Overview of Hyperbaric Oxygen Therapy for Intracranial Abscess
The very first machine to treat people using a high pressure, oxygen-filled environment was invented by a British clergyman called Nathaniel Henshaw way back in 1662. Since then, similar machines, known as hyperbaric devices, have been used to treat various health conditions. However, until 1955, these devices weren’t widely used, mainly because there wasn’t much scientific evidence to support their effectiveness. The turning point came in 1955 when a group of scientists led by Churchill-Davidson investigated if this high-pressure oxygen therapy, or Hyperbaric Oxygen Therapy (HBOT), could boost the effectiveness of radiation treatment in cancer patients.
HBOT is a treatment method in which 100% pure oxygen is supplied in a specially-designed chamber that is pressurized to more than 1.4 times the normal atmospheric pressure (ATA). It is believed that the high pressure helps to generate reactive oxygen species which can contribute to killing harmful bacteria and viruses. Presently, HBOT is undergoing tests to see if it can also help in treating various other conditions, including infections in the brain (intracranial abscesses) such as cerebral abscesses, and infections in the space between the skull and the outer lining of the brain (subdural and epidural empyema).
An intracranial abscess is when pus gathers in a particular area within the brain. This condition is quite rare, affecting only about 0.3 to 1.3 out of 100,000 people. However, people with specific conditions such as HIV or AIDS are at a much higher risk.
An intracranial abscess can occur due to different reasons. One way is through direct spread, where the infection spreads from another part of the body such as the sinuses, ears or teeth, to the brain. This happens in about 60% of cases. Another way is through hematogenous seeding, where infectious agents are carried to the brain through the bloodstream, often leading to multiple abscesses. Finally, the condition can also occur due to cranial trauma, when a severe head injury causes microorganisms to enter the skull directly.
The most common types of bacteria that cause brain abscesses are Streptococcus and Staphylococcus, specifically the viridans group streptococci (VGS) and Staphylococcus aureus. Anaerobes, which are bacteria that can live without oxygen and are usually found in the mouth, are also commonly found in brain abscesses. When doctors are trying to determine the cause of an infection, they take into account the health of a person’s immune system. Those with weakened immune systems may be infected by a wider range of organisms, including fungi.
Even though brain abscesses are quite rare, they can be very severe and often have high death rates. However, thanks to advancements in medical technology, the outlook for patients with this condition has improved significantly over the years. Nowadays, the death rate has decreased from 40% to 10%, and the number of patients who fully recover has increased from 33% to 70%. This change has been possible due to the development of more advanced imaging technology like computed tomography (CT), which helps doctors diagnose the condition more quickly and accurately. It’s also due to advancements in neurosurgical procedures that have made it possible to drain the abscess more effectively and more safely. And of course, the development of more effective antibiotics to treat the infections has been an important factor as well.
Anatomy and Physiology of Hyperbaric Oxygen Therapy for Intracranial Abscess
Hyperbaric Oxygen Therapy (HBOT) is a type of treatment that uses pure oxygen in a pressurized room to help heal the body. The way it works is connected to two scientific principles. First, Dalton’s law explains that the amount of each gas in a mixture adds up to the total pressure of the mixture. So, when the pressure changes, or we alter the amounts of different gases, the pressure of one specific gas in the mixture will also change. Second, Henry’s law tells us that the amount of a gas in a liquid directly matches its pressure and how well it can dissolve. This is important in HBOT because it helps increase the amount of oxygen in the blood.
When we breathe in normal air under normal conditions, our red blood cells (hemoglobin) carry most of the oxygen, and only a tiny bit dissolves directly into our blood (about 3 mL per liter of blood). But, when breathing in pure oxygen, the amount of dissolved oxygen in blood increases to 15 ml per liter. When using HBOT at 2.5 times normal air pressure (ATA), it can dissolve up to 60 mL of oxygen per liter of blood. This high concentration of oxygen delivers enough oxygen for normal metabolism without needing red blood cells. Plus, the increased amount of oxygen in the blood makes it easier for oxygen to reach cells, thanks to a process called diffusion. This allows oxygen to travel further from blood vessels and reach even more cells.
