Cerebral hypoxia

Share on facebook Share on twitter Bookmark & Share Printer-friendly version Cerebral hypoxia occurs when there is not enough oxygen getting to the brain. The brain needs a constant supply of oxygen and nutrients to function.

Cerebral hypoxia refers to the outer part of the brain, an area called the cerebral hemisphere. However, the term is often used to refer to a lack of oxygen supply to the entire brain.

Causes

In cerebral hypoxia, sometimes only the oxygen supply is interrupted. This can be caused by:

Breathing in smoke (smoke inhalation), such as during a fire Carbon monoxide poisoning Choking Diseases that prevent movement (paralysis) of the breathing muscles, such as amyotrophic

lateral sclerosis (ALS) High altitudes Pressure on (compression) the windpipe (trachea) Strangulation

In other cases, both oxygen and nutrient supply are stopped, caused by:

Cardiac arrest (when the heart stops pumping) Cardiac arrhythmia Complications of general anesthesia Drowning Drug overdose Injuries to a newborn that occurred before, during, or soon after birth (See: Cerebral palsy) Stroke Very low blood pressure

Brain cells are extremely sensitive to a lack of oxygen. Some brain cells start dying less than 5 minutes after their oxygen supply disappears. As a result, brain hypoxia can rapidly cause severe brain damage or death.

Symptoms

Symptoms of mild cerebral hypoxia include:

Change in attention (inattentiveness) Poor judgment Uncoordinated movement

Symptoms of severe cerebral hypoxia include:

Complete unawareness and unresponsiveness (coma) No breathing No response of the pupils of the eye to light

Exams and Tests

Cerebral hypoxia can usually be diagnosed based on the person's medical history and a physical exam. Tests are done to determine the cause of the hypoxia, and may include:

Angiogram of the brain Blood tests, including arterial blood gases and blood chemical levels CT scan of the head Echocardiogram Electrocardiogram  (ECG), a measurement of the heart's electrical activity Electroencephalogram  (EEG), a test of brain waves that can identify seizures and show how

well brain cells work Evoked potentials , a test that determines whether certain sensations such as vision and touch

reach the brain

Magnetic resonance imaging  (MRI) of the head

If only blood pressure and heart function remain, the brain may be completely dead.

Treatment

Cerebral hypoxia is an emergency condition that need to be treated right away. The sooner the oxygen supply is restored to the brain, the lower the risk of severe brain damage and death.

Treatment depends on the cause of the hypoxia. Basic life support is most important. Treatment involves:

Breathing assistance (mechanical ventilation) and oxygen Controlling the heart rate and rhythm Fluids, blood products, or medications to raise blood pressure if it is low Medications including phenytoin, phenobarbital, valproic acid, or general anesthetics to calm

seizures

Sometimes a person with cerebral hypoxia is cooled to slow down the activity of the brain cells and decrease their need for oxygen. However, the benefit of this treatment has not been firmly established.

Outlook (Prognosis)

The outlook depends on the extent of the brain injury. This is determined by how long the brain lacked oxygen, and whether nutrition to the brain was also affected.

If the brain lacked oxygen for only a very brief period of time, a coma may be reversible and the person may have a full or partial return of function. Some patients recover many functions, but have abnormal movements such as twitching or jerking, called myoclonus. Seizures may sometimes occur, and may be continuous (status epilepticus).

Most people who make a full recovery were only briefly unconscious. The longer a person is unconscious, the higher the risk for death or brain death, and the lower the chances of recovery.

Possible Complications

Complications of cerebral hypoxia include a prolonged vegetative state. This means the person may have basic life functions such as breathing, blood pressure, sleep-wake cycle, and eye opening, but the person is not alert and does not respond to his or her surroundings. Such patients usually die within a year, although some may survive longer.

Length of survival depends partly on how much care is taken to prevent other problems. Major complications may include:

Bed sores Clots in the veins (deep vein thrombosis) Lung infections (pneumonia) Malnutrition

Can You Prevent Brain Hypoxia?

