Physical Examination Findings in Breakthrough Seizures
A thorough physical examination for breakthrough seizures should focus on identifying potential triggers including medication non-compliance, metabolic abnormalities, and neurological changes, with particular attention to vital signs, neurological status, and signs of injury.
Initial Assessment
Vital Signs
- Check temperature: Fever may indicate infection as a trigger
- Blood pressure: Hypertension could suggest hypertensive encephalopathy
- Heart rate and rhythm: Arrhythmias can cause cerebral hypoperfusion
- Oxygen saturation: Hypoxia can lower seizure threshold
- Respiratory rate: Abnormal patterns may indicate postictal state or ongoing seizure activity
General Appearance
- Level of consciousness: Assess for postictal state or non-convulsive status epilepticus
- Evidence of trauma: Look for tongue biting, facial/scalp lacerations, shoulder dislocations
- Skin examination: Check for needle marks (substance use), rashes (infectious causes), or bruising
Neurological Examination
Mental Status
- Orientation: Assess for postictal confusion or altered mental status
- Memory: Recent and remote memory deficits may indicate postictal state
- Language: Aphasia may indicate focal seizure with Todd's paralysis
Cranial Nerves
- Pupillary response: Asymmetry may indicate structural lesions
- Extraocular movements: Nystagmus may be present with certain antiepileptic medications
- Facial symmetry: Asymmetry may indicate Todd's paralysis
Motor System
- Focal weakness: May indicate Todd's paralysis (temporary weakness following seizure)
- Tone: Increased tone may indicate ongoing seizure activity
- Deep tendon reflexes: Asymmetry may suggest focal lesion
Specific Findings to Look For
Signs of Medication Issues
- Nystagmus, ataxia, or diplopia: May indicate toxic levels of antiepileptic drugs 1
- Gingival hyperplasia: Associated with phenytoin use
- Tremor: May indicate valproate toxicity
- Skin rashes: May indicate drug reaction or Stevens-Johnson syndrome
Signs of Metabolic Derangements
- Check for signs of:
Signs of Substance Use/Withdrawal
- Alcohol withdrawal: Tremor, tachycardia, hypertension, diaphoresis
- Stimulant use: Mydriasis, tachycardia, hypertension
- Ethanol and acetaminophen levels should be checked routinely in patients with breakthrough seizures 3
Special Considerations
For New-Onset vs. Breakthrough Seizures
- In established epilepsy with breakthrough seizures, routine neuroimaging is not necessary unless there are new focal neurological findings 1
- In contrast, new-onset seizures typically require neuroimaging (CT or MRI) 1
For Postictal Assessment
- Document duration of postictal state
- Assess for postictal Todd's paralysis (temporary weakness following seizure)
- Check for postictal aphasia or other focal deficits that may localize seizure focus
Common Pitfalls to Avoid
Missing subtle status epilepticus: Non-convulsive status epilepticus should be considered in any patient with unexplained confusion 2
Overlooking medication non-compliance: Check for medication levels when available, particularly for medications with narrow therapeutic windows
Failing to check for alcohol or drug use/withdrawal: These are common triggers for breakthrough seizures 3
Neglecting to examine for traumatic injuries: Patients may have sustained injuries during seizure activity
Missing signs of infection: Infections, particularly CNS infections, can lower seizure threshold
Documentation Recommendations
- Document exact seizure semiology (as reported by witnesses)
- Note time of last antiepileptic medication dose
- Record duration of postictal state
- Document any focal neurological findings and their evolution over time
- Note any signs of injury sustained during seizure
By systematically evaluating these elements during physical examination, clinicians can better identify potential causes of breakthrough seizures and guide appropriate management decisions.