Siobhan Deshauer, Wieslaw Oczkowski

Internal Medicine Rapid Refreshers is a series of concise information-packed videos refreshing your knowledge on key medical issues that general practitioners may encounter in their daily practice. This episode gives on overview of the acute management of a seizure.


  1. Definition
  2. Etiologies
  3. Acute management
  4. Special scenarios
  5. After resolution
  6. Credits

Useful links



I’m Siobhan Deshauer, a senior medical resident at McMaster University. In this video we will go through a practical approach to the acute management of a seizure. This Rapid Refresher is intended for independent practicing physicians who are returning to general internal medicine during the coronavirus disease 2019 (COVID-19) pandemic. Always remember that you’re never alone managing patients. There are physicians that you can call at home or in the hospital that will be happy to provide additional assistance.


There are many types of seizures. In this video we will be focusing primarily on general tonic-clonic seizures.

It is important to recognize status epilepticus. Status epilepticus is a seizure lasting >5 minutes or multiple seizures without recovery to the neurologic baseline in between.


Common causes include alcohol withdrawal or substance abuse, infections (eg, meningitis), metabolic abnormalities (eg, hyponatremia, hypoglycemia, hyperglycemia), antiepileptic medication nonadherence, or taking medications that lower the seizure threshold (eg, lithium, bupropion, penicillins).

If you see focal neurologic deficits, consider a tumor or stroke as a possible etiology.

Acute management

Our approach is going to be based on how long the seizure lasts.

In the first 5 minutes go back to basics and think about your ABC: airway, breathing, and circulation. For airway and breathing, place the patient on their side to reduce the risk of aspiration. Get a set of vital signs, apply oxygen if required, and place a nasal airway if appropriate. For circulation, the patient will require 2 intravenous (IV) lines and should have cardiac monitoring attached. If this is happening on a ward, you’ll have to call the hospital’s rapid response team to bring a cardiac monitor and required medications.

Your first investigation should always be the capillary glucose level. If it’s low (ie, the patient is hypoglycemic), give thiamine 100 mg IV push (bolus) and then 50% dextrose in water (D50W) 50 mL IV push, which is the equivalent of 1 ampule of D50W. If there’s no IV access yet, then give glucagon 1 mg intramuscularly (IM).

Next ask for your routine bloodwork (blood testing): complete blood count (CBC), electrolytes, extended electrolytes, lactate, antiepileptic drug levels if appropriate, and a blood gas.

If the seizure continues for >5 minutes, there are 2 medications that you should give: a benzodiazepine to abort the seizure and a second antiepileptic medication as maintenance therapy to prevent future seizures.

When you’re choosing benzodiazepines, you have a number of options. If the patient has IV access, then give lorazepam 4 mg IV or diazepam 10 mg IV. Both of these should be administered over 2 minutes. If the patient does not have IV access, then give midazolam 10 mg IM or diazepam 20 mg rectally. You can repeat the benzodiazepine dose in 3 to 5 minutes if the patient continues to seize.

At the same time that you give the benzodiazepine, you can give the second antiepileptic medication as maintenance therapy. Phenytoin is typically the most readily available agent. The starting dose is a loading dose of 20 mg/kg IV. If that’s not available or it’s not tolerated by the patient, consider giving valproic acid or levetiracetam.

If the seizure continues for >10 minutes, call the intensive care unit (ICU) if they are not already present. The patient may require more aggressive seizure management, like intubation and sedation.

If you are concerned about airway management at any point in the management of the seizure, call the ICU or a code blue for more assistance.

Special scenarios

There are 2 specific scenarios I’d like to discuss: alcohol withdrawal and pregnancy.

If the patient has a history of alcohol abuse or you suspect that they’re in withdrawal (see Acute Alcohol Withdrawal), they will likely require higher doses of benzodiazepines, so you may need to repeat the dose a few times. In this case it’s very important to monitor for respiratory depression.

If the patient is pregnant, the seizures are eclampsia (see Eclampsia) and should be treated with magnesium sulfate 4 g IV load followed by an infusion of 1 to 2 g/h IV.

After resolution

After resolution of the seizure, you want to prevent recurrence.

If the patient has only received a benzodiazepine, then give a second anticonvulsant agent, like phenytoin, levetiracetam, or valproic acid.

Consider the patient’s setting. If they are on the ward, they should be moved to a step-down monitored bed (ie, a location with closer monitoring due to a lower nurse-to-patient ratio than a standard ward bed).

Finally, consider the etiology more closely. If the patient has focal neurologic deficits, they’ll likely require urgent neurologic imaging.

In summary, when managing a tonic-clonic seizure, always think about your ABCs, get a capillary glucose first, and treat with a benzodiazepine and a secondary anticonvulsant agent. If the patient doesn’t have IV access, you can give IM midazolam or rectal diazepam. And if you’re ever concerned about airway protection or airway compromise, call a code blue (ie, a code indicating an emergency situation in the hospital).


For more information, see the chapter on seizures from the McMaster Textbook of Internal Medicine, which will be linked above.

I’d like to thank those who collaborated on the project, including intensivist Doctor Roman Jaeschke (Divisions of Critical Care and Internal Medicine) and neurologist Doctor Wieslaw Oczkowski (Division of Neurology; editor for this video).

See also
  • COVID-19 resource hub Resources helpful in addressing the coronavirus disease 2019 (COVID-19) epidemic.
  • COVID-19 McMaster Survival Guide The COVID-19 McMaster Survival Guide is a concise, comprehensive, and practical manual addressing a broad range of topics related to COVID-19. Updated on an ongoing basis.
  • Cellulitis Cellulitis: a clear overview of approach, investigations, and management, highlighting red flags and other points to remember.
  • Non–ST-segment elevation ACS Non–ST-segment elevation acute coronary syndrome (NSTE-ACS/NSTEMI): the important points to remember regarding diagnosis, investigations, management, and risk stratification.
  • Syncope Syncope: the essential points to remember when assessing and managing patients.
  • COPD exacerbation Chronic obstructive pulmonary disease (COPD) exacerbation: the key diagnostic investigations and management principles that you need to keep in mind.
  • Diabetic ketoacidosis (DKA) Diabetic ketoacidosis: all that you need to remember about presentation, diagnosis, and management reviewed in less than 10 minutes.

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