You can prevent brain hypoxia by monitoring certain health conditions. For example, see a doctor if your blood pressure is too low, and keep your inhaler nearby at all times if you are asthmatic. Avoid high altitudes if you are susceptible to altitude sickness. For people who are unexpectedly deprived of oxygen (during a fire, for example), immediate cardiopulmonary resuscitation (CPR) helps to prevent the condition from getting worse.

TreatmentThere are three different levels of migraine treatment:

Preventative treatment (stopping attacks from happening) Acute treatment (treating an attack as soon as it happens) Rescue treatment (dealing with an attack if acute treatment does not work)

Some people are prescribed a number of different drugs before they find a treatment course that suits them. You may find it useful to keep a note of all the drugs you have taken, and how they affected your attacks. This can help you to discuss your treatment history with a doctor long after these details may have been forgotten. A sample record form is available for download.Preventative treatment

Disabling headaches continue to happen in some people, even after they have made serious attempts to identify and avoid trigger factors, and make lifestyle changes. You should talk to your doctor if you find yourself in this situation, as you may need to take medication to try and stop the attacks from happening.How often you have a headache is not the only thing a doctor will look at to decide whether to prescribe preventative medication. The decision will be based on the effect the headaches are having on your life.When headaches are affecting you badly, a doctor can prescribe a number of different preventative medications. Migraine preventatives have usually been developed to treat other conditions. Experience has shown that these drugs also stop migraine attacks from happening.Therefore, you may be prescribed:

an anticonvulsant, such as divaloproex sodium (sodium valproate), topiramate or gabapentin an antidepressant such as amitriptyline an antihistimine, such as cyproheptadine a beta-blocker, such as propranolol, metoprolol, timolol, nadolol an anti-inflammatory drug, such as pizotefen

Other drugs not listed here may also be used, based on the experience of your doctor. It is important to remember that if a doctor prescribes, for example, an antidepressant for your migraines, you are not necessarily suffering from depression.A doctor will also talk to you about how long you should take preventative medication.Migraine-preventative medication is usually used for between 3 and 18 months. This treatment generally leads to a big reduction in the number of headaches the sufferer has. This improvement often carries on when the sufferer stops taking the preventative drug. These drugs can therefore help to break a cycle of migraine in some cases. It is important to record fully any attacks that happen when your are taking preventative medication. You need to watch and record what is happening, to help the doctor decide if the medication is helping to cut down the headaches.However, some medicines containing combinations of drugs with codeine or caffeine have been strongly suspected of causing the condition known as chronic daily headache. Over-the-counter analgesics often fail because they are taken too late in the migraine attack cycle. The digestive process slows down during a migraine attack. This can reduce drug uptake in the stomach, and the medicine is therefore not effective. Take analgesics in soluble form where possible, as this helps uptake in the stomach. If you can recognize the warning signs that a migraine attack is starting, you should take your medication at this time.Prescription only medicines

Your doctor can prescribe a number of stronger pain killers, and other medicines that may help to stop a migraine attack. Anti-sickness (anti-nausea or anti-emetic) drugs taken several minutes before an analgesic can help to reduce nausea and speed up the action of the pain killer. Commonly prescribed anti-emetics include domperidone and metoclopramide. Stronger analgesics available include naproxen, diclofenac sodium and tolfenamic acid. Details are on our currently used drugs page.Many sufferers with severe migraines are treated with one of a class of migraine-specific drugs called triptans. A number of different triptans are now available in the UK. Almotriptan, eletriptan, frovatriptan, naratriptan, rizatriptan, sumatriptan and zolmitriptan all work in the same way, but the different characteristics of each drug will suit different people. Triptans can be taken as pills, as quick-dissolving tablets, as a nasal spray, or as an injection. On average, patients who take triptans by mouth get relief from the symptoms of migraine in around half an hour. A doctor will be able to talk to you about your specific needs, and the best way to take your medication.Ergotamine preparations, or sometimes a sedative, can be prescribed when none of above drugs are effective. However, the BNF states 'the value of ergotamine for migraine is limited by difficulties in absorption and by its side effects, particularly nausea, vomiting, abdominal pain, and muscle cramps. It is best avoided'.As with migraine preventative medication, a doctor prescribing acute treatments will base their decision on an assessment of disability (the effects of the migraine attacks, not necessarily how often they happen).

