All that blacks out is not syncope: a neurological view of transient loss of consciousness

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1 All that blacks out is not syncope: a neurological view of transient loss of consciousness Dr Simon Taggart Consultant Clinical Neurophysiologist. JCUH, Middlesbrough.

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3 Misdiagnosis of Blackouts Sutula 1981: 20% of patients with refractory epilepsy in tertiary centre had non-epileptic seizures Smith et al 1999: 25% of patients referred to tertiary epilepsy centre had non-epileptic seizures. Zaidi et al 2000: alternative diagnosis found in 36% of patients on anti-epileptic drugs

4 Mortality in Blackouts Increased in syncope At 5years, 50.5% in cardiac syncope, 24.1% in syncope of unknown cause Increased in epilepsy SMR 2.1( ) 1, 2.3( ) 2 Related to cause of epilepsy (eg brain tumour) Directly or indirectly from epileptic seizures (status epilepticus, accidental drowning) SUDEP: Sudden, unexpected, witnessed or unwitnessed, nontraumatic and nondrowning death in patients with epilepsy with or without evidence for a seizure, and excluding documented status epilepticus, in which post mortem examination does not reveal a (structural or toxicologic) cause for death. 1. Lhatoo et al Annals of Neurol 2001: 49(3); Hauser et al, Epilepsia 1980: 21(4);

5 Differential diagnosis of Blackouts (non-exhaustive) Syncope Epilepsy Psychogenic non-epileptic seizures Cataplexy Transient CSF obstruction Transient ischaemic attack - anterior and posterior circulation Panic attack Falls Hypoglycaemia Basilar migraine

6 Blackouts clinical diagnosis: individual attacks Subjective account 12 hours before, several hours after 1 st hand witness accounts Second by second account Ban medical jargon from descriptions Strip out second hand descriptions First worst and last episodes 2 nd hand accounts Much less informative, much more misleading

7 Syncope v GTCS During blackout Syncope Generalised tonic clonic seizure Pallor Common Rare Cyanosis Rare Common Duration of loss of consciousness Movements <20seconds A few clonic or myoclonic jerks; brief tonic posturing (few seconds); duration <15 sec; always begin after loss of consciousness >60seconds Prolonged tonic phase (~30 sec), then prolonged rhythmic clonic movements (~30 60 sec); duration >1 min Lateral tongue biting Rare Common Hypersalivation Rare Common EEG Generalised slowing Ictal EEG pattern Adapted from Hirsch L, Ziegler D, Pedley T. Seizures, syncope and their mimics In: Rowland L, ed. Merritt s Neurology, 11th ed. New York: Lippincott Williams & Wilkins; 2005:13 20.

8 Syncope v GTCS After blackout Syncope Generalised tonic clonic seizure Confusion/disorientation Rare; <30seconds Common; several minutes or longer CK elevation Rare Common (esp hours) EEG between events Normal IEDs (interictal epileptic discharges) Features that are not helpful for differentiation Incontinence, dizziness, fear, injury other than lateral tongue biting, eye movements (rolling back), brief automatisms, vocalizations. Adapted from Hirsch L, Ziegler D, Pedley T. Seizures, syncope and their mimics. In: Rowland L, ed. Merritt s Neurology, 11th ed. New York: Lippincott Williams & Wilkins; 2005:13 20.

9 Epileptic Seizures The clinical manifestation of excessive and/or hypersynchronous, usually selflimited abnormal activity of neurones of the cerebral cortex

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11 Generalised tonic clonic seizures No relation to posture, uncommonly precipitated Rigid collapse with LOC: bilateral posturing/rigidity of limbs and trunk tonic phase ~20-30 seconds Strong rhythmical jerking of limbs often more apparent in arms than legs clonic phase ~1-3mins, gradually slows before stopping Deep unconsciousness immediately after jerking stops ~ 30 seconds+ Gradual recovery of orientation characterised by confusion, amnesia for early period of recovery, agitation - >5minutes

12 Syncope Abrupt, transient and self-limiting loss of consciousness associated with loss of postural tone, caused by a sudden fall in cerebral perfusion

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16 Convulsive syncope Limp collapse with LOC Motor features usually delayed by seconds Brief tonic phase Brief myoclonic phase Brief clonic phase Rapid recovery of consciousness No amnesia for early stage of recovery (NB sometimes in elderly) May be precipitated, related to posture, associated with prodrome but may not.

