Severe but reversible encephalopathy associated with cefepime

Danger in plain sight: determining who is at highest risk for cefepime induced neurotoxicity and its associated morbidity and mortality

Cefepime is a fourth-generation cephalosporin that is widely used to treat sepsis but is associated with a potentially dangerous neurotoxicity syndrome, cefepime-induced neurotoxicity (CIN). As a result, patients treated with cefepime may be at higher risk for morbidity, including seizures, and mortality. Though the recent ACORN trial concluded that cefepime does not increase the risk of mortality, most of these patients were not critically ill or elderly, two of the most at risk populations for CIN. Further, diagnosis may be difficult in the critical care setting as patients may have multiple reasons for encephalopathy. Therefore, this population in particular should be studied and monitored closely for CIN. Importantly, there are not well defined diagnostic criteria for CIN to guide evaluation and management. Defining the risk factors for CIN and using laboratory and EEG to help support the clinical diagnosis could be helpful in early recognition of CIN to help institute treatment and to rule out seizures. In this mini review, we highlight risk factors for CIN, discuss the possible value of EEG, and propose a diagnostic and management approach in the evaluation and management of CIN.

Cefepime-induced neurotoxicity: systematic review

BACKGROUND

Cefepime-induced neurotoxicity (CIN) has been well acknowledged among clinicians, although there are no clear diagnostic criteria or specific laboratory testing to help with its diagnosis. We aimed to summarize the existing evidence regarding CIN and provide future agendas for research.

METHODS

Following the PRISMA Extension for Scoping Reviews, we searched MEDLINE and Embase for all peer-reviewed articles using keywords including 'cefepime', 'neurotoxicity', 'encephalopathy' and 'seizure', from their inception to 20 January 2022.

RESULTS

We included 92 articles, including 23 observational studies and 69 cases from case reports and case series, in the systematic review. Among 119 patients with CIN, 23.5% were in the ICU at the time of diagnosis and nearly 90% of the cases showed renal dysfunction.Cefepime overdoses were described in 41%. The median latency period of developing CIN from cefepime initiation was 4 days, and about 12% developed CIN during empirical treatment. CIN patients commonly manifested altered mental status (93%), myoclonus (37%) and non-convulsive seizure epilepticus (28%). A serum cefepime trough level of >20 mg/L would put patients at risk for CIN. CIN-related symptoms were ameliorated in 97.5% by dose reduction or discontinuation of cefepime, with median time to improvement of 3 days. No CIN-associated deaths were reported.

CONCLUSIONS

This systematic review summarizes the current evidence and characteristics of CIN. In the current situation where there are no CIN diagnostic criteria and the drug monitoring platform is not routinely available, candidates for cefepime should be carefully selected. Also, based on these findings, it needs to be appropriately dosed to avoid the development of CIN.

Clinical Pharmacokinetics and Pharmacodynamics of Cefepime

Cefepime is a broad-spectrum fourth-generation cephalosporin with activity against Gram-positive and Gram-negative pathogens. It is generally administered as an infusion over 30-60 min or as a prolonged infusion with infusion times from 3 h to continuous administration. Cefepime is widely distributed in biological fluids and tissues with an average volume of distribution of ~ 0.2 L/kg in healthy adults with normal renal function. Protein binding is relatively low (20%), and elimination is mainly renal. About 85% of the dose is excreted unchanged in the urine, with an elimination half-life of 2-2.3 h. The pharmacokinetics of cefepime is altered under certain pathophysiological conditions, resulting in high inter-individual variability in cefepime volume of distribution and clearance, which poses challenges for population dosing approaches. Consequently, therapeutic drug monitoring of cefepime may be beneficial in certain patients including those who are critically ill, have life-threatening infections, or are infected with more resistant pathogens. Cefepime is generally safe and efficacious, with a goal exposure target of 70% time of the free drug concentration over the minimum inhibitory concentration for clinical efficacy. In recent years, reports of neurotoxicity have increased, specifically in patients with impaired renal function. This review summarizes the pharmacokinetics, pharmacodynamics, and toxicodynamics of cefepime contemporarily in the setting of increasing cefepime exposures. We explore the potential benefits of extended or continuous infusions and therapeutic drug monitoring in special populations.

Atypical or Typical Triphasic Waves-Is There a Difference? A Review

SUMMARY

The entity of triphasic waves (TWs) and TW encephalopathy has derived from the subjective art of EEG interpretation. Indeed, there are few if any guidelines regarding many different aspects of TWs. The authors seek to shed light on the nature and the diagnostic characteristics of various types of TWs, differentiating "typical" from "atypical" forms. The authors conclude that morphologies in the form of bursts of well-formed, smoothly contoured, negative-positive-negative, bilateral, symmetrical and synchronous, regular, reactive, periodic or rhythmic, 1.5 to 2.0 Hz, fronto-central, triphasic complexes with fronto-occipital lag meet the criteria for typical TWs and are highly suggestive of toxic-metabolic encephalopathies. These are most frequently hepatic, uremic, or sepsis-associated encephalopathies with multi-organ failure. In such cases, atypical TWs (frontopolar or parieto-occipital maximum, negative-positive or negative-positive-negative, asymmetric and asynchronous, unreactive, irregular, multifocal, continuous with spatiotemporal evolution, sharper and without fronto-occipital/occipito-frontal lag, or triphasic delta waves) are rarely seen. Atypical TWs are encountered in Angelman syndrome, toxic encephalopathies, hyperthyroidism/hypothyroidism, Hashimoto encephalopathy, nonconvulsive status epilepticus, dementia, sepsis-associated encephalopathy, cerebrovascular disorders, and certain boundary syndromes. Investigations describing TWs with uncommon etiologies revealed few with typical TWs, suggesting that the term "TWs" has been overused in the past. Triphasic waves arise from the interaction of multiple factors including toxic, metabolic, infectious, and structural disorders that affect circuits between thalamus and cortex. The patient's metabolic status, presence of potentially neurotoxic drugs, cerebral atrophy, white matter disease, dementia, or seizures help differentiate typical from typical TWs. Future studies will determine whether this dichotomy is heuristically and clinically helpful.

