1. BHS occur most commonly within the first 18 months of age
BHS occur most commonly within the first 18 months of age. Virtually all breath-holders cease experiencing episodes by 7–8 years of age. 70 EEGs in 129 children with breath-holding spells were almost always normal.71 Cardiac arrest was observed following ocular compression. With an arrest lasting 3–6 sec, there were no clinical or electrical abnormalities. However, with a longer cardiac arrest (7–13 sec) bisynchronous slow waves appeared. This was usually accompanied by clouding or loss of consciousness. When the arrest lasted more than 14 sec, one or two generalized clonic jerks appeared without affecting the EEG. This could be followed by a generalized tonic contraction resembling decerebrate rigidity and accompanied by complete flattening of the EEG. Thus, during a syncopal event the EEG initially shows mild generalized slowing. This is followed by high-voltage frontal delta activity. If the cerebral hypoperfusion persists, the EEG flattens. With recovery, the EEG normalizes in a reverse sequence.71–73 Occasionally, patients may experience protracted seizures or status epilepticus following BHS.74,75 Typically, interictal EEG findings in these patients are normal or rarely vertex spikes. They were termed episodes anoxic-epileptic seizures. Administration of an AED frequently ablates the lengthy seizures, although BHS may continue to occur.76 Patients with cyanotic BHS may follow this EEG evolution without significant bradycardia or asystole. Prolonged QT syndrome is a rare, but potentially malignant, cause of anoxic seizure. It is recommended that an EKG to screen for prolonged QT syndrome be performed in all cases.77
Source: Generalized Epilepsy, Atlas of Pediatric EEG
Citation: Laoprasert P. Atlas of Pediatric EEG; 2011 Available at: Accessed: October 07, 2017
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