• Delirium: a syndrome of impaired consciousness, attention, cognition or perception (abrupt/ recent onset)
• Dementia: A failing intellectual functions including cognitive dysfunction, disorder of mood and affect and disorder of behaviour (gradual)

• Primary cerebral disease
• Systemic disease

1. Infection
2. Fluid or electrolyte disturbance
3. Metabolic derangement, Cardiopulmonary disease
4. Anaemia

• Intoxication
• Withdrawal syndromes

1. Benzodiazepam
2. Alc

• Miscellaneous

1. Faecal impaction
2. Urinary retention
3. Decreased sensory input: visual, auditory
4. Hypothermia or hyperthermia
5. Environmental change (deconditioning) especially hospitalisation
6. Trauma, Burns, Fractures, Surgery

• Complete blood count, Electrolyte levels (Na, K, Ca), Blood chemistry panel
• Urinalysis, Blood culture (evidence of infection)
• Electrocardiogram, Cardiac isoenzyme levels, CXR, Arterial blood gases (pul cond?)
• Syphilis serology, Thyroid function tests, Toxicology screens, Drug levels
• CT/ MRI of the brain (CNS causes), Lumbar puncture
• Electroencephalogram (Dx delirium, exclude non-convulsive status epilepticus)

1. Haloperidol (Haldol)
2. Benzodiazepines for delirium secondary to alcohol and sedative withdrawal

• Temporal physiologic dysfunction of brain
• Self limiting abnormal hypersynchronous electrical discharges of cortical neurones
• Depends on the location of discharges, route of electrical spread, the extent of subcortical and brain stem involvement -> different clinical seminology (features of epileptic event; therefore can localise site and cause of event)

• Definitions (important):

1. Seizure: a transient epileptic event, a symptom of disturbed brain function
2. Epilepsy: recurrent seizure, unprovoked

• Can have ML implications

1. Neurogenic vasodepressor and vasovagal reaction (vasovagal attack: sudden impairment of VR to brain causing transient cerebral dysfunction; aka syncope)
2. Sympathetic nervous system failure (postural-orthostatic hypotension)
3. Reduced CO inadequate intravascular volume (hypovolaemia) (eg. reduced HR due to failing heart)
4. Miscellaneous: hypoxia, anaemia, hyperventilation (sudden panic attack - Dx by Hx), hypoglycemia (secondary to Tx for DM, rarely spontaneous)

1. Congenital
2. Idiopathic or cryptogenic
3. Infective (eg. meningitis, encephalitis)
4. Trauma
5. Vascular (eg. Stroke - ischaemic, haemorrhagic)
6. Neoplastic (eg. Stroke; may also be common in paed but histol Dx different)
7. Degenerative (eg. Dementia)

Classification of Seizures (Outline) - According to site of onset

Partial (Focal) seizure (starts in part of brain)

1. Simple partial seizure (consciousness not impaired during event; did not propagate - eg. Motor seizure: jerking of hands continuously, sometimes lasting minutes)
2. Complex partial seizure (consciousness impaired; able to respond but response not normal)

• Begins and ends gradually; can result in dream like state; may become pal
• Can react to surroundings eg. Moving head when spoken to
• Autonomism - lip smacking, fondling, grimacing
• May be difficult to distinguish in MR people (eg. Rocking, swaying)
• West's syndrome + Lennox syndrome need special care

1. West's syndrome

• Seen in infants: tonic-seizure; EEG shows typical pattern
• Poor Px (only 10% become free of seizure + dev normally; often intractable)
• Manifestations of serious condition even though they don't appear serious

1. Lennox syndrome

• Found in very young children (age 3-7)
• Several types of seizure occur side by side (most frequently myoclonic static syndrome) - Tonic seizures; Drop attacks; Freq injuries; MR; Often intractable

1. Partial seizure with secondary generalisation (after onset of partial seizure, seizure becomes generalised and presents with convulsions)

1. Absence seizure, Myoclonic seizure

1. Tonic-clonic seizure, tonic seizure, clonic seizure

1. Tonic-clonic = grand mal seizures

• Tonic: m's stiffen, tension of m's causing breathing to stop
• Then body jerks = clonic phase, lack of oxygen b/c using more energy, Pt may turn blue
• Tongue may be bitten and blood mixed with saliva
• M's relax and Pt exhausted
• Contraction of UB m's at beginning or relaxation at end, may be incontinent
• Pt's may sleep, wander around confused
• Acute Tx during tonic-clonic position = lateral position, let saliva and blood exit mouth to prevent suffocation

