Cayla Van Alstine MSIII, Sana Ozair MD, and Nicholas Ludvik MD University of South Alabama College of Medicine Department of Internal Medicine
Incidence of autoimmune encephalitis tripled since 1995. With prevalence of 13.7/100,000 persons and novel distinct clinical pathologies, appropriately identifying autoimmune encephalopathies is imperative to facilitate timely treatment and maximize healthcare utility. Modified diagnostic criteria attempt to circumvent limitations of antibody testing, yet multi-disciplinary teams and procedures are often still imperative for optimal outcomes. Obesity can complicate diagnostic procedures and delay timely diagnosis. Point of Care Ultrasonography (POCUS) offers internists a chance to overcome these diagnostic challenges. This diagnostically complex case highlights the need for greater training in POCUS in internal medicine.
75-year-old Caucasian female presented to emergency department as stroke alert. Patient recently discharged from outside hospital with diagnosis of stroke and pneumonia. Antibiotics prescribed but not taken. Medical history included diabetes, chronic obstructive pulmonary disease, and coronary artery disease. Family reported acute worsening mentation, aphasia, and right-sided weakness. Exam at admission significant for fever (39.9°C), tachycardia, elevated blood pressure, obese female appearing ill, complete disorientation, and absence of nuchal rigidity. Serology significant for creatinine 1.08mg/dL, C-reactive protein 0.7mg/dL, sedimentation rate 75mm/hour, WBC 13. Computed tomography brain revealed subacute stroke without acute findings. Sepsis protocol and broad-spectrum antibiotics initiated. Neurology and infectious disease consulted. Given fever, confusion, and elevated sedimentation rate consistent with central nervous system inflammation, medicine and infectious disease sought lumbar puncture (LP) with cerebrospinal fluid (CSF) analysis as next diagnostic step. Internal medicine attempted LP but were unable to obtain CSF due to patient's habitus. Neurology and radiology were unavailable to assist. Day 3 of hospitalization patient progressed from disoriented to obtunded. Antiviral and antifungal therapy were added. Neurology obtained electroencephalogram revealing triphasic waves and generalized background slowing. Microbiologic testing including blood culture, fungal culture negative to date. Lumbar puncture performed by neurology at that time revealed WBC 191cells/mcl, total protein 95mg/dL, and reactive lymphocytes. This established preemptive diagnosis of autoimmune encephalitis and autoantibody testing was obtained and found to be positive. A five-day course of intravenous immunoglobulin therapy was initiated with marked improvement in her condition.
Autoimmune encephalopathies include a far-reaching group of pathologies that often present in severe and rapidly progressive forms. Severity and duration of symptoms directly impact patient outcomes. Timely initiation of immunotherapy is critical to maximize patient recovery. Therefore, early clinical detection and treatment should be the standard of care to optimize patient outcomes. Diagnosis relies heavily on neurological assessments and detection of autoantibodies in CSF. Landmark-oriented lumbar puncture has been shown to fail to obtain CSF at a rate of approximately 19% in neurological clinics. Failure rate is higher in patients with obese habitus. Thus, the use of POCUS in this patient to obtain ultrasound-guided LP would likely have led to earlier diagnosis and therapy. Autoimmune encephalopathy has shown rising incidence and cost of care of approximates 2 billion US dollars annually. This highlights the need for physicians to pursue a clear and timely diagnosis as well as the need for healthcare systems to invest in POCUS to enable physicians to reach an accurate diagnosis with greater efficiency and safety.
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