Assessing disability will help a doctor to prescribe the right care to suit you. Ideally, the individual features of your headaches should be matched to a suitable plan for managing them at an early stage. This avoids having to keep going back to see the doctor, who may have to increase the level of treatment if lower levels fail. You should record details of the attacks throughout the treatment programme to help the doctor assess the effect of the medication.Rescue medication

There may be times when acute medication does not give enough relief from an attack. Your doctor may prescribe different medication to use at these times. ‘Rescue medication’ can be used if your acute treatment does not work. An antinausea (antiemetic) medication (to stop sickness), plus an anti-inflammatory or pain-relieving medication may be prescribed. You should write down when you use rescue medication in your migraine diary. Using rescue medication a lot suggests that your acute treatment needs changing.Side effects

The action of any drug in the body is complicated. Drugs can act on many places in the body, not just the parts we want them to. This can lead to ‘side effects’ happening, as well as the planned benefits. When prescribing medication, a doctor will talk to you about the possible side effects. These will also be listed on the information sheet that comes with the medication. Write down any changes you feel or notice that you think might be a side effect of the medication. It is important to tell a doctor about these changes. Some side effects go away with time, but a doctor may want to reduce the dose or change the medication.Dangers of over-using medication - Chronic Daily Headache

There is a condition called 'medication overuse headache', that has been linked with over-using pain killers, such as paracetamol. Some patients with medication overuse have daily headache, when it is called Chronic Daily Headache, meaning headache on at least fifteen days in any one month. The term means only that the headache is frequent; it can have many causes other than medication overuse. Some medicines containing combinations of drugs with codeine or caffeine have also been strongly suspected of causing medication overuse headache. Therefore, rather than managing migraine, regular use of these drugs on more than three days a week can actually make the headaches worse. It is important to avoid over-using medication. You should get medical advice if you are using painkillers on more than three days a week.Mechanical pain relief

Many sufferers use mechanical techniques to relieve the pain of migraine attacks. Simple techniques that can be tried include:

Temperature - both hot or cold. Try applying an icepack, or a hot water bottle, to the painful area. Hot or cold showers help some sufferers, or try soaking the hands and feet in hot or cold water.

Pressure. Try applying pressure to the pulse points on the side of the forehead or neck to relieve the headache.

Manipulation in the form of massage and reflexology are more complicated techniques, and you may need to find a trained practitioner to get the best results. Osteopathy and chiropractic are also manipulative techniques. To prevent harm, these techniques should only be carried out by a registered practitioner; your doctor may be able to recommend one.Biofeedback

The biofeedback technique has been used to reduce the number of attacks and the pain of migraine in some sufferers. Biofeedback training teaches people to control certain body functions they do not normally think about controlling. For example, a headache sufferer could learn to raise the temperature of a part of the body, say the hands. Redirecting blood to the hands reduces blood flow in the head, and the headache pain eases. You need professional help to learn the skill of biofeedback. Once a sufferer learns the technique, it can be practised anywhere.Botox

Botox is the brand name for botulinum toxin A, a toxin secreted by the bacterium that causes botulism. The potential of Botox as a useful medical intervention was discovered by scientists developing a vaccine to protect against botulism. They found that when injected into muscle, the toxin stays in the injected area (rather than travelling into the bloodstream), and causes the injected muscle to relax.Following this discovery, Botox has for many years been used in the treatment of disorders involving abnormal muscle contraction. More recently, the toxin has become a household name as a glamour drug, associated with ageing celebrities who rely on the toxin’s paralytic powers to ward off facial wrinkles. Certain Botox users found that wrinkles were not the only unwanted feature soothed by the treatment; the drug also appeared to have a preventative effect on their headaches.In 2010 Botox was given regulatory approval for treatment as a preventative for chronic migraine.  More details on Botox can be found in our fact sheet on Botox.