• Seizure phenomenology
• Crucial for seizure diagnosis
• For correct management of epilepsy
• Localisation value: temporal vs. extratemporal [temporal: most surgical amenable epilepsies]

1. Idiopathic: no cause ID, most genetically related
2. Symptomatic: ID cause (eg. Tumour, trauma, infection, etc) - eg. Frontal lobe tumour causing frontal lobe epilepsy (individual for that tumour)
3. Cryptogenic: Pt has underlying pathology but not as yet ID based on Ix

1. Idiopathic
2. Symptomatic
3. Cryptogenic

1. Juvenile myoclonic epilepsy
2. Childhood absence epilepsy
3. Epilepsy with generalised tonic-clonic seizure on awakening
4. [3 most common in Western literature; may be different in HK population, but no data yet]

• Symptomatic generalised epilepsies

1. Infantile spasm
2. Progressive myoclonic epilepsies
3. Myoclonic epilepsy and ragged red fibres (MERRF) - mitochondrial myopathy

• Idiopathic

1. Benign childhood epilepsy with centrotemporal spike
2. Benign childhood epilepsy with occipital paroxysms

• Symptomatic

1. Frontal lobe epilepsy
2. Temporal lobe epilepsy
3. Occipital lobe epilepsy
4. Parietal lobe epilepsy

• Electroencephalography (EEG)

1. [can help classify seizure and epilepsy and help with Mx]
2. Interictal EEG: bet seizure attacks
3. Ictal EEG: catch seizure, only feasible if freq seizures (eg. Absence seizures 30-200 attacks/d)
4. Video-EEG telemetry (if less freq like complex-partial seizures - 1-2/w)

1. SPECT: single photon emission computed tomography: cerebral perfusion
2. PET: positron emission tomography: with radioisotope can study actually O2 consumption (metab) of BR

• Intracarotid amytal test

1. Ultrashort acting barbiturate into carotid artier (t1/2 - 5 minutes)
2. Anaesthetise one side of brain language and memory function of that side

• An essential tool in the diagnosis and treatment of seizures.
• To record a patient's EEG during actual seizures or other spells, along with synchronised videotaping of behavioural events.
• Indications: (1) Confirm Dx - 1/3 [may be cardiac seizure or pseudoseizure] (2) Pre-surg eval [clinical seminology, clinical onset, locate site of lesion]
• SLIDE: rrregular spikes + wave discharge 2-3Hz (eg. childhood onset epilepsy - epsilon)
• 4-5 grid over temporal lobe surface under dura (recording = seizure onset gradually builds up and becomes generalised) - can localise where onset of seizure is so can resect that particular region by neurosurgery)

Hippocampal Sclerosis (Surgically Treatable Condition)

• Stereotyped neuronal loss (eg. Damage during childhood)
• CA1, CA3, CA4, fascia dentata (most severe in CA2)
• Hyperintense signal in T2W (hippocampus smaller in affected side)
• A common cause of temporal lobe epilepsy
• History of febrile convulsion in childhood
• Often refractory to anticonvulsants therapy
• High success rate with epilepsy surgery
• Note: if well-controlled with meds, no need for surg

• Neural migration disorder
• Mature looking neurones of variable size and number
• X-linked

• Dev abn
• Irreg masses of grey matter are located in white matter
• Overlying cerebral cortex is thinned out and abn looking

• Types of low grade brain tumour freq seen in paed intractable focal epilepsy
• Px usu. excellent following surg removal

• Type of congenital vascular malformation
• Unlike AVM, the risk of death from bleeding is low
• Causes epilepsy (eg. Cavernous angioma in middle part of temporal lobe causing visual temporal epilepsy)

1. Avoid precipitating factors (eg. Sleep deprivation)
2. Advice against risky activity of epilepsy (eg. Work at hts - eg. Construction site worker, swimming alone, riding bicycle alone, driving MV - onus on driver license application to inform transport department)
3. Anticonvulsants
4. Surgery for epilepsy
5. Neuroprosthetic devices (eg. Vagal nerve stimulator)
6. Ketogenic diet

1. Phenytoin, Valproate acid, Carbamazepine
2. Phenobarbital, Primdone, Ethosuxamide, Benzodiazepines

• New AEDs

1. Lamotrigine, Vigabatrin, Felbamate, Gabapentin, Topiramate, Zonisamide, Clobazam

• Controversial
• Likelihood of recurrent seizures (if abn neuroimaging, several episodes - may put on Tx immediately)
• Risk of the treatment itself
• Success rate of treatment
• Consequence of further seizures to the patient

1. Aetiology of the seizures (eg cerebral injury)
2. EEG findings (epileptiform disturbances)

"If Pt has 2 seizures within few mths, put Pt on anticonvulsant prophylaxis"

The goal of treating patients with epilepsy is to control seizures completely without causing unacceptable side effects.

