Pediatrics: Brain

Question 1

Definition of benign enlargement of the subarachnoid space in infancy

Answer 1

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.

Question 2

Enlarged extra-axial fluid space with medial displacement (or non visualization) of the corital veins…

Answer 2

Think subdural hygroma or chronic subdural hematoma

Question 3

What is the most common cause of macrocephaly?

Answer 3

Benign enlargement of the subarachnoid space in infancy (due to immature villa)

Question 4

Treatment for benign enlargement of the subarachnoid space in infancy?

Answer 4

None, usually resolved after 2 years without treatment

Question 5

Pts with benign enlargement of the subarachnoid space in infancy are at an increased risk for…

Answer 5

Subdural hematomas (spontaneous or with minor trauma)

Note: If there are multiple subdural of different ages, you should still think non accidental trauma.

Question 6

Periventricular leukomalacia

Answer 6

Hypoxic-ischemic encephalopathy of the newborn caused by hypoxic injury (usually during birth), that results in cerebral palsy 50% of the time

Question 7

Which pts are at highest risk for periventricular leukomalacia?

Answer 7

Premature and low birth weight infants (<1500g)

Question 8

Which areas of the brain are most commonly affected in periventricular leukomalacia?

Answer 8

Watershed areas (especially the white matter that is dorsal and lateral to the lateral ventricles)

Question 9

How can you tell whether there is periventricular leukomalacia?

Answer 9

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.

Question 10

The posterosuperior periventricular white matter is symmetrically hyperechoic, but not as hyperechoic as the choroid plexus…

Answer 10

Blush (physiologic brightness of the posterosuperior periventricular white matter)

Note: If it is less hyperechoic than choroid plexus, then it is likely normal.

Question 11

Hyperechoic posterosuperior periventricular white matter in a newborn that is equal echogenicity to the choroid plexus…

Answer 11

Think flaring or grade I periventricular leukomalacia

Note: Flaring should resolve by day 7 of life.

Question 12

How can you differentiate flaring from grade I periventricular leukomalacia?

Answer 12

Flaring should resolve by day 7 of life, whereas PVL would persist

Question 13

Periventricular blush vs flaring

Answer 13

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)

Question 14

How long does it take cavitary periventricular cysts to develop in periventricular leukomalacea?

Answer 14

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).

Question 15

What makes periventricular leukomalacea grade 4?

Answer 15

Subcortical cysts

Note: This is actually more common in full term infants than preterms, unlike other grades of PVL.

Question 16

At what age does the germinal matrix regress?

Answer 16

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.

Question 17

Germinal matrix hemorrhage in a full term infant…

Answer 17

Choroid plexus hemorrhage (the germinal matrix doesn’t exist after 36 weeks gestation)

Question 18

Screening for germinal matrix hemorrhage

Answer 18

Transcranial ultrasound in premature infants (<32 weeks or symptomatic with lethargy/seizures)

Question 19

When should a newborn receive screening for germinal matrix hemorrhage?

Answer 19

Within the first week of life, when most germinal matrix hemorrhages occur

Note: Premature infants <32 weeks gestation should be screened.

Question 20

How can you differentiate germinal matrix hemorrhage from a normal choroid plexus?

Answer 20

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.

Question 21

Echogenic material at the junction of the caudate nucleus and thalamus in a premature infant…

Answer 21

Grade 1 germinal matrix hemorrhage

Question 22

Linear T1 hyperintense lesion at the junction of the caudate nucleus and thalamus in a premature infant…

Answer 22

Grade 1 germinal matrix hemorrhage

Question 23

Germinal matrix hemorrhage grading

Answer 23

• 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)

Question 24

Grade 4 germinal matrix hemorrhage

Answer 24

Germinal matrix hemorrhage with hemorrhage in the brain parenchyma secondary to venous infarction

Question 25

Grade 1 germinal matrix hemorrhage may leave _____ after resolution

Answer 25

Subependymal cysts

Question 26

Which grades of germinal matrix hemorrhage can lead to hydrocephalus?

Answer 26

Grades 2, 3, and 4

Question 27

Complications of grade 4 germinal matrix hemorrhage

Answer 27

- Hydrocephalus - Porencephalic cyst (infarcted hole left over) Note: All grade 4 germinal matrix hemorrhages have venous infarctions, which is what causes the parenchymal hemorrhages.