Seizure Diagnosis Flashcards
Key concept for seizure diagnosis:
- Accurate history taking is key
- EEG serves as a confirmatory
Diagnosis components:
- History taking
- Investigations
- Neurological examination (e.g., mental status, level of consciousness, motor reflexes, focal deficits => to rule out other conditions)
- Concomitant medical conditions (possible causes of provoked seizure)
History taking:
- Description of onset, duration, characteristics
- Best provided by person who witnessed the event
- Pt is useful is describing details of aura, preservation of consciousness, post-ictal state
Diagnosis:
- Positive identification of the classical characteristics
- Aura (complex partial, secondary generalized, GTC, NOT absence)
- Cyanosis (GTC - tonic phase)
- Loss of consciousness
- Motor manifestations (tonic, clonic, myoclonic, GTC)
- Generalized stiffness of limbs and body (tonic)
- Jerking of limbs (clonic, myoclonic)
- Tongue biting (GTC)
- Urinary incontinence (GTC)
- Post-ictal confusion (complex partial, secondary generalized)
- Muscle soreness
What are some differential diagnosis to seizures?
- Syncope (fit vs faint)
- Transient ischemic attack (should have no neurological deficit)
- Migraine
- Psychogenic nonepileptic seizures (PNES)
What is an essential investigation tool for diagnosis and classification of seizures and epileptic syndromes?
Scalp Electroencephalography (EEG)
Explain how EEG is used to diagnose and classify seizures
Epileptiform discharges on EEG confirms diagnosis of seizure/epilepsy
However, normal EEG does NOT preclude the possibility of epilepsy because:
- Not real time, electrical discharges no longer present post-seizure
- Not all epileptic patients have abnormal EEG (only 50% chance of showing epileptiform activity in a first awake EEG, 80-90% in repeated awake-sleep EEGs)
T/F
EEG can be abnormal in normal persons
True
- Possible false positive epileptiform discharges in asymptotic adults (0.5-1% false positive chance)
What is a video EEG and when might it be used?
What is it?
- Video recording + EEG recording to allow for correlation of brain discharges with outward manifestations
When is it used?
- Not routinely done as it is expensive and labor-intensive
- Typically only used if EEG unable to diagnose
What is a video EEG and when might it be used?
What is it?
- Video recording + EEG recording to allow for correlation of brain discharges with outward manifestations
When is it used?
- Not routinely done as it is expensive and labor-intensive
- Typically only used if EEG unable to diagnose
Useful in?
- Differentiate epileptic seizures from PNES
- In PNES, there is outward manifestation but no brain discharges on the EEG
What are two other diagnostic investigations that are done to rule out contributing factors/causes?
- Magnetic resonance imaging (MRI) with gadolinium
- Biochemical/toxicology
These investigations must be done even if pt has diagnosis as epilepsy, in order to rule out other contributing factors
MRI w gadolinium
- Who is it ordered for?
- What does it identify/exclude?
Ordered for pt who present with:
- first seizure
- focal neurological deficits
- suggestion of focal onset seizure
Identifies/rules out focal lesions (structural/anatomical cause of seizure)
- Mesial temporal sclerosis
- Brain injury/lesion
- Focal cortical dysplasia
- Remote injury (e.g., old stroke)
- Tumor
- Vascular malformation
Biochemical/toxicology
- What does it rule out?
- What is used?
Rules out electrolyte abnormalities
Serum prolactin:
- Considerable variability, hence not used routinely
- Typically elevated 3-4 fold (more likely after GTC)
Creatine kinase (CK):
- Raised after GTC (due to muscle breakdown)
