Seizure types
What is an absence seizure? What category of seizure does it fall under?
- brief lapse in awareness (Lose + regain consciousness quickly)
- often mistaken for daydreaming
- Generalised seizure
What are ion channels, how do they relate to epilepsy?
- cellular structures, trans-membrane chennels that allow ion passage
- dysfunction→ altered signaling → epilepsy
What does EEG stand for? What does it do?
- Electroencephalogram
- Diagnostic tool, records brain activity
What does AED mean in the context of epilepsy? What main subtype of AEDs is used to treat epilepsy
Antiepileptic drug
- anticonvulsants
What are the main excitatory/ inhibitory neurotransmitters in the brain? What are their receptors called and how do they function differently in epilepsy?
- Glutamate → NMDA; GABA → GABA receptors
- NMDA → fast or long-lasting activation, GABA receptors → dysfunctional
What is a focal seizure?
- affects one part of the brain
- does not impair consciousness
Explain acquired causes of epilepsy.
EG: head trauma → post-traumatic epilepsy
What is an atonic seizure?
- loss of muscle tone during seizure
- leads to falls
What diet is recommended for people with epilepsy and why?
- ketogenic diet
- high fat, low carb
- can help control seizures
What is status epilepticus? How do you treat it?
- seizure lasts >5 minutes
- ongoing /does not return to normal
- usually tonic-clonic
- medical emergency; treat with benzos
What are tonic-clonic seizures? To which seizure category do they belong?
- Tonic phase (stiff/flexed tone) followed by clonic phase (violent muscle contractions)
- loss of consciousness
- Generalised seizures
What is cortical dysplasia?
- common genetic cause of epilepsy
- causes abnormal brain structure
What is the postictal state? What can it entail?
- state after seizure
- characterised by confusion and fatigue
- Todd's paralysis/ paresis: in arms/ legs; lasts about 15 hours, subsides in 2 days
- Causes by temporary and severe suppression of seizure-affected area in the brain
Which surgical procedure(s) may be performed to help treat epilepsy?
- lobectomy and lesionectomy
- removal/ disconnecting brain region causing the seizure
What is the Jacksonian March? during which type of seizure does it occur?
- Starts in one muscle group + spreads
- Simple partial seizure: strange sensations / jerking movements
- aware of what is happening + remembers episode
What are focal impaired-awareness seizures?
- repetitive, purposeless movements
- EG lip-smacking/ fidgeting
What is Neurocysticercosis?
- infectious disease that causes seizures,
- especially in developing countries.
What is a prodrome?
- symptom: often aura
- sensory disturbances/ unusual feelings
What is VNS? How is it performed and what other conditions can it potentially be used to treat (Name 4)?
- vagal nerve stimulation
- electrical stimulation of vagus nerve
- incision to expose LEFT vagus nerve, lead implanted from chest to neck + connected to generator
- Treatment-resistant depression, cluster headache migraines, anxiety disorders, rheumatoid arthritis, Crohn's disease, PTSD, obesity, heart failure (improves rate modulation and parasympathetic tone)
Name some (At least 3) DDs for seizures.
Substrates: sugar, oxygen
Isoniazid
Cations: Na, Ca, Mg
Kids: pregnancy/ eclampsia
Drugs
Rum: alcohol withdrawal
Illnesses: chronic
Trauma
3 antis: antihistamines, antidepressants, anticonvulsants
Rat poison
SICK DRIFT3R
A 19-year-old man is brought to the emergency department for evaluation of abnormal behavior. He was having lunch with his family when he noted a pungent smell of burning rubber followed by uncontrollable lip smacking. The patient became unresponsive for a minute after which his whole body started shaking, and he fell to the ground. The patient experienced urinary incontinence during the episode. Past medical history is significant for seizures in childhood precipitated by high fevers. The patient’s temperature is 37.0°C (98.6°F), pulse is 80/min, respirations are 20/min, and blood pressure is 135/85 mmHg. The patient appears confused and is unable to recall what happened. Physical examination shows bite marks on the tongue. Which of the following is the most likely diagnosis?
A. Juvenile myoclonic epilepsy
B. Simple focal seizure
C. Focal seizure with secondary generalisation
D. Stroke
- Focal seizure with secondary generalisation
Major takeaway
Seizures originating from the temporal lobe are usually preceded by olfactory hallucinations followed by automatisms. It can be simple (if the consciousness is retained) or complex (if there is loss of consciousness). Moreover, focal seizures can secondarily generalize into tonic-clonic seizure.
Main explanation
Focal seizures are defined as seizures originating in a single cerebral hemisphere. These are usually preceded by aura, depending on the area involved in the abnormal discharges, and are sub-divided into simple or complex based on whether consciousness is intact or lost. This patient most likely had a complex focal seizure arising from the temporal lobe, based on localization findings of olfactory hallucinations (smelling burning rubber) followed by automatisms (lip smacking) and loss of consciousness. Moreover, it secondarily generalized into tonic-clonic seizure, as evidenced by generalized shaking and tongue biting. Seizures arising from the temporal lobe are usually due to mesial temporal sclerosis, which is associated with childhood febrile seizures.
