Hypoxic Ischemic Encephalopathy: Signs, Symptoms, Treatment

CARBON MONOXIDE POISONING: Poisoning by a gas called carbon monoxide. Carbon monoxide

prevents the blood from receiving enough oxygen. Breathing stops first, then the heart stops.

PROBLEMS WITH HEMOGLOBIN: Hemoglobin is a substance that carries oxygen in the blood. If this

substance is not functioning properly, there will not be enough oxygen in the blood that reaches the brain.

SEPTIC SHOCK: A form of shock when poisons are released from harmful organisms (known as bacteria)

in the blood. The bacteria are in the blood because they have spread from an infection somewhere else in

the body.

GENERAL ANESTHESIA: The use of substance to prevent sensation. This is generally done before

many types of surgery so that the patient does not feel pain. While being operated on, the patient

receives air to breathe. If the air does not have enough oxygen, HIE can result.

DISEASES THAT PREVENT THE MOVEMENT OF MUSCLES THAT HELP IN BREATHING: The names

of diseases that can do this are amyotrophic lateral sclerosis (ALS), myasthenia, and Guillain-Barre

syndrome. A disease called poliomyelitis (also known as polio) can also cause this to happen, but the

disease is not seen much today.

BRAIN DAMAGE: Damage to an area in the lower part of the brain that controls breathing, known as the

medulla. This damage can be caused by a trauma such as a car accident, bleeding or a lack of oxygen in

the area of the medulla, and epilepsy. Epilepsy is a brain condition that is characterized by changes in

sensation, abnormal behaviors, loss of consciousness, convulsive seizures, or all of these. Convulsive

seizures are sudden abnormal, severe involuntary muscle movements, with a racing heart and other

symptoms.

WHAT HAPPENS NEXT & HOW LONG DOES IT TAKE BEFORE THE TISSUE DIES?

If the oxygen supply continues to be reduced, the cells in the brain will break down in an attempt to

produce energy. In the process of breaking down, the cells cause such damage to themselves, that they

die. Massive amounts of calcium (a metallic element) present in the body are believed to flow into the

tissue area in large amounts and assist in the death of the cells. It takes about five minutes (sometimes

longer), for a tissue to die that is not receiving enough oxygen. Tissues are made up of groups of cells.

HOW IS HYPOXIC ISCHEMIC ENCEPHALOPATHY TREATED?

The purpose of treatment for HIE is to prevent serious injury from occurring. To do this, the flow of

oxygen, as well as proper heart and lung functioning needs to be restored immediately. To restore heart

functioning, an electric shock may need to be applied to the heart. If breathing, oxygen flow in the blood,

and heart functioning is restored within 3 to 5 minutes, then recovery can occur. However, if the oxygen

blood flow is cut off for more than 5 minutes, permanent brain injury usually results.

Increased blood pressure, heart action, and low body temperatures may help the person resist permanent

injury if the blood flow is cut off for slightly more than 5 minutes. However, breathing, oxygen flow in the

blood, and heart functioning must be restored for recovery to occur.

WHAT IS COMMONLY SEEN IN PATIENTS WHO RECOVER FROM A BRIEF DECREASE IN OXYGEN

TO THE BRAIN?

As was mentioned earlier, recovery can occur from a decrease in oxygen to the brain, if the oxygen

supply is restored within three to five minutes. Typically, such a patient is in a coma for a few days. A

coma is a state of deep unconsciousness in which there are no voluntary movements, no responses to

pain, and no verbal speech. Eventually, consciousness is regained, which is followed by confusion,

abnormal movements, and an inability in recognizing visual objects even though vision is intact. Some

patients pass through this phase quickly and make a full recovery. However, others are left with different

degrees of permanent disability from brain damage (see below).

WHAT ARE SOME OF THE PERMAMENT DISABILITIES THAT CAN OCCUR FROM BRAIN DAMAGE

DUE TO A LACK OF OXYGEN?

Permanent disabilities that can occur from brain damage due to a lack of oxygen include the following.

Please note that these disabilities often overlap in various combinations, although any one of them may

be the main disability experienced.

• Abnormal movements.

• Long-term coma (see last section).

• Seizures: sudden, violent, involuntary muscle movements.

• Inability in recognizing visual objects even though vision is intact.

• Loss of muscle coordination due to damage to an area in the back of the brain known as the cerebellum.

• Rapid, uncontrollable jerking muscle movements that occur at rest or at movement.