Triphasic Waves: Historical Overview of an Unresolved Mystery

SUMMARY

Triphasic waves are a fascinating and mysterious EEG feature. We now have to accept that, at times, epileptiform discharges may have a blunted "triphasic morphology," and that there may be great difficulty in distinguishing between these often similar forms. The aim of this review was to describe the evolution in our understanding of triphasic waves that has occurred regarding the pathophysiology of triphasic waves, their most frequent causes, and the diagnostic difficulties involved in interpretation and differentiation from nonconvulsive status epilepticus.

Acute Toxicity and Triphasic Waves-The Example of Cefepime

PURPOSE

Triphasic waves (TWs) have been associated with a host of medication toxicities, and cefepime has emerged recently as a frequently encountered offending agent. This investigation aims to evaluate cefepime-induced encephalopathy and to report the associated clinical, EEG expression with TWs, and the radiologic findings.

METHODS

A retrospective multicenter observational study examining adult patients with cefepime-induced encephalopathy with generalized periodic discharges on either routine or continuous EEG between January 2014 and January 2020. Clinical, electrographic, and radiologic data were collected. Patients in whom cefepime was not the sole causative factor for their encephalopathy were excluded.

RESULTS

Twenty-seven patients with cefepime-induced encephalopathy marked by generalized periodic discharges with triphasic morphology were identified at both centers, whereas no patients were presenting with generalized periodic discharges without TWs. Patients had a median age of 63 years (interquartile range, 56-73). Fifty-six percent of the cohort (15 patients) were <65 years of age. Eighteen patients (67%) had either acute or chronic kidney impairment (either acute kidney injury or chronic kidney disease or both), whereas 81% had preexisting white matter disease on brain imaging. Of these, 14 patients (51%) were classified as either moderate or severe. In the majority of the patients, TWs were either state-dependent or stimulus-sensitive, and in one third of them presented only as stimulus-induced pattern. All patients improved with discontinuation of cefepime.

CONCLUSIONS

Cefepime toxicity should be considered in the differential diagnosis in encephalopathic patients with TWs. The presence of preexisting white matter disease in these patients should heighten the degree of suspicion, especially in younger patients and patients without renal dysfunction.

Clinical, Electroencephalographic Features and Prognostic Factors of Cefepime-Induced Neurotoxicity: A Retrospective Study

BACKGROUND

The incidence of cefepime-induced neurotoxicity (CIN) has been previously underestimated, and there have only been sporadic reports from critical neurological settings. The present study aimed to investigate the potential factors associated with disease development, electroencephalography (EEG) sub-classification, and outcome measures.

METHODS

The 10-year medical records of patients who underwent EEG between 2007 and 2016 at a tertiary medical center in Taiwan, and developed encephalopathy after cefepime therapy were retrospectively reviewed. Age- and sex-matched controls were included for further analysis. Demographic data, the occurrence of clinical seizures, non-convulsive status epilepticus (NCSE), use of antiepileptic drugs (AEDs), receiving maintenance or urgent hemodialysis, EEG findings, and functional outcomes were analyzed. The Chi-square test and a logistic regression model were applied to survey significant prognostic factors relating to mortality.

RESULTS

A total of 42 CIN patients were identified, including 25 patients from wards and 17 from intensive care units; their mean age was 75.8 ± 11.8 years. Twenty-one patients (50%) had chronic kidney disease, and 18 (43%) had acute kidney injury. Among these patients, 32 (76%) received appropriate cefepime dose adjustment. Three patients had a normal renal function at the time of CIN onset. The logistic regression model suggested that maintenance hemodialysis and longer duration of cefepime use were independently associated with the development of CIN, with odds ratios of 3.8 and 1.2, respectively. NCSE was frequently noted in the CIN patients (64%). Generalized periodic discharge with or without triphasic morphology was the most common EEG pattern (38%), followed by generalized rhythmic delta activity and generalized spike-and-waves. AEDs were administered to 86% of the patients. A total of 17 patients (40%) did not survive to hospital discharge. Adequate cefepime dose adjustment and early cefepime discontinuation led to a better prognosis.

CONCLUSIONS

CIN was associated with high mortality and morbidity rates. Neurotoxic symptoms could still occur when the cefepime dose was adjusted, or in patients with normal renal function. Patients with maintenance hemodialysis or a longer duration of cefepime therapy tended to develop CIN. Early recognition of abnormal EEG findings allowed for the withdrawal of the offending agent, resulting in clinical improvements and a better prognosis at discharge.

Cefepime-Induced Encephalopathy in a Tertiary Medical Center in Korea

Background and Purpose

Cefepime is a widely used fourth-generation cephalosporin. It is commonly used as a first-line antibiotic to treat various infectious diseases such as hospital-acquired pneumonia, urinary tract infections, and bacterial meningitis. The primary outcome of this study was the development of cefepime-induced encephalopathy (CIE) at a tertiary medical center in Korea. We also aimed to describe the clinical features of CIE.

Methods

We enrolled 1,793 consecutive patients treated with cefepime. The CIE group included 44 patients who experienced altered consciousness after receiving cefepime without any other obvious cause and showed full recovery after stopping cefepime. This study collected demographic data, laboratory findings, and clinical data including the cause of infection, duration for onset of altered consciousness, duration of cefepime treatment, dosage of cefepime, duration of recovering consciousness after stopping cefepime, sequelae after encephalopathy, and electroencephalography data.

Results

Forty-four (2.5%) patients were included in the CIE group. The age was significantly higher in the CIE group than in the control group (71.2±10.8 years vs. 64.7±16.1 years, mean±standard deviation; p=0.007), and females constituted a significantly large proportion in the CIE group (27 of 44, 61.4%). The CIE group had higher blood urea nitrogen (34.7±22.6 mg/dL vs. 23.0±17.5 mg/dL, p<0.001) and creatinine (2.2±2.5 mg/dL vs. 1.1±1.3 mg/dL, p<0.001), and lower estimated glomerular filtration rate (eGFR) (56.3±46.0 mL/min/1.73 mm² vs. 98.8±66.3 mL/min/1.73 mm², p<0.001). Multivariate analysis showed that only eGFR was significantly related to CIE.

Conclusions

The incidence of CIE was 2.5% in this study. It is essential to consider the possibility of CIE occurring, especially in patients with lower values of eGFR and dialysis.

