Panic attacks mistaken for relapse of epilepsy

The diagnostic value of clinical EEG in detecting abnormal synchronicity in panic disorder

Electroencephalographic (EEG) findings repeatedly reported abnormal synchronous or even epileptiform discharges in panic disorder. Although less frequently occurring in patients with panic disorder, these deviant EEG features during panic attacks were also observed in intracranial EEG. For this purpose, our article reviews the consideration of abnormal synchronous neuronal activity in different neurocircuits, particularly limbic, as a suggested condition of panic attacks. Therapeutic approaches of anticonvulsants have shown reductions of symptoms and frequency of attacks in numerous patients suffering from panic disorder, supporting the presumption of underlying abnormal synchronous neuronal activity. Thus, scalp EEG recordings are still recommended for discovering indications of abnormal synchronous neuronal activity in panic patients.

Electroencephalogram abnormalities in panic disorder patients: a study of symptom characteristics and pathology

Background

Since the 1980s, a high EEG abnormality rate has been reported for patients with panic disorder. However, how the EEG abnormalities of panic disorder patients are related to the clinical features and pathology of these patients has yet to be clarified. In this study we investigated whether or not EEG abnormalities are related to the 13 symptoms in the DSM-IV criteria for a diagnosis of panic attacks.

Methods

Subjects were 70 patients diagnosed with panic disorder.

Logistic regression analysis was performed with EEG findings as dependent variables and age, sex and with or without the 13 symptoms as independent variables.

Results

(1)EEG findings for panic disorder patients with EEG abnormalities: Of the 17 patients, 13 had repeated slow waves in the θ-band; the most prevalent EEG abnormality found in this study. Paroxysmal abnormality interpreted as epileptiform was found in only two cases. (2)Nausea or abdominal distress (37.7% vs 82.45%, OR-12.5), derealization or depersonalization (7.5% vs 47.1%, OR = 13.9,) and paresthesias (43.4% vs 64.7%, OR = 7.9,) were extracted by multivariate analysis as factors related to EEG abnormalities.

Conclusion

Of the 70 patients studied, 17 had EEG abnormalities. Among these 17 cases, "repeated slow waves in the θ-band" was the most common abnormality. The factors identified as being related to EEG abnormalities are nausea or abdominal distress, derealization or depersonalization, and paresthesias. The study indicated that physiological predispositions are closely related to panic attacks.

Potentiation of panic-like behaviors of the rat by subconvulsive doses of strychnine

The present study was carried out to determine possible panicogenic effects of strychnine administered in subconvulsive doses to rats. Two experiments were conducted to assess two major features of panic in animal models: panic-related flight (through the observation of wild running [WR]) and defensive fights. In the first one, 20 adult male Wistar rats were injected with six different doses of strychnine ranging from 0.5 to 4.0 mg/kg. After 15 min of free observation, the animals were submitted to high-intensity acoustic stimulation and the incidence of WR was recorded. Higher doses of strychnine (above 2.5 mg/kg) easily evoked seizures, but lower doses raised the incidence of WR in a dose-dependent manner. The most effective dose for WR (1.5 mg/kg) was used in the second experiment, in which we investigated the effects of strychnine on sleep-deprivation-induced fights (SDIFs) that have defensive characteristics. For this purpose, 40 subjects were submitted to 5 days of REM-sleep deprivation by the single-platform method and were then assigned into two groups, i.e., strychnine vs. control. After the injections, the animals were observed in social groupings for SDIF recordings over a period of 60 min. The strychnine-treated groups had more SDIF than the control groups (P<.05, Mann-Whitney U test). We conclude that the high level of neural excitability promoted by partial blockade of the glycinergic system can contribute to the manifestation of panic reactions.

Psychiatric complications in patients with epilepsy: a review

At least 50-60% of patients with epilepsy develop psychiatric disturbances, particularly mood, anxiety, and psychotic disorders. This article, aimed at the non-psychiatric clinician, reviews the differential diagnosis and treatment of psychiatric disturbances in epilepsy and focuses on the evaluation of psychiatric phenomena relative to the ictal state or the periictal and interictal periods. Pharmacological and non-pharmacological therapies are reviewed. A final section discusses potential interactions between antiepileptic and psychiatric medications.

