Semiology for focal-onset seizures
Frontal lobe
Disinhibited behaviors
Confusion
Automatisms
Temporal lobe
Confusion
Auditory hallucinations
Chewing, lip smacking
Parietal lobe
Paresthesias (warmth, cold, tingling, numbness)
Loss of awareness
Confusion
Occipital lobe
Scotomas
Visual hallucinations
Confusion
Semiology for generalized seizures
Tonic
Increased muscle tone
Clonic
Rhythmic jerking
Tonic clonic
Increased muscle tone with rhythmic jerking
Atonic
Loss of muscle tone
Myoclonic
Muscle contractions
Seizures present with a spectrum of clinical manifestation and severity. The following terms are used frequently to define the spectrum of seizure activity [5, 7, 8]:
Seizure – uncontrolled electrical impulses in the brain that manifest as focal or generalized rhythmic activity lasting 10 s to 5 min.
Status epilepticus (SE) – a single seizure lasting more than 5 min or recurrent seizures without return to neurologic baseline in the intervening period(s).
Generalized convulsive status epilepticus (GCSE) – status epilepticus that is clinically evident, e.g., tonic-clonic, clonic, or myoclonic movements.
Nonconvulsive status epilepticus (NCSE) – status epilepticus without tonic-clonic, clonic, or myoclonic movements, but often with impairment in mental status with or without subtle signs (e.g., eye, facial, or finger movements) and associated with electrographic evidence of seizure activity. Similar to convulsive status epilepticus, more than 5 min or >30 min of total ictal activity in any hour of recording is consistent with NCSE. Can be focal or generalized. NCSE is common among critically ill comatose patients and accounts for 20% of all SE [9].
Refractory status epilepticus (RSE) – can initially be GCSE or NCSE; it is defined by failure to respond to first- or second-line antiepileptic therapy. RSE occurs in a significant number of patients who present with GCSE.
Super refractory status epilepticus (SRSE) – status epilepticus that persists or recurs more than 24 h after appropriate anesthetic therapy
New-onset refractory status epilepticus (NORSE) – refractory status epilepticus without an obvious etiology after an initial workup.
The most common cause of SE is a prior history of epilepsy. For these patients, a number of circumstances can lower seizure threshold including recent alterations in antiepileptic medication dosing, systemic infection, or new drug exposure. Patients in the Neuro ICU can develop SE as a result of old or new cerebral insult including stroke, tumor, subdural hemorrhage, hypoxic-ischemic injury, metabolic disarray, and ethyl alcohol withdrawal (Table 12.2). The increased utilization of continuous EEG monitoring in the ICU setting has proved very useful in the evaluation of patients with fluctuating neurologic symptoms and unexplained coma. Timely identification of NCSE can focus treatment and improve outcome in neurologically ill patients.
Table 12.2
Provoked seizure etiologies
Primary neurologic disorders | Systemic disorders | Drugs that lower seizure threshold |
|---|---|---|
Head trauma | Hypo/hyperglycemia | Antibiotics |
CNS infections | Hyponatremia | Antidepressants |
Stroke | Hypomagnesemia | Antipsychotics |
Cerebrovascular diseases | Hyperthyroidism | Stimulants |
Encephalopathy | Sleep deprivation | Chemotherapy drugs |
Anoxic brain injury | Hyperthermia | Beta-blockers |
Intracranial hemorrhage | Uremia | Narcotics |
CNS structural abnormalities | Withdrawal ETOH | Antihistamines |
Neurodegenerative disease | Withdrawal sedatives | Analgesics |
12.2 Case Study
A 78-year-old man is transferred from another hospital to the Neuro ICU. The wife initially states that he was in his usual state of health watching TV when his eyes rolled back and he began to shake all over. Paramedics arrived at the scene, where the patient had stertorous breathing and depressed level of consciousness. He was intubated in the field and taken to the local hospital. While in the CT scan, he had a “GTC” seizure. He was treated with a benzodiazepine IV push and the seizure terminated. CT scan revealed an 8 mm acute on chronic left subdural hemorrhage with 4 mm of midline shift. He was loaded with fosphenytoin and admitted to the ICU for further management. On the way to the ICU, he begins “jerking” on the right side and the nurse administers more Ativan. On arrival to the ICU, a continuous infusion of midazolam and continuous EEG monitoring are ordered STAT.
Upon further questioning, the wife states that her husband was tripped by the dog about 2 months ago and has become increasingly unsteady but attributed it to an old knee injury. The patient’s cEEG showed lateralized periodic discharges over the right temporal parietal region that evolved into frank electrographic seizures despite antiseizure therapy. He was started on a propofol infusion titrated to seizure suppression and remained seizure-free for 30 h. The infusion was slowly tapered over several hours at which point the nonconvulsive seizures recurred. He was bolused with IV midazolam and started on an infusion. Given his refractory seizures, the decision was made to go to the OR for SDH evacuation.
12.3 Initial Evaluation
12.3.1 Airway
The inability to maintain the airway is the most immediate risk to a patient with CSE. Factors that affect adequate oxygenation and ventilation include a clenched jaw, paradoxical or poorly coordinated respirations, secretions, and vomitus. Implementing precautions, including placing the patient on their side and supplying 100% oxygen via a face mask while performing continuous cardiopulmonary monitoring, are essential to minimizing the need for intubation secondary to hypoxic respiratory failure. However, despite these efforts intubation may be necessary and should be determined on a case-by-case basis. Short-acting paralytics should be used so as not to mask clinical seizure activity for a prolonged period of time.
