Neonatology
Intraventricular Hemorrhage (IVH)
Intraventricular
hemorrhage (IVH) can affect premature
infants, usually born prior to 34 weeks gestation.
In these infants, the blood vessels of the brain
are immature and fragile, and are prone to breakage
in the first few days when blood pressure and
blood flow to the brain tend to fluctuate.
The upper part of the brain consists of the two
cerebral hemispheres. Within each hemisphere is
a semicircular chamber called a ventricle, in
which fluid is produced (cerebrospinal fluid).
The fluid from both hemispheres flows toward the
central and lower parts of the brain through narrow
channels, and then moves toward and around the
spinal cord. The part of the brain in which blood
vessels break is called the germinal matrix, which
is a small region next to the ventricles where
new nerve cells and other cells are produced.
The germinal matrix is more prominent and more
fragile in smaller premature infants. The germinal
matrix disappears by approximately 34 weeks so
that, after that time, bleeding is unlikely.
Classification
IVH is diagnosed by ultrasound of the brain, which
is performed routinely on premature infants. IVH
is classified as grades 1 to 4 as follows:
Grade 1: Bleeding in the germinal matrix
only. No blood in the ventricles.
Grade 2: Bleeding in the germinal matrix
and in the ventricle(s), without enlargement
of the ventricle(s).
Grade 3: The quantity of blood in the
ventricle(s) is large enough to cause enlargement
of the ventricle(s).
Grade 4: Blood in extended areas of the
brain beyond the germinal matrix.
Implications
Implications for neurological development depend
on the severity of the hemorrhage.
- Grade 1 and 2 bleeds are reabsorbed and often
have no permanent effects.
- Grade 3 bleeds can cause deficits due to stretching
of the brain that occurs when the ventricles
are dilated.
- Grade 4 IVH is usually associated with permanent
effects due to the direct damage of brain tissue
by the bleeding; the degree of permanent deficit
relates to the size and location of the bleeding.
It is very difficult to predict the degree of
long-term effects resulting from neonatal brain
injury, since most brain development has yet to
occur, and significant compensation for deficits
can take place.
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