A 20-year-old woman is brought to the emergency department by her partner after finding the patient unconscious in her room in soiled clothes this afternoon. The partner states the patient has been under significant stress lately due to upcoming exams. Past medical history is significant for migraine, for which the patient takes topiramate. Vitals are within normal limits. The patient appears tired and confused and is unable to recall what happened. Physical examination shows a bite mark on the tongue. Which of the following is the most likely cause of this patient’s loss of consciousness?
A. Vasovagal syncope
B. generalised tonic-clonic seizure
C. psychogenic non-epileptic seizure
D. migraine attack
B.
Major takeaway
Careful history and examination are crucial to avoid delay or misdiagnosis of a seizure. GTCS manifests as loss of consciousness, tonic-clonic activity, postictal confusion and associated findings of tongue biting, incontinence and amnesia.
Main explanation
The examination findings in this patient, together with loss of consciousness and postictal state, are consistent with a diagnosis of generalized tonic-clonic seizure (GTCS). It is the most common type of generalized seizures, and it manifests as a generalized stiffness of muscles (tonic phase) that is followed by jerking and twitching (clonic phase). The patient loses consciousness during the episode and remains in deep sleep for a few minutes, followed by postictal confusion. The episode can be overlooked if the patient is alone. However, it is usually accompanied by tongue bite, urinary and/or fecal incontinence and amnesia of the event, all of which are seen in this patient. Certain triggers or precipitants tend to lower seizure threshold. These include, but are not limited to, strong emotions, flashing lights, fever, stress and lack of sleep (as in this patient).
A 32-year-old woman comes to the clinic for a routine health evaluation. While sitting in the waiting room, the patient experiences an episode of crying during which she falls to the ground and starts rolling side-to-side. The patient’s eyes are closed shut and could not be opened by a nurse. The episode lasts for about 3 minutes, after which the patient is able to stand up and sit in a chair. The patient has experienced similar episodes several times in front of family members before. The patient has suffered from post-traumatic stress disorder after a sexual assault several years ago; the condition is now being managed with sertraline. The patient’s temperature is 37.0°C (98.6°F), pulse is 80/min, respirations are 35/min, and blood pressure is 135/85 mmHg. Physical examination shows no abnormalities. The patient is alert and oriented. Oral examination reveals no tongue lesions. Which of the following is the most likely diagnosis?
A. Malingering
B. Factitious disorder
C. Medication side-effect
D. Psychogenic non-epileptic seizure
D
Major takeaway
Diagnosis of PNES requires a high index of suspicion, as its clinical findings can be confused with those of a generalized seizure. The condition is more commonly seen in female patients with a past history of emotional, physical, or sexual abuse, and it presents with variable motor activity, pelvic thrusting, and forced closure of the eyes. Postictal confusion, urinary incontinence, and tongue biting are not seen in PNES and can help differentiate from a generalized tonic-clonic seizure.
Main explanation
This patient’s findings of jactitation (rolling from side to side), forced closure of eyes, vocalization (crying) and rapid reorientation, together with the history of sexual assault, makes the diagnosis of Psychogenic Non-Epileptic Seizures (PNES) most likely in this case.
PNES is defined as sudden disruption of motor, sensory, autonomic or cognitive function that is of psychologic origin (instead of excessive synchronous neuronal activity seen in seizures). It is most common in the third decade of life and has female predominance. Risk factors include learning disabilities, or a history of physical or psychosocial trauma (unwanted pregnancy, physical, verbal or sexual abuse, or assault). It typically lasts longer than 2 minutes and presents with inconsistent findings (e.g., variable motor activity, pelvic thrusting, and forced closure of eyes). According to DSM-V criteria, the diagnosis does not require a provider to judge whether the episode was intentionally produced, as this aspect of the presentation may not be reliably discerned, and such a judgement would not change management, which consists of psychological evaluation.
A 13-year-girl is brought to the emergency department by her parent due a recent episode of unresponsiveness. The parent states the patient was playing in the yard 30 minutes ago when she started complaining of an abnormal sensation in her chest. This complaint was followed by repetitive fidgeting of the right hand, accompanied by blank staring and unresponsiveness that lasted for about a minute, after which the patient lost consciousness. She has not had any previous similar episodes. Past medical history is significant for a viral infection last month, for which the patient was hospitalized and treated with an intravenous medication. Vital signs are within normal limits. The patient appears tired but is responsive. The patient’s speech is incomprehensible. The remainder of the physical examination shows no abnormalities. Which of the following parts of the brain is most likely involved in this patient’s episode?
A. Frontal lobe
B. Temporal
C. Occipital
D. Cerebellum
B
Major takeaway
Clinical findings of complex focal seizures depend on the area of the brain involved. Complex focal seizures originating in the temporal lobe are the most common and often present as a rising epigastric sensation or olfactory hallucination, followed by blank staring, automatisms and brief loss of consciousness.
Main explanation
This patient most likely had complex focal seizure arising from the temporal lobe. Abnormal discharges in this area are typically preceded by an aura (e.g. rising sensation in epigastrium, smelling burning rubber) followed by blank staring, automatisms and post-ictal loss of consciousness, all of which are seen in this patient. Her history of a viral infection was most likely herpes encephalitis, which may have caused necrosis and subsequent scarring in the temporal lobe.
Focal seizures are defined as seizures originating in a single cerebral hemisphere. These are usually preceded by aura, depending on the area involved in abnormal discharges, and can be subdivided into: