Opisthotonus and other unusual neurological sequelae after outpatient anaesthesia

Toxin-Induced Coma and Central Nervous System Depression

Many medications and toxins may induce central nervous system (CNS) depression. Even when the intention is to induce CNS depression, other nervous system adverse effects may occur, such as with anesthetics. Pain medications produce characteristic CNS toxicities. Sedative hypnotics may induce altered mentation among systemic toxicities. Stimulants may mimic coma when discontinued abruptly. Acute and chronic carbon monoxide poisoning can lead to altered mental status and prolonged cognitive difficulties. Some medications and environmental toxins can mimic brain death. High clinical suspicion and early recognition of these effects is vital to treatment, most of which is supportive.

Propofol Frenzy: Clinical Spectrum in 3 Patients

Postsedation neuroexcitation is sometimes attributed to intravenous injection of the sedative-hypnotic drug propofol. The movements associated with these events have strongly suggested convulsive activity, but they rarely have been comprehensively evaluated. We present video recordings of 3 healthy young patients who underwent elective surgery under conscious sedation and emerged from sedation with transient but repetitive violent motor activity and impaired consciousness. These manifestations required considerable mobilization of multiple health care workers to protect the patient from inflicting harm. All patients received propofol, and all fully recovered without adverse sequelae. We postulate that these movements are propofol related. Importantly, we found no evidence of seizures clinically or electrographically.

[Perioperative considerations in vagal nerve stimulator implantation]

Vagal nerve stimulation has become an a important tool in the treatment of refractory epilepsy, which continues to be the main indication for this technique. Other therapeutic indications are emerging, however, and vagal nerve stimulation has now been approved for major depression. Additional possible uses under study include morbid obesity, Alzheimer disease, chronic pain syndromes, and certain neuropsychologic disorders. This review considers perioperative aspects relevant to using this therapeutic procedure with a view to facilitating better and more integrated management of its application.

A case of propofol-induced delayed-onset refractory myoclonic seizures

Propofol, a GABA-mediated inhibitor of excitatory neurotransmitter, is a popular intravenous agent for general anesthesia and sedation. Its side effects reportedly include opisthotonus, seizures, and myoclonus, and are usually manageable. We present a patient who developed propofol-induced delayed-onset refractory myoclonic seizures that resisted antiepileptic drugs.

Effect of propofol on seizure-like phenomena and electroencephalographic activity in children with epilepsy vs children with learning difficulties

There is an ongoing debate as to whether propofol exhibits pro- or anticonvulsant effects, and whether it should be used in patients with epilepsy. We prospectively assessed the occurrence of seizure-like phenomena and the effects of intravenous propofol on the electroencephalogram (EEG) in 25 children with epilepsy (mean (SD) age: 101 (49) months) and 25 children with learning difficulties (mean (SD) age: 52 (40) months) undergoing elective sedation for MRI studies of the brain. No child demonstrated seizure-like phenomena of epileptic origin during and after propofol sedation. Immediately after stopping propofol, characteristic EEG changes in the epilepsy group consisted of increased beta wave activity (23/25 children), and suppression of pre-existing theta rhythms (11/16 children). In addition, 16 of 18 children with epilepsy and documented EEG seizure activity demonstrated suppression of spike-wave patterns after propofol sedation. In all 25 children with learning difficulties an increase in beta wave activity was seen. Suppression of theta rhythms occurred in 11 of 12 children at the end of the MRI study. In no child of either group was a primary occurrence or an increase in spike-wave patterns seen following propofol administration. The occurrence of beta wave activity (children with learning difficulties and epilepsy group) and suppression of spike-wave patterns (epilepsy group) were transient, and disappeared after 4 h. This study demonstrates characteristic, time-dependent EEG patterns induced by propofol in children with epilepsy and learning difficulties. Our data support the concept of propofol being a sedative-hypnotic agent with anticonvulsant properties as shown by depression of spike-wave patterns in children with epilepsy and by the absence of seizure-like phenomena of epileptic origin.

Dystonic reaction to propofol attenuated by benztropine (cogentin)

IMPLICATIONS

Neuroexcitatory movements associated with propofol anesthesia are well recognized. Here we report on the successful use of benztropine (2 mg) to abolish abnormal dystonic movements after propofol anesthesia. Forty-five case reports are reviewed, and a treatment strategy for abnormal movements during propofol anesthesia is provided.

