Perioperative seizures

Dr. S. Parthasarathy MD., DA., DNB, MD (Acu),

Dip. Diab.DCA, Dip. Software statistics- Phd

Mahatma Gandhi Medical college and research institute , puducherry , India

Definition • A seizure can be defined as the clinical manifestation of

an abnormal and excessive discharge of neurones, seen

as alteration of consciousness, motor, sensory or

autonomic events.

• Epilepsy is defined as recurrent (two or more) epileptic

seizures unprovoked by any immediately identifiable cause.

• Epilepsy includes seizures but seizures ??

Incidence

• Only epilepsy – incidence • 0.5 – 1 %

• But peri operative seizures – incidence ??

• EEG monitoring in potential patients ?? • It can also miss ??

Classification

• General • Partial • Unclassified

Causes • Epilepsy • Tumours • Infections • Metabolic • Alcohol • Stroke

• Its Same

Differential diagnosis

• Syncope • Migraine • Narcolepsy • Non epileptic seizures

Investigations

• EEG • CT scan • MRI • PET scan

How does it relate to us ??

• Sudden seizures – periop• Epilepsy – anaesthetic considerations• ICU status epilepticus

Clinical setting

• Commonest setting

• LA toxicity

• Intercostal • IVRA • Cervical plexus • Epidural then others

Test dose

• There may be premonitory symptoms, such as peri oral

tingling, or feelings of dissociation following a test dose.

• Epinephrine ??

• Catheter malfunction

• Catheter position change

• Axillary ??

• Field blocks

Maximum dose for infiltration (mg/kg)

• Lidocaine 3 - 4• With adrenaline 7• Bupivicaine 2• With adrenaline 3• Prilocaine 6• With adrenaline/octapressin 8• Additive

Basic treatment

• Airway • Oxygen • Ventilate • Support

• Other than benzodiazepines

Surgery – what type ??

What Type of Surgery Places the Patient at Risk for Seizures?

• Neuro surgery 20 %

• Leave alone head injury • Supratentorial tumors • Cerebral abscess 90 % • Drainage 15 – 20 %

• Preop seizure history -- incidence is very much higher

CAROTID AND CARDIAC SURGERY

• Clamping • Emboli • Stents and tubes

Other surgeries

• extensive bowel surgeries • Burns and plastic surgeries • Gut obstruction

• Fluid shifts – seizures

• Electrolytes

• Clinical settings

Hyponatremia – usually 115 is cut off

• TURP syndrome • Extensive bowel surgeries • Other scopies where irrigation is done • Plastic and burn reconstruction – massive fluid shifts • Drugs like diuretics • Water intoxication • SIADH. Vomiting • Renal and hepatic disorders

Hypocalcemia

• Low albumin; • abnormal acid-base status and electrolytes; • drugs used during the peri-operative period• transfusion of large volumes of citrated blood; • Parathyroid surgeries ,thyroid , CPBs• Sepsis , CRF • Calcium chelators in radiographic contrast

Eclampsia

In pregnant – other than

• Epilepsy, eclampsia, drugs

• Posterior reversible encephalopathy • Amniotic fluid embolism • Cortical vein thrombosis

Intraop seizures – wrong drugs

• Tranexemic acid into the intrathecal space

In an ICU

• Seizures

• Posttraumatic brain injury• CNS infections• Endocrine and metabolic disorders• Drugs or toxins

Seizure prone electrolyte disturbances

• Hyponatremia• Hypokalemia• Hypocalcemia• Hypoglycemia and hyperglycemia• Hypomagnesemia

Drugs

• Amphetamine • SSRIs • Tricyclics • Levodopa • Deriphyllin • Phencyclidine • Withdrawal of antiepileptics• Methergin

Alcohol related

• hyponatremia, hypomagnesemia, or hypoglycemia

• Thiamine

Anesthesia related

• Tramadol Pethidine ,• etomidate • Enflurane ,sevo • Atracurium• Flumezanil

• Ketamine methohexital ??, propofol • Hypocapnia ??

EEG monitoring in sevo

Other settings

• Renal failure --- erythropeitin ?? • Hepatic failure • Hypothyroidism • Hashimato s

• Inciting factors • Fever , infection , sleeplessness

Reflex Anoxic Seizures and Anaesthesia

• What is this ?? • ocular pressure, venepuncture, accidental

trauma and fear • Young female school children

• Grand mal like • EEG changes may not be present

What should we do

• Patient Should not fall • Oxygen • Bag and mask • Two IV lines • Glucose • Thiamine • Benzodiazepines

Settings at a glance

• Local anaesthetic toxicity • TURP • Eclampsia • Neuro surgeries • CPBs • Drug intake • Drug withdrawal

Post operative period

• Postoperative generalized shaking is usually because of shivering, which may be thermoregulatory or non-thermoregulatory.

• The latter is thought to be secondary to the

effects of volatile anaesthetics, pain or both.

Pseudoepileptic seizures

• common in the postoperative period. • resemble tonic–clonic seizures • NO abnormal electrical discharges• history of convulsions and/or psychosomatic illness. • flamboyant, last longer than 90 s , asynchronous limb

movements, side-to-side head movements, closed eyes (including a resistance to eye opening).

• There is no cyanosis or post-ictal period• may be incontinence or tongue-biting. • Seizures may settle with reassurance. • Plasma prolactin concentrations tend to be raised after epileptic

seizures and normal after pseudo-seizures.

In fits • Case ?? • Massive fluid shifts• Epileptic • Systemic illness • Drugs, alcohol • Hypoxemia • Electrolytes , blood glucose, RFT, LFT • CT brain • Oxygenation, benzodiazepines

Status epilepticus

• The traditional definition of status epilepticus as a seizure

lasting or recurring without regaining of consciousness over a

30 min period is primarily useful for epidemiological

purposes.

• Can we wait for 30 minutes ??

• In clinical practice, most convulsive seizures abate within 2–3

min and a seizure that continues for more than 5 min has a

low chance of terminating spontaneously.

Physiological changes • Increased cerebral metabolism • Increased blood flow, • increased glucose and lactate concentration• Increased catecholamine secretion

• 30 – 60 minutes

• hyponatraemia, potassium imbalance,• evolving metabolic acidosis, consumptive

coagulopathy, rhabdomyolysis, and multi-organ• failure

Stages

• Premonitory (0 -5 min) • Early (5-10 minutes) • Established ( 10 – 30 minutes )• Refractory ( 30 – 60 minutes)

• Pre-monitory stage (out of hospital or first 5 min)

• BUCCAL OR RECTAL MIDAZ

Early stage (first 5–10 min)

• Iv ACCESS • OXYGEN • GLUCOSE , THIAMINE • BENZODIAZIPINES

Established CSE (5–30 min)

• Phenytoin • Phenobarbital • Valproate • levetiracetam

Refractory status (30–60 min)

• Refractory CSE (RSE), where SE continues in spite of administration of two AEDs (e.g. benzodiazepines and phenytoin), is associated with a high risk of complications.

• These include tachyarrhythmias, pulmonary oedema, hyperthermia, rhabdomyolysis, and aspiration pneumonia.

To continue till ??

• Maximal therapy should be maintained until

12–24 h after the last clinical or electrographic

seizure, after which the dose should be

tapered. If seizures recur, therapy can be re-

instituted or altered

Non-convulsive status epilepticus

• Impaired consciousness • Automatism

• EEG patterns

Summarize

• Status definition • Complications • Stages • Treatment