Scoring medical conditions:Syncope, and the San Fransisco Syncope rule
We’re going to add some useful scores and calculators to the blog. This was following a request for more useful ‘real life’ practical scoring systems which are often not focussed on when teaching medical students. Lecturers often correctly focus on the important pathophysiology a problem or condition. We feel that the use of validated scores (like this one) add practical value to medical undergraduates.
Why not try out some of these scores in your own practice/ when on the wards/ in the GP surgery to try and help identify why that patient has been discharged, or
The San Francisco CHESS algorithm from the Annals of Internal Medicine, 2006, click to enlarge
what the reason was for that particular management plan.
Take Syncope: its a massive subject, but its important for the general physicians to the oncologist treating a patient in outpatients, to the surgeon with his post op patient who has just collapsed. For simplicity we’ll define syncope as a sudden and temoporary loss of conciousness (there are numerous definitions).
A review article in the NEJM defines it as the following
Syncope is a sudden and brief loss of consciousness associated with a loss of postural tone, from which recovery is spontaneous.
Syncope does NOT refer to dizziness/ or other symptoms such as vertigo (the illusion of movement). Its
a really difficult topic to cover the causes are numerous:
- Neurally Mediated (25% of cases)
- Vasovagal
- Situational/ other causes
- Dehydration/ orhtostatic (10%)
- Cardiac (20%)
- arrhythmia/ obstructive cardiac lesions etc
- Psychiatric (probably about 1-2%)
- Drugs (probably about 5%)
- Unknown
This isn’t going to cover all of these things, but lets look to see if there is a score to help us with this. There is! the CHESS score, or San Francisco Syncope rule.
Does the patient have CHESS?
CCF or history of CCF
Haematocrit <30%
ECG abnormal (non sinus rhythm or new changes compared to old ECG)
Shortness of breath
Systolic BP of<90mmHg at triage
As a rule of thumb (you can read the paper) to avoid serious adverse events admit patients with syncope with ANY of the above features: MI, PE, stroke, serious arrhythmia. Click the picture to the right for a full screen shot of the algorithm.
This has a sensitivity of >95% and a specificity of around 60%.
Read more about the study in Annals of Emergency Medicine.
The clinical bottom line: guidelines change and evolve, and your hospital / primary care centre/ doctor may not follow these guidelines. The take home message is there are simple predictive factors that can be used as a rule of thumb that you can keep in the back of your mind when seeing patients with syncope, and these scoring tools are useful as an educational aid. Remember no scores are 100% accurate, and any algorithm like this will lead to the discharge of patients that will go on to have serious medical pathology. Its use is as a guide.
Ref: Ann Emerg Med. 2006;47:455-456
This is the first in a series of articles on simple scoring systems for application by medical students. Why not post comments on other scores you have found useful as a student, with a reference.