What is the approach to a comprehensive neurological assessment for a patient with a history of neurological conditions, such as epilepsy (seizure disorder) or multiple sclerosis (MS), and current medications, including antiepileptic drugs (AEDs)?

Comprehensive Neurological Assessment for Patients with Epilepsy or Multiple Sclerosis on Antiepileptic Drugs

For patients with epilepsy or MS on antiepileptic drugs, conduct a detailed multidisciplinary neurological, neuropsychiatric, and neuropsychological assessment that specifically evaluates seizure control, medication adverse effects, cognitive-behavioral changes, and sensorimotor dysfunction. 1

Core Assessment Components

History Documentation

Seizure Characterization:

• Classify all prior seizures as provoked (within 7 days of acute insult such as electrolyte abnormalities, withdrawal, toxic ingestions) versus unprovoked (without acute precipitating factors) 2
• Document remote symptomatic seizures from CNS or systemic insults occurring more than 7 days in the past, including history of stroke or traumatic brain injury 2
• Record seizure frequency, duration, and any changes in pattern since starting AEDs 1
• Note any focal features, auras, or postictal deficits including Todd's paralysis 2

Medication Review:

• Document all current AEDs with doses, duration of therapy, and therapeutic drug levels if available 1
• Identify polypharmacy patterns, as MS patients on AEDs average 5.4 concurrent medications with 60% using additional CNS-active drugs 3
• Screen for enzyme-inducing AEDs (carbamazepine, phenytoin, phenobarbital, primidone) that interact with psychotropic, immunosuppressant, cardiovascular drugs, and oral contraceptives 4
• Assess for drug interactions, particularly with macrolide antibiotics, antifungals, verapamil, diltiazem, and isoniazid which inhibit carbamazepine metabolism 4
• Note any lamotrigine use in women on oral contraceptives, as contraceptive steroids stimulate lamotrigine metabolism 4

Comorbidity Assessment:

• Evaluate for neuropathic pain, as gabapentin (12.7%) and pregabalin (7.7%) are commonly prescribed in MS patients 3
• Screen for depression and anxiety, noting amitriptyline use (9.7% in MS patients) 3
• Document alcohol use/dependence or withdrawal history as a significant seizure risk factor 2
• Identify conditions increasing seizure risk: hypocalcemia, other electrolyte abnormalities, fever-related seizures 2

Neurological Examination

Cognitive-Behavioral Assessment:

• Perform detailed neurobehavioral evaluation to identify symptoms of abnormal brain function, including attention, memory, executive function, and language 1
• Assess for medication-induced cognitive side effects, particularly with older AEDs (phenobarbital, primidone) which have more adverse cognitive effects than newer agents 5
• Screen for mood changes, anxiety, depression, apathy, psychosis, or personality changes that may indicate disease progression or medication effects 1

Sensorimotor Examination:

• Document focal neurologic deficits, pyramidal signs, extrapyramidal signs, or movement disorders 1
• Evaluate for medication-induced parkinsonism, dyskinesias, or gait disturbances 1
• Assess for cortical visual abnormalities, aphasia, apraxia, or agnosia suggesting atypical presentations 1
• Note any fluctuating course suggesting superimposed delirium or rapidly progressive disease requiring urgent evaluation 1

Laboratory Testing

Essential Tests:

• Obtain serum glucose and sodium levels, as these are the most frequent abnormalities requiring immediate intervention in seizure patients 2
• Consider pregnancy testing if patient has reached menarche 2
• In patients with known cancer or renal failure, obtain calcium and magnesium levels 2
• Consider toxicology screening if drug exposure or substance abuse is suspected 2

Additional Testing When Indicated:

• Perform lumbar puncture (after head CT) in immunocompromised patients to rule out CNS infection 2
• Consider serum ferritin if symptoms suggest restless legs syndrome, as iron deficiency can be associated with secondary causes 6

Neuroimaging

MRI Indications:

• MRI is the preferred imaging modality for non-emergent evaluation of seizures, as it is more sensitive than CT for detecting epileptogenic lesions 2
• Obtain MRI with dedicated epilepsy protocol for focal seizures or refractory epilepsy (84% sensitivity with 3T scanner) 2
• Consider brain MRI with contrast if there is history of brain disease/injury, cerebral palsy, microcephaly, macrocephaly, abnormal neurologic findings, or epilepsy 1

CT Indications:

• Perform emergent head CT without contrast for: age >40 years, history of malignancy or immunocompromised state, fever or persistent headache, focal seizure onset, new focal neurological deficits, persistent altered mental status, recent trauma, patients on anticoagulation 2
• For low-risk patients (young, returned to baseline, normal neurologic exam, reliable follow-up), deferred outpatient MRI is acceptable 2

Electroencephalography

• Obtain EEG as part of the neurodiagnostic evaluation, as abnormal EEG findings predict increased risk of seizure recurrence 2
• Consider EEG if seizures or paroxysmal events are suspected, or to evaluate for nonconvulsive seizures 1

Quality of Life Assessment

Health-Related Quality of Life Evaluation:

• Use disease-specific instruments to assess HR-QOL, as successful treatment of motor symptoms may not correlate with improvements in quality of life 1
• Document impact of neuropsychiatric dysfunction (anxiety, sleep disturbance) and sensorimotor dysfunction (extrapyramidal features) on daily functioning, as these increase morbidity and care burden 1

Common Pitfalls to Avoid

• Do not miss alternative diagnoses: 28-48% of suspected first seizures have alternative diagnoses (syncope, nonepileptic seizures, panic attacks) 2
• Do not overlook metabolic causes: Failing to identify hypoglycemia or hyponatremia may miss treatable seizure causes 2
• Do not assume alcohol withdrawal: Alcohol withdrawal seizures should be a diagnosis of exclusion; search for symptomatic causes before labeling as withdrawal seizures 2
• Do not ignore drug interactions: With widespread polypharmacy in MS patients on AEDs, be aware of pharmacodynamic interactions and excessive adverse effects 3
• Do not delay specialist referral: Patients with atypical presentations, rapid progression, fluctuating course, or persistent abnormal examination require dementia subspecialist or neurologist evaluation 1

Disposition and Follow-up

• Patients with first unprovoked seizure who have returned to clinical baseline in the ED need not be admitted 2
• Consider admission if: persistent abnormal neurologic examination, abnormal investigation results, or patient has not returned to baseline 2
• The mean time to first seizure recurrence is 121 minutes (median 90 minutes) with >85% occurring within 6 hours 2
• Arrange reliable outpatient neurology follow-up for medication management and ongoing monitoring 1