Approach to convulsive status epilepticus: Clinical sciences

Convulsive status epilepticus is a neurologic emergency that refers to persistent tonic-clonic seizure activity lasting five or more minutes, or multiple seizures without return to baseline in between. This condition occurs when inhibitory mechanisms responsible for terminating seizures fail to work, or when pathways that lead to prolonged seizures are overactivated. Some common causes of status epilepticus are medication changes or noncompliance in patients with known epilepsy, substance use, metabolic derangements, and acute brain injury from infectious and non-infectious processes.

Now, if your patient presents with chief concerns suggestive of convulsive status epilepticus, first, perform an ABCDE assessment. You should consider all patients with convulsive status epilepticus unstable, so be sure to stabilize their airway, breathing, and circulation. Sometimes, you might even need to intubate your patient and start mechanical ventilation. Next, obtain IV access and put your patient on continuous vital sign monitoring, including heart rate, blood pressure, and pulse oximetry, as well as cardiac telemetry.

Once you are done with acute management, obtain a focused history and physical exam, and order labs, including fingerstick glucose, CBC, CMP, and a toxicology screen. Also, don’t forget to check anti-seizure medication levels. History will reveal a tonic-clonic seizure that started 5 or more minutes ago, or multiple seizures without return to baseline in between. Additionally, the physical exam will demonstrate altered mental status and alternating body stiffening and jerking movements consistent with a tonic-clonic seizure.

At this point, you can diagnose convulsive status epilepticus, so your next step is to proceed with treatment! First, take a look at the fingerstick glucose because hypoglycemia can be an acute symptomatic cause of status epilepticus and seizures in general. If the patient’s glucose level is less than 60 milligrams per deciliter, you should give thiamine and dextrose. Be sure to administer thiamine before dextrose to minimize the risk of developing Wernicke encephalopathy, since thiamine is required in the metabolism of glucose.

If fingerstick glucose levels are normal, or if the seizure persists, it’s time to administer the first-line treatment for convulsive status epilepticus, which is a benzodiazepine, such as lorazepam, midazolam, or diazepam. If the seizure persists after 3 to 5 minutes, you can give a second dose of the same medication. If this doesn’t stop the seizure, move on to a second-line treatment, which is a bolus of an anti-seizure medication, such as fosphenytoin, valproic acid, levetiracetam, or phenobarbital.
If the second-line treatment fails to abort the seizure, proceed with a third-line treatment, which includes giving a second anti-seizure medication or inducing a therapeutic coma with an anesthetic drip using midazolam, propofol, or pentobarbital.

Finally, consider EEG monitoring as a way to guide escalation or de-escalation of your anesthetic drip. You can also use EEG to evaluate for non-convulsive status epilepticus, which is a state where the brain is still seizing, but there are few, if any, physical manifestations of seizure activity. In this case, your patient might have subtle signs, such as eyelid fluttering or mouth twitching, or they could simply remain altered without any physical indication that a seizure is ongoing.

A high proportion of patients with convulsive status epilepticus can convert to non-convulsive status epilepticus, so this is an important thing to look out for if your patient does not return to their baseline mental status! Additionally, EEG can help you differentiate epileptic from non-epileptic events, such as psychogenic non-epileptic seizures, which are triggered by psychological factors, such as emotional trauma or stress. In other words, in this condition, there are no abnormal electrical discharges in the brain, so you will see no EEG findings of epileptic seizures.

Now, here’s a clinical pearl to keep in mind! Hypoglycemia is not the only glucose abnormality that can cause convulsive status epilepticus. Hyperglycemia can also cause seizures, which is especially common in individuals with type 2 diabetes mellitus who go into a hyperosmolar hyperglycemic state.

Alright, once the seizure has resolved, your next step is to assess the patient’s history of medication or substance use. If your patient has a known history of epilepsy and is on an anti-seizure medication, they might report missed doses or a change in their medication dose. Additionally, if the level of their anti-seizure medication is low or undetectable, you can diagnose subtherapeutic anti-seizure medication level as the cause of status epilepticus.

Now, moving on to intoxication and withdrawal as potential causes of seizures! In this case, history might reveal a recent substance use or use of psychiatric medications. Additionally, the patient’s friends and family might report that they found the patient on the floor next to a medication container. Finally, some individuals might report a history of chronic benzodiazepine or alcohol use!

Next, the physical exam may demonstrate evidence of substance use, such as smell, residue, or injection marks on the skin. The exam could also be consistent with a known toxidrome, such as with certain pupillary changes, depending on the substance. In this case, you should consider intoxication or withdrawal, which can occur with both prescription and non-prescription substances.

Now, if the toxicology screen reveals substances that can cause seizures, such as cocaine, amphetamines, or phencyclidine; or if you find supratherapeutic levels of prescription medications, including antidepressants, antipsychotics, and anti-seizure medications, diagnose intoxication. On the other hand, if the toxicology screen is negative for benzodiazepines in a patient with chronic benzodiazepine use, or similarly, if an ethanol level is undetectable in a patient with chronic alcohol use, diagnose withdrawal as the cause of status epilepticus.

Now, let’s go back and take a look at individuals with no history of contributory substance or medication use. In this case, consider metabolic derangement, so be sure to assess the CMP results. If you notice severe electrolyte abnormalities, such as severe hypo- or hypernatremia, hypo- or hypercalcemia, or hypomagnesemia, then you should diagnose metabolic derangements as the cause of status epilepticus.