Makindo Medical Notes

Related Subjects: |Status Epilepticus (Epilepsy) |Coma management |Lorazepam |Phenytoin |Levetiracetam |Epilepsy - General Management |First Seizure |Epilepsy in Pregnancy |Febrile seizures

About

• Mesial Temporal Lobe Epilepsy (MTLE): A common form of focal epilepsy that originates in the mesial structures of the temporal lobe, such as the hippocampus, amygdala, and parahippocampal gyrus.
• MTLE is one of the few types of epilepsy that may be amenable to surgical treatment, offering a potential cure for patients who do not respond to medication.

Aetiology

• The exact cause of MTLE is debated and can be either congenital or acquired.
• Acquired causes: MTLE may develop following prolonged febrile seizures (febrile status epilepticus), head trauma, or central nervous system infections.
• Congenital causes: Coexisting congenital abnormalities, such as cortical dysplasia, can also be seen in some patients.
• It is often associated with hippocampal sclerosis (HS), characterized by neuronal loss and gliosis in the hippocampus.

Pathology

• Histopathological examination often shows pyramidal and granular cell neuronal loss in the hippocampus (hippocampal sclerosis).
• This neuronal loss is accompanied by gliosis, which contributes to the epileptic network within the temporal lobe.

Clinical Features

• Seizure type: MTLE typically presents with complex partial (focal) seizures that originate in the temporal lobe.
• Seizure onset is usually in childhood or early adolescence.
• Aura: Many patients report auras before seizures, often described as a rising epigastric sensation, fear, déjà vu, or olfactory hallucinations.
• Automatisms: During seizures, patients may exhibit complex automatisms, such as lip-smacking, chewing, or hand movements.
• Memory loss: Transient post-ictal memory loss and confusion are common after seizures.
• Dysphasia: If the seizure focus is in the dominant temporal lobe, patients may experience difficulties with speech and language (dysphasia) during and after seizures.

Investigations

• MRI: High-resolution MRI is the imaging modality of choice and typically shows a shrunken, T2 hyperintense hippocampus, a classic sign of hippocampal sclerosis.
• PET/SPECT scans: Interictal (between seizures) hypometabolism in the temporal lobe can be detected on PET or SPECT imaging.
• EEG: Electroencephalography may reveal interictal epileptiform discharges from the temporal lobe, helping to localize the seizure focus.

Management

• Medical treatment: MTLE often responds poorly to antiepileptic drugs (AEDs), making it a medically refractory condition in many patients.
• Surgical treatment: Surgical resection of the affected temporal lobe, particularly the hippocampus, has a high success rate in achieving seizure freedom in patients who do not respond to AEDs. Accurate diagnosis is crucial for surgical candidacy.
• Post-surgical care: After surgery, patients often experience significant improvement in seizure control and quality of life, but regular follow-up is necessary to monitor for any residual seizures or complications.

Cases — Mesial Temporal Lobe Epilepsy (MTLE)

• Case 1 — Rising Epigastric Aura + Déjà Vu 🔄: A 24-year-old man describes stereotyped episodes starting with a rising epigastric sensation, followed by déjà vu and fear. During events, he stares blankly and makes lip-smacking movements. Afterwards, he is confused for several minutes. Diagnosis: MTLE with focal impaired-awareness seizures (aura + automatisms). Management: First-line carbamazepine/lamotrigine; consider epilepsy surgery if refractory.
• Case 2 — Hippocampal Sclerosis on MRI 🧠: A 30-year-old woman has seizures with sudden behavioural arrest, manual automatisms, and postictal confusion. MRI shows hippocampal atrophy and sclerosis. EEG: temporal sharp waves. Diagnosis: MTLE due to hippocampal sclerosis. Management: Antiseizure medication; surgical referral (anterior temporal lobectomy) if drug-resistant.
• Case 3 — Refractory MTLE with Generalisation ⚡: A 36-year-old man has focal seizures with olfactory aura (“burning rubber”), progressing to bilateral tonic–clonic seizures despite multiple medications. Strong family history of epilepsy. Diagnosis: Refractory MTLE with secondary generalisation. Management: Epilepsy surgery workup (video-EEG, neuropsych testing, imaging); discuss vagus nerve stimulation if unsuitable for resection.

Teaching Commentary 🧠

Mesial temporal lobe epilepsy is strongly associated with hippocampal sclerosis. 🔑 Clinical features: - Auras: rising epigastric sensation, déjà vu, fear, or olfactory hallucinations. - Ictal: impaired awareness, staring, automatisms (lip-smacking, fumbling). - Postictal: confusion, dysphasia (if dominant hemisphere). Dx: MRI (hippocampal sclerosis), interictal EEG (temporal sharp waves). Rx: carbamazepine, lamotrigine, levetiracetam; if drug-resistant, surgery (temporal lobectomy) offers up to 70% seizure freedom. MTLE is a common exam favourite because of its classic aura and surgical curability.