From the Guidelines
Management of suspected encephalitis complicating a middle ear infection requires immediate hospitalization and aggressive treatment, prioritizing empiric antimicrobial therapy with acyclovir and appropriate coverage for bacterial pathogens, as well as urgent neuroimaging and lumbar puncture when safe to do so. The most critical aspect of managing suspected encephalitis is initiating empiric antimicrobial therapy as soon as possible, given the high morbidity and mortality associated with delayed treatment, especially for herpes simplex virus encephalitis 1.
Empiric Antimicrobial Therapy
- Start with acyclovir (10 mg/kg IV every 8 hours) to cover herpes simplex virus, as recommended by the Infectious Diseases Society of America 1.
- Add a third-generation cephalosporin (such as ceftriaxone 2g IV every 12 hours or cefotaxime 2g IV every 4-6 hours) plus vancomycin (15-20 mg/kg IV every 8-12 hours) to cover common bacterial pathogens including Streptococcus pneumoniae and Haemophilus influenzae.
Diagnostic Approach
- Obtain urgent neuroimaging, with MRI preferred over CT, to assess for complications such as brain abscess or venous sinus thrombosis 1.
- Perform a lumbar puncture for CSF analysis if there are no contraindications, as it is essential for diagnosing and guiding treatment, with clinical assessment rather than CT scanning determining the safety of performing an LP 1.
Additional Management
- Consult neurology and infectious disease specialists immediately.
- Control seizures if present with benzodiazepines followed by levetiracetam or phenytoin.
- Manage increased intracranial pressure with head elevation, mild hyperventilation, and mannitol or hypertonic saline if severe.
- Surgical consultation for possible mastoidectomy or other drainage procedures may be necessary to address the primary ear infection.
- Continue antimicrobial therapy for 2-4 weeks depending on the identified pathogen and clinical response.
This approach is guided by the principle of minimizing morbidity, mortality, and improving quality of life, and is supported by the most recent and highest quality studies available, including those from the Infectious Diseases Society of America and the Association of British Neurologists and British Infection Association 1.
From the Research
Management of Suspected Encephalitis
The management of suspected encephalitis complicating a middle ear infection involves prompt assessment and treatment. Some key points to consider include:
- The early use of intravenous acyclovir in herpes simplex encephalitis (HSE) is essential, as it can decrease death and morbidity 2, 3.
- All patients with suspected encephalitis may need to be commenced on acyclovir, as rapid diagnostic tests are not freely available 4.
- Empirical therapy with intravenous aciclovir should be given to cover herpes simplex virus (HSV) until the cause is established, as HSV encephalitis may be fatal and leaves up to 50% of survivors with long-term sequelae 5.
- The use of adjunctive immunomodulatory therapy, such as glucocorticoids and intravenous immunoglobulin (IVIG), may be beneficial in severe cases of HSV encephalitis, although this is not currently recommended in treatment guidelines 6.
Diagnosis and Treatment
Diagnosis of encephalitis is typically established through a combination of clinical presentation, cerebral imaging, and lumbar puncture. Treatment should be initiated promptly, with acyclovir being the preferred drug for HSV encephalitis. The duration of acyclovir therapy may need to be extended beyond 21 days in some cases, particularly if there is persistently positive HSV-1 CSF PCR 2, 6.
Considerations for Middle Ear Infection
In cases where encephalitis is suspected to be complicating a middle ear infection, it is essential to consider the potential for bacterial meningitis and to initiate antibiotic therapy promptly, if necessary. The emergence of penicillin and cephalosporin resistance in Streptococcus pneumoniae may necessitate more complex antibiotic regimens 5.