Successful Treatment of Otogenic Brain Abscess

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Successful Treatment of Otogenic Brain Abscess with Transmastoid Approach and Ultrasound-Guided Aspiration

Introduction

Otogenic brain abscesses are among the most severe complications of suppurative otitis media. Despite the widespread use of antibiotics reducing mortality and morbidity over the years, patient deaths still occur due to cerebral hernia or brain abscess rupture. In such critical cases, the right time and method for abscess drainage are crucial. This article presents the successful management of a young male patient with an otogenic brain abscess and cerebral hernia using transmastoid middle skull base craniectomy and ultrasound-guided abscess aspiration.

Case Presentation

A 22-year-old man presented to our hospital with severe right-sided headache, neck pain, and nausea. He had a history of intermittent right ear otalgia and hearing loss for a month. Physical examination showed signs of acute mastoiditis and meningeal irritation. An urgent computed tomography (CT) revealed a soft-tissue density filling the middle ear cavity and mastoid, along with a bone defect of the tegmen tympani. Magnetic resonance imaging (MRI) demonstrated inflammation of the right temporal lobe and immature abscess formation (Figure 1A). Intravenous antibiotics (ceftriaxone and vancomycin) and mannitol were prescribed immediately.

The next day, the patient’s symptoms worsened. He had a 2-minute convulsion and then lost consciousness. Physical examination showed mydriasis of the right eye. Contrast-enhanced CT revealed an enlarged intracranial lesion in the inferior part of the temporal lobe near the skull base, measuring 3.2 cm × 2.8 cm × 3.2 cm. A small pus cavity had formed, and a sign of cerebral hernia was also present. An urgent radical mastoidectomy of the right side was performed. During the operation, only granulation tissue was found in the mastoid (no cholesteatoma). The tegmen was eroded with an 8 mm × 5 mm bone defect, and the inflammatory dura bulged. After removing the adherent granulation tissues, a 6 cm × 7 cm bony plate was drilled at the middle skull base through the mastoid cavity until the normal dura was exposed, reducing intracranial pressure.

Ultrasound-Guided Aspiration

Since the pus cavity was too small to locate, ultrasound was introduced for guidance. We used the ALOKA Prosound a7 ultrasonic apparatus with a multi-frequency burr-hole transducer (UST-5268P-5) dedicated to brain scans. Using saline in the mastoid cavity as the medium, gray-scale ultrasonography first identified a 1.0 cm × 0.7 cm anechoic area with echogenic foci inside (Figure 1B and 1C). Then, the color Doppler mode was used to identify the optimal puncture path without damaging blood vessels. An ultrasound-guided aspiration needle was advanced into the abscess cavity freehand through the middle cranial fossa dura, and only 1 mL of pus was aspirated. The brain tissue then retracted, and the pulse was visible. After this operation, the patient recovered consciousness and had isocoria with a normal light reflex.

Follow-Up and Second Surgery

After 2 weeks of anti-infective therapy (during which the cerebral abscess matured), a second surgery was performed by a neurosurgeon to drain the pus, and a catheter was indwelled. All symptoms disappeared after another 5-week course of intravenous antibiotics. The patient was discharged home. Two months later, his left-side muscle strength grade was V–. No other complications of the brain abscess were left during the 3-year follow-up.

Discussion

Importance of Cerebral Abscess Management

Cerebral abscesses remain one of the most severe complications of otitis media. Although mortality rates have generally dropped, complications still occur. When intracranial complications become life-threatening, surgical intervention is often required immediately. The key problem in the operation technique is the precise location and puncture of the abscess.

Aspiration Techniques

Cerebral abscess aspiration is a rapid and safe procedure, especially with stereotactic techniques like intraoperative ultrasound or CT scan guidance. Compared to craniotomy, imaging-guided stereotactic aspiration is considered a better choice for brain abscess management. CT-guided stereotaxy (1) is a good option for most cerebral abscesses except the most superficial and large ones. However, it requires a long preparation time and high cost, making it unavailable in many hospitals. A needle puncture from the transmastoid approach is often used but requires an experienced surgeon to judge the abscess location based on preoperative CT or MRI scans (2).

Ultrasound-Guided Aspiration Advantages

In 1986, Nagle et al (3) reported a case of a 1000 g neonate with a frontal brain abscess successfully aspirated in the intensive care nursery with ultrasound guidance. The method of ultrasound guidance is applied in a single burr hole approach for real-time imaging (4). However, a burr hole must be made first due to transdural attenuation. In our case, the patient with an otogenic brain abscess due to acute middle ear infection was treated with radical mastoidectomy immediately when cerebral hernia symptoms appeared. During the mastoidectomy, a 6 cm × 7 cm bone plate of the middle cranial fossa was opened, effectively decompressing intracranial pressure. To improve the surgery’s effect without increasing trauma and prolonging the operating time, ultrasound was introduced to guide the aspiration of the immature abscess. This was successful, similar to most single-stage trans-mastoid drainage of otogenic brain abscesses (5).

Transmastoid Approach Benefits

Most otogenic brain abscesses are mainly located within the inferior temporal lobe. If punctured from other approaches, the puncture pathway would be too far from the target, potentially causing cortex damage or iatrogenic spread of infection into the ventricles. Through the transmastoid approach, the puncture path is short, easier to locate and monitor, and thus associated with much lower surgical risk. The body of the probe was Z-type, convenient to hold. With grooves on both sides, it can easily be installed into the puncture frame. After attaching the probe to the dura, the pus cavity site was clearly visualized. The pus cavity volume shrank significantly immediately after aspiration. Although residual inflammation continued to grow and a second aspiration was needed through a burred hole 2 weeks later, we believe the first single-stage mastoidectomy with ultrasound-guided aspiration by the trans-mastoid approach was crucial for good outcomes.

Conclusion

This case demonstrates the successful treatment of an otogenic brain abscess using the transmastoid approach with ultrasound-guided aspiration. The combination of surgical decompression and precise ultrasound-guided aspiration can effectively manage such complex cases, providing a valuable treatment option. Further studies may explore optimizing this technique and its application in different patient populations.

Declaration of Patient Consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

Funding

This work was supported by grants from the Peking University Third Hospital Clinical Project Fund (No. BYSY2017025) and The China Capital Health Development Project (No. 2016-2-4094).

Conflicts of Interest

None.

References

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  2. Choi J, Choi JI, Kim SD. Management of otogenic brain abscess using the transmastoid approach. J Korean Neurosurg Soc 2014;55:178–180. doi: 10.3340/jkns.2014.55.3.178.
  3. Nagle RC, Taekman MS, Shallat RF, Cohen RA. Brain abscess aspiration in nursery with ultrasound guidance. Case report. J Neurosurg 1986;65:557–559. doi: 10.3171/jns.1986.65.4.0557.
  4. Strowitzki M, Schwerdtfeger K, Steudel WI. Ultrasound-guided aspiration of brain abscesses through a single burr hole. Minim Invasive Neurosurg 2001;44:135–140. doi: 10.1055/s-2001-18126.
  5. Mukherjee D, Das C, Paul D. Single-stage trans-mastoid drainage of otogenic brain abscess: a single-institution experience. Indian J Otolaryngol Head Neck Surg 2016;68:179–184. doi: 10.1007/s12070-016-0969-1.

doi: 10.1097/CM9.0000000000000796

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