Intraventricular hemorrhage (IVH) is bleeding into the ventricles of the brain. One characteristic of the immature brain is a weakness of the blood vessels next to the ventricles. The ventricles are cavities that store cerebrospinal fluid (CSF) which nourishes the brain. Of particular concern is a collection of tiny and fragile blood vessels in the germinal matrix, which is the area of brain adjacent to the floor of the ventricles. This is a part of the brain that is active during fetal development but that disappears at about the 35th week of pregnancy. These blood vessels are thin and vulnerable to fluctuations in blood flow through them, which can cause them to rupture and bleed. The younger and smaller the baby, the higher the risk these blood vessels may be ruptured, usually in the first few days of life. A rupture causes blood to flow into a ventricle or ventricles of the brain.
Grades of IVH
IVH is categorized into grades of severity: grade I is considered mild, grade II moderate, and grade III & IV severe. About 50% of extremely premature babies will sustain an IVH, whereas only about 15% of older premature babies, many of whose germinal matrix has already disappeared, will have an IVH.
| Classification | Medical name | What it means |
|---|---|---|
| Grade I | Subependymal or germinal matrix hemorrhage (SEH/GMH) | The bleeding is restricted to the germinal matrix and blood has not entered the ventricles. |
| Grade II | Intraventricular hemorrhage (IVH) | Some blood is present in the ventricles, but not enough to enlarge them. |
| Grade III | Ventriculomegaly (VM) | Enough blood has entered the ventricles that the ventricles are enlarged. |
| Grade IV | Parenchymal hemorrhage (IPH) | The bleeding into the ventricles has resulted in a decreased blood supply to other parts of the brain, causing ischemic damage with subsequent bleeding. |
If the IVH is classified as grade I or II, the chance that there will be long-term damage is small because the blood remains contained within the ventricles and the additional fluid does not cause excessive pressure.
In grade III IVH, the bleeding is substantial enough to cause a swelling or obstruction of the narrow channels feeding into and out of the ventricles. This may interfere with the normal replenishment and flushing of the CSF. The result can be hydrocephalus, which is a build-up of CSF in the ventricles, which puts pressure on surrounding brain tissues. This can then result in injury to that area of brain under pressure. If the bleeding is more severe, blood that has flowed into and filled the ventricles will permanently block CSF flow and lead to hydrocephalus with enlargement of the head, excessive pressure within the skull, and the need for a surgical intervention to relieve the pressure. A small tube or catheter called a ventriculoperitoneal shunt (VP shunt) is inserted to drain off the spinal fluid.
A grade IV IVH results from congestion to the brain tissue around the ventricles when a large IVH has occurred. This results in bleeding into the brain tissue itself with destruction of that area of brain. Lasting brain damage is almost always the result, the severity of which is determined by the extent and location of the bleeding.
Why does IVH happen?
Because premature babies have fragile blood vessels, an IVH can occur simply as a result of changes to blood pressure and flow that occurs with birth. Although blood pressure changes occur in most people without bleeding, in the premature baby, the walls of the vessels are vulnerable during these changes. Blood pressure fluctuations can occur as a result of many different conditions, and are often a result of difficulties at the time of birth or lung and breathing complications.
Mechanical ventilation, which is often needed immediately after the birth of a premature baby, can also lead to fluctuations in blood flow. This is particularly likely when the baby is breathing out of sync with the ventilator, which creates additional pressures within the lung and blood vessels in the brain. Much work has been done over the years in an attempt to reduce this particular risk factor and improve a baby’s assisted breathing in general.
The bleeding of IVH occurs typically within the first 48 hours following birth, and it is very unlikely to occur again at a later date.
Intraventricular hemorrhage (IVH) is bleeding into cavities in the brain called the ventricles. The blood vessels in the immature brain, including those in the germinal matrix next to the ventricles, are weak. The germinal matrix is a part of the brain that is active during fetal development but that disappears at about the 35th week of pregnancy. The blood vessels are thin, fragile, and vulnerable to fluctuations in blood flow, which can cause them to rupture and bleed.
The younger and smaller the baby, the higher the risk these blood vessels may be ruptured, usually in the first few days of life. A rupture causes blood to flow into one or both ventricles. The ventricles of the brain are normally filled with cerebrospinal fluid (CSF).
