Quantification of respiratory parameters in patients with temporal lobe epilepsy

Abstract

Sudden unexplained death in epilepsy (SUDEP) is a major cause of mortality in patients with epilepsy 1,2 . The aetiology of SUDEP remains unclear and may be multifactorial. Autonomic dysfunction affecting cardiac or pulmonary systems has been postulated as a major factor in SUDEP. Cardiac rate and rhythm disturbances and respiratory abnormalities have been identified during seizures [3][4][5][6] . Seizures can alter respiratory rate and pattern, producing tachypnoea, hypopnoea or apnoea, and secretions. Apnoea is com- AbSTrACT -Dysfunction affecting cardiac or pulmonary systems has been postulated as a major factor in sudden death in epilepsy (SUDEP). Whilst the majority of studies of cardiorespiratory function have focused on changes during seizures, here we investigate whether epilepsy influences basal respiratory parameters in patients with temporal lobe epilepsy (TLE) during the interictal period. Spirometry was performed in 10 females and 10 males. Measurements of Vital Capacity (VC), Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1) and ratios of FEV1 to FVC (FEV1/FVC) were obtained, and these values were analyzed as percentages of predicted values. None of the patients had chronic obstructive pulmonary disease and no significant alterations in respiratory function tests were found among these patients. No association between seizure frequency, antiepileptic drugs and SUDEP could be found in this study. Although the study did not identify any specific respiratory abnormality in TLE patients during the interictal period, re-evaluation of clinical data on pulmonary disorders in people with epilepsy should be better investigated.KEy WorDS: epilepsy, SUDEP, respiratory parameters. Quantificação de parâmetros respiratórios em pacientes com epilepsia do lobo temporalrESUMo -Alterações cardíacas e pulmonares têm sido propostas como principais fatores de risco no fenô-meno da morte súbita em epilepsia (SUDEP). Enquanto a maioria dos estudos tem verificado as alterações da função cardiorrespiratória durante as crises epilépticas, nosso estudo avaliou a função pulmonar de indivíduos com epilepsia do lobo temporal (ELT) no período interictal. Vinte pacientes com ELT (10 homens e 10 mulheres) participaram de nosso estudo. Nos testes de função pulmonar foram mensurados os seguintes parâmetros: Capacidade Vital Forçada (CVF), Capacidade Vital Lenta (CVL), Volume Expiratório Forçado no primeiro segundo (VEF1) e o Índice VEF1/CVF. os resultados foram comparados aos valores de normalidade preditos na literatura. Nenhum dos pacientes apresentou doença pulmonar obstrutiva ou restritiva e alterações significativas nos testes de função pulmonar. Não foram encontradas associações entre a freqüência de crises, drogas antiepilépticas e SUDEP. Embora nosso estudo não tenha identificado qualquer anormalidade respiratória específica em indivíduos com ELT durante o período interictal, os dados clínicos sobre transtornos pulmonares em indivíduos com epilepsia devem ser melhor avaliados.

Respiratory findings in sudden unexpected death in epilepsy: a point of convergence for clinical pulmonologists and neurologists

“…However, our research group recently investigated whether epilepsy influences basal respiratory parameters in patients with temporal lobe epilepsy during the interictal period. (6) Although our study did not identify any specific respiratory abnormality in temporal lobe epilepsy patients during the interictal period, we believe that clinical data related to pulmonary disorders in individuals with epilepsy should be better investigated. (6) Understanding the cardiorespiratory mechanism involved in SUDEP could be a key to prevention.…”

“…(6) Although our study did not identify any specific respiratory abnormality in temporal lobe epilepsy patients during the interictal period, we believe that clinical data related to pulmonary disorders in individuals with epilepsy should be better investigated. (6) Understanding the cardiorespiratory mechanism involved in SUDEP could be a key to prevention. One pathogenetic mechanism of SUDEP apnea could be epileptic activity transmitted to the cerebral respiratory centers, (1) culminating in a lethal vicious cycle of events.…”

Sudden unexpected death in epilepsy: A critical view of the literature

“…138,[152][153][154] However, the difficulties in the identification of laryngospasm are of particular concern as it could be underestimated. Ictal and postictal bradypnea, apnea, and/or hypoxia 119,135,138,[155][156][157] could play a pathogenetic role in SUDEP (Tables 4 and 5). 60,135,138,[150][151][152][153][154][156][157][158][159][160][161][162][163][164][165][166][167][168] The extent of desaturation during a seizure has been related to the appearance of repolarization anomalies (ie: QT interval prolongation or shortening).…”

Sudden unexpected death in epilepsy: From the lab to the clinic setting

“…Some authors have reported ictal/postictal respiratory changes with hypoventilation in patients who died of SUDEP [30,77], but ictal hypoxemia is more likely to take place during generalized seizures, prolonged complex partial seizures, and AED reduction. Some authors also suggested that postictal generalized EEG suppression is associated with respiratory inhibition, which may culminate in SUDEP [81]. Although this could not be proven, postictal generalized EEG suppression seems to be a marker of seizure severity and may be correlated with intrinsic pulmonary dysfunction [82].…”