Case Presentation: A 75 year old with a presented with a chief complaint of fever. The patient reported headache, dizziness, myalgia, dyspnea, constipation, and denied nausea. On assessment, the patient was mildly febrile and tachycardic with other vital signs within normal limits. The remainder of the exam demonstrated normal cardiovascular, respiratory, abdominal exam and gross neurologic examination. Admission laboratory results were notable for a leukocytosis with neutrophilic predominance, mild hyponatremia and mild acute kidney injury. Further infectious workup demonstrated negative urinalysis, chest radiograph without a focal infiltrate. CT head without contrast showed sinus opacification suggestive of acute sinusitis. The patient was admitted to the medicine service due to concern for sepsis of unclear etiology and started on empiric antibiotics with vancomycin and ertapenem. Admission blood cultures subsequently grew Streptococcus sp. During the hospital stay, the patient became more somnolent and was noted to have nuchal rigidity on a subsequent more comprehensive neurologic exam. A brain MRI was obtained which demonstrated a subdural empyema.
Discussion: Hospitalists commonly care for patients presenting with fever and sepsis. We present the potential diagnostic challenge a subdural empyema may pose for hospitalists in initial sepsis workup, particularly if a negative head CT provides false reassurance against intracranial infection. Intracranial subdural empyema (ISE) is a rare but serious infection, defined as a pyogenic infection within the space between dura and arachnoid mater. While previously considered rapidly fatal, earlier recognition and decreased time to treatment have been credited with improved mortality rates. In younger patients it is more commonly associated with otitis and sinus infections, while in older patients ISE are more commonly associated with neurosurgical procedures or trauma, including falls. Patients often present both with symptoms of an infection as well as an expanding intracranial mass; symptoms may include fever, headache, vomiting, altered sensorium and seizures. However, the classic triad of headache, fever, and nausea is only present in half of presentations. CT brain can be normal in 63% of cases, as it was in our patient. MRI has greater sensitivity and is therefore the gold standard in all patients with suspicion of ISE. Infections are commonly polymicrobial, with Streptococcus and Staphylococcus commonly seen; however anaerobic gram positive, gram negative and fungal species have also been identified.
Conclusions: Hospitalists should be familiar with the presentation of intracranial subdural empyema, both due to the high risk of morbidity and mortality as well as the importance of timely diagnosis. Patients with recent sinus or otitis infections as well as recent neurosurgical procedures and trauma are particularly at risk. A complete neurologic exam is warranted for any patient presenting with sepsis and altered mental status. CT brain is not sensitive enough to rule out intracranial infection.This case was identified through the national collaborative Achieving Diagnostic Excellence through Prevention and Teamwork (ADEPT).