Flashcards in OHCM - Epilepsy: Diagnosis Deck (49):
Seizures may take ...?
Many forms, but for each individual patient they tend to be stereotyped.
Convulsions are ...?
The motor signs of electrical discharges.
Many of us would have seizures in ...?
Abnormal metabolic circumstances - eg hyponatremia, hypoxia (eg reflex anoxic seizures in faints): we would not normally be said to have epilepsy.
The prevalence of active epilepsy is ...%.
Elements of seizure - A prodrome:
Lasting HOURS-DAYS may rarely precede the seizure.
--> NOT part of the seizure itself, the patient or others notice a change in mood or behavior.
Elements of seizures - An aura is ...?
Part of the seizure of which the patient is aware, and may precede its other manifestations.
The aura may be ...?
A strange feeling in the gut, or an experience such as deja vu (disturbing sense of familiarity), or strange smells or flashing lights.
The aura implies what?
Partial (focal) seizure, often, but not necessarily, from the temporal lobe.
Post-ictally there may be ...?
4. Sore tongue.
5. Temporary weakness after a focal seizure in motor cortex (Todd's palsy).
6. Dysphasia following a focal seizure in the temporal lobe.
Causes - Idiopathic?
2/3 are idiopathic - often familial.
Causes - Structural:
1. Cortical scarring (eg head injury years before onset).
2. Developmental (eg dysembryoblastic neuroepithelial tumor or cortical dysgenesis).
3. Space-occupying lesion.
5. Hippocampal sclerosis (eg after a febrile convulsion).
6. Vascular malformations.
Causes - Others:
1. Tuberous sclerosis.
Non-epileptic causes of seizures:
4. Incr. ICP.
5. Alcohol or benzodiazepine withdrawal.
Causes - Metabolic disturbance:
6. Liver disease.
7. Infection (eg meningitis, encephalitis, syphilis, cysticercosis, HIV).
9. Drugs (TCAs, cocaine, tramadol, theophylline).
Diagnosis - 3 key questions:
1. Are these really seizures?
2. What type of seizure is it?
3. Any triggers?
Are these really seizures?
1. A detailed description from the witness of "the fit" is vital (but ask yourself: "Are they reliable?" In the heat of the moment many witnesses report twitching when none took place.
2. Tongue-biting + slow recovery = very suggestive.
3. Not everything that twitches is epilepsy --> Reflex anoxic convulsions are particularly difficult.
Try hard not to diagnose epilepsy in error. - Why?
Therapy has significant side-effects, and the diagnosis is stigmatizing and has implications for employment, insurance, and driving.
What type of seizure is it?
Partial or generalized?
The ATTACK'S ONSET = Key concern here.
If the seizure begins with focal features = Partial seizure - HOWEVER RAPIDLY it then generalizes.
4. Certain sounds.
5. Flickering lights/TV.
6. Contrasting patterns.
In assessing a 1st-ever seizure, consider also:
1. Is it really the first?
2. Was the seizure provoked?
3. Prompt investigation.
Is it really the first seizure?
Ask the family and the patient about past funny turns/odd behavior. Deja vu and odd episodic feelings of fear may well be relevant.
Was the seizure provoked?
1. PROVOKED 1st seizures are less likely to recur (3-10% unless the cause is irreversible, eg an infarct or glioma).
2. If it is unprovoked, recurrence rates are 30-50%.
Provocations are different to triggers:
Most people would have a seizure given sufficient provocation, but most people do not have seizures however many triggers they are exposed to, so triggered seizures = epilepsy.
1. With admission for 24h for bloods, drugs screen, LP (if safe).
3. CT/MRI + enhancement --> or else infective causes, eg TB, may be missed.
4. Admit to substantiate ideas of pseudoseizures, or for recurrent seizures.
Seizure classification - Main 2 categories:
1. Partial seizures.
2. Primary generalized seizures.
A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifesting as SEIZURES.
Partial seizures - Categories:
1. Simple partial seizure.
2. Complex partial seizure.
3. Partial seizure with secondary generalization.
Partial seizures - Definition:
Focal onset, with features referable to a part of one hemisphere. Often seen with underlying structural disease.