• Choreoathetosis: abnormal body movements characterized by a choreic (involuntary, irregular, dance-

like, movements of the arms, legs, and face) and athetoid (involuntary, slow, twisting movements of the

hands, fingers, toes, and feet) pattern.

• Dementia: a mental disorder that gets worse over time and is characterized by confusion, impaired

thinking abilities, poor memory, poor judgment, personality changes, unawareness of the environment,

unresponsiveness, and doing things based on impulse.

• Disorientation (confusion), severely impaired memory of recent events (also known as anterograde

amnesia, and an inability to learn new skills.

There are some patients that will make a recovery and then get worse after a period of 1 to 4 weeks.

These patients usually feel confused, irritable, and experience a lack of interest in things. Some patients

feel agitated and high-strung. This worsening of symptoms is uncommon and not well understood. It is

known as delayed postanoxic encephalopathy. Many patients survive it, but some are left with serious

impairments in thinking and movement. Some patients continue to worsen and die within 1 to 2 weeks.

After death, such patients are found to have experienced widespread destruction of myelin in the brain.

Myelin is a substance that makes up the tube-shaped covering of various nerve fibers in the body and

helps them transmit messages fast.

There are also some patients that slowly get worse over weeks and months until they stop speaking, are

stiff, and cannot help themselves in any way. In such patients, the damage is mostly located in an area

known as the basal ganglia. The basal ganglia are paired groups of nerve cells located deep within the

brain that play an important part in smooth, continuous muscle movements and in starting and stopping

movements.

WHAT ARE SIGNS THAT CAN HELP TELL IF SOMEONE WILL RECOVER FROM HYPOXIC ISCHEMIC

ENCEPHALOPATHY?

The doctor or nurse should look for signs that the brainstem is intact. The brainstem is an area in the

lower part of the brain that connects it with the spinal cord. This area of the brain controls many functions

crucial for life to continue. One such sign includes the pupil of the eye widening in response to light. The

pupil is the dark circle in the middle of the eye. Another sign is the ciliospinal reflex, in which the pupils

widen by scratching or pinching the skin of the neck or face.

Yet another sign is called "doll's head eye movements": If the brain stem is functioning normally, the eyes

will move in the opposite direction when quickly rotated from side to side. If the signs mentioned above

are not present, especially the widening of the pupils in response to light, the patient's condition is likely

hopeless.

The most severe cases of HIE are those in which the responses described above are not present, the

patient is totally unaware of his/her environment, natural breathing stops, and there is no electrical activity

in the brain detected with tests. If severe, continuing seizures (sudden, violent, involuntary muscle

movements) occur that do not respond to treatment, a poor outcome is likely.

DO ANY PATIENTS SURVIVE SEVERE HYPOXIC ISCHEMIC ENCEPHALOPATHY?

Yes. However, some patients do not speak afterwards, will not respond to others, and are unaware of

their environment for weeks, months, or years. Some improvement may occur over the long-term, but the

patient appears not to know anything about the present, has lost the ability to reason, live independently,

recall memories from the past, and interact with others in a socially acceptable way.

WHAT HAPPENS TO PATIENTS WHO HAVE BRAIN DEATH FROM SEVERE HYPOXIC ISCHEMIC

ENCEPHALOPATHY?

In patients with severe HIE, in which brain death occurs, the decision must be made as to whether to end

life support. However, doctors must be very careful in stating that brain damage cannot be reversed

because anesthesia (see above), drug overdose, and severely low body temperature can appear like

irreversible brain damage. When properly treated however, recovery from these conditions may be

possible. Many victims of HIE have their organs donated to science.

ARE ANY AREAS OF THE BRAIN SAFE FROM THE EFFECTS OF NOT RECEIVING OXYGEN?

No. However, the brainstem is more resistant than other areas of the brain to a lack of oxygen, unless

severe brain damage has occurred. The brainstem is an area in the lower part of the brain that connects it

with the spinal cord. This area of the brain controls many functions crucial for life to continue.

WHAT IS THE ORIGIN OF THE WORDS, HYPOXIC ISCHEMIC ENCEPHALOPATHY?

Hypoxic comes from the Greek word "hypo" meaning "under", the word "oxygen," and the Greek word

"ikos" meaning "pertaining to." Ischemic comes from the Greek word "ischein" meaning "to hold back" the

Greek word "haima" meaning "blood," and the Greek word "ikos" meaning pertaining to." Encephalopathy

comes from the Greek word "enkephalos" meaning "brain," and the Greek word "pathos" meaning

"suffering."