[Fatal Outcome of Agranulocytosis after Re-Exposure to Metamizole and Cefepime-Induced Encephalopathy]

Fatal Outcome of Agranulocytosis after Re-Exposure to Metamizole and Cefepime-Induced Encephalopathy Abstract. We present the case of an 83-year-old female patient who died as a result of likely drug-induced complications, namely agranulocytosis caused by metamizole and cefepime-induced encephalopathy. Agranulocytosis precipitated a cascade of events that eventually led to death. As prescription of metamizole has increased over the past decades, it is important to keep in mind its serious adverse drug reactions. Metamizole must be stopped immediately at the onset of symptoms such as fever, mucositis and sore throat, and re-exposure in patients who have previously developed leukopenia under metamizole must be avoided. This can be achieved by meticulous documentation in the medical records and the use of an emergency or allergy alert card which the patient carries at all times. When using cefepime, renal function should be closely monitored, especially in multimorbid geriatric patients, and the dose should be adjusted accordingly.

Cephalosporin-related neurotoxicity: Metabolic encephalopathy or non-convulsive status epilepticus?

Metabolic encephalopathy and Non-Convulsive Status Epilepticus (NCSE) have been reported with cephalosporin use, particularly cefepime. We aimed to analyze the clinical and EEG findings in patients with cephalosporin-related neurotoxicity (CRN) at our hospital identified via the hospital EEG database, and to critically review CRN case reports in the literature. A Medline search was performed to identify CRN cases where a representative sample of EEG was provided. EEGs were analyzed using published criteria differentiating NCSE from triphasic waves (TW). Eleven patients at our hospital were identified with CRN (9 cefepime, 2 ceftriaxone): all had an encephalopathy with decreased consciousness and/or confusion. One patient had clinical seizures and 6 had multifocal myoclonus. All patients had abnormal EEGs, all with moderate to severe generalized slowing and 10 also with TW. Recovery was related to cephalosporin withdrawal rather than antiepileptic therapy. Analysis of 37 EEG samples of CRN patients reported in the literature as NCSE (30) or TW (7) revealed that most did not meet criteria for NCSE, with 33 showing TW, 1 showing generalised epileptiform discharges and 3 being uninterpretable. CRN usually produces a toxic encephalopathy rather than NCSE, and is commonly associated with triphasic waves on EEG. In most patients anti-epileptic and/or sedative drugs do not hasten clinical improvement.

A Treatable Encephalopathy in a Peritoneal Dialysis Patient - Cefepime-Induced Encephalopathy

We report a patient with end-stage renal disease on peritoneal dialysis, who developed encephalopathy after receiving a few doses of cefepime. He recovered clinically and electroencephalographically after having discontinued the culprit agent and undergone hemodialysis. This case highlights the importance of promptly recognizing this reversible encephalopathy, which can lead to the avoidance of unnecessary workup, reduce the length of hospital stay, and thereby improve the patients’ outcome.

Cefepime-induced encephalopathy: Neural mass modeling of triphasic wave-like generalized periodic discharges with a high negative component (Tri-HNC)

AIM

Cefepime, a fourth-generation cephalosporin, acts as a GABA_A receptor antagonist. Cefepime-induced encephalopathy (CIE) is frequently overlooked. We aimed to clarify the clinical features, characteristic electroencephalography (EEG), and mechanisms of CIE to aid in its early recognition.

METHODS

CIE cases documented by a single-center consultation-liaison team between April 2015 and March 2017 were retrospectively reviewed. For further investigation, neural mass modeling was performed in silico.

RESULTS

Three patients with CIE refused medication/examination and showed overt pain, palilalia, and much greater deterioration of eye and verbal response than the motor response, which was possibly related to GABAergic dysfunction. Triphasic wave-like generalized periodic discharges with a high negative component (Tri-HNC) were identified on the EEG of all three cases. The simulation reproduced the characteristic feature of 2-3 Hz Tri-HNC and recovery course on EEG, and a possible involvement of individual differences in pharmacological intervention. It also suggested that auto-inhibition (synaptic inputs from interneuron to interneuron) dysregulation contributed to generating Tri-HNC in CIE.

CONCLUSION

As CIE is iatrogenic and continues unless cefepime is stopped, early recognition is crucial. Physicians should be vigilant about altered mental status, pain, and verbal changes in patients taking cefepime. Tri-HNC on EEG can expedite the diagnosis of CIE, and the association between Tri-HNC and CIE suggests that an excitatory and inhibitory imbalance due to the dysfunction of GABAergic interneurons is the underlying mechanism. This modeling may offer a new method of investigating disorders related to GABAergic dysfunction.

Clinical neurophysiology of altered states of consciousness: Encephalopathy and coma

The neurophysiologist will commonly encounter patients with encephalopathy/delirium (altered consciousness with impaired cognition, usually with sleep-wake cycle alteration and lethargy) or coma (an eyes-closed state of unresponsiveness) in the hospital setting. Assessing the background frequency of the EEG, as well as the presence or absence of other features (reactivity, periodic discharges such as triphasic waves), can provide insight into the patient's underlying condition and in some cases may provide prognostic information. The literature of postanoxic arrest EEG patterns continues to expand. Other neurophysiologic tests, such as somatosensory evoked potentials, auditory mismatch negativity, and even EMG, may also play a role in assessing brain function; distinguishing among a locked-in state, minimally conscious state, persistent vegetative state, and waking/unresponsive states; and assessing the potential for recovery after brain injury.

Cefepime-induced Neurotoxicity: Five Cases Reported in a Single Institution

Cefepime is a fourth-generation cephalosporin widely used to treat gram-positive and gram-negative infections. Its half-life is approximately two hours in patients with normal renal function and may increase to 13.5 hours in patients with acutely or chronically impaired renal function. Although dosage adjustment is recommended for patients with renal insufficiency to prevent drug accumulation, toxicity has been reported in patients even with normal renal function. One underreported complication of cefepime toxicity is cefepime-induced encephalopathy (CIE). While the pathophysiology is unclear, treatment involves early discontinuation of this antibiotic to decrease morbidity and mortality. We report five cases of cefepime-induced encephalopathy occurring within one year at a single institution.

