It is estimated that 20-25% of epileptic patients fail to achieve good control with antiepileptic drug (AED) treatment; thus, refractory epilepsy (RE) has been described in patients who have adequate therapeutic levels of AEDs without control of seizures. Multidrug resistance genes have been reported to be highly expressed in brain of patients with RE. Persistent low plasma levels of AEDs and high brain expression of the multidrug resistance product P-glycoprotein (P-gp) have been previously communicated in a case report of RE secondary to tuberous sclerosis. Here, the authors report a case of an 8-year-old boy diagnosed with partial RE with focal seizures who was admitted to hospital for a severe episode of subintrant crisis. The patient received polytherapy with carbamazepine (CBZ), phenytoin (PHT), and valproic acid (VA); however, habitual doses of these AEDs failed to control the patient's symptoms. AED blood levels were monitored for 25 consecutive days and showed low values in 8/25 (33%) for CBZ, 10/25 (40%) for PHT, and 25/25 (100%) for VA of samples studied. Because the patient developed focal status epilepticus, surgical treatment by callosotomy was done, resulting in a significant improvement in epileptic symptoms. The immunostaining of brain specimens showed significantly increased expression of P-gp not only in vascular endothelial cells and related astrocytes but also in neurons. Overexpression of P-gp in the brain does not explain the low blood levels of AEDs described in these cases. Different mechanisms such as drug-drug interactions and drug transporters can be involved in the results observed. The P-gp overexpression and/or its pharmacologic induction should be considered as a potential mechanism responsible for drug resistance to epilepsy treatment and highly suspected in patients with persistent subtherapeutic AEDs plasma levels.

Polyglutamine expansions in the transcriptional co-repressor Atrophin-1, encoded by ATN1, cause the neurodegenerative condition dentatorubral-pallidoluysian atrophy (DRPLA) via a proposed novel toxic gain of function. We present detailed phenotypic information on eight unrelated individuals who have de novo missense and insertion variants within a conserved 16-amino-acid ''HX repeat'' motif of ATN1. Each of the affected individuals has severe cognitive impairment and hypotonia, a recognizable facial gestalt, and variable congenital anomalies. However, they lack the progressive symptoms typical of DRPLA neurodegeneration. To distinguish this subset of affected individuals from the DRPLA diagnosis, we suggest using the term CHEDDA (congenital hypotonia, epilepsy, developmental delay, digit abnormalities) to classify the condition. CHEDDA-related variants alter the particular structural features of the HX repeat motif, suggesting that CHEDDA results from perturbation of the structural and functional integrity of the HX repeat. We found several non-homologous human genes containing similar motifs of eight to 10 HX repeat sequences, including RERE, where disruptive variants in this motif have also been linked to a separate condition that causes neurocognitive and congenital anomalies. These findings suggest that perturbation of the HX motif might explain other Mendelian human conditions.

We describe a patient who developed bilateral cavernous sinus septic thrombosis secondary to a suppurative lesion on the left cheek. Despite clinical improvement, left oculomotor symptoms recurred suddenly. A carotid artery aneurysm within the cavernous sinus was diagnosed by means of magnetic resonance imaging and confirmed by digital angiography. Follow-up angiograms showed an initial decrease in the aneurysm size, with subsequent enlargement. A latex contrast-filled balloon was successfully placed within the aneurysm, preserving the carotid parent artery blood flow. Our case illustrates the usefulness of the detachable balloon technique in the treatment of bacterial aneurysms of the cavernous sinus as an alternative treatment to carotid artery ligation. (Stroke 1989;20:1751-1754

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