Propofol sedation produces dose-dependent suppression of lidocaine-induced seizures in rats

The association of propofol with excitatory motor activity, such as myoclonic jerking and opisthotonus, in humans and in animals suggests that it may aggravate clinical seizure activity in some circumstances, although evidence suggests that under other circumstances, propofol inhibits seizure activity. In the current study, we assessed the effect of sedating doses of propofol on lidocaine-induced seizure activity in spontaneously breathing rats receiving no other anesthetics. Adult Sprague-Dawley male rats, 300-400 g, were divided into a control group and three experimental groups representing three graded levels of propofol sedation. The control rats then received a lidocaine infusion at the rate of 150 mg x kg(-1) x h(-1), resulting in a slow, progressive increase in systemic lidocaine concentrations. At the onset of electroencephalographic (EEG) seizure activity, arterial lidocaine concentrations were obtained. The treated rats received propofol according to three different dose schedules: Dose 1 = 10 mg x kg(-1) x h(-1) after a 2.5-mg/kg bolus; Dose 2 = 20 mg x kg(-1) x h(-1) after a 5-mg/kg bolus; Dose 3 = 40 mg x kg(-1) x h(-1) after a 10-mg/kg bolus. After 30 min, a steady level of sedation, dependent on the dose of propofol, was achieved. The lidocaine infusion was then started, and systemic lidocaine levels were obtained at the onset of EEG seizure activity. The lidocaine was continued until the onset of death by cardiac arrest. Plasma lidocaine was measured by gas chromatography. Analysis of variance and Dunnett's t-test were used for comparisons with the control values. Continuous propofol sedation increased the seizure dose of lidocaine from 37.7 +/- 3.5 mg/kg (mean +/- SEM) to 52.5 +/- 2.6 mg/kg (Dose 1, P < 0.05) and 67.9 +/- 8.6 mg/kg (Dose 2, P < 0.05), and completely abolished lidocaine seizures at Dose 3. The lethal dose of lidocaine, 89.4 +/- 10.5 mg/kg control versus 108.7 +/- 10.3 mg/kg (Dose 1), 98.3 +/- 10.1 mg/kg (Dose 2), and 93.5 +/- 10.4 mg/kg (Dose 3) did not differ among groups. The lidocaine levels at seizure threshold were increased in the propofol-treated rats: 16.9 +/- 0.5 microg/mL control versus 19.2 +/- 0.7 microg/mL (Dose 1, P = not significant) and 23.7 +/- 1.8 microg/mL (Dose 2, P < 0.05). Continuous propofol sedation in spontaneously breathing rats receiving no other anesthetics exerts a protective effect against lidocaine-induced seizures in a monotonic, dose-dependent fashion. The cardiac arrest dose of lidocaine is unaffected by propofol under these conditions.

IMPLICATIONS

The i.v. anesthetic drug propofol, given to rats to produce sedation, was found to suppress seizure activity caused by overdosage of the local anesthetic lidocaine.

Refractory dystonia during propofol anaesthesia in a patient with torticollis-dystonia disorder

PURPOSE

To report a case of refractory dystonia under propofol anaesthesia in a patient with Torticollis-Dystonia disorder.

CLINICAL FEATURES

A 38-yr-old man presented for an MRI scan for investigation of a Torticollis-Dystonia disorder. There was a biphasic response to propofol with complete amelioration of the torticollis and limb dystonia initially with subsequent recurrence under deep propofol anaesthesia. Coadministration of midazolam, diazepam, and thiopentone were not successful in abolishing the recurrent dystonia.

CONCLUSIONS

Propofol should preferably be avoided in patients with torticollis and dystonias. Where complete control of movements is required, it may be necessary to consider general endotracheal anaesthesia with muscle relaxants.

Large-dose propofol alone in adult epileptic patients: electrocorticographic results

The primary objective of this study was to evaluate the electrophysiologic effects of large-dose propofol, used as the sole anesthetic in patients with epilepsy. Nine patients with medically intractable complex partial epilepsy undergoing a three-stage approach to the surgical management of epilepsy were recruited. State I involved placement of the intracranial electrode array, while Stage II consisted of extraoperative localization of the seizure focus. The patients were studied during induction of anesthesia for Stage III (removal of electrodes and resection of seizure focus). Unpremedicated patients were induced with a propofol infusion (0.5 mg.kg-1.min-1) until one of the following occurred: 1) electrical seizure activity, 2) burst suppression, or 3) total dose of 10 mg/mg. Electrocorticography (ECoG) was recorded continuously during this period. Two patients were excluded from the study after experiencing delayed awakening after the Stage I procedure. Both had received propofol along with other anesthetics. No ECoG evidence of seizure activity was detected in the seven patients completing the study. Burst suppression was attained in six patients using a mean dose of 5.7 mg/kg +/- 2.6. We conclude that large dose propofol alone does not trigger electrical epileptiform activity on the ECoG of seizure patients.