Neurological Adverse Effects Attributable to β-Lactam Antibiotics: A Literature Review

β-lactam antibiotics are commonly prescribed antibiotic drugs. To describe the clinical characteristics, risk markers and outcomes of β-lactam antibiotic-induced neurological adverse effects, we performed a general literature review to provide updated clinical data about the most used β-lactam antibiotics. For selected drugs in each class available in France (ticarcillin, piperacillin, temocillin, ceftazidime, cefepime, cefpirome, ceftaroline, ceftobiprole, ceftolozane, ertapenem and aztreonam), a systematic literature review was performed up to April 2016 via an electronic search on PubMed. Articles that reported original data, written in French, Spanish, Portuguese or English, with available individual data for patients with neurological symptoms (such as seizure, disturbed vigilance, confusional state, myoclonia, localising signs, and/or hallucinations) after the introduction of a β-lactam antibiotic were included. The neurological adverse effects of piperacillin and ertapenem are often described as seizures and hallucinations (>50 and 25% of cases, respectively). Antibiotic treatment is often adapted to renal function (>70%), and underlying brain abnormalities are seen in one in four to one in three cases. By contrast, the neurological adverse drug reactions of ceftazidime and cefepime often include abnormal movements but few hallucinations and seizures. These reactions are associated with renal insufficiency (>80%) and doses are rarely adapted to renal function. Otherwise, it appears that monobactams do not have serious neurological adverse drug reactions and that valproic acid and carbapenem combinations should be avoided. The onset of disturbed vigilance, myoclonus, and/or seizure in a patient taking β-lactam antibiotics, especially if associated with renal insufficiency or underlying brain abnormalities, should lead physicians to suspect adverse drug reactions and to consider changes in antibacterial therapy.

Ictal Interictal Continuum Patterns

PURPOSE OF REVIEW

To present data available on the epidemiology and significance of rhythmic and periodic patterns that lie on the ictal interictal continuum and propose an algorithm for the clinical approach to patients exhibiting these patterns.

RECENT FINDINGS

There is accumulating evidence on the prognostic implications of various rhythmic and periodic patterns in the critically ill population. These patterns are not only associated with increased seizure risk but have also been associated with worse outcome and increased long-term risk of epilepsy in recent studies. There is emerging evidence suggesting that certain EEG features as well as ancillary studies including serum, neuroimaging, and invasive multimodality monitory can assist in the risk stratification of neuronal injury associated with these patterns, allowing for a targeted approach to these patterns. We present a case illustrating the clinical nuances of these patterns. We propose an algorithm for a personalized and targeted approach to ictal interictal patterns based on risk stratification according to clinical, EEG, imaging, and invasive monitoring markers.

Cefepime-induced neurotoxicity: a systematic review

BACKGROUND

Cefepime is a widely used antibiotic with neurotoxicity attributed to its ability to cross the blood-brain barrier and exhibit concentration-dependent ϒ-aminobutyric acid (GABA) antagonism. Neurotoxic symptoms include depressed consciousness, encephalopathy, aphasia, myoclonus, seizures, and coma. Data suggest that up to 15% of ICU patients treated with cefepime may experience these adverse effects. Risk factors include renal dysfunction, excessive dosing, preexisting brain injury, and elevated serum cefepime concentrations. We aimed to characterize the clinical course of cefepime neurotoxicity and response to interventions.

METHODS

A librarian-assisted search identified publications describing cefepime-associated neurotoxicity from January 1980 to February 2016 using the CINAHL and MEDLINE databases. Search terms included cefepime, neurotoxicity, encephalopathy, seizures, delirium, coma, non-convulsive status epilepticus, myoclonus, confusion, aphasia, agitation, and death. Two reviewers independently assessed identified articles for eligibility and used the Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) for data reporting.

RESULTS

Of the 123 citations identified, 37 (representing 135 patient cases) were included. Patients had a median age of 69 years, commonly had renal dysfunction (80%) and required intensive care (81% of patients with a reported location). All patients exhibited altered mental status, with reduced consciousness (47%), myoclonus (42%), and confusion (42%) being the most common symptoms. All 98 patients (73% of cohort) with electroencephalography had abnormalities, including non-convulsive status epilepticus (25%), myoclonic status epilepticus (7%), triphasic waves (40%), and focal sharp waves (39%). As per Food and Drug Administration (FDA)-approved dosing guidance, 48% of patients were overdosed; however, 26% experienced neurotoxicity despite appropriate dosing. Median cefepime serum and cerebrospinal fluid (CSF) concentrations were 45 mg/L (n = 21) and 13 mg/L (n = 4), respectively. Symptom improvement occurred in 89% of patients, and 87% survived to hospital discharge. The median delay from starting the drug to symptom onset was 4 days, and resolution occurred a median of 2 days after the intervention, which included cefepime discontinuation, antiepileptic administration, or hemodialysis.

CONCLUSIONS

Cefepime-induced neurotoxicity is challenging to recognize in the critically ill due to widely varying symptoms that are common in ICU patients. This adverse reaction can occur despite appropriate dosing, usually resolves with drug interruption, but may require additional interventions such as antiepileptic drug administration or dialysis.

Cefepime induced neurotoxicity: A case series and review of the literature

Cefepime is a fourth generation cephalosporin which is bactericidal for broad spectrum of organisms. This is a case-series of three patients who presented to our hospital with confusion secondary to cefepime use to treat urinary tract infection (UTI) and health care associated pneumonia (HCAP), after excluding other common etiologies of altered mental status (AMS). Of these three patients, one had progressive expressive aphasia and the other two demonstrated asynchronous myoclonic activity of the limbs. The symptoms were seen within four to five days of initiating the treatment and resolved within three days of discontinuation of cefepime. Acute structural abnormalities were excluded by computed tomography (CT) and magnetic resonance imaging (MRI) of the brain. Electroencephalogram (EEG) showed diffuse slowing activity with triphasic waves consistent with encephalopathy. In one patient, renal function was within normal limits, whereas it was abnormal in two patients. To our knowledge, this is the first report of cefepime induced asynchronous myoclonus and expressive aphasia in a patient with normal kidney function.

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Recognizing cefepime neurotoxicity could be challenging in acute care settings.

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Caution is recommended in patients with renal and hepatic impairments.

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Patients may present with expressive aphasia and/or myoclonus even with normal kidney function.

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Fortunately in most cases, neurotoxicity is reversible upon discontinuation of cefepime.

