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Hyperbaric oxygen therapy (HBOT) involves administering 100% oxygen at pressures above 1.4 ATA and is being explored as an adjunctive treatment for intracranial abscesses, including cerebral abscesses and subdural and epidural empyema. These abscesses develop during life-threatening infections, resulting in localized pus collections within the cranial cavity. Although the incidence is up to 1.3 per 100,000 individuals, intracranial abscesses occur more frequently in high-risk populations, such as patients with HIV/AIDS. Surgical aspiration or evacuation combined with antibiotics remains the standard treatment for intracranial abscesses. However, HBOT has shown promise as a valuable adjunct in certain cases. A retrospective cohort study found that patients receiving HBOT experienced lower morbidity, fewer reoperations, and a higher likelihood of returning to baseline function compared to those treated with standard therapy alone. Treatment duration varies based on clinical response and imaging findings, with reports averaging 14 sessions. Although HBOT has antimicrobial benefits through reactive oxygen species, neurological sequelae remain a challenge, underscoring the need for effective adjunctive therapies. This activity highlights the potential of HBOT in enhancing outcomes for patients with intracranial abscesses through effective collaboration among healthcare providers. Objectives: Identify the indications for hyperbaric oxygen therapy as an adjunctive treatment in patients with intracranial abscesses. Implement evidence-based protocols for administering hyperbaric oxygen therapy, including appropriate pressure settings and session durations based on clinical guidelines. Apply knowledge of the physiological mechanisms by which hyperbaric oxygen therapy enhances antibiotic efficacy and immune function in the context of intracranial infections. Collaborate with the interprofessional healthcare team to develop individualized treatment plans incorporating hyperbaric oxygen therapy and standard management strategies. Access free multiple choice questions on this topic.

The first hyperbaric chamber was constructed in 1662 by Nathaniel Henshaw, a British clergyman. Over the years, various hyperbaric devices were used to treat different ailments, with varying degrees of success until 1955. Until then, the use of hyperbaric methods had minimal scientific support. The clinical application of hyperbaric oxygen therapy (HBOT) began in 1955 when Churchill-Davidson and colleagues explored its potential to enhance the effects of radiation therapy in cancer patients.[1] HBOT is a therapeutic modality that delivers 100% oxygen in a chamber or environment pressurized to more than 1.4 atmospheres absolute (ATA). The antimicrobial effects of HBOT are partly attributed to generating reactive oxygen species. HBOT is being explored as an adjunctive treatment for various conditions, including intracranial abscesses, with common examples being cerebral abscesses and subdural and epidural empyema. Please see StatPearls' companion resources, "Brain Abscess," "Subdural Empyema," and "Epidural Abscess," for more information about these clinical conditions. Intracranial Abscess An intracranial abscess is a localized, encapsulated collection of pus within the cranial cavity. While brain abscesses are relatively rare, occurring in only 0.3 to 1.3 per 100,000 individuals, their incidence is significantly higher among high-risk patients, particularly those with HIV infection or AIDS.[2][3][4] Etiology and pathogenesis: The development of an intracranial abscess involves several mechanisms, as mentioned below. Direct spread: This occurs when an initial infection spreads contiguously into adjacent tissues, such as the sinuses, ears, mastoid air cells, or teeth, affecting up to 60% of patients. Hematogenous seeding: Infectious agents can reach the brain via the bloodstream, often leading to multiple abscesses. Cranial trauma: Penetrating head injuries can provide a direct route for microorganisms to enter the skull.

