This is because visibility of an object depends on many factors, such as the objects material, size, anatomic location and surrounding structures, as well as the patients body habitus. X-ray beams only show an object if that objects composition blocks the rays from traveling through, making it radiopaque and appearing lighter or white on the image. This also requires it to not be stuck behind something that blocks the beams first. Objects that are radiopaque include items made of most metals except aluminum, bones except most fish bones, and glass. If the material does not block the x-ray beams it is considered radiolucent and will appear dark which prevents visualization. This includes material such as most plastics, most fish bones, wood, and most aluminum objects.Other diagnostic imaging modalities, such as magnetic resonance imaging, computed tomography, and ventilation perfusion scans play a limited role in the diagnosis of foreign body aspiration.Signs on x-ray that are more commonly seen than the object itself and can be indicative of foreign body aspiration include visualization of the foreign body or hyperinflation of the affected lung. Other x-ray findings that can be seen with foreign body aspiration include obstructive emphysema, atelectasis, and consolidation.While, x-ray can be used to visualize the location and identity of a foreign body, rigid bronchoscopy under general anesthesia is the gold-standard for diagnosis since the foreign body can be visualized and removed with this intervention.
Atypical absence seizures:
Occur only in the context of mainly severe symptomatic or cryptogenic epilepsies of children with learning difficulties who also have frequent seizures of other types, such as atonic, tonic and myoclonic. Have slower onset and termination and changes in tone are more pronounced. Have particular ictal characteristics: EEG is of slow (less than 2.5 Hz) spike and slow wave. The discharge is heterogeneous, often asymmetrical and may include irregular spike and slow wave complexes, fast and other paroxysmal activity. Background interictal EEG is usually abnormal. Syndromes
Absence seizure syndromes are childhood absence epilepsy, epilepsy with myoclonic absences, juvenile absence epilepsy and juvenile myoclonic epilepsy. Other proposed syndromes are Jeavons syndrome (eyelid myoclonia with absences), and genetic generalised epilepsy with phantom absences. Absence seizures are also known to occur to patients with porphyria and can be triggered by stress or other porphyrin-inducing factors. Treatment
Treatment of patients with absence seizures only is mainly with ethosuximide or valproic acid, which are of equal efficacy controlling absences in around 75% of patients. Lamotrigine monotherapy is less effective, controlling absences in around 50% of patients. This summary has been recently confirmed by Glauser et al. (2010), who studied the effects of ethosuximide, valproic acid, and lamotrigine in children with newly diagnosed childhood absence epilepsy. Drug dosages were incrementally increased until the child was free of seizures, the maximal allowable dose was reached, or a criterion indicating treatment failure was met. The primary outcome was freedom from treatment failure after 16 weeks of therapy; the secondary outcome was attentional dysfunction.