Stroke Mimics Early experience of a ‘stroke divert’ in

rural Cambridgeshire

What’s a Stroke mimic?

A patient labelled as suffering either stroke/TIA or possible stroke/TIA, subsequently diagnosed with another condition

Mimic activity

• What mimic rate did we expect?• 30% often quoted• 2011, 50% coming from UCL HASU• Can London really monitor this activity?

ABN 2012: CHANGES IN WORKLOAD AND CASE MIX IN A LONDON HASU OVER TIME J Winston, et al. Royal Free; UCL

Audit admission rates and case mix over 15 months. Admission rates increased linearly. Thrombolysis call rates did not contribute significantly to this increase.

Case mix changes assessed by studying discharge summaries from 2 months 1 year apart (October 2010 and 2011).

Male bias in 2010 and a female bias in 2011 (p<0.05 by χ2test). Number with a TIA/infarct/ICH was similar (127 and 128).

Number of non-stroke diagnoses at discharge increased significantly (46 to 76).

Implications for acute general neurological/stroke services in the UK.

(UC)London HASU data

Figure 1 The proportion of suspected stroke patients with an eventual diagnosis of stroke or TIA, from a systematic review and meta-analysis of case series, stratified by the context of assessment (emergency department, primary care, stroke unit/neurovascular clinic, ambulance or other referral sources). The width of each diamond represents the 95% CI of the pooled proportion

Fernandes PM,Whiteley WN, Hart SR, et al.Pract Neurol 2013;13:21–28.

Mimic literature review

New pathway

• 60% of Hinchingbrooke catchment diverted to CUH– Balance to PDH

The flow diverter

• Ambulance tool• Hinchingbrooke ED attendees assess with

Rosier• In Hosp cases discussed

– NB; Manchester divert for Tpa only with repat of non treated cases straight back from ED to DGH or home

Pathways from other services -London

• possible scenarios: 3a. 999 call – Ambulance will attend and paramedics will assess the

patient. If found to be FAST positive they will be taken to the nearest HASU (category A call).

– If FAST negative and a stroke is still suspected they will also go to the nearest HASU.

Mimic mix (varies with age)

Stroke chameleons--Unusual clinical manifestations of strokes and strokes disguised as other clinical processes

acute confusional states seizures with acute stroke sensory symptoms movement disorders

Impact of mimic activity

– Workload for • ambulance, ED, radiol, Gmed, Neuro and stroke

– Capacity planning– Further deskilling of DGHs

Addenbrooke’s experience

• Stroke – Admission rate, transfer times, LOS, thrombolysis,

outcomes and repatriation rate• Mimics

– Diagnoses, Admission rates, Bed days and LOS

Case finding - method

• NHS awash with data• Francis, Bristol babies..

• Existing CUH stroke database• ED ‘4 hour’ data base

– 8000+ attendances per calendar month– Cases found using GP post code

Case finding - method– Xls data sheet from ED

• postcodes of cases and GPs • routinely collected clinical data)

– Assume attendees with non Hunts GP could not be Hunts area stroke transfers

– Existing ‘pathways’ for ENT, Ophthalmology, and major trauma excluded. Tertiary referrals ditto.

– retrospective summaries and imaging review (me and MS)• Further notes review ongoing

Results

– 199 probable pathway transfers over 24 weeks• 21 from Hinchingbrooke ED (8 vascular)

– 159 definite pathway transfers• 85 mimics • 74 vascular

– stroke 58– TIA 16

– Predicted; • 112 strokes + 30-60 mimics per year

58

16

85

41

All probable pathway transfers n=199

StrokeTIAMimic?

8558

16

Definite stroke pathway transfers

Mimic

Stroke

TIA

Ambulance transfers n=148

63

63

202

Vasc, 13 TIA

Mimic

unknown, prob mimicsunknown, prob vasc

76% admitted50 vasc, 292 bed days

Conclusions

• Total stroke numbers predictable• Mimic rate at least 100%

What next

• Data should inform pathway design– Ambulance, ED, Radiology, stroke teams etc– Impact on sustainability of stroke and other local

services

• Mimic – management planning– Mimic tariffs