HBOT is being studied as a possible additional treatment for intracranial abscesses, which are infections inside the brain. Here are some reasons scientists think it might work:
- Reducing brain swelling: HBOT may help by constricting blood vessels and slowing blood flow in the brain, leading to less swelling and pressure.
- Fighting anaerobic organisms: These are the types of bacteria that cannot survive in an oxygen-rich environment. Since HBOT creates a high-oxygen situation in the body, it could starve these bacteria and stop them from growing.
- Boosting immune cell function: HBOT may help the body fight off infections better by improving the way some white blood cells (neutrophils) destroy harmful bacteria.
- Treating skull infections: If an infection spreads to the bone of the skull, HBOT could help by increasing the amount of oxygen in the area, thus promoting healing.
Why do People Need Hyperbaric Oxygen Therapy for Intracranial Abscess
The Undersea and Hyperbaric Medical Society (UHMS) suggests that Hyperbaric Oxygen Therapy (HBOT) can be a helpful additional treatment for brain abscesses. Brain abscesses are a collection of pus, immune cells, and other material in the brain, usually from a bacterial or fungal infection. HBOT is a treatment where you breathe in pure oxygen in a pressurized room or tube.
This therapy is recommended in the following cases:
- When the patient’s immune system is weakened, making it harder for them to fight off the infection
- If there are multiple abscesses present in the brain
- If the abscesses are located in a deep or important part of the brain
- For patients who can’t have surgery for medical reasons
- For patients who are not good candidates for surgery because of other health conditions
- When the patient is not responding to standard treatments, such as surgery and antibiotics, or their condition is getting worse
Remember, HBOT is considered an additional treatment and should be used alongside standard treatments for brain abscesses. Also, every patient’s situation is unique. So what is best for one person may not be the best for another. It’s always good to have a detailed discussion with the healthcare provider to understand the best treatment option.
When a Person Should Avoid Hyperbaric Oxygen Therapy for Intracranial Abscess
There is a situation where you absolutely cannot have Hyperbaric Oxygen Therapy (HBOT), a treatment where you breathe in pure oxygen in a pressurized room to help heal wounds. If you have an untreated pneumothorax, which is a condition where air gets trapped between your lungs and chest wall, HBOT isn’t safe. During the treatment, the pressure might cause the trapped air to dangerously expand, leading to a condition called tension pneumothorax; this could result in serious, life-threatening complications.
There are also situations where HBOT might not be recommended, but it’s not a definite no-go:
If you have claustrophobia, which is a fear of enclosed spaces, you might find the hyperbaric chamber stressful and it can trigger anxiety or panic attacks.
If you have an obstructive lung disease like chronic obstructive pulmonary disease that affects your lungs’ ability to exchange gas, HBOT might be riskier for you.
A condition called asymptomatic pulmonary blebs, which are small air pockets in the lungs, could possibly rupture under the increased pressure during HBOT, leading to a pneumothorax.
If you have upper respiratory or sinus infections, the pressure changes during HBOT can worsen your symptoms or cause damage to your ears and sinuses due to the changes in pressure (this is called “barotrauma”).
If you’ve recently had ear or chest surgery, the healing tissue might be more vulnerable to the pressure changes and get damaged.
And finally, if you have uncontrolled seizures, HBOT might lower the barrier to having a seizure in certain individuals.
Even if these conditions apply, it doesn’t mean you definitely can’t have HBOT. Healthcare professionals will evaluate each patient’s situation individually and balance the possible benefits against the risks. Sometimes, they might be able to make adjustments to the treatment plan so that a patient with these conditions can safely receive HBOT.
Equipment used for Hyperbaric Oxygen Therapy for Intracranial Abscess
Hyperbaric oxygen therapy (HBOT) is a treatment where the patient is placed inside a special chamber. There are two types of these chambers:
* Monoplace chamber: In this type of chamber, the patient breathes in 100% pure oxygen under pressure. This is done directly within the chamber.
* Multiplace chamber: In this type of setup, more than one patient can receive the treatment simultaneously. The patients are still inhaling 100% pure oxygen under pressure, but this time it’s done indirectly. This means the oxygen is delivered through methods like a mask, a head hood or a tube placed in their windpipe (endotracheal tube).
