Tratamiento del estado epiléptico

What is status epilepticus?¹²

Convulsive status epilepticus is defined as a convulsive seizure which continues for a prolonged period (longer than five minutes), or when convulsive seizures occur one after the other with no recovery between. Convulsive status epilepticus is an emergency and requires immediate medical attention. Non-convulsive status epilepticus (a prolonged seizure manifesting as altered mental status rather than convulsions) is uncommon but often overlooked; management is usually less urgent.

How common is status epilepticus? (Epidemiology)³⁴

• Estimated incidence is between 9 - 40 cases per 100,000 person/years. The incidence is higher in poorer populations. It recurs in about a third of patients.

• Risk factors include age under 5 years or elderly age, genetic predisposition, intellectual disability, encephalitis and structural brain pathology or brain injury.

• Potential precipitants include drug withdrawal, intercurrent illness, metabolic disturbance (eg, hypoglycaemia), cerebrovascular event and alcohol intoxication or withdrawal.

Symptoms of status epilepticus (presentation)

This would be the same as any convulsion but unremitting. The diagnosis of tonic-clonic status is usually clear, although it needs to be distinguished from psychogenic non-epileptic seizures (PNES, previously known as pseudo-seizures) which are non-epileptic attacks with a psychological basis. ⁵

Diagnóstico diferencial

Non-epileptic status should be considered. See the separate Non-epileptic seizures article.

Management of status epilepticus¹

• Give immediate emergency care and treatment for prolonged (lasting five minutes or more) or repeated (three or more in an hour) convulsive seizures in the community.

• Treatment should be administered by trained clinical personnel or, if specified by an individually agreed protocol drawn up with the specialist, by family members or carers with appropriate training.

First-line treatment in the community

• General protective measures - eg, ensuring the head is protected, releasing any constricting neck wear, moving away from a dangerous position.

• Resuscitation as required: secure the airway and assess respiratory and cardiac function.

• Use buccal midazolam or rectal diazepam as first-line treatment for prolonged or repeated seizures in the community.

• Depending on response to treatment, the person's situation and any personalised care plan, call an ambulance, particularly if:

  • The seizure is continuing five minutes after the emergency medication has been administered.

  • The person has a history of frequent episodes of serial seizures or has convulsive status epilepticus.

  • This is the first episode requiring emergency treatment.

  • There are concerns or difficulties monitoring the person's airway, breathing, circulation or other vital signs.

Treatment in hospital

• Immediately:

  • Secure airway, give high-concentration oxygen.

  • Assess cardiac and respiratory function, check blood glucose levels and secure IV access in a large vein.

  • Administer IV lorazepam as first-line treatment. Administer IV diazepam if IV lorazepam is unavailable, or buccal midazolam if unable to secure immediate IV access. Administer a maximum of two doses of the first-line treatment (including pre-hospital treatment).

  • If seizures continue, administer IV levetiracetam, phenytoin or sodium valproate as second-line treatment.

• Refractory convulsive status epilepticus:

  • Administer IV phenobarbital to treat adults with refractory convulsive status epilepticus, or consider a general anaesthetic. Administer IV midazolam or thiopental sodium to treat children and young people with refractory convulsive status epilepticus.

  • Adequate monitoring, including blood levels of anti-epileptic drugs (AEDs), and critical life systems support are required.

Emergency investigations in hospital

• Pulse oximetry; blood gases.

• Blood for glucose, renal function, electrolytes, liver function, calcium and magnesium; FBC and clotting; AED levels.

• 5 ml of serum and 50 ml of urine samples should be saved for future analysis, including toxicology, especially if the cause of the status epilepticus is uncertain.

Other therapy

• Correct hypoglycaemia if present.

• Parenteral thiamine should be considered if alcohol abuse is suspected.

• Pyridoxine (vitamin B6) should be given if the status epilepticus is caused by pyridoxine deficiency.

Gestión posterior

• Identify and treat any underlying cause. Status is associated with community-acquired bacterial meningitis and seizures. Seizures occurring in the acute phase of the illness are predictors of poor outcome.

• Identify and treat medical complications - eg, CXR to evaluate the possibility of aspiration.

• Regular AEDs should be continued at optimal doses and the reasons for status epilepticus should be investigated.

• An individual treatment pathway should be formulated for children, young people and adults who have recurrent convulsive status epilepticus.

• Only prescribe buccal midazolam or rectal diazepam for use in the community if there has been a previous episode of prolonged or serial convulsive seizures.

Non-convulsive status epilepticus in adults and children ^{6 1}

This is less common than tonic-clonic status epilepticus. Treatment for non-convulsive status epilepticus is less urgent than for convulsive status epilepticus. Non-convulsive status (eg, absence status or continuous focal seizures with preservation of consciousness) may be difficult to diagnose. In non-comatose patients it may present as confusion, personality change or psychosis. Acute management should aim to stop the seizure and a long-term plan should then be made.

Prognosis ^{3 78}

The true morbidity and mortality of status epilepticus is unclear. Short-term mortality has ranged from 0.5-30% with age over 65 frequently identified as the most significant risk factor.

The Status Epilepticus Severity Score (STESS), consisting of the variables level of consciousness, seizure type, age above or below 65, and history of prior seizure, older age, lower levels of consciousness, generalised convulsive/nonconvulsive morphologies, and absence of prior seizures. Various studies have suggested that a STESS score of 3-4 or more is indicative of a poor prognosis.

Prevención

Good seizure control in pre-existing epilepsy is the key to preventing status epilepticus.