• For poorly controlled seizures
• Small pacemaker-like device placed under the skin and periodically stimulates a nerve (like vagus) in the side of the neck with a small amt of electrical current (only on L side)
• Effective in reducing seizure freq and severity

• Remove the epileptogenic area
• Limit the spread of the abnormal electrical propagation during ictus
• Avoid postoperative neurological deficits by identifying areas of cerebral cortex mediating essential neurological functions

1. Frontal lobectomy (removing one frontal lobe has no adverse effects for Pt)
2. Temporal lobectomy
3. Hemispherectomy (eg. Encephalitis) - motor function can shift to other hemisphere, Surg before age 9-10yo

• Functional procedure/disconnection surgery [confine spread of electrical discharge]

1. Multiple subpial transection (MST): divide subpial area, more complicated mapping and surgical technique
2. Corpus colostomy (esp drop attacks only anterior 2/3 CC divided else disconnec'n synd)

• Social stigma
• Public awareness and understanding
• Paediatric and Adolescence: may stop learning due to intractable seizure
• Women of reproductive age: when to get pregnant? >90% pregnancies normal
• Geriatric epilepsy
• Neuropsychological issues: disease itself or anti-convulsants can cause neuropsych issues
• Medical legal issues

• Recurrent epileptic seizures without full recovery of consciousness before next seizure begins

OR

• More or less continuous clinical and/or electrical seizure activity lasting >30 minutes, whether or not consciousness is impaired

• Need to treat promptly
• Survival worse if not treated within 1 hour

• Medical emergency
• Prolonged seizure activity causes neuronal damage
• EEG monitoring is essential
• Systemic factors exacerbate SE-induced neuronal damage
• The longer the duration, the later the EEG stage, and the more subtle the motor manifestations, the harder SE is to stop
• A predetermined Rx protocol more effective: benzodiazepine (if not effective) + phenotoluene (infusion) (if not effective) + ICU (chromophobe - GA)

1. Normal consciousness
2. Confusion - Cloudiness of sensorium
3. Drowsiness - Inability to sustain a wakeful state without external stimulation
4. Stupor - roused only by vigorous and repeated stimuli
5. Coma - appears to be asleep and incapable of being aroused by external stimuli

1. Diseases with no focal or lateralising neurologic signs (intoxication, metabolic, sepsis, shock, post-seizure state, hypertensive encephalopathy, hyperthermia or hypothermia, concussion)
2. Diseases cause meningeal irritation ± fever (SAH, meningitis, encephalitis)
3. Diseases cause focal brainstem and cerebral signs (haemorrhage, infarction, abscess, tumour)

• Look for underlying cause of coma and manage accordingly
• Supportive therapy
• Prevent complications

1. Bladder care: UTI
2. Chest physio: Chest infection
3. Physical measures to prevent bed sore
4. Pneumatic compression boots and SC heparin: lower limbs DVT

• Eye opening (1 nil, 2 pain, 3 speech, 4 spontaneous)
• Motor response (1 nil, 2 extensor, 3 flexor-abn, 4- flexor WD, 5 localises pain, 6 obeys)
• Verbal response (1 nil, 2 groans, 3 inappropriate, 4 confused, 5 oriented) (T intubated)

1. Absence of cerebral function
2. Absence of brain stem function
3. Irreversibility of the state

• Confirm by two examinations (~ at 24 hrs intervals)
• Controversial: can be performed in shorter period of time, but must be 2 examiners (probably not by transplant team!) - eg. Neurol, ICU team

• No spontaneous eye movement
• Pupil reflex, Corneal reflex, Oculocephalic reflex (Doll sign), Caloric reflex (nystagmus), Gag reflex
• Apnoea test (disconnect from ventilator and provide adequate O2 to Pt - if BS death, no resp movt + CO2 will increase = most noxious stimulator of resp movt) (if no spontaneous resp movt = +ve apnoea test)

• Depressant drugs
• Neuromuscular blocking drugs
• Hypothermia
• Metabolic endocrine disturbance (hypothyroidism - myxoedema coma- urgent Tx give T3)