Epilepsy

Key Differential Diagnoses

Other causes of reduced conscious level 
Other causes collapse ( especially faint with twitching = 'convulsive syncope')
Psychiatric (pseudoseizure)

Key Investigations

Glucose (BM)
FBC, ESR, CRP
U+E, LFT/GGT, Bone, Glucose, Drug levels
CXR, ECG
CT (± LP, if meningo-encephalitis possible cause); unless known Ep with normal pattern

Key Treatments

?IV LORAZEPAM 4 mg slowly (over 2 min); if still fitting on arrival, rpt after 10 mins
± IV PHENYTOIN 18 mg/kg
± PABRINEX 2 vials tds
± IV GLUCOSE 20 mls 50%

Key Management
Decision

IV anti-epileptic agents (status)
Ventilation
CT head

Introduction

• About 2% of adults have a seizure at some time during their life
• Two thirds of these people never have another one
• Status epilepticus is best defined as tonic-clonic seizure activity lasting > 5-10 mins; or ≥ 2 seizures between which patients do not fully regain consciousness
• The previous definition of > 30 min duration is not helpful as untreated generalized seizures lasting > 60 mins may result in permanent brain damage; and longer-lasting seizures may be fatal. This newer definition was devised to encourage more prompt identification and treatment
• For practical purposes, a patient who is still fitting on arrival, despite initial treatment by paramedics, should be considered as having status, and treated accordingly
• Status usually occurs in patients known to have epilepsy. If it is first presentation of epilepsy, then a structural lesion is likely (50%)
• Never assume that this is a pseudoseizure; leave that to neurology team
• Following a seizure, the patient is not allowed to drive for a year

[Ref]

Definition

A neurological disorder that is characterised by recurrent unprovoked seizures

Epidemiology

1% of population have active epilepsy. 2% population will have one seizure in lifetime; 2/3rds of these never have another one
30% elderly who have a first fit, present with status
Small but significant acute mortality (2% die in first month)

Seizure Types

1. Generalised (no evidence of focal onset)
2. Partial (seizures that start with a focal onset, as they originate from one hemisphere)
- Simple (consciousness not impaired)
- Complex (consciousness impaired)
- With secondary generalisation

Causes

Idiopathic (2/3); 4 other big groups of causes:
1.  Cerebral
- SOL
- Infection
- Trauma (cause or effect of seizure)
- CVA
- Other (inflammatory eg, vasculitis, MS, degenerative (eg dementia))
2.  Metabolic (increased/decreased glucose, calcium and sodium)
3.  Major system failures (eg hypoxia secondary to cardiac, renal or hepatic failure)
4.  Drugs/overdose (prescribed, alcohol/recreational; excess or withdrawal)

Symptoms

Very variable
Patient may not have any memory of event
Of focal neurology

Key questions (may have to ask later; witnesses important)

"Are you known to have epilepsy?"
"Have you ever been treated for mental illness, and/or seen a psychiatrist?" (pseudoseizures are common in such patients and/or psychiatric medication could be the problem)
"What is your current medication, and has anyone changed it, in last 4-6 weeks?"
"Do you use alcohol/recreational drugs?"
Note: recording a witness's account of event, and the drug list is vital (may have to ask relatives, GP and/or read ambulance/paramedic report); ask the witness to describe the collapse - any prodrome? What was actual 'fit' like (eg if small amplitude, fibrillatory type, more likely to be tonic-clonic); loss consciousness?, tongue-biting, where on tongue? etc

Signs

Very variable
Note: tongue biting, and disorientation make epilepsy more likely in 'collapse?cause'; their absence does not exclude diagnosis
From normal, to mildly confused, to any level of consciousness
Note: think about status in a patient with unexplained coma, signs can be subtle (or absent; patients in status can have no signs of twitching etc)

Signs head injury (in fact, examine the whole body, you may be missing something)
Epilepsy warning bracelet etc
Signs of alcohol/recreational drug use
Focal neurology (if grand mal, neuro examination may be difficult, you may have to come back, when stopped fitting)
Note: extensor plantars during seizure makes pseudoseizure less likely; unilateral weakness can be cause (eg, CVA) or effect (Todd's paresis)

Blood

Glucose (BM)
FBC, ESR, CRP
U+E, LFT/GGT, Bone, Glucose
BC (if infected)
(Epilepsy) drug levels (neurologist will ask! Mainly to assess compliance. This is especially true for phenytoin)
ABG, if unwell

