Stabilizing Your Emergency Seizure Patient

It’s a full moon on Friday the 13th, and your ER shift is already off to a great start. A 3 year old Border Collie is presented for having three seizures within the past hour, and he is having a generalized seizure for the fourth time as he is being wheeled back into treatment. Your skilled nurses manage to pop an IV catheter into his left cephalic vein and a dose of midazolam later, he is sedate and disoriented, but no longer seizuring. He is stable, so you pop him in the ICU and turn to face the hit by car, the big dog/little dog, and the blocked cat. Before you know it you hear that “nails on the chalkboard” equivalent sound of the ICU cage shaking, and you see your Border Collie going into his fifth seizure of the day.?

ER vets are heroes and will handle all of this like a walk in the park. As a neurologist on the other hand, most of this sounds like chaos, and certainly outside of my comfort level. However, I would be happy to share my (humble) opinion on how I can make one of these cases less of a problem! For those of you that would rather manage anything than a difficult epileptic, I hope this newsletter helps provide a starting point to enable you to quickly set your epileptic patient up for success.?

Step 1: Stabilization

1. If your patient is actively seizuring, administer 0.25mg/kg midazolam intranasally or intramuscularly, and then obtain venous access. If your patient is not actively seizuring, start by placing an IV catheter
2. Assess your patient to ensure that they are systemically stable. Then perform a neurologic exam. Keep in mind that they will likely be in the post-ictal state, meaning that they will have variable mentation, cranial nerve, gait, and postural reaction deficits. Their neurologic exam will need to be repeated frequently as they become seizure free to differentiate between post-ictal changes and true neurologic deficits.
3. If your patient is stuporous or comatose after prolonged seizure activity, or if they have concern for increased intracranial pressure (elevated blood pressure and low heart rate), administer mannitol or hypertonic saline to reduce cerebral edema.?
4. Establish your patient’s seizure history and previous medications.?
5. Prioritize your differential list:Is this a known epileptic? Have they been previously diagnosed with an intracranial cause or are they presumed idiopathic?Is this a first time seizure? Ask about possible toxin exposure and run bloodwork to rule out a metabolic cause.?

Step 2: Make a change

Whether your patient is a known epileptic who is already on 4 medications, or whether this is their first time having a seizure, unless you have already identified a metabolic or a toxic condition that you are in the process of correcting, your patient needs some form of NEW or INCREASED maintenance anticonvulsant therapy. It’s ok if you need a little bit of time to formulate your long term plan. Maybe you need to check drug levels of phenobarbital or potassium bromide. Maybe you want to run bloodwork to make sure it is safe to start phenobarbital. Maybe your patient is having an MRI tomorrow. Regardless, that midazolam was a bandaid, and time is ticking. If your patient has already had multiple seizures that day, or if they have had a several minute long seizure, it is likely that once that midazolam wears off, they will have another. Levetiracetam is safe in almost all cases, and is a good option for a case where you need to do “something” while you establish your long term plan. Go ahead and give your patient 40- 60mg/kg of levetiracetam orally or IV while continuing your workup.?

Step 3: Formulate your long term plan

Without the ability to perform an MRI and a CSF analysis, you are limited to the following diagnostic tests during your workup:?

1. Neurologic exam
2. CBC/ chemistry/ urinalysis
3. Blood pressure
4. Thoracic radiographs (if there is concern for metastatic disease or aspiration pneumonia)
5. Virtual consultation with a neurologist?
6. Measuring blood levels of current anticonvulsant medications
7. Infectious disease testing if indicated (fungal, Rickettsial, protozoal)

Once you get the results of these tests, you will be able to better inform your client of the best anticonvulsant options for their pet.?

For a drug naive dog with no systemic contraindications and a history of severe cluster seizures or status epilepticus, I usually start by loading phenobarbital (4mg/kg PO or IV q6 hours for 4 total doses). For a drug naive cat, I usually choose my drug based on how likely it will be that the owner will be able to administer it at home consistently. Levetiracetam is great because it is safe and comes in a liquid, but it is almost never an option for cat owners, since it has to be given 3 times a day. Zonisamide can often be dosed only once a day in cats. Phenobarbital is small and easy to hide in food, so this is a viable option as well. For an in depth conversation about selecting the right anticonvulsant for your specific patient’s needs, book a consultation with a neurologist.

Step 4: If there is a second seizure, intervene

Despite your best efforts to immediately manage your patient with a longer acting anticonvulsant, many of them will continue to have seizures while you are initiating your maintenance therapy. The sooner you break the seizure cycle, the better. Therefore, if my patient has a second seizure, I will repeat my dose of midazolam (0.25mg/kg IV) and then start them on a CRI of 0.25mg/kg/hr. Once your patient is 24 hours seizure free, begin weaning them off by about 25% every 4-6 hours.?

I wish I could say that this is a foolproof way to stop your patient’s seizures and get them out of the ER. However, many of our refractory epileptics require even more advanced interventions. Collaborating with a neurologist early on in the case can enable you to control your patient’s seizures sooner and ultimately save your client money!