How is Hyperbaric Oxygen Therapy for Intracranial Abscess performed
The UHMS, a medical society, offers advice on how to use hyperbaric oxygen therapy (HBOT) for brain abscesses. Hyperbaric oxygen therapy is a treatment in which the patient breathes pure oxygen in a pressurized room or tube.
* Pressure: The suggested pressure is between 2.0 to 2.5 ATA. ATA stands for atmospheres absolute, which measures pressure.
* Oxygen time: Each hyperbaric treatment should take between 60 to 90 minutes.
* Number of treatments: Depending on the patient’s health, treatments can be given once or twice every day.
How long should the treatment last?
There are no set rules for the ideal number of HBOT treatments for brain abscesses. However, in one large study, the average number of treatments was 14 for patients without a bone infection called osteomyelitis. The duration of treatment should be tailored to the individual patient and should be based on:
* Medical imaging: Scans like CT or MRI scans can be used to track the size and healing of the abscess.
* Physical symptoms: Positive changes in neurological symptoms can help guide decisions about the treatment plan.
Possible Complications of Hyperbaric Oxygen Therapy for Intracranial Abscess
Barotrauma is a type of injury caused by changes in pressure. Here are some common types:
* The most common is in the middle ear, especially for those who have multiple treatments. This happens when there’s a difference in pressure between the middle ear and the pressurized chamber used in treatment. Symptoms might include ear pain, a ruptured eardrum, and even loss of hearing.
* The second most common type affects the sinuses, often those who already have issues like upper respiratory infections or allergies. This can cause sinus pain and congestion.
There can also be complications affecting the lungs:
* If someone has multiple treatments, they can develop a condition known as pulmonary oxygen toxicity. This is when the lungs get irritated from being exposed to high oxygen levels for a long time, causing tightness in the chest.
* Pulmonary barotrauma is another complication and although it’s rare, it can be severe. It happens when pressure changes damage the lung tissue, possibly leading to conditions like a collapsed lung or air build-up in the chest.
Central Nervous System Oxygen Toxicity is another important condition to note:
* Seizures are a rare but serious complication that can happen. They have only been reported in one out of every 62,614 sessions, so it’s not something that happens often. The risk can increase if treatments last longer (over 90-120 minutes) or the pressure goes over what’s usually expected.
* In terms of dealing with these seizures, the immediate step is to lower the concentration of oxygen being used. Medications to prevent further seizures can also be administered if necessary.
What Else Should I Know About Hyperbaric Oxygen Therapy for Intracranial Abscess?
Despite progress in lowering death rates, treating brain abscesses (a collection of pus in the brain) remains a significant challenge. The aftereffects of these abscesses can have a big impact on the patient’s personal and professional life, emphasizing the urgent need for more effective and less invasive treatment methods.
Using antibiotics to treat brain abscesses has several limitations. For instance, they might not readily cross the barrier between the bloodstream and the brain, enter the abscess, or work well in the low-oxygen, acidic environment of the abscess. Plus, the lack of oxygen in the abscess can weaken the body’s white blood cells’ ability to consume and destroy bacteria, a process called phagocytosis. This reduces the antibiotic’s effect on the bacteria.
Hyperbaric Oxygen Therapy (HBOT) may be a promising alternative treatment method. HBOT involves breathing 100% oxygen in a pressurized chamber. There are several ways this treatment might help overcome the obstacles of traditional treatment.
- It increases oxygen delivery, which can help correct low oxygen levels in brain tissue.
- It can help kill bacteria, especially those that can’t survive in oxygen-rich environments (anaerobic bacteria).
- Increased oxygen levels in tissue could improve the penetration and effectiveness of antibiotics.
- Improved oxygen levels could also enhance the body’s immune response against infections by boosting the white blood cells’ ability to destroy bacteria.
- HBOT can also reduce brain swelling by constricting blood vessels and reducing inflammation in the brain.
While still limited, recent data suggests that combining traditional treatment with HBOT may be beneficial for treating brain abscesses. Results show that patients treated with HBOT had lower disease severity, fewer requirements for additional surgery, and were more likely to return to their previous level of functioning compared to those receiving standard treatment alone.
Overall, preliminary evidence suggests that HBOT could be a valuable addition to standard treatment for brain abscesses, although more research is required to confirm this.