Severe IVH may first be suspected just by looking at the baby. Because the ventricles in the brain are filling up, pressure is created. Since the skull bones have not fused, a swelling of the head or the soft bones at the top of the head called the fontanelles, may be visible. Also, because weakened blood vessels in the brain are susceptible to damage from sudden blood pressure changes, abnormal blood pressure readings may alert medical staff to the possibility of IVH.
Because IVH can occur due to injury, if the condition is suspected, the circumstance of the premature baby’s birth, for example a particularly rough and prolonged labour, will be looked into, as will signs of infection, as they may be an indication of IVH.
Although IVH can have no initial symptoms, seizures, major clinical deterioration with anemia, hypotension, and metabolic acidosis may all be signs. At times, premature babies with IVH may appear not to be thriving and sickly in general.
A head ultrasound will be performed to confirm the diagnosis. Additional tests include blood work to check for anemia, metabolic acidosis, and infection. If IVH is confirmed, it will be classified on a scale from Grade I to Grade IV, which is the most severe.
Treatment of intraventricular hemorrhage (IVH)
Intraventricular hemorrhage (IVH) is bleeding into the ventricles of the brain. IVH is generally caused by blood pressure changes that cause the immature blood vessels of the baby’s brain to rupture. It may occur because of direct trauma to the baby’s head, even as a result of normal vaginal delivery if excessive pressure is exerted on the head by the bony pelvis or by forceps or vacuum). In most cases, the IVH does not produce any symptoms or signs since they are usually small bleeds. They are only visible on ultrasound scans of the baby’s head. The bleeding gradually stops and the blood vessels heal themselves. There are no immediate treatments necessary. If damage has occurred to brain tissue, this does not heal and there may be long-term problems with development.
In more severe cases of IVH, other treatments may be necessary. Blood pressure must be monitored and maintained in the normal range. At times, the bleeding and pressure within the ventricles of the brain can interfere with the flow of cerebrospinal fluid (CSF). Over time, typically a few weeks, it may cause a condition called hydrocephalus, where there is a build-up of CSF in the ventricles of the brain due to blocked flow from blood clots. This causes enlargement of the baby’s head.
The treatment of hydrocephalus may involve the surgical placement of a shunt, which is a thin tube that drains off the CSF from the brain to another part of the body such as the abdomen. Prior to surgery, CSF may be drained off using a needle to relieve pressure in the ventricles and relieve symptoms of increased pressure on the brain.
What are the complications of IVH?
There are two main ways in which IVH can potentially cause damage. First, IVH may affect the flow of CSF in the ventricles and second, IVH may cause damage to brain tissue adjacent to the ventricles. Once damage has occurred to brain tissue, it cannot be reversed. However, physical damage to brain tissue does not necessarily mean damage to brain function. The areas of the brain that are often affected by an IVH, those adjacent to the ventricles, are those responsible for motor functions. Commonly, problems with vision and hearing, and other higher cognitive functions are associated. The extent of any long-term effect will often depend on the severity of the bleeding: babies with severe IVH are likely to develop some kind of neurological disability. Cerebral palsy (CP), a condition that interferes with motor coordination, is frequent. There is however, a wide range of disability with CP: those with hemiplegia are affected on one side of body only and children with milder forms of spastic diplegia, affecting only the legs, are usually able to walk with minimal supports.
Luckily, many babies who have a mild IVH go on to develop normally or with only minimal disabilities associated with learning.
Follow up care for IVH
The extent of a brain injury as revealed by imaging technology such as head ultrasounds and magnetic resonance imaging (MRI) does not necessarily predict the future ability of the child. Predicting the future effect of a specific type or severity of brain injury can be reasonably accurate in some cases, particularly in severe injury. However, a prognosis may be inaccurate, particularly when injury appears to be mild on brain imaging.
Also, the disability arising from brain injury is usually not immediately apparent but may take months to appear.
Brain injuries tend to fall into the category of “the damage is done and cannot be undone,” in the sense that the actual physical damage cannot be repaired. Whether this translates into disability is another story. There is usually no risk of re-injury in a premature baby who has suffered brain damage, but the extent of the injury may not be immediately apparent. Therefore, sequential scans of the baby’s brain will be done to evaluate whether there is a need for an intervention such as shunt surgery. In this situation, blood in the cavities inside the brain called the ventricles blocks the flow of cerebrospinal fluid (CSF) and causes a build-up of pressure. This pressure must be relieved by placing a small catheter, called a shunt, inside the brain and draining off the excess fluid into another part of the body, usually the abdomen.