New techniques in the management of Transient loss of consciousness (TLOC) or Blackout

Abstract

Collapse is defined as an "abrupt loss of postural control" and is very common presentation to primary and secondary care. It accounts up to 3% of emergency department cases, and 6% of hospital admissions. Many patients are labelled with "collapse?cause". It should be appreciated that collapse can be with or without TLOC/blackout. Causes without TLOC include falls, transient ischemic attacks, cerebrovascular accidents, road traffic accidents, metabolic abnormalities and intoxication. However, most collapse patients have TLOC. Most common causes are syncope, epilepsy or psychogenic blackouts. There are many similarities and overlap of clinical features leading to misdiagnosis. There are huge variations in the ways TLOC patients are assessed and managed. Patients are dealt by different specialties in different clinical settings. There is lack of clinical tools for assessment and poor risk stratification. Most clinicians take a "safe approach" and as a result, TLOC patients are often admitted to hospital unnecessarily and over investigated, which can increase confusion and healthcare cost. We have therefore tried to approach these issues via a dedicated "Rapid Access Blackout Triage Clinic" (RABTC). In this thesis, we have addressed the problem of TLOC in five projects arising from the triage of patients seen in that clinic. Chapter 1 expands the scene-setting for the thesis. Chapter 2 reports outcomes of a specialist nurse-lead RABTC. The clinic uses custom clinical evaluation and risk stratification tools for patients with TLOC with cardiologist supervision (author). Nearly two thirds of patients presenting to the RABTC are over 65 years. Chapter 3 reports outcome of pacemaker insertions in elderly patients for minor ECG abnormalities that are not current indications for pacemaker insertion. We speculated that such abnormalities could progress suddenly and transiently at the time of TLOC. Patients underwent pacemaker implantation directly avoiding further investigations, delay, and the risk of further blackouts and injury. Large numbers of patients with blackouts referred to the RABTC have had many investigations elsewhere with no conclusion. In chapter 4, we studied the effect of long term insertable ECG monitor (ILR) which can help making early diagnosis and avoid unnecessary investigations. We explored the impact of the ILR on time to Symptom/ECG correlation and time-to-diagnosis. There remains nearly half of the patients where even ILR is unable to explain the TLOC. Ideally, ILR would detect ECG, Blood Pressure and the Electroencephalogram, (EEG). These physiological parameters would be sufficient to distinguish between syncope, epilepsy and psychogenic blackouts. In Chapter 5 the results of in-depth analysis of the ECG in these patients are presented. Heart rate variability was used to calculate sympathovagal balance. The patients were recruited using video telemetry data from a Regional epilepsy centre. Finally, treatment of TLOC depends on its underlying cause and by far the most common cause is reflex syncope. So far, no treatment has proven benefit in this situation. One drug, midodrine an alpha-adrenoceptor agonist, has had several albeit unsatisfactory randomised controlled trial. We describe our experience of midodrine in this condition in Chapter 6. Chapter 7 summarises what has been contributed by this thesis.

Date of Award	1 Aug 2017
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Adam Fitzpatrick (Supervisor) & Paul Cooper (Supervisor)