SEIZURES

 

Etiology:

  1. Idiopathic/Non-compliance
     
  2. Cardiovascular = shock, bradycardia, tachypnea, hypotension, hypertensive emergency
     
  3. Infection = meningitis, sepsis
     
  4. Structural = tumor, intracranial hemorrhage, CVA, post-traumatic
     
  5. Toxic/Metabolic/Drugs = uremia, Na, glucose, INH, ETOH w/d, TCA, Ca, Mg

S & S :

  1. Seizures are classified into Generalized (absence, myoclonic, tonic/clonic) and Partial (simple, complex).
     
  2. Depending on the brain area most involved in seizure activity, patients may have generalized or  focal seizure. Thus patient may manifest with aphasia  only,  or general tonic/clonic seizure.
     
  3. A generalized seizure presents generally with alteration of mental status, prolonged post-ictal state, incontinence (may be present also in syncope) and presence of injury  (may also be present in syncope). These features may help in distinguishing a seizure  from a vasovagal syncope, in which prior to seizure and decrease in  Mental State, there is loss of muscle tone, diaphoresis, palpitation and lightheadedness. In  vasovagal case, recovery is fast and no post-ictal state. Of note; generalized seizures almost always stop spontaneously within 2 minutes.

Diagnosis :

  1. To diagnose  the cause of the seizure  you must consider  all possible etiologies.  The following  can be the algorithm:
     
    1. Known seizure disorder:
       
      •  Antiepileptic drug serum level.  CBC, SMA, Ca, Mg, Tox screen are probably not needed in a known seizure disorder.
    2. First time seizure:
      • Do CT scan. MRI (if available) is really  the test of choice
         
      • If  SAH (on CT or suspected) or r/o meningitis - do LP.
         
      •  R/O metabolic and/or infectious etiology. Electrolyte abnormality,  BUN, abnormal Ca, Mg, sepsis, CVA, low glucose, drug OD, ETOH WD, INH, TCA. R/O intracranial mass.
         
  2. In  generalized seizure, CPK is elevated after 2-3 hrs in 15-20%  of cases but is absent in other subset  of  seizures. Prolactin will be elevated in 90% of generalized seizures and 70%  of complex partial SZ. Prolactin peaks in 20 min and returns to normal in 60 min. HCO3 is generally decreased (acidosis secondary to lactic acidosis).The pseudoseizure as compared to true seizure has different patterns:  no real post-ictal state, pelvic thrusting and side-to-side head motion are  often (not always) observed. Noxious stimuli like smelling  salts  of ammonia will "wake up" the patient.
     
  3. EEG has no place in ER

Treatment:

  1. 1. Non-compliant pt :
     
    • Pt is loaded with Phenytoin IV 18mg/kg not exceeding 50mg/min. This achieves steady state after 1hr and pt can be safely  discharged. PO takes  6hrs to achieve steady state. The reason  why pt is on monitor is because of  Phenytoin IV vectors and not because of Phenytoin itself. What if pt takes antiseizure medication whose level is not routinely done by your hospital or the "therapeutic dose" is tailored to pt ? In this case it is safe to administer an extra dose of pt's medication as long there are no side effects of OD present such as ataxia, vertigo, nistagmus, GI discomfort, lethargy.
       
  2. Break-through seizure :
     
    • This should be treated by small increase of medication dose only if seizure activity had become more frequent recently. Only one documented  break-through seizure can occur in well controlled patients where no treatment is needed. Close F/U with neurologist must be provided.
       
  3. First-time seizure :
     
    • Must get CT and SMA, Ca, Mg, FS. The latter are definitively WNL if pt is back to base-line. If CT is positive, call for proper consult. If CT is negative, many neurologists will advise against anticonvulsant treatment. Yet an ER doctor not having the guarantee  of  F/U, and discharging  a seizure prone pt to the streets where he can be harmed, may choose a more "safe" treatment modality (i.e. loading pt with antiseizure medication) until EEG is arranged.  Starting patient on antiseizure medication doesn't interfere with EEG. In any case, there is no right or  wrong choice in using  one vs. another modality of treatment.
                            
  4. Status epilepticus :
     
    • This, if not controlled within  1hr will cause anoxic encephalopathy.  The status must be controlled with Benzodiazepines, and the only  ones that are reliably and rapidly (and relatively short T1/2) absorbed by IM administration (if  IV access is not available) are Lorazepam (Ativan ) 2 mg and  Midazolam (Versed ) 1-5mg.  If  IV is available Diazepam (Valium ) 5-10 mg is given. Its antiseizure activity lasts only 20 min but overall T1/2 is  30hrs that interferes with  neuro checks.  Once seizure is controlled  Phenytoin 18mg/kg not exceeding 50mg/min is given.  If Benzo + Phenytoin regimen did not control the seizure Phenobarbital 10mg/kg is given @ 100mg/kg and additional 10mg/kg if previous dose was not effective.  It is prudent to provide respiratory support with ETT especially when Benzo is already aboard.
       
  5. ETOH w/d seizure (Rum fits) :
     
    • This is treated with Benzodiazepines. The most commonly prescribed is Librium (Chlordiazepoxide) that can be given IM, PO or IV. It is approved for ETOH w/d, yet being metabolized by oxidative process in liver, the liver disease may prolong its effect by giving active metabolites. The benzodiazepines that are metabolized by  conjugation such as Ativan (Lorazepam), Serax (Oxazepam),Versed (Midazolam)  do not give active products and have more predictable effects.  In addition to Benzodiazepines, Thiamine 100mg + IV D5NS + MgSO4 prn + KCl prn.  MVI (gives the banana color = "Banana bag") are integral part of ETOH w/d treatment.  Pt started on Benzodiazepines can be discharged home with tapering doses of Benzodiazepines only  if reliable environment and good family support are guaranteed. It is also possible to discharge pt who had seizure, was given benzodiazepines but who is known to go out and drink since his seizure was precipitated by w/d.
       
  6. Post-traumatic seizure:
     
    • Seizure post-trauma to the head may develop within 24hrs (immediate sz), within first wk (early sz) and beyond first wk (late sz). The overall incidence is 5%, the immediate being most frequent and  the most relevant to the ER personnel.  This must be treated immediately with Phenytoin loading dose as described above. The reason why one develops seizures can be hypoxia, contusion, IC hemorrhage.  Prophylactic Phenytoin loading  is suggested also in case of obvious severe head injury such as depressed skull fx or penetrating head injury. The early and late post-traumatic seizures require Phenytoin loading as well.
       
  7. Cocaine-induced seizure:
     
    • Probably related to vascular spasm and/or sympathetic state. Treated with Benzodiazepines.
       
  8. INH-induced seizure:
     
    • Seizures related to INH use are 2ry to vitamin B6 deficit. Treatment is initiated with Benzodiazepines, and then vitamin B6 is given 1gr for every gram of  INH ingested.  If dose of  INH is unknown then 5gr  of  B6 are given. It has been shown that B6 and  Benzodiazepines work synergistically.
       
  9. TCA-induced seizure:
     
    • TCAs lower the seizure threshold. Usually of  2min duration (like most other seizures).  Can be associated with  QRS complex > than 0.10 sec. The usual anti-seizure modality is used (Benzo, Phenytoin). Alkalinization is used if pt has acidosis and further acidosis 2ry to seizure worsen the arrhythmias. 

Disposition:

  1. It should be stated in patient's discharge instructions "Do not drive until final diagnosis".
  2. In certain states it is obligatory to notify motor vehicle authorities.

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