FIGURE 72.1 Diagnostic approach to seizures The most common causes are in bold type An LP with analysis of the cerebrospinal fluid (CSF) is the only way to make the diagnosis of meningitis and should be performed when meningitis is being considered An elevated CSF protein, CSF pleocytosis, and a low CSF glucose level are all suggestive of CNS infection CSF cultures, Gram stain, latex studies, and polymerase chain reaction may identify a specific agent Ideally, CSF cultures should be obtained before antibiotic therapy is initiated However, in the critically ill or unstable patient, antibiotics should not be withheld until an LP is performed Furthermore, in cases in which a potential metabolic disease is being considered, CSF lactate, pyruvate, and/or amino acid level determinations can be used to diagnose a specific metabolic disorder In these cases, it is often helpful to collect an extra tube of CSF for later analysis In any patient with signs of increased intracranial pressure, an LP should not be performed until head imaging can be done Electrolyte abnormalities may also cause seizures, with hyponatremia, hypocalcemia, and hypomagnesemia being the most common Unfortunately, seizures caused by electrolyte derangements are often refractory to anticonvulsant therapy and patients will continue to seize until the underlying abnormality is corrected In general, the routine screening for electrolyte abnormalities in a patient with brief seizure is of low value Serum electrolytes should be measured in all patients with seizure with significant vomiting or diarrhea; patients with underlying renal, hepatic, neoplastic, or endocrinologic disease; patients who are taking medications that may lead to electrolyte disturbances; or patients who have seizures that are refractory to typical anticonvulsant management Another clinical scenario involves hyponatremic seizures in infants, typically younger than months, after prolonged feedings of dilute formula (“infantile water intoxication”) Other patients may be evaluated on a case-by-case basis IV calcium, magnesium, and hypertonic (3%) sodium chloride should be used to treat the appropriate abnormal condition In the case of hyponatremia, 3% sodium chloride should be infused rapidly until the seizure activity has been stopped; subsequent to seizure resolution, a slower rate of sodium correction should be used to avoid possible central pontine myelinolysis Rarely, other chemistries can be helpful in identifying specific organ dysfunction, either as a cause of the seizure activity or as an assessment of systemic injury An elevated blood urea nitrogen or creatinine level suggests renal insufficiency (with associated findings such as hypertension and electrolyte disturbances) as a potential cause Elevated liver function tests (transaminases or coagulation times) can be a reflection of hepatic failure Metabolic acidosis or hyperammonemia can suggest an underlying metabolic disorder In patients with prolonged seizures, an arterial or venous blood gas level can help in assessing adequacy of ventilation and a creatine kinase level can identify possible rhabdomyolysis Toxicologic screening can also be helpful in the seizing patient because certain ingestions are managed with specific antidotes or treatments In general, the toxicologic screen should be directed at agents known to cause seizures (Table 72.1 ) or those suggested by a clinical toxidrome Radiologic imaging of the patient with seizure generally consists of a computed tomography (CT) scan for emergent imaging or, preferably, a magnetic resonance imaging (MRI) study if the patient’s condition allows The following situations should be considered emergent: (i) a patient who has signs or symptoms of elevated ICP, (ii) a patient who has a persistent focal neurologic deficit (Todd paresis vs stroke), and in selected patients with a focal seizure or, (iii) a patient who has seizures in the setting of head trauma, (iv) a patient who has persistent seizure activity or status epilepticus, or (v) a patient who appears toxic Until C-spine injury is ruled out, it is important to maintain C-spine immobilization when head trauma is a concern Patients with transient generalized seizures in whom a cause of the seizure activity is identified probably not require any further head imaging studies Patients with transient generalized seizures in whom no cause is identified and who appear clinically well can have their head imaging performed on a nonemergent basis in coordination with a pediatric neurologist In the past, because of easier availability and lack of a need for sedation for most patients, CT scans were most often the study of choice in the ED for a patient who presented with a seizure However, given the heightened awareness of the risks of ionizing radiation associated with CT scans, patients who not require emergent imaging may have an MRI study instead An MRI study also has several other advantages; MRI is better at identifying underlying white matter abnormalities, disorders of brain architecture, lesions of the neurocutaneous syndromes, lesions in the posterior fossa and the brainstem, and small lesions EEG is an important diagnostic tool in the evaluation of seizure types, response to treatment, and prognosis A limited EEG screen in the acute setting can rule out subclinical or nonconvulsive SE and help with differentiating seizures from some cases of psychogenic nonepileptic seizures or PNES (formerly known as pseudoseizures) When there is uncertainty regarding ongoing seizure activity, an urgent electroencephalogram (EEG) should be obtained In the emergency department, this can be a limited study, with application of only a few electrodes to determine if the background is consistent with a normal awake individual (i.e., psychogenic nonepileptic seizure) or the diffusely slow and depressed background of SE Over recent years, various products and protocols have emerged for quick lead placement (e.g., helmets, etc.) among actively seizing patients EMERGENCY TREATMENT OF AN ACTIVE SEIZURE Prolonged seizure activity is a true medical emergency Although the duration of seizures used to define status has varied over time, an accepted definition for the purposes of clinical practice defines SE as a single unremitting seizure lasting longer than minutes or frequent clinical seizures without an interictal return to the baseline clinical state This corresponds with the time at which urgent treatment should be initiated, which is the new focus of the definition With this proactive, management based definition, following stabilization of the ABCs, further treatment is directed at stopping any seizure activity This section will focus on three elements of seizure management: prevention and preparation, antiepileptic medication use, and post stabilization measures Prevention and Preparation PEM providers often encounter patients who start seizing during the ED visit Many of these patients are patients with known epilepsy, some are being treated with antiepileptic drugs (AEDs), and for some increased seizure frequency or a breakthrough seizure is the reason for the ED encounter The PEM clinician will be best advised to assess these patients promptly and be able to answer the following questions: What AEDs is this patient taking, what is the dosage and when is the next dose due? Were any doses missed? Were any doses possibly un(der)absorbed (e.g., vomiting or diarrhea)? Are the parents aware of any recent AED levels of any of the medications involved? When in doubt, AED levels should be obtained promptly Subtherapeutic levels of AEDs are found in nearly a third of pediatric epilepsy patients actively seizing in the ED Furthermore, some AEDs, including phenytoin, carbamazepine, gabapentin, tiagabine, and vigabatrin, can precipitate generalized convulsive SE, particularly the myoclonic type, as well as nonconvulsive (absence) SE What is the active seizure plan for this patient? Many children with refractory epilepsy have their own status epilepticus (SE) plan, which may different that the one proposed for first time seizures These patients should be advised to seek such a plan with their primary neurologist if they have not yet done so History of prior SE episodes, including whether certain AEDs were successful or failed, may guide the PEM clinician in decisions about treatment If any drug needs to be loaded on an active alert patient, it should be loaded promptly in the fastest way possible (which may very well be oral administration) Also, oral administration is less likely to generate excessive sedation and respiratory depression ... (e.g., helmets, etc.) among actively seizing patients EMERGENCY TREATMENT OF AN ACTIVE SEIZURE Prolonged seizure activity is a true medical emergency Although the duration of seizures used to define... regarding ongoing seizure activity, an urgent electroencephalogram (EEG) should be obtained In the emergency department, this can be a limited study, with application of only a few electrodes to... clinically well can have their head imaging performed on a nonemergent basis in coordination with a pediatric neurologist In the past, because of easier availability and lack of a need for sedation