Direct spread: This occurs when an initial infection spreads contiguously into adjacent tissues, such as the sinuses, ears, mastoid air cells, or teeth, affecting up to 60% of patients. Hematogenous seeding: Infectious agents can reach the brain via the bloodstream, often leading to multiple abscesses. Cranial trauma: Penetrating head injuries can provide a direct route for microorganisms to enter the skull. Streptococcus and Staphylococcus species are the most common bacterial causes of brain abscesses, with viridans group streptococci (VGS) and Staphylococcus aureus being the most prevalent. Anaerobes are also commonly found in brain abscesses, originating from the normal oral flora. When determining the cause of an infection, it is essential to consider the patient's immune status. Bacterial abscesses are typically observed in immunocompetent individuals, whereas immunocompromised patients may be infected by various organisms, including fungi.[5] Factors Contributing to Improved Outcomes Although brain abscesses are a rare condition, mortality rates remain high among affected patients. However, the prognosis for these individuals has significantly improved compared to historical data. A systematic review and meta-analysis revealed that over the past 6 decades, the case fatality rate has decreased from 40% to 10%, while the proportion of patients achieving full recovery has increased from 33% to 70%.[6] Additionally, a study of 289 patients with pyogenic brain abscesses treated between 1999 and 2006 reported a mortality rate as low as 2.7%.[7] Several factors, as mentioned below, have contributed to this positive trend. Computed tomography: The advent of computed tomography (CT) imaging has significantly improved outcomes by enabling faster diagnoses and facilitating less invasive, more precise neurosurgical interventions, such as stereotactic aspiration. One retrospective study showed a reduction in mortality from 40% to 20% within the first decade following the introduction of CT. Neurosurgical techniques: Advancements in neurosurgical procedures and the precision offered by CT-guided interventions have improved abscess drainage and reduced complications. Antimicrobial therapy: The development of more effective antibiotics has been crucial for controlling infections.

Barotrauma Middle ear barotrauma: This is the most frequent complication, particularly in patients undergoing multiple treatments. This arises due to pressure differences between the middle ear and the hyperbaric chamber. Symptoms may include ear pain, tympanic membrane rupture, and even hearing loss. Sinus barotrauma: This is the second most common complication, often affecting individuals with preexisting conditions such as upper respiratory infections or allergic rhinitis. This complication typically manifests as sinus pain and congestion. Pulmonary Complications Pulmonary oxygen toxicity: This condition may develop with multiple treatments, causing chest tightness due to lung irritation from extended exposure to high oxygen concentrations. Pulmonary barotrauma: This is a rare but severe complication caused by pressure changes that damage lung tissue, potentially leading to pneumothorax or pneumomediastinum.[12] Central Nervous System Oxygen Toxicity Seizures: Seizures are a rare but serious complication, with an incidence of only one seizure reported per 62,614 hyperbaric sessions involving 2334 patients. The risk increases with prolonged exposure (over 90–120 min) or when pressures exceed 2.8 ATA. Management: If a seizure occurs, the oxygen concentration should be immediately reduced, and anticonvulsant medications may be administered as needed.[13]

The primary treatment for intracranial abscesses usually involves a combination of the below-mentioned criteria. Antibiotics: Targeted antibiotic therapy is crucial for controlling the infection. The choice of antibiotics depends on the suspected or identified causative organisms. Drainage: Surgical drainage or aspiration of the abscess is often necessary to remove the purulent material and reduce intracranial pressure. Various techniques can be used, including stereotactic aspiration, open craniotomy, or endoscopic drainage. HBOT is being explored as an adjunctive therapy for intracranial abscesses, and key considerations are mentioned below.[14] First-line treatment: HBOT is not intended as the primary therapy but should be used alongside standard antibiotic and surgical management. Unstable patients: HBOT is generally not recommended for individuals with unstable vital signs or those in need of urgent surgical intervention. Replacement for antibiotics: HBOT serves as a complementary therapy (adjunct) to enhance antibiotic effectiveness, not as a substitute for antibiotic treatment. Potential risks: HBOT carries risks such as barotrauma and oxygen toxicity, which require careful monitoring and management. However, HBOT shows significant potential as an adjunctive therapy, supported by its physiological benefits and evidence from case reports and series.[15][16]

The management of intracranial abscesses necessitates a collaborative approach involving an interprofessional healthcare team, which includes neurosurgeons, infectious disease specialists, neurologists, neurocritical care nurses, radiologists, pharmacists, and rehabilitation specialists.