Pediatrics: Brain Flashcards
Definition of benign enlargement of the subarachnoid space in infancy
Enlarged extra axial fluid spaces >5 mm (cortical veins are not displaced, remain subjacent to the inner table)
Note: This is thought to be due to immature villa and will resolve over time.
Enlarged extra-axial fluid space with medial displacement (or non visualization) of the corital veins…
Think subdural hygroma or chronic subdural hematoma
What is the most common cause of macrocephaly?
Benign enlargement of the subarachnoid space in infancy (due to immature villa)
Treatment for benign enlargement of the subarachnoid space in infancy?
None, usually resolved after 2 years without treatment
Pts with benign enlargement of the subarachnoid space in infancy are at an increased risk for…
Subdural hematomas (spontaneous or with minor trauma)
Note: If there are multiple subdural of different ages, you should still think non accidental trauma.
Periventricular leukomalacia
Hypoxic-ischemic encephalopathy of the newborn caused by hypoxic injury (usually during birth), that results in cerebral palsy 50% of the time
Which pts are at highest risk for periventricular leukomalacia?
Premature and low birth weight infants (<1500g)
Which areas of the brain are most commonly affected in periventricular leukomalacia?
Watershed areas (especially the white matter that is dorsal and lateral to the lateral ventricles)
How can you tell whether there is periventricular leukomalacia?
The white matter should always be less bright (less hyperechoic) than the choroid plexus. If there are white matter regions brighter than choroid plexus, this suggests leukomalacia.
The posterosuperior periventricular white matter is symmetrically hyperechoic, but not as hyperechoic as the choroid plexus…
Blush (physiologic brightness of the posterosuperior periventricular white matter)
Note: If it is less hyperechoic than choroid plexus, then it is likely normal.
Hyperechoic posterosuperior periventricular white matter in a newborn that is equal echogenicity to the choroid plexus…
Think flaring or grade I periventricular leukomalacia
Note: Flaring should resolve by day 7 of life.
How can you differentiate flaring from grade I periventricular leukomalacia?
Flaring should resolve by day 7 of life, whereas PVL would persist
Periventricular blush vs flaring
Periventricular blush is a normal periventricular hyperechogenicity (less hyperechoic than choroid)
Perventricular flaring is a term used when you aren’t sure whether its physiologic or grade I periventricular leukomalacea (you need to wait past day 7 of life to discriminate flaring from grade I PVL)
How long does it take cavitary periventricular cysts to develop in periventricular leukomalacea?
Up to 4 weeks
Note: If they show you a 1 day old newborn with periventricular cysts, the ischemic injury probably occurred at least 2 weeks prior (not during birth as is usually the case).
What makes periventricular leukomalacea grade 4?
Subcortical cysts
Note: This is actually more common in full term infants than preterms, unlike other grades of PVL.
At what age does the germinal matrix regress?
36 weeks gestation
Note: You can only have germinal matrix hemorrhage in a premature infant less than 36 weeks gestation. By 32 weeks gestation, you only have germinal matrix in the caudothalamic groove.
Germinal matrix hemorrhage in a full term infant…
Choroid plexus hemorrhage (the germinal matrix doesn’t exist after 36 weeks gestation)
Screening for germinal matrix hemorrhage
Transcranial ultrasound in premature infants (<32 weeks or symptomatic with lethargy/seizures)
When should a newborn receive screening for germinal matrix hemorrhage?
Within the first week of life, when most germinal matrix hemorrhages occur
Note: Premature infants <32 weeks gestation should be screened.
How can you differentiate germinal matrix hemorrhage from a normal choroid plexus?
Choroid plexus will not extend anterior to the caudothalamic groove (the junction between the caudate and the thalamus)
Note: The caudothalamic groove is where the germinal matrix lies in premature infants.
Echogenic material at the junction of the caudate nucleus and thalamus in a premature infant…
Grade 1 germinal matrix hemorrhage
Linear T1 hyperintense lesion at the junction of the caudate nucleus and thalamus in a premature infant…
Grade 1 germinal matrix hemorrhage
Germinal matrix hemorrhage grading
- 1 (blood in caudothalamic groove)
- 2 (blood in ventricles)
- 3 (blood in ventricles with ventricular dilatation)
- 4 (blood in brain parenchyma secondary to venous infarction)
Grade 4 germinal matrix hemorrhage
Germinal matrix hemorrhage with hemorrhage in the brain parenchyma secondary to venous infarction
Grade 1 germinal matrix hemorrhage may leave _____ after resolution
Subependymal cysts
Which grades of germinal matrix hemorrhage can lead to hydrocephalus?
Grades 2, 3, and 4
Complications of grade 4 germinal matrix hemorrhage
- Hydrocephalus
- Porencephalic cyst (infarcted hole left over)
Note: All grade 4 germinal matrix hemorrhages have venous infarctions, which is what causes the parenchymal hemorrhages.