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.Excessive alcohol can cause a blackout phenomenon.Hence, any history of drug-related amnesia may help clarify mitigating causes.llSocial history and family history is relevant.Pantoni et al found that patients with TGA have a higher incidence of personal or family background of psychiatric conditions compared with patients who have had a TIA.Prognostically, patients with TGA are less likely to experience a cardiovascular or cerebrovascular event compared with patients who have had a TIA.lPhysical:lNeurologic examination of the patient typically fails to demonstrate any abnormalities (other than memory dysfunction).llIf any lateralizing or focal findings are noted on the examination, then the diagnosis of TGA should be questioned.lCauses: The exact mechanism that produces TGA is unclear.lThe most compelling evidence in favor of migraine is that patients who suffer from a TGA event have a slightly higher incidence of a previous migraine.llHowever, patients with TGA rarely report an associated headache.llThey also do not report nausea, photophobia, or phonophobia.llSeizure (eg, temporal lobe) is unlikely.llTGA events are not associated with alteration of consciousness or stereotypical movements.llEEG does not demonstrate epileptiform activity.llTIA as indicative of cerebrovascular disease is unlikely.llStudies have demonstrated that patients with TGA have fewer cerebrovascular risk factors than those with known cerebrovascular or coronary artery disease.llThe prognosis for TGA is often better than for TIAs.llOne theory proposed by Lewis is that venous congestion causes disrupted blood flow to the thalamic or mesial temporal structures.llThe frequently cited triggers for TGA can increase either sympathetic activity and/or intrathoracic pressure.llThis, in turn, could cause back-pressure in the jugular venous system, disrupting intracranial arterial flow with secondary venous congestion/ischemia to memory areas in the brain.llConditions predisposing to this scenario might include venous anatomy anomalies, integrity of jugular vein valves, timing of the trigger, and severity of the inciting event.In support of the above concept of venous congestion is Schreiber et al's finding of a higher prevalence of internal jugular vein valve incompetence in patients with TGA versus normal controls.However, the authors of this study could find no particular internal jugular vein valve incompetence associated venous circulatory patterns that could indicate a direct cause/effect with TGA.lOther Problems to be Considered:Lab Studies:lCBC with differentialllElectrolyte panelllScreening clotting tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), INRllWhen a patient initially presents with TGA, stroke must be ruled out.lImaging Studies:lBrain MRI and/or CT scanllAny patient presenting with features of TGA should receive an imaging test to rule out a stroke possibility, especially if significant risk factors are present.llMRI with DWI can readily demonstrate acute ischemic changes early and guide management.llIf an MRI cannot be obtained readily, then at least a CT scan should be done initially if the patient is presenting to an emergency department.lOther Tests:ECG, EEG: These tests are important if the diagnosis of TGA is in doubt.If symptoms have occurred more than once, then at least a routine EEG should be done to help investigate a seizure possibility by demonstrating any interictal activity.Medical Care: Once TGA is diagnosed, provide reassurance to the patient and schedule at least one follow-up visit with a neurologist.Diet: No dietary restrictions are necessary.Activity: Avoid activities that could produce an unusual increase in intrathoracic pressure (see trigger factors).Medical/Legal Pitfalls:lRemember that stroke is in the differential diagnosis of TGA, especially if presenting within 24 hours of symptom onset.llStrokes, particularly in the distribution of the posterior cerebral circulation, can present with an amnestic state.llStroke should be ruled out in the initial workup.llLook for risk factors and treat accordingly.For example, smoking, hypercholesterolemia, diabetes, and hypertension are all modifiable risk factors.llIf seizures are a consideration, then perform appropriate workup, including EEG and MRI of the brain.Treatment with an anticonvulsant depends on the outcome of this workup.l [ Pobierz całość w formacie PDF ]