migraineDiagnose As a migraine sufferer, you are in a powerful position to take control of the condition.Information on migraine is available from The Migraine Trust, and from your doctor. However, migraine is a complicated condition, which varies widely between individuals. The symptoms of an attack vary from person to person, but also from attack to attack in the same person. The things that trigger your attacks will also be individual to you.

UnderstandOnce a diagnosis has been made, you, the sufferer, are in the best position to learn about your condition.Your doctor will be able to help you unravel all of the information that you gather. Migraine sufferers have a right to appropriate care for their condition, but may achieve the best results if they also take responsibility for managing their condition. To assist in gaining a better understanding of your migraine, try out our online migraine diary.

ManageMigraine is a condition which responds well to self-help. Access to up to date information, a strong partnership with your doctor, treatment where needed, and the support of those around you, can all help you to take control of your condition.For more information read our fact sheets, general information,research articles and FAQs covering most aspects of migraine and other headache disorders.

Migraine Headache Medical Treatment

Despite medical advances, migraines can be difficult to treat. About half of migraineurs stop seeking medical care for their headaches because they are dissatisfied with therapy.

Migraines can be treated with two approaches: abortive and preventive.

Abortive: The goal of abortive therapy is to prevent a migraine attack or to stop it once it starts. The prescribed medications stop a headache during its prodrome stage or once it has begun and may be taken as needed. Some can be administered as a self-injection into the thigh; others, as a wafer that melts on the tongue, or as a nasal spray. These forms of medication are especially useful for people who vomit during a migraine, and they work quickly.

Abortive treatment medications include the triptans, which specifically target the chemical serotonin. The triptans are used only to treat headache pain and do not relieve pain from back problems, arthritis, menstruation, or other conditions. Triptan medications include:

Sumatriptan (Imitrex) Sumatriptan/Naproxen (Treximet) Zolmitriptan (Zomig) Eletriptan (Relpax) Naratriptan (Amerge) Rizatriptan (Maxalt) Frovatriptan (Frova) Almotriptan (Axert)

The following drugs are also specific and affect serotonin, but they affect other brain chemicals as well. Occasionally, one of these drugs works when a triptan does not.

Ergotamine tartrate (Cafergot) Dihydroergotamine (D.H.E. 45 Injection, Migranal Nasal Spray) Acetaminophen-isometheptene-dichloralphenazone (Midrin)

The following drugs are mainly used for nausea, but they sometimes have an abortive or preventive effect on headaches:

Prochlorperazine (Compazine) Promethazine (Phenergan)

The next drugs are weak members of the narcotic class. They are not specific for migraine, but they can help relieve almost any kind of pain. Since they are habit forming, they are less desirable choices than the specific headache drugs listed above. These drugs should be used primarily as a "backup" for the occasions when a specific drug does not work.

Butalbital compound (Fioricet, Fiorinal) Acetaminophen and codeine (Tylenol with Codeine)

Preventive: This type of treatment is considered if a migraineur has more than one migraine per week. The goal is to lessen the frequency and severity of the migraine attacks. Medication to prevent a migraine can be taken daily. Different drug classes have been used successfully as preventive therapies. Preventive treatment medications include the following:

Medications used to treat high blood pressure - Beta blockers (propranolol [Inderal]), calcium channel blockers (verapamil [Covera])

Antidepressants - Amitriptyline (Elavil), nortriptyline (Pamelor) Antiseizure medications - Gabapentin (Neurontin), valproic acid(Depakote), topiramate (Topamax) Some antihistamines and anti-allergy drugs, including diphenhydramine(Benadryl)

and cyproheptadine (Periactin) Continue Reading