grade 4 is haemorrhagic infarction of the brain parenchyma. Grade 4 lesions are thought most likely due to areas of venous infarction, rather than extension of haemorrhage following ventricular rupture. US will show an intraparenchymal echogenic mass and if the haemorrhage is large secondary mass effect such as depression of the Sylvian fissure or midline shift can be identified. With time the haematoma will liquefy and become hypoechoic. Complete resolution can result in a porencephalic cyst, if the infarct is periventricular.
Grade 1 & 2 haemorrhages have better prognosis with a 15% risk of handicap.
Grade 3 & 4 haemorrhages have a mortality of approximately 50% and a 35% risk of handicap in survivors.
The aetiology of a large proportion of cerebral infarctions in children is unknown. In neonates the most common cause of embolic cerebral infarction is congenital cyanotic heart disease. Other causes include vasculopathies, infection, coagulopathies, metabolic disorders and vascular malformations. Cranial ultrasound is less sensitive than CT in the detection of cerebral infarction in neonates. The most common appearance on US is an ill defined area of hyperechogenicity. Focal regions of hyperechogenicity within the echogenic area would suggest areas of haemorrhage. Cystic degeneration of the infarct would develop over the next 2-4 weeks. On CT a well defined wedge shaped area of hypoattenuation involving both the white matter and the cortex is identified. Areas of haemorrhage are hyperdense.
In our case the intraventricular haemorrhage was felt to be due to germinal matrix haemorrhage. The subarachnoid and subdural haemorrhage was thought to be secondary to the coagulopathy. The areas of infarction developed secondary to hypoxia.
Our patient had multiple risk factors that would have predisposed him to intracranial haemorrhage and infarction: he was born prematurely, he suffered an episode of collapse with systemic hypotension, from which he was initially resuscitated, and he had a coagulopathy secondary to his septicaemia.
Differential Diagnosis List
Germinal matrix haemorrhage and cerebral infarction.
Final Diagnosis
Germinal matrix haemorrhage and cerebral infarction.
