Kahane Philippe, Ryvlin Philippe, Hoffmann Dominique, Minotti Lorella, Benabid Alim Louis
Neurophysiopathologie de l'Epilepsie, CHU de Grenoble, France.
Epileptic Disord. 2003 Dec;5(4):205-17.
Patients having a hypothalamic hamartoma (HH) frequently present gelastic or dacrystic seizures, and they often later experience multiple additional seizure types which lead to a severe epileptic encephalopathy. There is now increasing evidence that the HH itself plays a crucial role in this syndrome, but the relationships between the lesion and the different types of seizures remain a questionable issue. Stereotactic intracerebral EEG recordings were performed in 5 patients suffering from a medically intractable epilepsy associated with a HH. The hamartoma was investigated in all cases, and various cortical areas were also evaluated in 4 of the 5 patients. The epileptic discharges arose and remained confined within the hamartoma in 3 of the 4 patients in whom laughing and crying episodes were recorded. In addition, interictal spikes were recorded from the hamartoma in 4 of the 5 patients, whereas the stimulation of the HH could reproduce gelastic or dacrystic episodes in 3. The three patients in whom other types of seizure were recorded showed that the latter were associated with cortical ictal discharges not affecting the HH. Ictal onset appeared either bifrontal, right fronto-central and lateral temporal, or bifrontal with a right side predominance. The cingulate gyrus was involved in all these 3 cases, and the lateralization of the ictal discharges was always ipsilateral to the predominating side of the hamartoma. Interestingly, these seizure types were sometimes immediately preceded by the laughing or crying attacks, as if ictal discharges within the hamartoma triggered those which seemed to originate in the cortex. Therefore, if these findings confirm the intrinsic epileptogenicity of HH, they also demonstrate that epileptic seizures associated with HH can exhibit different types of electroclinical patterns. We propose a speculative pathophysiology in which the mamillo-thalamo-cingulate tract would serve as a relay of HH discharges towards the cortex, the excitability of which would then progressively increase, first leading to cortical interictal epileptiform abnormalities and then to seizures of cortical origin. Whether this proposal of secondary epileptogenesis is valid or not remains a major issue, since it could provide arguments on the moment to discuss surgery.
患有下丘脑错构瘤（HH）的患者经常出现痴笑发作或啼哭发作，随后往往还会经历多种其他发作类型，进而导致严重的癫痫性脑病。现在越来越多的证据表明，HH本身在这种综合征中起着关键作用，但该病变与不同类型发作之间的关系仍然是一个有争议的问题。对5例患有与HH相关的药物难治性癫痫的患者进行了立体定向脑内脑电图记录。在所有病例中均对错构瘤进行了研究，并且在5例患者中的4例中还评估了各个皮质区域。在记录到哭笑发作的4例患者中的3例中，癫痫放电起源于错构瘤并局限于错构瘤内。此外，5例患者中有4例在错构瘤记录到发作间期棘波，而刺激HH可在3例中重现痴笑或啼哭发作。记录到其他类型发作的3例患者显示，这些发作与不影响HH的皮质发作期放电有关。发作起始表现为双额叶、右额中央和外侧颞叶，或双额叶且右侧占优势。扣带回在所有这3例中均有累及，发作期放电的侧化总是与错构瘤占优势的一侧同侧。有趣的是，这些发作类型有时紧接在哭笑发作之前，就好像错构瘤内的发作期放电触发了似乎起源于皮质的发作期放电。因此，如果这些发现证实了HH的内在致痫性，那么它们也表明与HH相关的癫痫发作可表现出不同类型的电临床模式。我们提出一种推测性的病理生理学，其中乳头体 - 丘脑 - 扣带回束将作为HH放电向皮质的中继，皮质的兴奋性随后会逐渐增加，首先导致皮质发作间期癫痫样异常，然后导致皮质起源的发作。这种继发性癫痫发生的提议是否有效仍然是一个主要问题，因为它可能为讨论手术时机提供依据。