17 Other neurological mimics of syncope Epileptic Tonic seizures Atonic seizures Psychogenic non-epileptic attacks Transient CSF obstruction Posterior circulation TIAs Meniere s disease Cataplexy

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19 3 rd Ventricle Posterior Fossa Craniocervical Junction

20 Neurological mimics of epilepsy Intermittent CSF obstruction Causes: Third ventricular tumours, posterior fossa tumours, Chiari malformations Symptoms: Headache associated with cough, brainstem symptoms: vertigo, ataxia, drop attacks Posterior circulation TIAs Drop attacks may occur in isolation May be independent history of attacks of ataxia, vertigo, unilateral, bilateral upper limb dysaesthesia +/- occipital headache Meniere s disease: Episodic fluctuating rotational vertigo, deafness tinnitus, aural fullness; Severe rotational vertigo can cause drop attacks.

21 Cataplexy Occurs as part of symptom complex of narcolepsy: excessive daytime sleepiness, sleep paralysis, cataplexy, hypnagogic hallucinosis Cataplexy: episodes of loss of postural tone triggered by emotion-laden situations, consciousness preserved,

22 The appropriate use of investigations Detailed clinical evaluation - repeated Video detailed review ECG U&Es, glucose (in acute situation) Brain imaging Only then Routine and sleep EEG Long-term EEG monitoring Tilt table

23 The problem with EEG routine interictal EEG is one of the most abused investigations in clinical medicine and is unquestionably responsible for great human suffering. David Chadwick 1990

24 Electroencephalography EEG first recorded form humans in by Hans Berger Gastaut demonstrated that EEG can differentiate syncope from epilepsy Interictal epileptic discharges associated with clinical diagnosis of epilepsy BUT only 29-55% with diagnosis of epilepsy have abnormal routine EEG, 0.5% of year olds without epilepsy have interictal epileptic discharge Some interictal abnormalities aid in prediction of further seizures 3 but not all Abnormalities increase in elderly and with learning disability and in chronic psychoses

25 Fp2-AVG Fp1-AVG F8-AVG F4-AVG Fz-AVG F3-AVG F7-AVG T4-AVG C4-AVG Cz-AVG C3-AVG T3-AVG T6-AVG P4-AVG Pz-AVG P3-AVG T5-AVG O2-AVG O1-AVG 1 sec 100 µv

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27 Electroencephalography Appropriate use of EEG in epilepsy To stratify the risk of further epileptic seizures after a single epileptic seizure To classify epilepsy When no witness account When reviewing diagnosis Diagnosis of non-convulsive status epilepticus and convulsive status epilepticus Use routine EEG +/- natural drowsiness Long-term EEG if routine EEG doesn t provide all answers Ambulatory EEG for interictal epileptic discharges: sensitivity 80% In-patient video-eeg: event capture rate 70%

28 Cardiac effects of epileptic seizures - and vice versa Ictal sinus tachycardia in greater than 90% of seizures: Keilson et al Arch Neurol 1989: 46: Ictal bradycardia or asystole in less than 1% of cases Rocamora et al: Epilepsia: 2003:44: Scheule et al: Neurology: 2007: 69: Unclear whether pacemaker insertion of benefit Cardiac arrhythmias documented in SUDEP Reduced heart rate variability documented in patients with SUDEP compared to control group heart rate variability reduced in refractory temporal lobe epilepsy: Ansakorpi et al: JNNP: 2002: 72: EEG/ECG evidence of hypoperfusion induced epileptic seizures

29 William Gowers Hans Berger Henri Gastaut