Other

CXR, ECG (to exclude arrthymia)
CT head; unless known to have idiopathic epilepsy, in its normal pattern. It is usually done immediately to exclude a mass (including abscess) or heamorrhage. Some experts say that CT can be deferred and possibly avoided in children with typical febrile seizures whose neurologic status rapidly returns to normal
± LP, if meningo-encephalitis or SAH possible cause

Key investigation

CT head (? SOL, incl subdural haematoma)

Differential diagnoses

Other causes of reduced conscious level 
Other causes collapse
Psychiatric (pseudoseizure)
New neurological event (eg, CVA) with no epilepsy

Specialist investigation

EEG should be done for any new case. Also useful if patient has presented as 'collapse?cause', and diagnosis not obviously epilepsy (yet). Also can be used to classify seizure type. Longer term, EEG/video telemetry may be useful
Toxicology screen (urine), if suspect OD

Treatment
(first line)

Drugs:
If suspect alcohol withdrawal, IV PABRINEX 2 vials tds, for 3-6d; give over 30 mins (resus equipment to hand); before changing to oral treatment (PO THIAMINE 100 mg tds, for one month)

If glucose < 4 mmol/L, give IV GLUCOSE, 20 mls 50%
Note: GLUCOSE increases risk of Wernicke's encephalopathy, so give IV PABRINEX first; if patient is alcohol dependent, hypoglycaemic and fitting

If fit continuing, consider IV LORAZEPAM 4 mg slowly, over 2 mins; watch for respiratory arrest at end of injection; repeat after 10 mins, if necessary
Note: large doses of a benzodiazepine may be required; if use, maintain airway and give oxygen, when fitting; if fitting continues, consider diagnosis as status epilepticus, and call for senior support and ITU:

± IV PHENYTOIN 18 mg/kg (<50 mg/min); make up in N Saline, not 5% Dextrose; then 100 mg tds maintenance dose (can be given PO, NG or slow IV infusion); eventually PO 150-300 mg od or bd;  don't put lorazepam in same line, they don't mix; require cardiac monitoring; beware hypotension, and avoid if bradycardic or heart block; a lot of newer drugs are now favoured in the longterm (leave longterm Rx to the specialist); phenytoin desired levels 10-20 mg/L

± IV PHENOBARBITAL SODIUM 10 mg/kg, at 100 mg/min; use if still fitting on Phenytoin; ITU should be there, if you are considering either drug 

± IV DEXAMETHASONE 10 mg (if considering vasculitis, or cerebral oedema)
± IV ANTIBIOTICS, if infected
                   
Procedures:
IV (+ fluids, if dry)
If drowsy, O2 saturation, continuous ECG monitoring (and watch trends)
If hypoxic, give OXYGEN (hypoxia increases mortality)
Maintain airway, recovery position if possible
Do not insert urinary catheter, unless continuing status epilepticus (may try to pull out)
Note: if you try to insert fingers in mouth, they may be bitten!

Key management decisions

IV anti-epileptic agents
CT head

Stop

Prescribed drugs that may have precipitated event
Warfarin/aspirin (if have had bleed)

Treatment
(second line)

Ventilation

If definitly known to be phenytoin-allergic, use IV PHENOBARBITAL SODIUM 10 mg/kg, at rate no more than 100 mg/minute; max 1g. If already on phenytoin, consider half-loading dose of IV phenytoin, or phenobarbital sodium. If you are dealing with Status, and using phenytoin (let alone phenobarbital), you need help from seniors, and ITU

Admit

Usually, unless makes rapid recovery

Bed plan

Observation ward (may go home later in day, or tomorrow)
± ITU

Referrals

Medical:            
Neurology
± ITU

Other:
Epilepsy nurse
± community alcohol service

Complications

Hypoxic brain damage
Consequences of collapse (bleeding tongue, fracture)

Prognosis

Worse, if fitting >1hr, hypoxic or old

2° Prevention + Health Promotion 

Anti-epileptic medication (or change, if known epilepsy, and control poor)
Reduce alcohol consumption
Following a seizure, a patient is not allowed to drive for a year
Consider specially trained dog

Don't forget

• Ring GP, to get an up-to-date drug list
• Don't call patient an 'epileptic' (judgemental, and may be untrue).  We are all 'epileptics' ie have an    epileptic potential
• Record in the notes, that you have A. asked the patient to contact DVLA; and, B. that they should not drive in the meantime for a year in the first instance
• Psychiatric history

Red flags

• Hypoxia (increases mortality)
• Status epilepticus
• LOC still reduced after 12 hrs, after last fit
• Increasing frequency of fits (especially in hospital)