Dandy-Walker syndrome presenting as opisthotonus: proposed pathophysiology

A patient with radiographically confirmed Dandy-Walker syndrome who presented with opisthotonus, a rarely reported clinical manifestation, is reported. From four separate pharmacologic trials (baclofen, diazepam, levodopa/carbidopa, and trihexyphenidyl), combination baclofen and diazepam therapy was determined to be most efficacious. Opisthotonus and extensor posturing remain only rudimentarily understood. We review the subject and propose a specific mechanism relating our patient's anatomic and physiologic conditions.

Neurological and psychiatric adverse effects of anaesthetics: epidemiology and treatment

The practice of anaesthesia has changed considerably over the past 20 to 30 years owing largely to technological advances in patient monitoring and an expanded and improved pharmacological repertoire. While patient safety in anaesthesia has greatly improved, the risk of neurological and psychiatric adverse effects of anaesthetics remains and is the focus of continued investigation. For example, a great deal of attention has recently been directed at intraoperative awareness. This adverse event can be caused by delivering an inappropriate amount or type of anaesthetic. Another risk of anaesthesia involves drug-induced unpleasant subjective states in patients. Those drugs most frequently associated with these states include ketamine, droperidol and scopolamine. This risk can often be attenuated by careful adjustment of drug dose and the use of adjunctive agents such as benzodiazepines which may produce amnesia of the unpleasant subjective state. While it is well established that modern anaesthetic drugs cause acute impairment of cognition and psychomotor functioning, there is little evidence that these drugs have long term impairing effects. Finally, a particular kind of surgery, cardiac surgery requiring cardiopulmonary bypass, can be associated with adverse neurological and psychiatric sequelae which, while not directly related to anaesthesia, are of intense interest to anaesthesiologists.

Comparison of total intravenous, balanced inhalational and combined intravenous-inhalational anaesthesia for tympanoplasty, septorhinoplasty and adenotonsillectomy

Two hundred and thirty-five consecutive Saudi patients aged between two and fifty-three years undergoing elective tympanoplasty (n = 32), septorhinoplasty (n = 68) or adenotonsillectomy (n = 135) were studied. They were randomized to receive either a total intravenous anaesthetic (10 ears, 23 noses, 44 throats) consisting of propofol for induction of anaesthesia followed by a propofol infusion, a combined intravenous-inhalational anaesthetic (11 ears, 22 noses, 46 throats) consisting of the above with isoflurane in oxygen-enriched air, or a balanced inhalational anaesthetic (11 ears, 23 noses, 45 throats) consisting of thiopentone for induction of anaesthesia and oxygen in nitrous oxide with isoflurane for maintenance. During tympanoplasty, all three anaesthetic techniques produced stable heart rates and arterial pressures. During septorhinoplasty, blood pressure rose in patients who received total intravenous anaesthesia, while combined and balanced techniques produced haemodynamic stability. During adenotonsillectomy, total intravenous anaesthesia produced a rise in both heart rate and blood pressure, the combined technique produced a rise in heart rate alone while balanced anaesthesia produced haemodynamic stability. Postoperatively, vomiting, pain scores and analgesic requirements were similar following all three types of anaesthetic within each surgical site subgroup. Our findings support the choice of balanced inhalational anaesthesia for all three types of ENT surgery and, where cost and facilities permit, total intravenous anaesthesia for tympanoplasty and combined intravenous-inhalational anaesthesia for septorhinoplasty.

Propofol and seizures

It is now clear that "seizure activity", excitatory phenomena, and/or a disorder of muscle tone are potential complications of the use of propofol. Whether this "seizure activity" is primarily, secondarily, or not at all a cerebral cortical event is still to be elucidated. Clearly propofol does have anticonvulsant activity, and also clearly it can produce an involuntary movement disorder, in certain patients, under certain conditions. Propofol is not the first anaesthetic drug to be implicated in the causation of seizures or abnormal movements nor indeed the first to appear to have anti-convulsant and proconvulsant activity (e.g. Althesin). While propofol has undoubtedly proved a very useful drug, the problem of convulsive phenomena creates a degree of background concern about its use. More needs to be known about the mechanism of this complication and any risk factors involved in determining who may have a seizure after propofol. In the clinical setting, the reporting of seizures possibly related to propofol should include--medical history, including personal or family history of epilepsy and movement disorders; a history of previous anaesthetics and whether propofol was used; regular medications; use of drugs or alcohol; history of chemical dependency; emotional state prior to induction; presence of hyperventilation or fever; a description of the alleged seizure, including rate of administration of propofol and amount given, time of onset of seizure in relation to time of drug administration, speed of onset of signs, quality of the abnormal movements, part of body involved, duration, any indication of a postictal state, any cardiovascular changes which may have accompanied the seizure, and any other possible triggers for the reaction such as other drugs used, including premedication; post seizure investigations including temperature, blood sugar, electrolytes, arterial gas analysis, neurological examination, EEG and CT scan. These actions and these investigations concerning propofol should not be delayed. It would appear appropriate to recommend to patients who experience apparent convulsive phenomena after propofol that they not be re-exposed to the drug.

