Paraneoplastic Limbic Encephalitis (Dementia)
Related Subjects:
| Anti-NMDA (NMDAR) Receptor Encephalitis
| Herpes Simplex Encephalitis (HSV)
| Acute Encephalitis
| Limbic Encephalitis
| Paraneoplastic Limbic Encephalitis (Dementia)
| Hashimoto's (Steroid Responsive) Encephalopathy
| Acute Disseminated Encephalomyelitis
| Dementias
🧠 About
- Definition: PLE is a rapidly progressive dementia associated with malignancies, especially lung (small cell), breast, and testicular cancers.
- Prognosis: ⚠️ Often poor, as it usually reflects underlying cancer with aggressive progression.
🏛️ Limbic Structures Involved
- Hippocampus (memory)
- Amygdala (emotion)
- Hypothalamus (autonomic control)
- Insular & cingulate cortex (integration of behaviour & cognition)
⚡ Aetiology
- Autoimmune: Triggered by an anti-tumour immune response that cross-reacts with limbic neurons.
- Associated Malignancies:
- Small cell lung cancer 🫁
- Breast cancer 🎗️
- Testicular cancer ⚽
- Autoantibodies: Anti-Hu (lung), Anti-Ta (testis), Anti-Ma (various).
- Occult Cases: Sometimes no cancer is identified despite autoantibodies.
🩺 Clinical Features
- 🧩 Neuropsychiatric: Delirium, confusion, memory loss, rapid personality changes.
- 📉 Severe Amnesia: Subacute onset, with profound short-term memory loss.
- ⚡ Seizures: Limbic-related, often temporal lobe.
- 🧠 Extended Involvement: Brainstem or cerebellum → gait ataxia, diplopia.
- 😴 Consciousness: Episodes of drowsiness, unresponsiveness.
- ❤️ Autonomic Dysfunction: BP instability, arrhythmias.
🔬 Investigations
- 💧 CSF: Elevated protein or mild pleocytosis (inflammatory picture).
- 🧠 MRI: Temporal lobe hyperintensities (T2/FLAIR).
- 📉 EEG: Temporal lobe slowing or epileptiform discharges.
- 🧪 Antibody Testing:
- Anti-Hu → SCLC
- Anti-Ta → testicular
- Anti-Ma → various
- 🖼️ Malignancy Search: CXR, CT chest/abdomen, PET; testicular ultrasound, mammography as indicated.
💊 Management
- 🎯 Treat underlying cancer: Key to improving neurological outcome.
- 💉 Immunosuppression:
- High-dose corticosteroids (first-line).
- IVIg or plasmapheresis in resistant cases.
- Cyclophosphamide or rituximab sometimes considered.
- ⚡ Supportive: Antiepileptics for seizures, autonomic stabilisation.
- 📉 Prognosis: Guarded, depends on cancer control and antibody type (onconeuronal antibodies tend to respond poorly).
📚 References
- Dalmau J, Rosenfeld MR. (2008). Paraneoplastic Syndromes Affecting the Nervous System. Clin Neurol Neurosurg, 110(3), 227-233.
- Höftberger R, Rosenfeld MR. (2015). Antibody-Mediated CNS Disorders. J Neuro-Oncol, 123(1), 87-99.
- Graus F, Dalmau J. (2012). Paraneoplastic Neurological Syndromes. Lancet Neurol, 11(1), 1-9.
- NINDS: Paraneoplastic Limbic Encephalitis
