Seizures: Causes, types, and management:
Seizures are a fairly common reason why emergency responders are called every day. Most of the time these patients have an existing history of seizure disorder/epilepsy, however a variety of conditions can also manifest with seizures or seizure-like activity. For this reason, the pre-hospital care provider must understand the pathophysiology behind seizures and how to manage them effectively.
Types of Seizures:
We usually divide seizures into 3 categories:
Generalized seizures
Partial seizures
Psychogenic seizures
Generalized seizures:
These seizures are caused by chaotic activity throughout several areas of the brain, and present in one of two ways: The Tonic-clonic seizure (Grand-Mal), or the Absence Seizure (Petit-Mal).
Tonic Clonic Seizures are usually preceded by an aura, which the patient is aware of prior to onset of convulsions. Next there is a loss of consciousness, followed by a tonic phase, a clonic phase, and finally a postictal state that may last several minutes. Absence seizures do not present with outward manifestations as dramatic as the Tonic-clonic seizure. In an Absence seizure, there is still often an aura, followed by a loss of conscious perception. The patient appears to “Space out” for 30-seconds to 1 minute (although it may be longer), with a postictal state that follows.
Partial seizures:
These seizures affect only one part of the brain and can present in simple or complex varieties. The simple partial seizure usually affects a single area of the body, and presents with convulsions in that region; often a single limb. The complex partial seizure involves alterations in LOC, repetitive movements or sounds, and changes in behaviour.
Psychogenic seizures:
Also called Psychogenic Non-epileptic seizures, these conditions are poorly understood. The patients may present with outward manifestations of generalized or partial seizures, however there is typically no aura prior to onset, and the patient's do not have a postictal state afterward. It is thought that these seizures are psychiatric in origin, however we are not truly certain of the cause as of yet.
Status Epilepticus:
This refers to any seizure lasting longer than 5 minutes, or multiple seizures without a return to baseline LOC in between. This condition is life threatening for several reasons.
During seizure, most patients are apneic. This leads to a state of hypoxia, metabolic acidosis, and damage to cells.
Prolonged seizure activity causes reduction in the threshold for action potential in nerve cells, meaning that the longer the seizure continues, the harder it is to stop it.
Prolonged muscle contraction, especially in anaerobic conditions can lead to myocyte damage and lysis, leading to rhabdomyolysis.
Trismus, and apnea make airway management difficult in these patients, and there is risk of aspiration of secretions.
Causes of seizures:
There are 3 main categories of causes for seizures:
Structural causes: These include tumours, vascular abnormalities such as aneurysms, elevated ICP, traumatic damage to the brain itself, or ischemia.
Metabolic causes: Metabolic acidosis, hypoxia, toxins, hyper/hypoglycemic states, etc.
Febrile causes: In children <5 years febrile seizure is a common complication of prolonged illness.
Things that may mimic a seizure or hide behind one:
Several conditions can present with seizure, or cause seizure. Common ones to be aware of include:
Stroke
Cardiac dysrhythmias
Electrolyte imbalances
Overdoses, particularly opioids
Hypoglycemia
Eclampsia
Syncope
Management of seizures:
As with all patients, we need to address our ABCs first. In a patient in active seizure, we need to ensure the airway is patient. Our best option here is to have suction ready, and be prepared to insert a nasal airway. Use of an OPA is not recommended as these patients usually have some degree of trismus and we don't want to put anything into the mouth. The patient should have high flow oxygen applied, as periods of apnea usually occur, and we want to ensure adequate oxygenation (remember hypoxia may be the cause of the seizure). If possible we want to establish IV access as well.
Once we have managed the ABCs we need to get a full set of vitals including Temperature, HR, BP, SPO2, ETCO2, and blood glucometry. All patients experiencing a seizure need to have cardiac monitoring applied as well. Once the seizure has stopped, a 12-lead ECG is recommended in all patients without prior history of seizure.
Physical assessment should look for seizure related occurences, including the presence of lateral tongue lesions, incontinence, and secondary injuries.
In an active seizure, our main priority should be to stop the seizure with administration of a benzodiazepine. Beyond that we want to treat the cause of the seizure following our protocols (hypoxia, hypoglycemia, opioids, etc.).
Once the seizure has stopped, the patient should be placed left lateral on the stretcher (or supine with the head elevated 30 degrees for airway management). The patient's LOA should be continually reassessed during care, and the patient should be transported rapidly to definitive care.
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