Diagnostic difficulties in the classification of transient neurological attacks.
BACKGROUND
It is frequently difficult to distinguish transient ischaemic attacks (TIA) from other transient (<24 h) neurological attacks (TNA). We aimed to classify patients with TNA and identify the most frequent problems in establishing a diagnosis.


METHODS
Analysis of a consecutive cohort of patients referred to a TIA Clinic during 5 years. TNA were classified as TIA, mimic and difficult to classify/possible TIA. Reasons limiting classification were listed and grouped.


RESULTS
Four hundred and fifty-eight patients were included. Diagnoses were as follows: TIA-259 (56.6%), mimic-90 (19.7%) and difficult to classify/possible TIA-109 (23.8%). Amongst the 109 patients, main difficulties in the differential diagnosis were between TIA and seizure, psychiatric disturbance, peripheral vertigo, pre-syncope and metabolic condition. The reasons contributing for classification difficulties were as follows: atypical symptoms (49 patients), paucity of details in symptoms description (24 patients), presence of focal symptoms accompanying psychiatric symptoms (anxiety or panic) (12 patients), restraints formulated by current criteria of TIA and migraine (16 patients), previous neurological deficit (eight patients).


CONCLUSIONS
This systematic study identified distinct groups of reasons limiting the diagnosis of TNA. Different clinical approaches should be applied according to specific reasons for classification difficulty. These strategies may help to clarify the aetiology of transient neurological symptoms and improve TIA diagnosis.
Department of Neurosciences (Neurology), Hospital de Santa Maria, Lisboa, Portugal. catarinagfonseca@gmail.com
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D000368:Aged; D001927:Brain Diseases / Q000145:classification / Q000175:diagnosis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000145:classification* / Q000175:diagnosis*; D008297:Male