Limbic encephalitis
Background
- Autoimmune encephalitis caused by autoantibodies against intracellular neuronal proteins
- Typically not limited to limbic system
- Majority of cases are paraneoplastic, particularly associated with small cell lung cancer, germ-cell testicular tumors, teratomas
Clinical Features
- Mimics HSV encephalitis
- Subacute presentation over days to weeks
- Short-term memory deficits
- Headache
- Irritability, sleep disturbance, agitation
- Delusions, hallucinations, psychosis
- Seizure
Differential Diagnosis
Altered mental status
Diffuse brain dysfunction
- Hypoxic encephalopathy
- Acute toxic-metabolic encephalopathy (Delirium)
- Hypoglycemia
- Hyperosmolar state (e.g., hyperglycemia)
- Electrolyte Abnormalities (hypernatremia or hyponatremia, hypercalcemia)
- Organ system failure
- Hepatic Encephalopathy
- Uremia/Renal Failure
- Endocrine (Addison's disease, Cushing syndrome, hypothyroidism, myxedema coma, thyroid storm)
- Hypoxia
- CO2 narcosis
- Hypertensive Encephalopathy
- Toxins
- TTP / Thrombotic thrombocytopenic purpura
- Alcohol withdrawal
- Drug reactions (NMS, Serotonin Syndrome)
- Environmental causes
- Deficiency state
- Wernicke encephalopathy
- Subacute Combined Degeneration of Spinal Cord (B12 deficiency)
- Vitamin D Deficiency
- Zinc Deficiency
- Sepsis
- Osmotic demyelination syndrome (central pontine myelinolysis)
- Limbic encephalitis
Primary CNS disease or trauma
- Direct CNS trauma
- Diffuse axonal injury
- Subdural/epidural hematoma
- Vascular disease
- SAH
- Stroke
- Hemispheric, brainstem
- CNS infections
- Neoplasms
- Paraneoplastic Limbic encephalitis
- Malignant Meningitis
- Pancreatic Insulinoma
- Seizures
- Nonconvulsive status epilepticus
- Postictal state
- Dementia
Psychiatric
Evaluation
- Diagnosis unlikely to be made in the ED
- Evaluate for alternative diagnoses
- MRI Brain- usually increased T2 signal involving one or both temporal lobes.[1]
- LP- CSF w/lymphocytosis (though usually <100), elevated protein, normal glucose, elevated IgG index, oligoclonal bands[2]
Management
- No randomized trials but may include IVIG, plasmapheresis, corticosteroids, cyclophosphamide and/or rituximab.[3]
- Treat underlying malignancy
Disposition
- Admit
See Also
External Links
References
- ↑ Nicholas, D (2003). "Clinical, Magnetic Resonance Imaging, and 7Electroencephalographic Findings in Paraneoplastic Limbic Encephalitis". Mayo Clinic Proceedings. 78 (11): 1363–1368.
- ↑ Vincent A, Buckley C, Schott JM, et al. (2004). "Potassium channel antibody-associated encephalopathy: a potentially immunotherapy-responsive form of limbic encephalitis". Brain. 127 (3): 701–712
- ↑ Tüzün E, Dalmau J (2007). Limbic encephalitis and variants: classification, diagnosis and treatment. The Neurologist. 13 (5).