Correlation between the fighting rates of REM sleep-deprived rats and susceptibility to the 'wild running' of audiogenic seizures

Sleep-deprived rats exhibit defensive fighting as well as explosive flights very similar to the wild-running of audiogenic seizures. In order to determine why sleep deprivation is a common factor that facilitates both panic and convulsive manifestations, the present study was undertaken to investigate whether rats that display sleep deprivation-induced fighting (SDIF) are the same as those that are susceptible to audiogenic wild-running (WR). Twenty-eight male adult Wistar rats were divided into two groups assigned to two experimental schemes. In the first, 18 subjects were submitted to REM-sleep deprivation for 5 days and had their SDIF evaluated in social grouping. After 1 week for recovery, their susceptibility to WR was tested in an acoustic stimulation trial (104 dB, 200 Hz, 60 s). Rats that did not present WR received a lactate infusion and were tested again by acoustic stimulation 40 min later. In the second experimental scheme, 10 subjects were initially evaluated for WR susceptibility and the number of SDIF was recorded in social grouping after 1 week. Three categories of WR-susceptibility were determined: WR-sensitive rats, intermediate WR-sensitive rats and WR-insensitive rats. The number of SDIF in each category was significantly different and there was a high positive correlation (r=0.89; Spearman test) between the number of SDIF and the level of WR-susceptibility. We conclude that the reasons why sleep deprivation exerts facilitatory effects on both panic and convulsive manifestations are due to overlappings of neural pathways responsible for both behavioral patterns and for the property of sleep deprivation to increase neuronal excitability.

The psychiatric perspectives of epilepsy

Psychiatric conditions occur frequently in epilepsy, and their manifestations are diverse. Evaluation and management require knowledge of disease processes relevant to epilepsy and to psychiatry, as well as the role of other factors that affect the expression of psychiatric illnesses: behaviors, temperament, cognition, and life events. This article describes a comprehensive approach for addressing psychiatric issues in epilepsy patients.

Topiramate: a new antiepileptic drug

OBJECTIVE

To review proposed mechanisms of action, clinical pharmacology, efficacy, safety, and tolerability of the antiepileptic drug (AED) topiramate.

METHODS

All available data from the clinical development program--published and unpublished data (provided by investigators or the RW Johnson Pharmaceutical Research Institute)--were analyzed, with emphasis on the results of double-blind, placebo-controlled trials. Data from open-label studies provided information about long-term efficacy and tolerability.

FINDINGS

Topiramate is highly effective in the control of previously therapy-resistant partial seizures, with or without secondary generalization. In the refractory adult patient population enrolled in controlled clinical trials, seizures were reduced by 50% or more in 27-47% of patients compared with 0-18% in placebo-treated patients and by 75% or more in 9-36% of the patients compared with 0-9% of those receiving placebo. The most common adverse effects involve the central nervous system and are mild to moderate in nature. Adverse effects include somnolence, fatigue, psychomotor slowing, and concentration problems. The currently recommended dosing is lower and titration slower than schedules used in the clinical trials; this may improve the tolerability of topiramate. Topiramate has few interactions with currently available AEDs, but phenytoin concentrations increased in some patients. Topiramate can be used initially as adjunctive therapy. Plasma topiramate concentrations are reduced substantially when used with enzyme-inducing AEDs. Open-label data and a single double-blind trial suggest that topiramate monotherapy may be effective. Open-label data also indicate that topiramate may be effective in generalized seizures of nonfocal origin, including those associated with Lennox-Gastaut syndrome.

CONCLUSIONS

The robust clinical effects of topiramate expand the therapeutic options for patients with epilepsy. Controlled clinical trials are needed to verify initial observations that topiramate may be effective against a broad spectrum of seizure types and to directly compare efficacy and tolerability with other new and standard AEDs.

Case study: seizure disorder presenting as panic disorder with agoraphobia

Seizure disorders can produce anxiety that is almost indistinguishable from psychiatric disorders. There are few reports of adolescents with seizure disorders that produce fear. The first case of an adolescent female who presented with panic disorder and agoraphobia which was a consequence of seizure activity is reported. Careful diagnostic evaluation and correlation with video electroencephalography were important in distinguishing seizure activity from panic disorder.