Prognosis of neurologic complications in critical illness

Neurologic complications of critical illness require extensive clinical and neurophysiologic evaluation to establish a reliable prognosis. Many sequelae of intensive care unit (ICU) treatment, such as delirium and ICU-acquired weakness, although highly associated with adverse outcomes, are less suitable for prognostication, but should rather prompt clinicians to seek previously unnoticed persisting underlying illnesses. Prognostication can be confounded by drug administration particularly because its clearance is abnormal in critical illness. Some neurological complications are severe, and can last for months or years after discharge from ICU. The most important ethical aspects regarding neurologic complications in critically ill patients are prevention, recognition, and identification, and prevention of self-fulfilling prophecies. This chapter summarizes the tool of prognostication of major neurological complications of critical illness.

Cefepime-Induced Non-Convulsive Status Epilepticus in a Patient with Normal Renal Function

Cefepime-induced encephalopathy including nonconvulsive status epilepticus has been known to develop in the patients with renal impairment. However, we report a 74-year-old woman with normal renal function who developed stuporous mental status during cefepime administration. Electroencephalogram (EEG) revealed 2 Hz rhythmic sharp-and-waves continuously, which suggested nonconvulsive status epilepticus (NCSE). After cefepime discontinuation, clinical symptoms recovered gradually and EEG findings showed only background slowing without epileptiform discharges. Cefepime-induced NCSE could be developed even in the patients with normal renal function, when they are elderly. Therefore, clinicians should be aware of the possibility of cefepime-induced NCSE when prescribing cefepime even to the patients with normal renal function.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.

Cefepime-induced encephalopathy with normal renal function

Cefepime is a fourth-generation cephalosporin that is frequently used in a wide array of infections. Since approval for use, concerns have been raised due to adverse effects including seizures, encephalopathy and myoclonus especially if renal dysfunction is present. Despite having appropriate renal dose adjustments, cases have been found with adverse neurological effects. On this occasion, we present a case of a patient with normal renal function that had demonstrated cefepime-induced encephalopathy with full resolution of symptoms following discontinuation of the medication.

Cefepime-Associated SIRPIDs in a Patient With Normal Renal Function

Cefepime has been associated with encephalopathy and with nonconvulsive seizure activity, primarily in patients with renal impairment. Here, we report a case of cefepime-associated encephalopathy in a patient with normal renal function with stimulus-induced rhythmic activity seen on electroencephalogram, which resolved on discontinuation of cefepime. We bring this to the attention of the neurohospitalist community, as cefepime is widely used in the hospital setting, and cefepime-related neurotoxicity may go overlooked, especially in patients with normal renal function. Neurologists must recognize drug-related patterns, as the treatment is removing a medication rather than adding an antiepileptic medication.

Intermittent hemodialysis treatment in cefepime-induced neurotoxicity: case report, pharmacokinetic modeling, and review of the literature

Cefepime is a broad-spectrum cephalosporin indicated for in-hospital treatment of severe infections. Acute neurotoxicity, an increasingly recognized adverse effect of this drug in an overdose, predominantly affects patients with reduced renal function. Although dialytic approaches have been advocated to treat this condition, their role in this indication remains unclear. We report the case of an 88-year-old female patient with impaired renal function who developed life-threatening neurologic symptoms during cefepime therapy. She was treated with two intermittent 3-hour high-flux, high-efficiency hemodialysis sessions. Serial pre-, post-, and peridialytic (pre- and postfilter) serum cefepime concentrations were measured. Pharmacokinetic modeling showed that this dialytic strategy allowed for serum cefepime concentrations to return to the estimated nontoxic range 15 hours earlier than would have been the case without an intervention. The patient made a full clinical recovery over the next 48 hours. We conclude that at least 1 session of intermittent hemodialysis may shorten the time to return to the nontoxic range in severe clinically patent intoxication. It should be considered early in its clinical course pending chemical confirmation, even in frail elderly patients. Careful dosage adjustment and a high index of suspicion are essential in this population.

Cefepime-induced encephalopathy in patients with haematological malignancies: clinical features and risk factors

BACKGROUND

Cefepime is an antibiotic that is widely used in patients with haematological malignancies (HM). Although its use has been reported to be associated with encephalopathy, only case reports or small case series have been reported so far.

PATIENTS AND METHODS

We conducted a retrospective cohort study of 243 patients with HM treated with cefepime at our hospital between August 2011 and May 2013. We also investigated the clinical features of patients with cefepime-induced encephalopathy (CIE).

RESULTS

Among 243 HM patients treated with cefepime, 10 were diagnosed with CIE, indicating a cumulative incidence of approximately 4.1%. The median creatinine level on commencement of treatment was 2.13 mg/dl (range 0.60-19.85) and the median initial dose of cefepime was 4.0 g/day (range 1.0-6.0). The median time between commencement of treatment and symptoms was 4.0 days (range 2-5). The most common clinical manifestations were decreased level of consciousness and myoclonus. Symptoms resolved fully in all patients. Univariate analyses showed that impaired renal function (creatinine clearance (CLCr) < 30 ml/min, acute renal failure, and chronic dialysis) was significantly associated with the development of CIE (univariate p < 0.0001, p = 0.020, and p = 0.0025, respectively). Receiver operating characteristic (ROC) analysis demonstrated that the threshold levels of creatinine, CLCr, and estimated glomerular filtration rate for CIE were 1.22 mg/dl, 22.96 ml/min, and 43.9 ml/min/1.73 m(2), respectively.

CONCLUSIONS

This study indicated that the development of CIE is associated with severely impaired renal function in patients with HM.

Uncovering clinical and radiological associations of triphasic waves in acute encephalopathy: a case-control study

BACKGROUND AND PURPOSE

Triphasic waves (TWs) are archetypal waveforms seen on electroencephalography (EEG) in some forms of encephalopathy. Their particular underlying pathological substrates are largely unexplored. This case-control study was designed to identify and quantify specific clinical and neuroradiological associations underlying TWs and to determine if TWs predicate outcome.

METHODS

From 2004 to 2012, adult encephalopathic patients with TWs (cases) were matched 1:1 with encephalopathic patients without TWs (controls) by Glasgow Coma Scale (GCS) and the frequency range of EEG background activity. Clinical characteristics, neuroimaging and outcomes were assessed.