Simple partial seizure:
Awareness is UNIMPAIRED, with focal motor, sensory (olfactory, visual etc), autonomic or psychic symptoms. NO POST-ICTAL symptoms.
Complex partial seizures:
1. Awareness is IMPAIRED.
2. May have a simple partial onset (=aura).
3. Impaired awareness at onset.
4. MC arises from the temporal lobe.
5. Post-ictal confusion is common with seizures arising from the temporal lobe, whereas recovery is rapid after seizures in the frontal lobe.
Partial seizure with secondary generalization:
In 2/3 of patients with partial seizures, the electrical disturbance, which starts focally (as either a simple or complex partial seizure), spreads widely, causing a secondary generalized seizure, which is typically convulsive.
Primary generalized seizures - Definition:
Simultaneous onset of electrical discharge throughout the cortex, with no localizing features referable to only one hemisphere.
Primary generalized seizures - Categories:
1. Absence seizures.
2. Tonic-clonic seizures.
3. Myoclonic seizures.
4. Atonic (akinetic) seizures.
5. Infantile spasms.
1. Loss of consciousness.
2. Limbs stiffens (tonic), then jerk (clonic). May have one without the other.
3. Post-ictal confusion and drowsiness.
1. Sudden jerk of a limb, face, or trunk.
2. The patient may be thrown suddenly to the ground, or have a violently disobedient limb: one patient described it as "my flying-saucer epilepsy", as crockery which happened to be in the hand would take off.
Atonic (akinetic) seizures:
Sudden loss of muscle tone causing a fall, no LOC.
Commonly associated with TUBEROUS SCLEROSIS.
The classification of epileptic syndromes ...?
Is separate to the classification of seizures, and is based on:
1. Seizure type.
2. Age of onset.
3. EEG findings.
4. Other features such as family history.
Localizing features of partial seizures - Temporal lobe:
2. Abdominal rising sensation or pain.
3. Dysphasia (ictal or post-ictal).
4. Memory phenomena.
5. Hippocampal involvement.
6. Uncal involvement.
7. Delusional behavior.
8. You may find yourself not believing your patient's bizarre story:
"I get orgasms when I brush my teeth."
Temporal lobe partial seizures - Automatisms:
Complex motor phenomena, but with impaired awareness and no recollection afterwards, varying from:
1. Primitive oral (lip smacking, chewing, shallowing).
2. Manual (fumbling, fiddling, grabbing) movements.
3. Complex actions (singing, kissing, driving a car, violent acts).
Temporal lobe partial seizures - Abdominal rising sensation or pain:
+/- ictal vomiting; or rarely episodic fevers or D&V.
Temporal lobe partial seizures - Memory phenomena:
1. Deja vu (when everything seems strangely familiar).
2. Jamais vu (everything seems strangely unfamiliar).
Temporal lobe partial seizures - Hippocampal involvement may cause:
Emotional disturbance: sudden terror, panic, anger, elation or derealization (out-of-body experiences) --> May manifest as excessive religiosity.
Temporal lobe partial seizures - Uncal involvement:
1. May cause hallucinations of smell or taste and a dreamlike state.
2. Seizures in auditory cortex may cause complex auditory hallucinations --> eg music, or conversations, or palinacousis.
Localizing features of frontal lobe partial seizures:
1. Motor features such as posturing, versive movements of the head and eyes, or peddling movements of the legs.
2. Jacksonian march (a spreading focal motor seizure with retained awareness, often starting with the face or a thumb).
3. Motor arrest.
4. Subtle behavioral disturbances (often diagnosed as psychogenic).
5. Dysphasia or speech arrest.
6. Post-ictal Todd's palsy.
Transient neurological deficit (paresis) after a seizure.
--> There may be face, arm, or leg weakness, aphasia or gaze palsy, lasting from 30min-36h. The etiology is unclear.
Localizing features of parietal lobe partial seizure:
1. Sensory disturbances - tingling, numbness, pain (rare).
2. Motor symptoms - due to spread to the pre-central gyrus.