12.3.2 Abortive Therapy
Benzodiazepines are first-line agents to control seizures [10–12]:
Lorazepam 4 mg IV push over 2 min, if still seizing after 5 min, repeat ×1 to a max of 0.1 mg/kg IV.
See Fig. 12.1 for status epilepticus management algorithm.
Fig. 12.1
Status epilepticus treatment algorithm
If no IV access is available, other options include:
Rectal diazepam gel (10–20 mg, 0.2 mg/kg)
Intranasal/buccal/IM midazolam 10 mg IV solution
12.3.3 History
Since etiology of seizures and SE varies significantly, a thorough evaluation of seizure characteristics and patient history is essential in guiding patient management:
Seizure characteristics – Describe the seizure including onset, semiology (gaze deviation, face or extremity jerking, automatisms, altered mental status), evolution (progressing generalization), how did it cease (e.g., on its own or with medication).
Seizure duration – Determine when the patient last seen normal or at baseline.
History of present illness – Obtain a thorough understanding of the events leading up to the seizure including preceding illness, cognitive or behavioral changes, trauma, recent changes in medications, lifestyle, use of illicit substances or alcohol, etc.
Past medical history – This should include questions about prior seizures, history of epilepsy, and epilepsy risk factors (e.g., prior trauma, stroke, CNS infection, febrile seizures) as well as psychogenic non-epileptic seizures.
Medication history – Special attention should be made to medications that lower seizure threshold. If the patient has a history of epilepsy, obtain information about antiseizure medication regimen recent dosing adjustments or a history of medications noncompliance.
12.3.4 Neurological Evaluation
A neurological assessment is imperative in the initial evaluation and will be fundamental in narrowing the list of differential diagnoses. A full assessment should include mental status, cranial nerves including fundoscopy, motor and sensory functioning, reflexes, and cerebellar exam.
Patients in NCSE can have pupillary abnormalities, including asymmetry and hippus. However, if the pupils are dilated, pinpoint, or unreactive, other life-threatening neurologic emergencies should be entertained, prompting an emergent neurology or neurosurgical consultation. Additionally, in NCSE the eyes may be open, but the patient is mute (eye open mutism), the eyes may be deviated with or without head version. Not all eye deviation is secondary to seizure and can be seen in cortical, thalamic, and brain stem lesions. In general, with ongoing seizures the eyes will deviate away from the brain lesion (especially if frontal), but with stroke or other lesions, they will deviate toward the side of the lesion. The exception to this rule involves lesions to the paramedian pontine reticular formation, in which lesions in the pons may cause contralateral eye deviation. Facial, eye, or limb twitches may be observed and may be induced with stimulation. Tone may be symmetrically or asymmetrically increased with hyperreflexia and clonus. “Awake” patients are more likely to exhibit automatisms (e.g., picking, lip smacking) and behavioral changes (perseveration, agitation, emotional lability, aggressiveness).After a self-limiting convulsive seizure, a patient’s exam should return to their baseline functioning over a short period of time. Patients who do not return to their baseline level of consciousness within 30–60 min should be evaluated for nonconvulsive seizures and status epilepticus and undergo monitoring with cEEG as soon as possible. Immediately in the post-ictal phase, the patient may have a focal motor deficit (Todd’s paralysis) that resolves over minutes to days.
Sometimes seizures are clear-cut and obvious in a clinical setting where the provider knows the patient and the history of the patient. However, many patients present without a diagnosis or history of seizures. The differential diagnoses for seizures can be extensive, so it is important to consider life-threatening diagnoses. There are several conditions that should be ruled out immediately or considered during the workup for a patient with seizures:
Basilar artery thrombosis – patients may present in coma or have multiple cranial neuropathies (papillary abnormalities, diplopia, dysphagia), cerebellar signs (ataxia, nystagmus, nausea/vomiting), weakness (hemiparesis, quadriparesis), paroxysmal spasms or posturing (decerebrate). Patients with concerns for basilar thrombosis require emergent recognition of signs/symptoms and neuroimaging for possible thrombolysis.
Ischemic stroke – patients can present with a wide range of symptoms depending on the location of the stroke and can easily mimic seizure activity or rarely be associated with ictal activity. Management of stroke requires early detection and treatment. Patients with focal deficits should be evaluated for possible TIA/stroke in case emergent treatment is warranted.
Meningitis/encephalitis – patient may complain of headaches, but typically have flu-like symptoms; patients may also present in a comatose state. Patients with fever and altered mental status need a lumbar puncture and antibiotics imminently; neuroinfections can cause seizures that should be treated concurrently. Lumbar puncture and antibiotics should not be delayed for other diagnostic testing if there is a strong concern for meningitis.
Sepsis – patient may present with encephalopathy, which is often an early sign in sepsis. Again treatment of sepsis with antibiotics should be prioritized. These patients are also at increased risk for seizures, especially nonconvulsive, that would otherwise be missed without the use of cEEG.
Hypoglycemia – patients with hypoglycemia may present in a coma, focal neurologic deficits, or seizure activity that is best treated with glucose administration. All patients with altered mental status should have a finger-stick glucose done to evaluate for the hypoglycemia as a potential etiology of their neurologic deterioration.
Nonconvulsive status epilepticus – GCSE is generally apparent and easy to identify, but NCSE may be more insidious. Patients may be in a coma for various reasons, which can all be complicated by NCSE, especially if it is not considered or recognized as delays in diagnoses are associated with worse outcomes. If identified, NCSE should be treated aggressively.Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