RESULTS

The mean age of 190 patients (95 with and 95 without TWs) was 66.6 years (±15.6). In multivariable analyses, patients with TWs had significantly higher odds for liver insufficiency [odds ratio (OR) = 8.10, 95% confidence interval (CI) 1.98-33.08], alcohol abuse (OR = 3.65, 95% CI 1.25-10.63), subcortical brain atrophy (OR = 2.82, 95% CI 1.39-5.71) and respiratory tract infections (OR = 1.28, 95% CI 1.01-4.71). With each additional independent predictor, the odds increased for the occurrence of TWs (1 predictor, OR = 2.40, 95% CI 1.16-5.13; ≥2 predictors, OR = 9.20, 95% CI 3.27-25.62). Mortality was 15% and tended to be higher in patients with TWs (19% with vs. 11% without TWs).

CONCLUSIONS

Alcohol abuse, liver insufficiency, infections and subcortical brain atrophy were independently associated with TWs in patients matched for clinical and EEG features of encephalopathy. These associations strengthen the hypothesis that TWs evolve from an interplay of pathological neurostructural, metabolic and toxic conditions. When matched for EEG background activity and GCS, TWs were not associated with death.

Cefepime neurotoxicity in the intensive care unit: a cause of severe, underappreciated encephalopathy

Introduction

Cefepime, a broad spectrum antibiotic, is commonly prescribed in intensive care units (ICU) and may be an overlooked cause of neurologic symptoms such as encephalopathy, myoclonus, seizures, and coma. We aimed to characterize cefepime neurotoxicity in the ICU.

Methods

We performed a retrospective study of adult ICU patients treated with intravenous cefepime for at least 3 days between January 1, 2009 and December 31, 2011. The primary outcome was the development of cefepime neurotoxicity, with the likelihood of causality ascribed via a modified Delphi method.

Results

This study included 100 patients. The mean age was 65.8 years (± 12.7 years). The median daily average dose of cefepime was 2.5 (IQR 2.0 to 3.5) grams. The median treatment duration was 6 (IQR 4 to 10) days. Renal failure in any form was present in 84 patients. Chronic kidney disease affected 40 patients, and 77 had acute kidney injury. Cefepime neurotoxicity occurred in 15 patients. Of these, seven were considered definite cases, three probable, and five possible. Neurotoxic symptoms included impaired consciousness (n = 13), myoclonus (n = 11), disorientation (n = 6), and nonconvulsive status epilepticus (n = 1). The dose of cefepime was appropriately adjusted for renal clearance in 64 patients (75.3%) without cefepime neurotoxicity and four patients (28.6%) with neurotoxicity (P = 0.001). Chronic kidney disease was present in 30 patients (35.3%) without neurotoxicity and in 10 (66.7%) of those with neurotoxicity (P = 0.04).

Conclusions

Critically ill patients with chronic kidney disease are particularly susceptible to cefepime neurotoxicity. Myoclonus and impaired consciousness are the predominant clinical manifestations. Neurotoxic symptoms occur more often when the cefepime dose is not adjusted for renal function, but can still occur despite those modifications.

Ceftazidime dosage recommendations in burn patients: from a population pharmacokinetic approach to clinical practice via Monte Carlo simulations

BACKGROUND

Ceftazidime dosage regimen recommendations based on pharmacokinetic/pharmacodynamic approaches are not available for burn patients.

OBJECTIVE

The goal of this study was to propose a continuous dosage regimen of ceftazidime in burn patients, taking into account different MICs and pharmacokinetic covariates.

METHODS

The population pharmacokinetic analysis was conducted by using software dedicated to the analysis of nonlinear mixed effects models. The population pharmacokinetic model was first developed and validated in 70 adult burn patients. Taking into account various MICs of pathogens, 3 Monte Carlo simulation trials were conducted by using target concentration intervals (10-100, 20-100, and 40-100 mg/L). The recommended dosages were defined as the minimum dose leading to the highest percentage of patients whose ceftazidime concentrations were included in the target interval.

RESULTS

Serum creatinine and age were identified as covariates of ceftazidime clearance. Age was also involved in volume of distribution. The simulations showed that a dose of 6 g/d did not allow achievement of the target interval in most patients. Regardless of dosage regimen, age, and serum creatinine, the mean percentage of patients reaching the 10- to 100-mg/L and the 20- to 100-mg/L target intervals were 99.4% (0.3%) and 96.1% (0.8%), respectively. For the 40- to 100-mg/L target interval, this percentage was only 76.4% (2.1%) (range, 65%-80%).

CONCLUSIONS

Age and serum creatinine level can be used at the bedside to determine the initial doses of ceftazidime. These Monte Carlo simulations highlight the need of a reappraisal of ceftazidime's use in burn patients. Doses between 3 and 16 g/d are proposed, taking into account the pathogens' MICs. However, for sepsis caused by a pathogen with an MIC ≥ 8 mg/L, an insufficient percentage of burn patients will reach the therapeutic target with the recommended dosages.

Pregabalin intoxication-induced encephalopathy with triphasic waves

This report documents the case of a 79-year-old woman presenting with encephalopathy and triphasic waves (TWs) due to pregabalin (PGB) intoxication. For the two years prior to admission, she had taken PGB to treat post-herpetic neuralgia. Brain MRI revealed mild leukoaraiosis and cortical atrophy. Electroencephalography showed continuous frontal-dominant TWs. These TWs were suppressed by intravenous lorazepam, but mental function was not improved. Laboratory tests revealed prerenal azotemia, which may elevate serum PGB and cause toxic encephalopathy with TWs. After fluid therapy and discontinuation of PGB, mental status recovered completely and TWs disappeared. I conclude that PGB intoxication due to deficient renal clearance can cause a reversible encephalopathy with TWs.

Ceftazidime dosage regimen in intensive care unit patients: from a population pharmacokinetic approach to clinical practice via Monte Carlo simulations

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

The large variability in drug pharmacokinetic disposition has already been described in ICU patients leading to important variations in drugs concentrations. The usual recommended dosage of ceftazidime is not adapted for all ICU situations and ceftazidime should be monitored closely. New recommendations have to be given for some specific cases.

WHAT THIS STUDY ADDS

Our results propose individual therapeutic drug monitoring taking into account: For the patient: the reason of admission in the ICU, the mechanical ventilation status and the creatinine clearance calculated by the modified diet in renal disease (MDRD). • For the antibiotics: the lung distribution, the minimal inhibitory concentration (MIC) of the strain to eradicate and the potential toxicity. AIM To predict the ceftazidime dosage regimen as a function of the glomerular filtration rate expressed by the modification of the diet in renal disease (MDRD), reason for admission and mechanical ventilation in intensive care unit (ICU) patients to treat Pseudomonas aeruginosa pneumonia.

