How to avoid a misdiagnosis in patients presenting with transient loss of consciousness

Abstract

Daily in the UK, frontline medical and paramedical staff are required to manage patients with “collapse?cause”. This universal colloquialism refers to patients who have had an abrupt loss of postural tone. Some of these patients would have had a “blackout” or a transient loss of consciousness (T-LOC). The three most important causes of T-LOC are syncope, epilepsy and psychogenic blackouts. Determining the correct cause is an important challenge; if the initial clinical diagnosis is wrong, investigations may be misdirected, and the final diagnosis and treatment incorrect. Syncope is much more common than epilepsy and may present with symptoms akin to the latter. This fact is not well appreciated and often leads to misdiagnosis. This article deals with the clinical features of the three main causes of blackouts, the value of investigations in arriving at a diagnosis and the problem of misdiagnosis. Pathways for managing patients presenting with blackouts are suggested.

First episode of consciousness loss: setting new standards in acute care management

“…The highest prevalence was in the youngest and the oldest patients with a male predominance especially for generalized seizures (figures [12][13][14]. …”

Syncope resistant to anticonvulsant therapy

“…1 Cardiovascular syncope is far more common than epilepsy. 2 Myoclonic jerks are common during cerebral hypoperfusion irrespective of aetiology and are not helpful in discriminating epilepsy from other causes of syncope. 3 This patient had sinus node dysfunction (SND) and its Benoy N Shah, 1 …”

Blackout? cause: misdiagnosis of cardiac arrest

“…1,2 This can lead to confusion with epilepsy. 3 Diagnosis of the precise cause of syncope may be difficult, but cardiac causes are more common than epilepsy.…”

“…4 It has been suggested that a patient with syncope and either preceding faintness or palpitation, an abnormal ECG, a history of structural heart disease, or a family history of sudden cardiac death should be referred initially to a cardiologist for investigation. 1 Both patients were initially referred for neurological investigation, despite both having a significant cardiac history and implanted devices. The correct diagnosis was made by either telemetry or interrogation of the device.…”