Understanding Neurology

Disorders of consciousness 8579CASE 3 (continued)This is very suggestive of encephalitis, witha mildly raised protein and a lymphocytosis.Could this be tuberculous meningitis, which inreality is a meningoencephalitis and often has asubacute or even a gradual onset? This isunlikely given the short history and the clinicalexamination gave no hint of any meningiticfeatures. Moreover, tuberculous meningitis ispredominantly basal meningitis with a highCSF protein and cranial nerve signs. PositiveHSV polymerase chain reaction (a sensitive andspecific test for herpes simplex) and a magneticresonance image (79) showing swelling of theright temporal lobe confirmed the clinicalsuspicion of herpes simplex encephalitis. HerEEG showed the classical periodic slow waveand sharp wave discharges over the righttemporal region.79 Diffusion-weighted magnetic resonanceimage of herpes simplex virus encephalitis,showing temporal lobe involvement.REVISION QUESTIONS1 In an acute confusional state the stream ofthought can be either slowed or accelerated.2 A lesion of the ascending reticular activatingsystem may cause a confusional state.3 Fluctuations in a confusional state may occur byday and by night, but are more marked by night.4 In an acute confusional state, remote memory isintact.5 There is no universal susceptibility to developingan acute confusional state.6 The predominant EEG rhythm in an acuteconfusional state is fast theta or alpha rhythm.7 Autonomic hyperactivity, e.g. a tachycardia, isusually present.8 The acute confusional state is alwaysaccompanied by increased psychomotor activity.9 Visual hallucinations are rarely seen in the acuteconfusional state.10 In an acute confusional state there isdisorientation for time before that for place orperson.11 The two subtypes of a confusional state nevercoexist in the same patient.12 Following recovery from an acute confusionalstate, the patient has an amnesia for the periodof confusion.13 There are specific features found at postmortemfollowing the acute confusional state.14 Emotional lability is a frequent accompanimentto the acute confusional state.15 The acute confusional state lasts