METHOD

A published and qualified population pharmacokinetic model was used to perform Monte Carlo simulations of ceftazidime concentrations. The serum target of 40-100 mg l(-1) was defined based on the minimal inhibitory concentration (MIC), the European break point (EBP), the pulmonary drug diffusion and toxicity. The recommended dosage regimens were based on the maximum percentile of the patients with simulated steady state concentrations reaching the target.

RESULTS

Steady-state was reached at 72 h whatever the MDRD. The simulations of serum concentrations generated higher percentiles of the population reaching the target after continuous administration. We recommend a 4 g continuous dose after the usual 2 g loading dose for patients with MDRD from 10 to 30 ml min(-1) , 6 g for MDRD between 40 and 80 ml min(-1) , 8 g for MDRD from 90 to 110 ml min(-1) , 10 g for MDRD from 120 to 190 ml min(-1) and 12 g day(-1) for patients with MDRD higher than 200 ml min(-1) .

CONCLUSION

Our study demonstrated that in ICU patients for a given MDRD, steady-state takes longer to reach in polytrauma patients than in patients with medical or post surgery reasons for admission. Continuous infusion ensures that a higher percentage of patients reaches the target than the same dose given by discontinuous administration and this only depends on MDRD.

Electroencephalographic abnormalities in baclofen-induced encephalopathy

We report a patient in whom the characteristic electroencephalographic features of baclofen intoxication are highlighted and emphasize the role of electrographic abnormalities in the diagnosis of this condition.

High cefepime plasma concentrations and neurological toxicity in febrile neutropenic patients with mild impairment of renal function

High-dose cefepime therapy is recommended for febrile neutropenia. Safety issues have been raised in a recent meta-analysis reporting an increased risk of mortality during cefepime therapy. Cefepime-related neurological toxicity has been associated with overdosing due to severe renal dysfunction. This study aimed to investigate the association between cefepime plasma concentrations and neurological toxicity in febrile neutropenic patients. Cefepime trough concentrations (by high-performance liquid chromatography) were retrospectively analyzed for 30 adult febrile neutropenic patients receiving the recommended high-dose regimen (6 g/day for a glomerular filtration rate [GFR] of >50 ml/min). The dose adjustment to renal function was evaluated by the ratio of the cefepime daily dose per 100 ml/min of glomerular filtration. The association between cefepime plasma concentrations and neurological toxicity was assessed on the basis of consistent neurological symptoms and/or signs (by NCI criteria). The median cefepime concentration was 8.7 mg/liter (range, 2.1 to 38 mg/liter) at a median of 4 days (range, 2 to 15 days) after the start of therapy. Neurological toxicity (altered mental status, hallucinations, or myoclonia) was attributed to cefepime in 6/30 (20%) patients (median GFR, 45 ml/min; range, 41 to 65 ml/min) receiving a median dose of 13.2 g/day per 100 ml/min GFR (range, 9.2 to 14.3 g/day per 100 ml/min GFR). Cefepime discontinuation resulted in complete neurological recovery for five patients and improvement for one patient. A multivariate logistic regression model confirmed high cefepime concentrations as an independent predictor of neurological toxicity, with a 50% probability threshold at ≥22 mg/liter (P = 0.05). High cefepime plasma concentrations are associated with neurological toxicity in febrile neutropenic patients with mild renal dysfunction. Careful adherence to normalized dosing per 100 ml/min GFR is crucial. Monitoring of plasma concentrations may contribute to preventing neurological toxicity of high-dose therapy for this life-threatening condition.

Prospective monitoring of cefepime in intensive care unit adult patients

Introduction

Cefepime has been associated with a greater risk of mortality than other beta-lactams in patients treated for severe sepsis. Hypotheses for this failure include possible hidden side-effects (for example, neurological) or inappropriate pharmacokinetic/pharmacodynamic (PK/PD) parameters for bacteria with cefepime minimal inhibitory concentrations (MIC) at the highest limits of susceptibility (8 mg/l) or intermediate-resistance (16 mg/l) for pathogens such as Enterobacteriaceae, Pseudomonas aeruginosa and Staphylococcus aureus. We examined these issues in a prospective non-interventional study of 21 consecutive intensive care unit (ICU) adult patients treated with cefepime for nosocomial pneumonia.

Methods

Patients (median age 55.1 years, range 21.8 to 81.2) received intravenous cefepime at 2 g every 12 hours for creatinine clearance (CL_Cr) ≥ 50 ml/min, and 2 g every 24 hours or 36 hours for CL_Cr < 50 ml/minute. Cefepime plasma concentrations were determined at several time-points before and after drug administration by high-pressure liquid chromatography. PK/PD parameters were computed by standard non-compartmental analysis.

Results

Seventeen first-doses and 11 steady states (that is, four to six days after the first dose) were measured. Plasma levels varied greatly between individuals, from two- to three-fold at peak-concentrations to up to 40-fold at trough-concentrations. Nineteen out of 21 (90%) patients had PK/PD parameters comparable to literature values. Twenty-one of 21 (100%) patients had appropriate duration of cefepime concentrations above the MIC (T_>MIC ≥ 50%) for the pathogens recovered in this study (MIC ≤ 4 mg/l), but only 45 to 65% of them had appropriate coverage for potential pathogens with cefepime MIC ≥ 8 mg/l. Moreover, 2/21 (10%) patients with renal impairment (CL_Cr < 30 ml/minute) demonstrated accumulation of cefepime in the plasma (trough concentrations of 20 to 30 mg/l) in spite of dosage adjustment. Both had symptoms compatible with non-convulsive epilepsy (confusion and muscle jerks) that were not attributed to cefepime-toxicity until plasma levels were disclosed to the caretakers and symptoms resolved promptly after drug arrest.

Conclusions

These empirical results confirm the suspected risks of hidden side-effects and inappropriate PK/PD parameters (for pathogens with upper-limit MICs) in a population of ICU adult patients. Moreover, it identifies a safety and efficacy window for cefepime doses of 2 g every 12 hours in patients with a CL_Cr ≥ 50 ml/minute infected by pathogens with cefepime MICs ≤ 4 mg/l. On the other hand, prompt monitoring of cefepime plasma levels should be considered in case of lower CL_Cr or greater MICs.