Propofol, seizures and generalized paroxysmal fast activity in the EEG

Propofol is a relatively new anesthetic agent used in outpatient surgery. Some investigators use it in the treatment of status epilepticus and in epilepsy surgery and have concluded that propofol has an anticonvulsant effect. Cases of seizure-like behaviors, myoclonus and opisthotonus following propofol anesthesia have been reported. Although rare, official warnings about this association have been issued. Different EEG abnormalities, and no abnormality, have been associated with propofol. We report a case of a healthy man who developed nonconvulsive seizures and generalized paroxysmal fast activity in his EEG following use of propofol for anesthesia.

Opisthotonos following propofol: a nonepileptic perspective and treatment strategy

In this report of opisthotonos during recovery from propofol anaesthesia, we relate clinical observations with scientific considerations, and propose a strategy for treatment of this rare side effect. Following a brief operative procedure, a healthy 29-yr-old woman developed recurrent opisthotonos while recovering from anaesthesia with alfentanil, propofol, and nitrous oxide. In contrast to accumulating reports, the patient remained conscious during each episode of back extension and retrocollis. The preservation of consciousness and similarities to strychnine-induced opisthotonos suggest to us that the mechanism may have a brainstem and spinal origin. Recent investigations show that propofol potentiates the inhibitory transmitters glycine and gamma-aminobutyric acid (GABA) which would enhance spinal inhibition during anaesthesia. Postanaesthetic opisthotonos, however, may be due to a propofol-induced tolerance to inhibitory transmitters. This rebound phenomenon would lead to an acute, enduring refractoriness in inhibitory pathways of the brainstem and spinal cord, resulting in increased activity of extensor motoneurons. We recommend a therapeutic strategy that restores inhibition by glycine and GABA at multiple sites; the preferred therapeutic agents would be diazepam and physostigmine. The episodes are usually short-lived, but two of the reviewed 17 patients developed recurrent retrocollis for four and 23 days following antiepileptic drug therapy. Since high doses of phenytoin and carbamazepine can result in opisthotonos, we recommend that anticonvulsants be reserved for postanaesthetic patients with electroencephalographic evidence of seizure activity.

[Diprivan and epilepsy]

Propofol can be used safely in patients with a history of epilepsy. In the known epileptic patient, propofol is not contra-indicated, provided that the anaesthetist ensures that the anti-epileptic treatment is correctly maintained.

Delayed seizures following sedation with propofol

Seizures occurred in two adolescents approximately six hours after sedation with propofol for bone marrow biopsy. Case #1 was a patient with chronic renal failure, hypertension, and anaemia. Case #2 had just been diagnosed with acute lymphocytic leukaemia. Neither child had experienced seizures before, and both recovered without neurological sequelae. Although other factors may have caused the seizures, the episodes have raised concerns about the safety of propofol for patients travelling home after out-patient surgery. Further study is required to explain the cause of this complication or, at least, to identify risk factors.

Postoperative opisthotonus and torticollis after fentanyl, enflurane, and nitrous oxide

Most drug-induced extrapyramidal symptoms are due to blockade of dopaminergic receptors and are treated with anticholinergic drugs. We report a patient with severe postoperative extrapyramidal symptoms which responded to physostigmine and indicated a different aetiology. A young, healthy female outpatient developed severe extrapyramidal symptoms after an uneventful 50 min anaesthetic with thiopentone, fentanyl (100 micrograms), enflurane, and nitrous oxide. Although the trachea was not extubated until she obeyed commands, the patient developed opisthotonus, which resolved initially after treatment with thiopentone (40 mg), diazepam (5 mg), and diphenhydramine (50 mg). The opisthotonus recurred approximately 25 min later, in association with torticollis, obtundation, and periodic apnoea. A tentative diagnosis of central anticholinergic syndrome was proposed, and fentanyl was considered to have been responsible. Naloxone (0.4 mg) induced no improvement, but physostigmine (2 mg) reversed the dystonic symptoms and periodic apnoea and improved her mental status. The response to physostigmine may have been due specifically to increased levels of acetylcholine at the cholinergic receptors, or to a nonspecific analeptic effect.