Cephalosporin-induced neurotoxicity: clinical manifestations, potential pathogenic mechanisms, and the role of electroencephalographic monitoring

OBJECTIVE

To review the clinical manifestations of cephalosporin-induced neurotoxicity, underlying potential mechanisms, role of electroencephalographic (EEG) monitoring, and management of neurotoxicity.

DATA SOURCES

A PubMed search (1970-May 2008) was conducted using search terms such as cephalosporins, neurotoxicity, seizures, and status epilepticus. The search was not limited to the English language and yielded approximately 187 articles.

STUDY SELECTION AND DATA EXTRACTION

Several case reports and case series were included to outline the salient clinical features of cephalosporin neurotoxicity. Laboratory studies investigating the potential mechanisms were also included. Reports outlining the EEG features of cephalosporin neurotoxicity were included and the role of continuous EEG monitoring was extracted. Finally, management strategies of such neurotoxicity are discussed.

DATA SYNTHESIS

Cephalosporin-induced neurotoxicity may manifest in a variety of clinical presentations, ranging from simple encephalopathy or mental status changes to myoclonus, asterixis, seizures, nonconvulsive status epilepticus, as well as coma. Patients who are elderly, those with renal insufficiency, and those with prior neurologic disease may be particularly prone to the neurotoxic effects. The main mechanism of neurotoxicity appears to involve gamma-aminobutyric acid A receptor inhibition, although other mechanisms may be possible. Cephalosporin neurotoxicity may be associated with a variety of EEG manifestations. Treatment mainly involves withdrawal of the offending drug, in addition to hemodialysis in patients with renal failure, and use of benzodiazepines or other anticonvulsants in patients who develop frank status epilepticus. Neurotoxicity can be prevented in high-risk cases with dosage adjustments and monitoring of serum concentrations.

CONCLUSIONS

Knowledge and awareness of the neurotoxic clinical manifestations, EEG findings, and underlying mechanisms are essential for clinicians in identifying and treating this potentially lethal but reversible complication of cephalosporin therapy. Further studies are needed to determine the most appropriate treatment paradigms for patients who develop status epilepticus as a result of cephalosporins.

[Pseudoperiodic EEG heralding a cefepime-induced encephalopathy]

Electroencephalography is a useful tool for the diagnosis and follow-up of toxic and metabolic encephalopathies. A pseudo-periodic pattern can indicate various brain pathologies and causes of mental confusion. Among these, cefepime encephalopathy should always be considered, particularly in cases of renal failure, because of the reversibility of the symptoms at drug withdrawal.

Cefepime-induced Encephalopathy with Triphasic Waves in Three Asian Patients

Cefasporins such as cefepime are beta-lactam antibiotics with a broad antimicrobial spectrum. They are commonly used as first-line agents in the treatment of many infections.1 Reversible encephalopathy is a known neurotoxic complication of cefalosporins.2 Previous case reports have documented triphasic waves on electroencephalography (EEG) in cephalosporin-induced encephalopathy.1-4 Cefalosporin-induced encephalopathy with triphasic waves has not been previously reported among Asians. We report 3 Asian patients with toxic encephalopathy and documented triphasic waves on EEG while on treatment with cefepime.

Efficacy and safety of cefepime: a systematic review and meta-analysis

Cefepime is a broad-spectrum cephalosporin with enhanced coverage against Gram-positive and Gram-negative bacteria. We did a systematic review of randomised trials that compared cefepime with another beta-lactam antibiotic, alone or with the addition of a non-beta-lactam antibiotic to both study groups. We searched Central, PubMed, Embase, Lilacs, new US Food and Drug Administration drug applications, conference proceedings, and references of the included studies. Two reviewers independently did the search and data extraction. 57 trials were included. All-cause mortality-the primary outcome-was higher with cefepime than other beta-lactams (risk ratio [RR] 1.26 [95% CI 1.08-1.49]). Sensitivity analyses by the trials' methodological quality revealed higher RRs for trials reporting adequate allocation-sequence generation (1.52 [1.20-1.92]) and allocation concealment (1.36 [1.09-1.70]). Baseline risk factors for mortality were similar. No significant differences between groups in treatment failure, superinfection, or adverse events were found. This Review provides evidence and offers possible explanations for increased mortality among patients treated with cefepime in randomised trials.

Lithium-induced confusional states: nonconvulsive status epilepticus or triphasic encephalopathy?

Lithium therapy can cause a confusional state by direct toxicity, precipitation of nonconvulsive status epilepticus, or by interplay with other neuroleptic medications to produce neuroleptic malignant syndrome or serotonin syndrome. These conditions resemble each other clinically, but EEG may help differentiate among them. We reviewed the EEG patterns with triphasic waves or rhythmic delta activity in lithium toxic patients and discuss clinical and EEG differentiation among syndromes. Lithium toxicity poses significant diagnostic challenges from EEG and clinical perspectives.

Cefepime neurotoxicity: case report, pharmacokinetic considerations, and literature review

A 67-year-old woman with diabetes mellitus, chronic renal insufficiency, and recurrent urinary tract infections experienced encephalopathy and myoclonus while receiving cefepime. The adverse drug event was accompanied by elevated cefepime levels and abnormal electroencephalograms. This syndrome resolved after discontinuation of cefepime. Neurotoxicity is a known but possibly underreported adverse event associated with cefepime in patients with renal impairment who receive relatively excessive doses. Most cases reverse on drug cessation. In patients with renal disease, the maintenance dosage should be reduced and the patient monitored for neurotoxicity. Cefepime toxicity should be suspected whenever a patient receiving the drug experiences a change in mental status or myoclonus.

Apport de l'EEG dans le diagnostic d'une intoxication au baclofène

In a young woman presenting with severe coma, the EEG helped diagnosing baclofen overdose. In this patient, the first EEG showed continuous multifocal pseudoperiodic sharp waves. The diagnosis was confirmed by the plasma dosage providing an 8-fold increase above normal baclofen therapeutic range. Following symptomatic therapy, the patient improved within a few days and the EEG normalised. Few other drugs may be responsible for such EEG changes, namely lithium, cephalosporin, and bismuth. In such cases, EEG contribution to the diagnosis should not be ignored.